10-K

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

[Mark One]

For the Fiscal Year Ended December 31, 2025

Commission File No. 001-33057

CATALYST PHARMACEUTICALS, INC.

(Exact name of registrant as specified in its charter)

355 Alhambra Circle, Suite 801Coral Gables, Florida 33134

(Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code: (305) 420-3200

Securities Registered Pursuant to Section 12(b) of the Exchange Act:

Title of Each Class Ticker Symbol Name of Exchange on Which Registered

Common Stock, par value $0.001 per share CPRX NASDAQ Capital Market

Securities registered pursuant to Section 12(g) of the Exchange Act: None

Indicate by check mark if registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes☒ No ☐

Indicate by check mark if registrant is not required to file reports pursuant to Rule 13 or Section 15(d) of the Act. Yes ☐No☒

Indicate by check mark whether the registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically, every Interactive Data File required to be submitted pursuant to rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer”, “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act:

Large accelerated filer ☒ Accelerated filer ☐

Non-accelerated filer ☐ Smaller reporting company ☐

Emerging Growth Company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards pursuant to Section 13(a) of the Exchange Act ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report ☒

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements ☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒

As of June 30, 2025, the last business day of the Registrant’s most recently completed second quarter, the aggregate market value of all voting and non-voting common equity held by non-affiliates was $2,514,112,459.

Indicate the number of shares outstanding of each of the issuer’s classes of common stock, as of the latest practicable date: 122,123,884 shares of common stock, $0.001 par value per share, were outstanding as of February 23, 2026.

Part III incorporates certain information by reference from the registrant’s definitive proxy statement for the 2026 annual meeting of stockholders. The proxy statement with respect to the 2026 annual meeting of stockholders will be filed no later than 120 days after the close of the registrant’s fiscal year ended December 31, 2025.

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DOCUMENTS INCORPORATED BY REFERENCE

Portions of the Definitive Proxy Statement to be filed for Catalyst Pharmaceuticals, Inc.'s 2026 Annual Meeting of Stockholders are incorporated by reference into Part III hereof.

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PART I 1

Item 1. Business 3

Item 1A. Risk Factors 33

Item 1B. Unresolved Staff Comments 57

Item 1C. Cybersecurity 57

Item 2. Properties 59

Item 3. Legal Proceedings 59

Item 4. Mine Safety Disclosure 59

Item 6. Selected Financial Data 61

Item 7A. Quantitative and Qualitative Disclosures About Market Risk 78

Item 8. Financial Statements and Supplementary Data 78

Item 9A. Controls and Procedures 79

Item 9B. Other Information 79

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections 79

PART III 80

Item 10. Directors and Executive Officers of the Registrant 80

Item 11. Executive Compensation 80

Item 12. Security Ownership of Certain Beneficial Owners and Management 80

Item 13. Certain Relationships and Related Transactions 80

Item 14. Principal Accounting Fees and Services 80

Item 15. Exhibits and Financial Statement Schedules 81

EXHIBITS FILED WITH FORM 10-K

EX 23.1 Consent of Independent Registered Public Accounting Firm

EX 31.1 Section 302 Certification of CEO

EX 31.2 Section 302 Certification of CFO

EX 32.1 Section 906 Certification of CEO

EX 32.2 Section 906 Certification of CFO

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PART I

You are urged to read this Annual Report on Form 10-K (Form 10-K) in its entirety. This Form 10-K contains forward-looking statements that involve risks and uncertainties. Our actual results may differ significantly from the projected results discussed in these forward-looking statements. Factors that may cause such a difference include, but are not limited to, those discussed below and in Item 1A, “Risk Factors.”

“We,” “our,” “ours,” “us,” “Catalyst,” or the “Company,” when used herein, refers to Catalyst Pharmaceuticals, Inc., a Delaware corporation, and its wholly owned subsidiary, Catalyst Pharmaceuticals Ireland, Ltd., a corporation organized in the Republic of Ireland.

Forward-Looking Statements

This Annual Report on Form 10-K contains “forward-looking statements”, as that term is defined in the Private Securities Litigation Reform Act of 1995. These include statements regarding our expectations, beliefs, plans or objectives for future operations and anticipated results of operations. For this purpose, any statements contained herein that are not statements of historical fact may be deemed to be forward-looking statements. Without limiting the foregoing, “believes”, “anticipates”, “proposes”, “plans”, “expects”, “intends”, “may”, and other similar expressions are intended to identify forward-looking statements. Such statements involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance or other achievements to be materially different from any future results, performances or achievements expressed or implied by such forward-looking statements. Factors that might cause such differences include, but are not limited to, those discussed in the section entitled “Risk Factors.”

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Whether we will be able to continue to successfully market and sell FIRDAPSE® and AGAMREE®, and continue to sell FYCOMPA® while maintaining full compliance with applicable federal and state laws, rules and regulations;

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Whether we will be able to continue to attract and retain the qualified personnel necessary to run our business;

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Whether we can continue to market our drug products on a profitable and cash flow positive basis;

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Whether any revenue or earnings guidance that we provide to the investment community will turn out to be accurate;

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Whether we will prevail in our currently pending Paragraph IV litigation with Hetero USA, Inc. regarding our FIRDAPSE® patents that expire in 2032, 2034, and 2037, which matter is currently scheduled to go to trial starting on March 23, 2026;

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Whether our estimates of the size of the market for FIRDAPSE® for the treatment of LEMS will prove to be accurate, and whether we can continue to increase FIRDAPSE® net product revenues as we have done in past periods;

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Whether the daily dose of FIRDAPSE® taken by patients changes over time and how that affects our net product revenues for FIRDAPSE® in future periods;

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Whether we will continue to be able to locate LEMS patients who are undiagnosed or are misdiagnosed with another disease, including LEMS patients who also have small cell lung cancer;

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Whether the addition of FIRDAPSE® to the NCCN Clinical Practice Guidelines for small cell lung cancer results in an increase in patients being treated with FIRDAPSE®;

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Whether patients will discontinue from the use of our products at rates that are higher than historically experienced or higher than we forecast;

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Whether new patients for our existing and future drug products can be successfully titrated to stable therapy.

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Whether we will be able to demonstrate, to the satisfaction of the FDA and third-party payors, that AGAMREE® offers advantages compared to other corticosteroids or competitor’s products;

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Whether DMD patients transitioning to current or future approved gene therapy treatments will delay initiating use of AGAMREE® while waiting for access to such gene therapy, or stop their AGAMREE® therapy during the course of their gene therapy treatment;

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Whether steroids will continue to be the foundational standard of care for the treatment of DMD as new DMD drugs are approved for commercialization in the future;

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Whether we will be able to continue to successfully sell FYCOMPA® now that generic competition for FYCOMPA® tablets and oral suspension have entered the market;

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Whether reduced revenue resulting from generic FYCOMPA® entering the market will require us to impair all or a portion of our intangible asset for FYCOMPA®;

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The extent to which payors will continue to provide coverage and reimburse for our products at the price that we charge for our products;

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The ability of our third-party suppliers and contract manufacturers to continue to supply sufficient product to meet our customers’ needs in a timely manner;

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The impact on our profits and cash flow of adverse changes in reimbursement and coverage policies or regulations from government and private payors such as Medicare, Medicaid, insurance companies, health maintenance organizations and other plan administrators, or the impact of pricing pressures enacted by industry organizations, the federal government or the government of any state, including as a result of increased scrutiny over pharmaceutical pricing or otherwise;

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Changes in the healthcare industry and the effect of political pressure from and actions by the current Administration, Congress and/or medical professionals seeking to reduce prescription drug costs, and changes to the healthcare industry occasioned by any future changes in laws relating to the pricing of drug products, including changes made in the Inflation Reduction Act of 2022, changes (if any) to be made by the current Administration (including the possibility of seeking to impose Most Favored Nation pricing on drug companies or to impose a 100% tariff on branded or patented pharmaceutical products unless a company is "building" a manufacturing plant in the United States) and/or the current Congressional administrations, changes to the review and approval process at the FDA, imposing tariffs on imported product, or changes in the healthcare industry generally;

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The potential impact of tariffs on our cost of sales for products that are manufactured, in whole or in part, outside of the U.S.;

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The potential impact on our business of “most favorite nation”, or Most Favored Nation pricing, such as proposed in the GUARD and GLOBE Medicare demonstration projects, on what we will realize from the sale of our drug products if Most Favored Nation pricing becomes applicable to even a portion of our drug products;

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The ability of our third-party suppliers and contract manufacturers to maintain compliance with current Good Manufacturing Practices;

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The ability of those third parties that distribute our products to maintain compliance with applicable law;

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Our ability to maintain compliance with applicable rules relating to our patient assistance programs for our products;

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The scope and strength of our intellectual property and the outcome of challenges to our intellectual property, and, conversely, whether any third-party intellectual property presents unanticipated obstacles for FIRDAPSE® or AGAMREE®;

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Whether there will be a post-closing review by antitrust regulators of our previous or future Paragraph IV patent settlements or our previous acquisition transactions, and the outcome of any such reviews if they were to occur;

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Whether we will be able to acquire additional drug products under development, complete development required to commercialize such products, and thereafter, if such products are approved for commercialization, successfully market such products;

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Whether the FDA will approve generic versions of FIRDAPSE® following the expiration of our orphan drug exclusivity on November 26, 2025, subject to any pending 30-month stays of approval as required under the Drug Price Competition and Patent Term Restoration Act of 1984;

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Whether our patents will be sufficient to prevent generic competition for AGAMREE® after our orphan drug exclusivity for this product expires;

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Whether our clinical studies of AGAMREE® and our SUMMIT registry study of DMD patients being treated with AGAMREE®, will be successful and the impact, if any, of the results of these studies on our business;

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Assuming we prevail in our currently ongoing patent litigation with Hetero, whether we are able to successfully develop additional indications for FIRDAPSE® and obtain the ability to commercialize FIRDAPSE® for these additional indications;

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Whether we and Santhera Pharmaceuticals Holding AG can successfully develop additional indications for AGAMREE®, and obtain the ability to commercialize AGAMREE® for these additional indications.

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The state of the economy generally;

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The impact on our business of a prolonged U.S. government shutdown;

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The scope, rate of progress and expense of our clinical trials and studies, pre-clinical studies, proof-of-concept studies, and our other drug development activities, and whether any trials and studies we undertake will be successful;

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Our ability to complete any clinical trials and studies that we may undertake on a timely basis and within the budgets we establish for such trials and studies;

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Whether FIRDAPSE® and AGAMREE® will be successfully commercialized in Canada on a profitable basis through KYE Pharmaceuticals, Inc., our sublicensee for the products in Canada;

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Whether FIRDAPSE® will be successfully commercialized in Japan on a profitable basis by DyDo Pharma, Inc., our sublicensee for the product in Japan;

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The impact on sales of FIRDAPSE® in the U.S. if an amifampridine product is purchased in Canada for use in the U.S.;

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Whether any efforts we undertake to expand the reach of FIRDAPSE® into other global regions will be successful;

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System failures or security or data breaches due to cyber-attacks, or cyber intrusions, including ransomware, phishing attacks and other malicious intrusions whether it occurs directly to us or indirectly through third parties; and

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Our ability to enhance our systems, processes, and procedures to appropriately support the growing complexity and scale of our business.

Our current plans and objectives are based on assumptions relating to the continued sale of FIRDAPSE®, AGAMREE® and FYCOMPA® and on our plans to seek to acquire or in-license additional drug products. Although we believe that our assumptions are reasonable, any of our assumptions could prove inaccurate. Considering the significant uncertainties inherent in the forward-looking statements we have made herein, which reflect our views only as of the date of this report, you should not place undue reliance upon such statements. We undertake no obligation to update or revise publicly any forward-looking statements, whether as a result of new information, future events or otherwise.

Item 1. Business

Overview

We are a commercial-stage, patient-centric biopharmaceutical company focused on in-licensing, developing, and commercializing novel high-quality medicines for patients living with rare and difficult to treat diseases. We currently sell three commercial stage drug products, FIRDAPSE® (amifampridine), AGAMREE® (vamorolone), and FYCOMPA® (perampanel). We are also currently seeking to further expand our product portfolio, with a focus on acquiring the rights to immediately and near-term accretive assets to treat rare (orphan) diseases across therapeutic areas, including clinical-stage opportunities with established proof of concept. With an unwavering patient focus embedded in everything we do, we are committed to providing innovative, best-in-class medications with the hope of making a meaningful positive impact on those affected by these conditions.

Currently, we have a total of 58field personnel supporting FIRDAPSE® and AGAMREE®. We also have 19 patient assistance liaisons and insurance navigation support personnel who support both FIRDAPSE® and AGAMREE®. Finally, we have 19medical science liaisons who help educate the medical community about scientific literature concerning our drug products and the diseases they treat.

When we launched AGAMREE® in March 2024, we utilized the FIRDAPSE® commercial and medical field-based forces to market AGAMREE®. In early 2025, we separated these field-based forces into two units, one for each function expressly focused on supporting FIRDAPSE® and one for each function expressly focused on supporting AGAMREE®. This strategic change was made in an effort to allow us to better focus the support for each product. This division of our field-based forces into two units became effective on April 1, 2025. Further, we have two national account directors on our commercial team who exclusively focus on the oncology market for LEMS patients who also have cancer.

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FIRDAPSE®

On November 28, 2018, we received approval from the FDA for our new drug application (NDA) for FIRDAPSE® Tablets 10 mg for the treatment of adult patients (ages 17 and above) with Lambert-Eaton Myasthenic Syndrome (LEMS), and in January 2019, we launched FIRDAPSE® in the U.S. Further, on September 29, 2022, the FDA approved our supplemental NDA (sNDA) to expand the indicated age range for FIRDAPSE® Tablets 10 mg for the treatment of LEMS to include pediatric patients six years of age and older. Additionally, on May 30, 2024, the FDA approved our sNDA increasing the indicated maximum daily dosage of FIRDAPSE® tablets for the treatment of patients with LEMS from 80 mg to 100 mg. We believe that this most recent sNDA approval offers healthcare providers and patients greater flexibility in treatment regimens for the management of LEMS. We are also planning to evaluate FIRDAPSE® in the future for the treatment of other diseases.

We sell FIRDAPSE® in the U.S. through a field-based force experienced in neurologic, central nervous system or rare disease products consisting at this time of approximately 23 field personnel, including sales (Regional Account Managers and Area Business Directors), National Account Directors and thought leader liaisons. This includes two national account directors who exclusively focus on the oncology market for LEMS patients with cancer. We also use non-personal promotion to reach the 20,000 neurologists who are potential LEMS treaters and the 16,000 oncologists who might be treating a LEMS patient who also has cancer (principally small cell lung cancer). Finally, we make available for online ordering a no-cost LEMS voltage gated calcium channel (VGCC) antibody diagnostic testing program for use by physicians who suspect that one of their patients may have LEMS and wish to reach a definitive diagnosis.

Further, we are continuing to expand our digital and social media activities to introduce our products and services to potential patients and their healthcare providers. We also work with several rare disease advocacy organizations (including the Myasthenia Gravis Foundation of America, the National Organization for Rare Disorders, and the LEMS Family Association) to help increase awareness and level of support for patients living with LEMS and to provide education for the physicians who treat this rare disease and the patients they treat.

On August 6, 2025, we reported that the National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines in Oncology (NCCN Guidelines®) for Small Cell Lung Cancer (SCLC) now include new additions involving LEMS, amifampridine, and the tests for PQ- and N-type VGCC antibodies. The updated NCCN Guidelines® for SCLC relating to LEMS now include symptom specificity—characterized by proximal muscle weakness and autonomic dysfunction. Under "Signs and Symptoms of Small Cell Lung Cancer” (SCL-A 2 of 2), the guidelines recommend diagnosis through a neurological evaluation, ideally in consultation with a neurologist, which may include testing for PQ- and N-type VGCC antibodies. Additionally, under “Principles of Supportive Care” (SCL-D), the guidelines recommend that amifampridine should be considered as a treatment in consultation with neurology. We are currently working to get these guidelines into the standard of care followed by oncology practices that treat patients with SCLC.

We are supporting the distribution in the U.S. of FIRDAPSE® through Catalyst Pathways®, our personalized treatment support program for patients who enroll in it. Catalyst Pathways® is a single source for personalized treatment support, education and guidance through the challenging dosing and titration regimen required to reach an effective therapeutic dose. The program also includes distributing the drug through a very small group of exclusive specialty pharmacies (primarily AnovoRx), which is consistent with the way that most drug products for ultra-orphan diseases are distributed and dispensed to patients. We believe that by using specialty pharmacies in this way, the task, which can be difficult, of navigating the health care system is far better for the patient needing treatment for their rare disease and the health care community in general.

In order to help patients with LEMS afford their medication, we, like other pharmaceutical companies which market drug products for orphan and ultra-orphan, rare diseases, have developed an array of financial assistance programs to reduce out-of-pocket costs that makes FIRDAPSE® accessible and affordable. A co-pay assistance program has been designed to reduce commercial patients’ out of pocket costs to as little as $0 whenever possible (currently an average of less than $2 per month). Our co-pay assistance programs, including the one for FIRDAPSE®, are not available to patients enrolled in state or federal healthcare programs, including Medicare, Medicaid, Department of Veterans Affairs (VA), Department of Defense (DoD), or TRICARE. However, we have, at times, donated funds to one or more qualified, independent charitable foundations dedicated to providing assistance to any U.S. LEMS patients in financial need who meet those independent organizations' guidelines. In addition, we have a program in place to help patients who are uninsured and underinsured. Subject to compliance with applicable regulatory requirements, our goal is that no LEMS patient is ever denied access to their medication for financial reasons.

FIRDAPSE® is currently marketed for the treatment of LEMS in Canada through our exclusive sublicensee, KYE Pharmaceuticals, Inc. (KYE). We supply product to KYE at agreed upon prices and we are also eligible to earn sales milestones and sales royalties based on net revenues from sales of the product in Canada. Further, FIRDAPSE® is commercially available (since January 21, 2025) for the treatment of LEMS in Japan through our sublicensee for Japan, DyDo Pharma, Inc. (DyDo). We generate revenue from DyDo through the receipt of additional milestone payments, as such milestones are achieved, and a transfer price on the product supplied by us to DyDo (in lieu of royalties).

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We control six U.S. patents for FIRDAPSE® that are listed in the FDA's Approved Drug Products with Therapeutic Equivalence Evaluations (Orange Book), the earliest of which expires in 2032 and the latest of which expires in 2037. Generic drug manufacturers were permitted to submit applications for the product challenging our patents starting in 2023 and the FDA is now permitted to approve such ANDA products following the expiration of our orphan drug exclusivity (ODE) on November 26, 2025, subject to any pending 30-month stays of approval as required under the Drug Price Competition and Patent Term Restoration Act of 1984 (Hatch-Waxman Amendments).

With respect to ANDA filers, in January 2023, we received Paragraph IV Certification Notice Letters from three generic drug manufacturers (Teva Pharmaceuticals USA, Inc. and Teva Pharmaceuticals, Inc. (collectively Teva), Hetero USA, Inc. (Hetero), and Lupin Pharmaceuticals, Inc. (Lupin)) advising that they each had submitted an ANDA to the FDA seeking authorization from the FDA to manufacture, use or sell a generic version of FIRDAPSE® in the U.S. The notice letters each alleged that the six patents protecting FIRDAPSE® that are listed in the Orange Book in connection with FIRDAPSE® are not valid, not enforceable, and/or will not be infringed by the commercial manufacture, use or sale of the proposed product described in these ANDA submissions. Under the Federal Food, Drug, and Cosmetic Act (FDCA), as amended by the Drug Price Competition and Patent Term Restoration Act of 1984, we had 45 days from receipt of the notice letters to determine if there were grounds to bring a lawsuit and, if so, to commence patent infringement lawsuits against these generic drug manufacturers in a federal district court, which would trigger a statutory stay precluding the FDA from final approval of the subject ANDA until May 26, 2026 or entry of judgment holding the patents invalid, unenforceable, or not infringed, whichever occurs first in all cases (but not earlier than the expiration of orphan drug exclusivity on November 28, 2025). In that regard, after conducting the necessary due diligence, we filed lawsuits on March 1, 2023 in the U.S. District Court for the District of New Jersey against each of the three generic drug manufacturers who notified us of their ANDA submissions, thus triggering the stay.

Additionally, in October 2023, we received a Paragraph IV Certification Notice Letter from a fourth generic drug manufacturer (Inventia Healthcare Limited (Inventia)), and after conducting the necessary diligence we filed a similar lawsuit against that manufacturer in November 2023 in the U.S. District Court for the District of New Jersey. On July 30, 2024, we settled this patent litigation with Inventia. In this settlement, Inventia acknowledged both the validity of our FIRDAPSE® patents and also the infringement by the ANDA filer's product of our patents. As part of the settlement, Inventia also agreed not to commercialize its product until the earlier of all FIRDAPSE® patents expiration or the entry into the market of another ANDA product meeting certain conditions.

In June 2024, Lupin converted five of its Paragraph IV Certifications in its ANDA to Paragraph III certifications acknowledging the validity and their ANDA’s infringement of five of those patents, the latest ending in 2034. We subsequently dismissed all of our claims against Lupin related to those five patents but maintained our claim against Lupin for the remaining Paragraph IV certification for U.S. Patent No. 10,626,088, which is the patent expiring in 2037.

On January 8, 2025, we reached a settlement with Teva in which Teva agreed not to market a generic version of FIRDAPSE® in the U.S. any earlier than February 25, 2035, if approved by the FDA, unless certain limited circumstances customarily included in these types of agreements occur. In accordance with the settlement agreement, the parties terminated all ongoing patent litigation between us and Teva regarding FIRDAPSE® patents pending in the U.S. District Court for the District of New Jersey. Later, on August 26, 2025, we reached a settlement with Lupin on substantially the same terms for market entry.

The pending FIRDAPSE® patent litigation against the remaining defendant, Hetero (relating to the FIRDAPSE® Orange Book-listed patents expiring in 2032, 2034 and 2037) remains ongoing. At this time, this trial is scheduled to start on March 23, 2026, which is prior to the expiration of the 30-month stay on FDA approval of Hetero’s ANDA under the Hatch-Waxman Amendments ending on May 26, 2026.

Since cases of this type are complex and the results of patent litigation with Paragraph IV challengers is always uncertain, there can be no assurance as to whether we will prevail in this litigation. As a result, there can be no assurance as to whether our currently ongoing litigation with Hetero will allow a generic version of FIRDAPSE® to be marketed in the U.S. prior to Teva's and Lupin's licensed entry into the market on February 25, 2035.

AGAMREE®

On June 19, 2023, we entered into a License and Collaboration Agreement (AGAMREE® License Agreement) and an Investment Agreement (Investment Agreement) with Santhera Pharmaceuticals Holding AG (collectively, Santhera). Under the AGAMREE® License Agreement, we contracted to obtain an exclusive North America license, manufacturing and supply agreement for Santhera’s investigational product candidate, AGAMREE®, a novel corticosteroid for the treatment of Duchenne muscular dystrophy, or DMD. Under the Investment Agreement, we agreed to make a strategic investment into Santhera.

Both transactions closed on July 18, 2023. Under the AGAMREE® License Agreement, upon closing we made a $75 million payment to Santhera in return for the exclusive North American license for AGAMREE®. Additionally, we hold the North American rights to any future approved indications for AGAMREE®. Finally, under our AGAMREE® License Agreement

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with Santhera, we agreed to purchase commercial supply of AGAMREE® from Santhera at agreed upon prices until we completed our process to transition to our own direct supplier. We are also in the process of transitioning final goods manufacturing to a U.S. location (estimated to be completed in 2026).

Concurrent with the closing of the AGAMREE® License Agreement, we made a strategic investment into Santhera in which we acquired 1,414,688 of Santhera’s ordinary shares (representing approximately 11.26% of Santhera’s outstanding ordinary shares immediately following the transaction) at an investment price of CHF 9.477 per share, with the approximately $15.7 million USD in equity investment proceeds to be used by Santhera for Phase IV studies of AGAMREE® in DMD and future development of additional indications for AGAMREE®. On February 23, 2026, the closing price of Santhera’s common shares on the SIX Swiss Exchange was CHF 16.46 per share (approximately$21.33USDbased on then-current exchange rates).

On October 26, 2023, the U.S. FDA approved Santhera’s NDA for AGAMREE® for use in treating DMD in patients aged two years and older. Shortly thereafter, as part of the previously described transaction, Santhera transferred the approved NDA to us. Additionally, following approval of the NDA for the drug, we became obligated to make a milestone payment of $36 million to Santhera, which we paid during the fourth quarter of 2023. We may also be obligated to pay future regulatory and commercial milestone payments to Santhera tied to calendar year sales of AGAMREE® (the first such sales-based royalty was achieved in the fourth quarter of 2025 when our AGAMREE® net product revenues for 2025 exceeded $100 million), as well as commercial royalties.

Since April 1, 2025, we have sold AGAMREE® in the U.S. through a dedicated field-based force of approximately 16, including sales (12 Regional Account Managers and two Area Business Directors) and two Area Marketing Directors. We are further supporting the distribution of AGAMREE® through our Catalyst Pathways® patient services program to ensure that patients have access to a dedicated, personalized support team that assists families through the AGAMREE® patient journey, from answering questions to coordinating financial assistance programs for eligible patients. Additionally, we have also donated to qualified, independent charitable foundations dedicated to providing assistance to DMD patients in financial need who meet the independent organization's guidelines. Subject to applicable regulatory requirements, our goal is to ensure that no DMD patient is ever denied access to their medication for financial reasons.

DMD, the most common form of muscular dystrophy, is a rare and life-threatening neuromuscular disorder characterized by progressive muscle dysfunction, ultimately leading to loss of ambulation, respiratory failure, and fatality. Current standard treatment for DMD involves corticosteroids, which often come with significant side effects. It is estimated that between 11,000 and 13,000 people in the U.S. are affected by DMD, with approximately 70% of patients currently receiving a corticosteroid treatment. We believe that steroids are and will continue to remain the foundational therapy for DMD patients and dosed concomitantly with other therapies.

AGAMREE®’s unique mode of action is based on differential effects on glucocorticoid and mineralocorticoid receptors and modifying further downstream activity. As such, it is considered a novel corticosteroid that we hope has the potential to demonstrate comparable efficacy to corticosteroids, with the potential for a better-tolerated side effect profile. This mechanism of action may allow vamorolone to emerge as an effective alternative to the current standard of care corticosteroids in children, adolescents, and adult patients with DMD. In that regard, we are currently enrolling up to 250 patients in our SUMMIT registry study to evaluate data about long-term patient safety and quality of life data from the use of our product, with the hope of offering a deeper understanding of the product's potential long-term benefits for patients, such as in the areas of stature, bone health, behavior, and cardiovascular health.

On October 13, 2023, Santhera announced that the European Union’s Committee for Medicinal Products for Human Use (CHMP) adopted a positive position in favor of AGAMREE® for the treatment of DMD patients aged four and older. In its recommendation for approval, CHMP acknowledged that there was a positive benefit-risk profile of AGAMREE® in such patient population, including certain safety benefits of AGAMREE® compared to standard of care corticosteroids in the treatment of DMD. Further, on December 18, 2023, the European Commission (EC) granted to Santhera marketing authorization for AGAMREE® for the treatment of DMD in patients ages four years and older and on January 12, 2024 Santhera announced that AGAMREE® had received approval by the Medicines and Healthcare products Regulatory Agency (MHRA) in the United Kingdom. Further, on January 15, 2024, Santhera announced that AGAMREE® was commercially launched in Germany. Additionally, on January 16, 2025, the National Institute for Health and Care Excellence (NICE) issued positive Final Guidance that recommends AGAMREE® for use in the National Health Service (NHS) in England, Wales and Northern Ireland for the treatment of DMD in patients four years of age and older and on February 13, 2025, Santhera announced an agreement with the German National Association of Statutory Health Insurance Funds (GKV-SV) on the

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reimbursement for AGAMREE® for the treatment of DMD. This agreement makes AGAMREE® the first product to receive an agreed federal price in Germany for the treatment of DMD in patients four years of age and older, independent of the underlying genetic mutation. Finally, on January 15, 2026, Santhera announced that the Swiss Agency for Therapeutic Products (Swissmedic) approved AGAMREE® for the treatment of DMD in patients four years of age and older.

We are currently taking the first steps seeking to expand the number of diseases that can be treated with AGAMREE®. In furtherance of that objective, we are currently conducting a Phase 1 study in healthy adults comparing a single dose of vamorolone, prednisone, and deflazacort, and studying the immunosuppressive effect of multiple ascending doses of AGAMREE®, which study will attempt to define the immunosuppressive dose of vamorolone for future indications and for the use of our product in conjunction with gene and cell therapies that are approved to treat DMD and require a concurrent immunosuppressive regimen of a corticosteroid when administered. We expect to have the results of both parts of this study by the end of the second quarter of 2026. Further, we are hopeful that the recent addition of DMD to the Recommended Uniform Screening Panel by the U.S. Department of Health and Human Services will help support earlier detection of the disease and more timely access to treatment options.

Further, we have established a joint steering committee with Santhera that is overseeing the lifecycle management and development of AGAMREE®. There can be no assurance that we can develop our product for the treatment of diseases other than DMD. Finally, we are currently in the process of validating a U.S. manufacturing site for the product, which we expect will be completed by the end of 2026.

In the U.S., AGAMREE® has New Chemical Entity exclusivity that expires in October 2028. AGAMREE® also has Orphan Drug Exclusivity expiring in October 2030. AGAMREE® is further protected by seven Orange Book listed patents expiring as early as May 28, 2029 and as late as July 16, 2040. The Company has also requested Patent Term Extension (PTE) and will update the relevant expiration date in the Orange Book upon a final determination by the U.S. Patent and Trademark Office (USPTO). On June 25, 2025, the FDA published a notice (Determination of Regulatory Review Period for Purposes of Patent Extension; AGAMREE®) in the Federal Register regarding the requested extension of patent numbers 8,334,279, 10,857,161, and 11,833,159, all of which currently expire on May 28, 2029, as listed in the FDA's Orange Book. With the publication of this notice, there is a 180-day period for third parties to submit comments and/or due diligence petitions to the FDA. If no comments or petitions are submitted within this period, the FDA will notify the USPTO so that the USPTO can then determine the length of the PTE for each patent for which an extension was requested. Upon completion of the PTE determination, USPTO will mail a Notice of Final Determination of PTE. We will then have one month from the mailing of the Notice of Final Determination to elect one of the three patents for an extension patent term.

The earliest a generic manufacturer could submit an ANDA for vamorolone is October 26, 2027. If we were to pursue a patent infringement action of any such ANDA challenges of any of AGAMREE®’s Orange Book patents, then the automatic statutory 30-month stay would prevent FDA approval of such ANDA until April 26, 2031.

On July 23, 2024 we entered into a license, supply and commercialization agreement with KYE, which is already our sublicensee for FIRDAPSE® in Canada, granting KYE the exclusive Canadian commercial rights to market AGAMREE® in Canada for DMD and other indications. Under the agreement, KYE was responsible for obtaining regulatory approval of the product from Health Canada and on April 8, 2025, we announced that Health Canada had accepted for review KYE's New Drug Submission (NDS) for AGAMREE®. Further, on October 2, 2025, KYE announced that Health Canada has approved AGAMREE® for the treatment of DMD in boys four years of age and older. Under our sublicense agreement with KYE for this product, we will supply product to KYE and also receive sales milestones and sales royalties based on net revenues from sales of the product in Canada.

FYCOMPA®

On December 17, 2022, we entered into an agreement with Eisai Co., Ltd. (Eisai) for the acquisition of the U.S. rights to FYCOMPA® CIII. FYCOMPA® is a selective non-competitive antagonist of AMPA receptors, the major subtype of ionotropic glutamate receptors. It was the first, and still is the only, drug of its class to be approved for epilepsy. Studies suggest that AMPA receptor antagonism can lead to reduced overstimulation and anticonvulsant effects, as well as inhibiting seizure generation and spread. FYCOMPA® is a controlled substance and is approved with a boxed warning in its labeling. FYCOMPA® is used to treat certain types of focal onset seizures (seizures that involve only one part of the brain) in adults and children four years of age and older. It is also used in combination with other medications to treat certain types of primary generalized tonic-clonic seizures (also known as a “grand mal” seizure, a seizure that involves the entire body) in adults and children 12 years of age or older. Perampanel is in a class of medications called anticonvulsants. It works by decreasing abnormal electrical activity in the brain.

On January 24, 2023, we closed our acquisition of the U.S. rights to FYCOMPA®. In connection with the acquisition, we purchased Eisai’s regulatory approvals and documentation, product records, intellectual property, inventory, and other matters relating to the U.S. rights for FYCOMPA®, in exchange for an upfront payment of $160 million in cash. We also agreed to

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pay Eisai royalty payments on net sales only after all FYCOMPA® patents are expired with such royalty payments reduced after generic equivalents enter the market.

In conjunction with the closing of the asset purchase, we entered into two additional agreements, a Transition Services Agreement (TSA) and a Supply Agreement. Under the Supply Agreement, Eisai agreed to manufacture FYCOMPA® for us for at least seven years at prices listed in the Supply Agreement (to be updated on a yearly basis), and under the TSA, a U.S. subsidiary of Eisai provided us with certain transitional services (which transition services ended on December 31, 2023).

Patent protection for FYCOMPA® tablets and oral solution was primarily derived from two patents listed in the FDA’s Orange Book. The first, U.S. patent no. 6,949,571 (the ‘571 patent), expired on May 23, 2025, including patent term extension. The second FYCOMPA® patent in the Orange Book is U.S. Patent No. 8,772,497 (the ‘497 patent), which will expire on July 1, 2026. The ‘497 patent, which covers certain polymorphic forms of the active pharmaceutical ingredient (API) used in both FYCOMPA® tablets and oral suspension. One of the Orange Book listed patents had been the subject of previous Paragraph IV certifications from three ANDA filers for the tablet formulation, which were not contested by Eisai prior to our acquisition of the drug. As a result, to our knowledge based on publicly available information, three ANDA filers for the tablet formulation have, to date, obtained approval for and are marketing a generic version of FYCOMPA® tablets and one ANDA filer has, to date, obtained approval for and is marketing a generic version of FYCOMPA® oral suspension. We will continue to sell FYCOMPA® tablets and oral suspension despite the loss of exclusivity, although we have ceased active marketing efforts for the product effective December 31, 2025.

Business Development

We continue to advance our strategic initiatives and portfolio expansion efforts, focusing on broadening and diversifying our rare (orphan) neurology product portfolio with innovative therapies that address critical unmet medical needs. In that regard, we are currently exploring immediate or near-term accretive, clinically differentiated and adequately de-risked opportunities, with a keen focus on rare (orphan) disease products across therapeutic areas and treatment modalities. These prospects include evaluating companies with existing commercial drug products or drugs in development, including clinical stage opportunities with established proof of concept, for potential licensing or acquisitions. We maintain a well-established U.S. presence, which remains the cornerstone of our commercial strategy, while continuously evaluating strategic opportunities to expand our global footprint.

We employ a disciplined, comprehensive, and exhaustive approach to identifying and evaluating opportunities that we believe will add significant value to our company over the near, mid, and long-term. However, no definitive agreements have been entered into to date to acquire the rights to any additional products, and there can be no assurance that any of the Company's business development initiatives will be successful.

Capital Resources

At December 31, 2025, we had cash and cash equivalents of approximately $709.2 million. Based on our current financial condition, including our profitability, cash flows generated from operations and forecasts of available cash, absent the use of cash to acquire potential business development opportunities, we believe that we have sufficient funds to support our operations for at least the next 12 months. There can be no assurance that we will continue to be successful in commercializing FIRDAPSE® and AGAMREE®, that our forecasts of revenues from sales of FYCOMPA® will be accurate now that generic competition has entered the market, or that we will continue to be profitable and cash flow positive. See “Item 7 - Management’s Discussion and Analysis of Financial Condition and Results of Operations” below for further information on our liquidity and cash flow.

Share Repurchase Program

On October 1, 2025, we announced that our Board of Directors has authorized a new share repurchase program to repurchase up to $200 million of shares of our common stock between October 1, 2025 and December 31, 2026. Repurchases under the new share repurchase program may be made through a variety of methods, including open market or privately negotiated purchases. The timing and amount of shares repurchased will depend on the stock price, business and market conditions, corporate and regulatory requirements, alternative investment opportunities, acquisition opportunities and other factors. We are not obligated to repurchase any specific amount of shares of common stock, and the new share repurchase program may be suspended or terminated at any time.

We are using existing cash on hand to fund our share repurchase program. We also believe that we can execute this share repurchase program without impairing the advancement of our business development strategy. In that regard, as of February 23, 2026, we have repurchased 1,740,713 shares of our outstanding common stock for an aggregate purchase price of approximately $39.9 million ($22.91average price per share).

Our Strategy

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Our goal is to acquire and integrate high-value, orphan designated, synergistic assets. We are dedicated to making a meaningful impact on the lives of those suffering from rare diseases, and we believe in putting patients first in everything we do. Specifically, we intend to:

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Continue to commercialize FIRDAPSE® for the treatment of LEMS and improve disease awareness. We are currently commercializing FIRDAPSE® in the U.S. and our partners are commercializing FIRDAPSE® in Canada and Japan. We are working to expand awareness of the disease, including to physicians treating LEMS patients who also have small-cell lung cancer, and helping health care providers and their patients understand the benefits of FIRDAPSE®. A cornerstone of our strategy is our continuing development of Catalyst Pathways®, our personalized treatment support program, and our development of the patient assistance programs that are required to further our goal that no LEMS patient be denied access to FIRDAPSE® for financial reasons within existing legal restrictions. We are also planning to evaluate FIRDAPSE® in the future for the treatment of other conditions.

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Continue to commercialize AGAMREE® for the treatment of DMD and seek to develop additional indications for the product. We are currently marketing AGAMREE® in the U.S. for the treatment of DMD. We are also hoping to evaluate our product for the treatment of other diseases and in furtherance of that objective we are currently taking steps that will help us in that goal, including our current Phase 1 trial to evaluate AGAMREE® against other steroids in an effort to first evaluate the dose equivalence between AGAMREE®, prednisone and deflazacort) and the immunosuppressive dose of AGAMREE®. We are also conducting the SUMMIT registry study in an effort to obtain real world data about the benefits of AGAMREE® over other corticosteroids. A cornerstone of our strategy is our continuing development of Catalyst Pathways®, our personalized treatment support program, and our development of the patient assistance programs that are required to further our goal that no DMD patient be denied access to AGAMREE® for financial reasons within existing legal restrictions. We are also planning to evaluate AGAMREE® in the future for the treatment of other conditions.

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Seek to acquire additional drug products. We intend to continue our efforts to broaden and diversify our product portfolio. In that regard, we are seeking immediate or near-term accretive acquisitions, including clinical stage opportunities with establish proof of concept, in rare (orphan) disease therapeutic categories. To accomplish these priorities, we are continuing to employ a disciplined approach to evaluating assets and we believe that this strategic expansion will better position our company to build out a broader, more diversified portfolio of drug candidates, which should add greater value to our company over the near and long-term.

FIRDAPSE® Product Overview

FIRDAPSE® is Catalyst’s registered trade name in the U.S. for amifampridine phosphate tablets. Amifampridine is the WHO (World Health Organization) registered INN (International Nonproprietary Name) and U.S. Adopted Name (USAN) for the chemical entity, 3,4-diaminopyridine, often abbreviated as 3,4-DAP or DAP. FIRDAPSE® contains the phosphate salt of amifampridine, hence the name “amifampridine phosphate.” We will refer to our drug by its trade name in the U.S. (FIRDAPSE®), by the INN and USAN (amifampridine), or by the specific salt in our product (amifampridine phosphate), throughout this report.

Amifampridine has been recommended as the first-line symptomatic treatment for LEMS by the European Federation of Neurological Societies (now known as the European Academy of Neurology). In December 2009, amifampridine phosphate received marketing approval from the European Commission (with the trade name FIRDAPSE®) for the symptomatic treatment of patients with LEMS. Safety data from clinical data published over the last 30 years in patients with LEMS or other neurological disorders treated with amifampridine show that amifampridine is well tolerated at doses up to 80 mg per day. In May 2024, the FDA approved our sNDA increasing the maximum daily dose to 100mg per day. Among the 1,279 patients or healthy subjects assessed in the literature, the most frequently reported adverse events (AEs) were perioral and peripheral paresthesias (unusual sensations like pins and needles), and gastrointestinal disorders (abdominal pain, nausea, diarrhea, and epigastralgia (pain around the upper part of the stomach)). These events were typically mild or moderate in severity, and transient, seldom requiring dose reduction or withdrawal from treatment.

Lambert-Eaton Myasthenic Syndrome (LEMS)

LEMS is a rare autoimmune neuromuscular disorder characterized primarily by muscle weakness of the limbs. The disease is caused by an autoimmune reaction where antibodies are formed against voltage-gated calcium channels on nerve endings, which damages the channels. These calcium channels are responsible for the transport of charged calcium atoms that activate the biochemical machinery responsible for releasing acetylcholine. Acetylcholine is the neurotransmitter responsible for causing muscles to contract and the failure to release enough of this neurotransmitter results in muscle weakness in LEMS patients. Additionally, LEMS is often associated with an underlying malignancy, most commonly small-cell lung cancer

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(SCLC), and in some individuals, LEMS is the first symptom of such malignancy. Diagnosing LEMS can also lead to the early detection of SCLC, according to the Lung Cancer Research Foundation and the National Institutes of Health.

LEMS generally affects individuals' extremities, especially the legs. As LEMS most affects the parts of limbs closest to the trunk, difficulties with climbing stairs or rising from a sitting position are commonly reported. Physical exercise and high temperatures tend to worsen the symptoms. Other symptoms often seen include weakness of the muscles of the mouth, throat, and eyes. Individuals affected with LEMS also may have a disruption of the autonomic nervous system, including dry mouth, constipation, blurred vision, impaired sweating, and/or hypotension.

LEMS is managed by treating the symptoms or treating the underlying autoimmune attack on voltage gated calcium channels. Unapproved treatments include steroids, azathioprine and intravenous immunoglobulin, which work by suppressing the immune system; and pyridostigmine and amifampridine, which enhance neuromuscular transmission. Plasma exchange has also been used to attempt to remove antibodies from the body. FIRDAPSE® is a symptomatic treatment and does not alter the underlying autoimmune condition. As a voltage gated potassium blocker, FIRDAPSE® prevents charged potassium atoms from leaving the nerve cells, which prolongs the period of depolarization. This allows more charged calcium atoms to enter the nerves, which enables the nerves to release acetylcholine and causes muscles to contract and to restore lost muscle strength in LEMS patients.

Based on currently available information, we estimate that there are approximately 3,600 LEMS patients in the U.S., approximately half of which we believe are presently diagnosed and identified and the remainder of which we believe are undiagnosed or misdiagnosed. We also have evidence that supports the possibility that there could be as many as 5,400 LEMS patients in the U.S., although the data we have is not conclusive. Further, we believe that half of the patients with LEMS have idiopathic LEMS and half of the patients with LEMS also have or will be diagnosed in the future with cancer (primarily small cell lung cancer). However, until awareness of the disease is increased, it is unlikely that the total number of LEMS patients in the U.S. can be determined with absolute certainty (as is typical of rare diseases), and the actual number of patients in the U.S. with LEMS may be higher or lower than our estimates.

Some of the factors that affect the addressable size of the population with a rare disease such as LEMS include the number of patients actually diagnosed with the disease, the number of patients who are misdiagnosed with other diseases, and the number of patients who are simply undiagnosed. Additionally, while there is an antibody test that positively identifies patients with LEMS which we offer at no cost to health-care providers to be used to definitively determine whether a patient has LEMS, the test is not particularly well known or utilized at this time by many neurologists. Further, many LEMS patients who have small cell lung cancer (SCLC) are not currently being treated for LEMS because many oncology medical professionals who treat SCLC patients are generally unfamiliar with how to diagnose and treat LEMS. All of these factors affect the ultimate number of patients who will benefit from treatment with FIRDAPSE®.

NCCN Guidelines for Small Cell Lung Cancer

On August 6, 2025, we announced that the National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines in Oncology for SCLC had been updated to include critical guidance on LEMS. These revised guidelines advise oncologists to look for symptoms of LEMS as part of the standard of care for SCLC. The guidelines further recommend considering early consultation with neurology for testing. Approximately 50% of LEMS cases are associated with underlying malignancies, and as many as 90% of patients with LEMS who had a SCLC malignancy went undiagnosed.

According to findings from a study published in StatPearls, as diagnosis of LEMS can precede a SCLC diagnosis by 5 to 6 years. Predominant clinical features of SCLC-related LEMS can include proximal muscle weakness, autonomic dysfunction, and impaired deep tendon reflexes, with a more rapid onset and progression in patients with SCLC-related LEMS. In such patients, management of symptoms with FIRDAPSE® and treatment of the primary malignancy can produce symptomatic improvement.

License Agreements for FIRDAPSE®

License Agreement with BioMarin

On October 26, 2012, we licensed the exclusive North American rights to FIRDAPSE® pursuant to a License Agreement (the License Agreement) between us and BioMarin Pharmaceutical Inc. (BioMarin). Under the License Agreement, we pay royalties to the third-party licensor of the rights sublicensed to us from the approval of FIRDAPSE® equal to 7% of net sales (as defined in the License Agreement between BioMarin and the third-party licensor) in any calendar year for the lesser of 7 years or the duration of any pending or issued patents licensed from the third-party licensor within a territory and 3.5% of net sales in any calendar year in territories without pending or issued patents or regulatory exclusivity. We are also obligated to pay royalties to our licensor equal to 7% of net sales (as defined in the License Agreement) in North America for any calendar year for sales

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up to $100 million, and 10% of net sales in North America in any calendar year in excess of $100 million for a term of seven years on a country-by-country basis. As of January 2026, our U.S. net sales are no longer subject to this royalty.

On May 29, 2019, we entered into an amendment to the License Agreement. Under the amendment, we expanded our commercial territory for FIRDAPSE®, which originally was comprised of North America, to include Japan. Additionally, in December 2023 our territory automatically expanded to include most of Asia, as well as Central and South America, upon the acceptance by the Ministry of Health, Labour and Welfare (MHLW) in Japan of an application to market our product in Japan. Under the amendment, we will pay royalties on net sales in Japan of a similar percentage to the royalties that we are currently paying under our original License Agreement for North America.

In January 2020, we were advised that BioMarin had sold certain rights under the License Agreement to SERB SA. We believe that we remain in compliance with our obligations under the License Agreement.

License Agreement with Jacobus Pharmaceutical Company, Inc. (Jacobus)

In May 2019, the FDA approved an NDA for RUZURGI®, Jacobus’ version of amifampridine (3,4-DAP), for the treatment of pediatric LEMS patients (ages 6 to under 17). In June 2019 we filed suit against the FDA and several related parties challenging this approval and related drug labeling. Jacobus later intervened in the case. We ultimately prevailed in our litigation in September 2021, when U.S. Court of Appeals for the 11th Circuit determined that the FDA’s approval of RUZURGI® violated our rights to Orphan Drug Exclusivity.

On July 11, 2022, we settled our disputes with Jacobus. In connection with the settlement, we licensed the rights to develop and commercialize RUZURGI® in the U.S. and Mexico. Simultaneously, we purchased, among other intellectual property rights, Jacobus’ U.S. patents related to RUZURGI®, its NDAs in the U.S. for RUZURGI®, and certain RUZURGI®inventory previously manufactured by Jacobus. At the same time, we received a license from Jacobus for use of its know-how related to the manufacture of RUZURGI®. Further, we settled our pending patent lawsuit against Jacobus, which has been dismissed without prejudice. Finally, Jacobus agreed that until the later of (i) the expiration of the royalty term or (ii) December 31, 2034, Jacobus and its affiliates, will not, directly or indirectly, research, develop, manufacture, commercialize, distribute, use or otherwise exploit any product competitive to FIRDAPSE® or RUZURGI®in the U.S. and Mexico, and Laura Jacobus, the sole shareholder of Jacobus, and two of Jacobus’ other officers, also signed individual non-competition agreements containing the same terms.

In connection with the settlement with Jacobus, we paid Jacobus $30 million of cash, of which $10 million was paid at the closing of the settlement on July 11, 2022, $10 million was paid on the first anniversary of the closing of the settlement, and the remainder was paid on the second anniversary of closing. We also pay Jacobus an annual royalty on our net sales (as defined in the License and Asset Purchase Agreement between us and Jacobus) of amifampridine products in the U.S. equal to: (a) for calendar years 2022 through 2025, 1.5% (with a minimum annual royalty of $3.0 million per year), and (b) for calendar years 2026 through the expiration of the last to expire of Catalyst’s FIRDAPSE®patents in the U.S., 2.5% (with a minimum annual royalty of $5 million per year); provided, however, that the royalty rate may be reduced and the minimum annual royalty may be eliminated under certain circumstances. Royalties will be trued up at the end of the year to the extent that royalties on net sales are below the minimum royalty.

Clinical Trials Supporting our NDA for FIRDAPSE® for LEMS and Approval of our NDA

We conducted two successful Phase 3 double-blind, placebo-controlled clinical trials evaluating FIRDAPSE®for the treatment of LEMS. The results of the first trial published in 2016 in Muscle & Nerve (Muscle Nerve, 2016, 53(5):717-725). The results of the second trial were published in March 2019 in the Journal of Clinical Neuromuscular Disease (J. Clin Neuromusc Dis 2019; 20:111-119). In March 2018, we submitted an NDA seeking approval of FIRDAPSE® for the treatment of LEMS. Our NDA was accepted for filing in May 2018 and, on November 28, 2018, the FDA granted approval of FIRDAPSE® for the treatment of LEMS in adult patients.

On September 29, 2022, the FDA approved our sNDA to expand the indicated age range for FIRDAPSE® for the treatment of LEMS to include pediatric patients, six years of age and older. Further, on May 30, 2024, the FDA approved our sNDA increasing the indicated maximum daily dose of FIRDAPSE® for adults and pediatric patients weighing more than 45 kg from 80 mg to 100 mg for the treatment of LEMS.

Required Post-Approval Studies

As part of the approval of our NDA for FIRDAPSE® for LEMS, the FDA required us to conduct two studies. The first was a clinical trial to evaluate the effect of hepatic impairment on the exposure of amifampridine after oral administration of FIRDAPSE® relative to that in subjects with normal hepatic function. The second was to perform a second carcinogenicity study of amifampridine phosphate in mice. Both have been completed and submitted to the FDA which considers these commitments complete. For a third commitment, we have also established a pregnancy surveillance program to collect and analyze information for a minimum of 10 years on pregnancy complications and birth outcomes related to FIRDAPSE®.

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Finally, in connection with the approval of our sNDA for FIRDAPSE® for the treatment of children ages six through seventeen with LEMS, we recently concluded a pediatric safety study of juvenile toxicity in a rodent and are awaiting comments regarding the results of that study from the FDA.

Compassionate Use Programs

We continue to make FIRDAPSE® available to a limited number of patients diagnosed with congenital myasthenic syndromes or Downbeat Nystagmus through investigator-sponsored compassionate use programs. Further, when we acquired the U.S. rights to RUZURGI® in July 2022, we agreed to continue to supply RUZURGI®to these patients with neuromuscular conditions other than LEMS who are without access to an approved drug and were being treated with RUZURGI® under investigator-sponsored INDs at the time of our settlement with Jacobus. However, this program has been discontinued because the API for RUZURGI® is no longer available and we are therefore unable to manufacture additional product.

Sales, Marketing and Distribution

Marketing of FIRDAPSE®

In January 2019, we launched FIRDAPSE® in the U.S. We sell FIRDAPSE® in the U.S. through a field-based force experienced in neurologic, central nervous system or rare disease products consisting at this time of approximately 23 field personnel, including sales (Regional Account Managers and Area Business Directors), National Account Directors and thought leader liaisons. This includes two national account directors who exclusively focus on the oncology market for LEMS patients with cancer. We also use non-personal promotion to reach the 20,000 neurologists who are potential LEMS treaters and the 16,000 oncologists who might be treating a LEMS patient who also has cancer (principally small cell lung cancer). Finally, we make available for online ordering a no-cost LEMS voltage gated calcium channel (VGCC) antibody diagnostic testing program for use by physicians who suspect that one of their patients may have LEMS and wish to reach a definitive diagnosis.

When we launched AGAMREE®, in March 2024, we utilized the FIRDAPSE® commercial field-based force for AGAMREE® as well. In early 2025, we made a strategic decision to separate our commercial field-based force into two units, one expressly focused on the marketing of FIRDAPSE® and one expressly focused on the marketing of AGAMREE®. This change occurred on April 1, 2025.

We are supporting the distribution of FIRDAPSE® through Catalyst Pathways®, our personalized treatment support program. Catalyst Pathways® is a single source for personalized treatment support, education and guidance through the challenging dosing and titration regimen to an effective therapeutic dose. It also includes distributing the drug through a very small group of exclusive specialty pharmacies (primarily AnovoRx), which is consistent with the way that most pharmaceutical products for ultra-orphan diseases are distributed and dispensed to patients. By using specialty pharmacies in this way, the difficult task of navigating the health care system is far better for the patient needing treatment for their rare disease and the health care community in general.

In addition, Catalyst Pathways® is the gateway for our free bridge medication for patients transitioning from investigational product while they are waiting for a coverage determination or, later on, for patients whose access is threatened by the bureaucratic complications arising from a change of insurer. The Catalyst Pathways® program is also the access point for our Patient Assistance Program, which provides longer-term free medication for those who are uninsured or functionally uninsured with respect to FIRDAPSE® because they may be unable to obtain coverage from their payer despite having health insurance.

We are continuing efforts on the challenging process to identify patients and their physicians who have diagnosed LEMS, but have not had access, awareness or understanding of this treatment for their rare disease. These patients often do not see their physician frequently, have many questions about changing treatment(s), and may not perceive the need to change to a new therapy. Further, we have begun to focus our commercial efforts to locate misdiagnosed and undiagnosed LEMS patients and provide educational and sales activities to help improve the diagnosis, understanding of the treatment, and information on the prescribing process. We plan to continue to support LEMS and rare disease patient organizational groups’ efforts to generate awareness and educate patients and physicians on the diagnosis of LEMS, the impact of the disease, and the support services and treatments available.

Access to FIRDAPSE®

In order to help patients afford their medication, we, like other pharmaceutical companies who are marketing drugs for ultra-orphan conditions, have developed an array of financial assistance programs that are available to reduce patient co-pays and deductibles to a nominal affordable amount. For eligible patients with commercial coverage, a co-pay assistance program designed to keep out-of-pocket costs to $10 or less per month (currently out-of-pocket costs can be as low as $0.00 per month) is available for all LEMS patients prescribed FIRDAPSE®. We have also donated to qualified, independent charitable foundations dedicated to providing assistance to LEMS patients in financial need. Our goal is to ensure that no LEMS patient is ever denied access to their medication for financial reasons.

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To date, FIRDAPSE®has been widely covered and reimbursed by private and public payors for the indicated small population of adult and pediatric LEMS patients.

Canadian Market

We market FIRDAPSE®for the treatment of LEMS in Canada through a sublicensee, KYE. Our product was approved for commercialization in Canada in 2020.

Japanese Market

In May 2019, we entered into an amendment to our license agreement for FIRDAPSE® with BioMarin. Under the amendment, we expanded our commercial territory for FIRDAPSE®, which originally was comprised of North America, to include Japan. Further, we were granted orphan drug designation in Japan for FIRDAPSE® for the symptomatic treatment of LEMS.

On June 28, 2021, we entered into a sub-license agreement with DyDo, pursuant to which we sub-licensed to DyDo the Japanese rights for FIRDAPSE® for the treatment of LEMS. In December 2021, we announced that DyDo had initiated a Phase 3 registrational study in Japan to evaluate the efficacy and safety of FIRDAPSE® for the treatment of LEMS. In December 2023, DyDo submitted a Japan NDA for FIRDAPSE® to the PMDA. On September 24, 2024, DyDo informed us that the MHLW of Japan has approved their New Drug Application for FIRDAPSE® for the treatment of LEMS and DyDo began commercialization of FIRDAPSE® in Japan on January 21, 2025.

Future Markets for FIRDAPSE®

Under the amendment to our license agreement that added Japan to our territory, our territory in which we have the right to seek to commercialize FIRDAPSE® has automatically expanded to include several countries in Asia-Pacific and South and Central America, and we are working to expand our FIRDAPSE®activities into some of these territories.

Intellectual property and regulatory exclusivity protections for FIRDAPSE®

The majority of our patent rights related to FIRDAPSE® are derived from our license agreement with BioMarin, which was transferred to SERB in 2020. In August 2020, the U.S. Patent and Trademark Office (USPTO) allowed Patent No. 10,793,893 (the ’893 patent) to our licensor and thereby to us, and the patent issued on October 6, 2020. The patent is directed to the use of suitable doses of amifampridine to treat patients, regardless of the therapeutic indication, that are slow metabolizers of amifampridine. Any drug product containing amifampridine with a label that states the patented dosing regimens and doses in the Dosing and Administration section prior to May 26, 2034, the expiration date of the patent, could possibly infringe this patent. Generic drug product labels would necessarily have to do this, and we intend to take all appropriate actions to protect our intellectual property.

In April 2021, the USPTO also allowed a further application in the family of licensed intellectual property, and this second patent, Patent No. 11,060,128 (the ’128 patent), issued on July 13, 2021. The patent is directed to the use of suitable doses of amifampridine to treat patients suffering with LEMS that are slow metabolizers of amifampridine. Any drug product containing amifampridine with a label for the treatment of LEMS, that states the patented dosing regimens and doses in the Dosing and Administration section of a product label, including generic drug product labels, could possibly infringe this patent prior to this patent’s expiration date.

Additional patents claiming priority from the patents noted above issued in March 2022 as Patent Nos. 11,268,128, 11,274,332, and 11,274,331, and extended our patent coverage to include fast metabolizers of amifampridine. These patents are now listed in the Orange Book for FIRDAPSE®.

As part of our transaction with Jacobus, we also acquired two patents. One of these patents, 10,626,088 issued by the USPTO on April 21, 2020, was suitable for listing in the Orange Book and has now been listed in further support of FIRDAPSE®.

On December 19, 2023 and January 16, 2024, the USPTO issued Patent Nos. 11,845,977 and 11,873,525, respectively. These new patents cover methods of treating LEMS with FIRDAPSE® under fasting and fed conditions of dosing. We are also pursuing additional patent applications for FIRDAPSE® in an effort to further protect our drug product.

There can be no assurance that we do not or will not infringe on patents held by third parties or that third parties in the future will not claim that we have infringed on their patents. In the event that our products or technologies infringe or violate the patent or other proprietary rights of third parties, we may be prevented from pursuing product development, manufacturing or commercialization of our products that utilize such technologies. For example, there may be patents or patent applications held by others that contain claims that our products or operations might be determined to infringe or that may be broader than we believe them to be. Given the complexities and uncertainties of patent laws, there can be no assurance as to the impact that future patent claims against us may have on our business, financial condition, results of operations, or prospects.

Until FIRDAPSE® was approved in November 2018, no drug product containing amifampridine for any indication had been approved by the FDA such that we received five-year “new chemical entity” exclusivity from the FDA. New chemical entity

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exclusivity provides a five-year period of marketing exclusivity for all indications and in the absence of an Orange Book listed patent, precludes a generic from submitting an ANDA until that five-year period has expired. Further, when FIRDAPSE® was approved for the treatment of LEMS patients, we received seven-year orphan drug exclusivity (ODE) for our product for the treatment of LEMS, precluding a generic filer from receiving final FDA approval until the ODE exclusivity period has expired. Because we had Orange Book listed patents for FIRDAPSE®, potential generic filers were permitted to submit ANDA filings to the FDA starting on the “NCE-1” date (November 28, 2022).

For a description of currently ongoing Paragraph IV litigation related to FIRDAPSE®, see “Item 1. Business – Overview – FIRDAPSE®.” The outcome of patent litigation with Paragraph IV challengers is always uncertain and there can be no assurance to whether we will prevail in this litigation. At present, our pending case against Hetero is currently scheduled to be tried beginning on March 23, 2026.

We have also in-licensed the FIRDAPSE® trademark, which was registered in the U.S. in March 2015.

Protection of our intellectual property and regulatory exclusivities is a strategic priority for our business. Our ability to protect and use our intellectual property rights and regulatory exclusivity in the future development and commercialization of our products, operate without infringing the proprietary rights of others, and prevent others from infringing our proprietary rights, is crucial to our future success. See Item 1A. “Risk Factors - Risks Related to Our Intellectual Property.”

AGAMREE® Product Overview

AGAMREE® is a structurally unique steroidal anti-inflammatory drug to treat children and adults living with DMD. In clinical studies, AGAMREE® showed evidence of inhibition of pro-inflammatory NF-kB (nuclear factor kappa light chain enhancer of activated B cells) pathways, which are, a family of highly conserved transcription factors that regulate many important cellular behaviors, in particular, inflammatory responses and cellular growth. This inhibition is achieved through high-affinity binding to the glucocorticoid receptor, high-affinity antagonism for the mineralocorticoid receptor, and membrane stabilization properties. It is hoped that AGAMREE® will demonstrate similar efficacy to traditional corticosteroids with reduced negative downstream impacts and side effects.

The FDA approved AGAMREE® for the treatment of DMD in patients aged 2 and older on October 26, 2023.

Clinical Trials Supporting AGAMREE®

A randomized, double-blind, placebo and prednisone-controlled trial of vamorolone was carried out in patients with DMD. The trial met the primary (time to stand velocity after 24 weeks for vamorolone, 6 mg/kg per day vs placebo) and first 4 sequential secondary motor function endpoints. Study participants receiving vamorolone, 2 mg/kg per day, and vamorolone, 6 mg/kg per day, showed improvements in multiple functional endpoints over the 24-week treatment period as compared to placebo. The statistical thresholds for the primary outcome and first 4 secondary outcomes for vamorolone treatment were met, and vamorolone demonstrated efficacy across both dose ranges. The differences in time to stand from supine velocity (TTSTAND) were clinically meaningful. The differences in 6-minute walk test (6MWT) were also clinically meaningful.

The trial validated previous open-label findings where a more normal growth trajectory was observed over 18-month and 30-month periods in vamorolone treated boys with DMD. Furthermore, bone turnover markers supported the improved profile of vamorolone on bone health.

Access to AGAMREE®

We are supporting AGAMREE® through our Catalyst Pathways® Program, which includes a dedicated, personalized support team that assists families through the AGAMREE® treatment journey, from answering questions to coordinating financial assistance programs for eligible patients.

Acquisition of AGAMREE®

On June 19, 2023, we entered into a License and Collaboration Agreement (License Agreement) and an Investment Agreement (Investment Agreement) with Santhera. Under the License Agreement, we contracted to obtain an exclusive North America license, manufacturing and supply agreement for Santhera’s investigational product candidate, AGAMREE® (vamorolone), a novel corticosteroid for the treatment of DMD. We also obtained the North American rights to any future approved indications for AGAMREE®. Further, under the Investment Agreement, we agreed to make a strategic investment into Santhera.

Both transactions closed on July 18, 2023. Under the License Agreement, upon closing, we made a $75 million payment to Santhera in return for the exclusive North American license for AGAMREE®. Additionally, following approval of the NDA for the drug, on October 26, 2023, we became obligated to make milestone payments of $36 million to Santhera, $26 million of which will be used by Santhera to make milestone payments to third parties. This payment were made in the fourth quarter of 2023. We are also obligated to pay future regulatory and commercial milestone payments to Santhera tied to calendar year sales of AGAMREE®, as well as commercial royalties.

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Concurrently with the closing of the License Agreement, we made a strategic investment into Santhera in which we acquired 1,414,688 of Santhera’s post-reverse split ordinary shares (representing approximately 11.26% of Santhera’s outstanding ordinary shares following the transaction) at an investment price of CHF 9.477 per share (corresponding to a mutually agreed volume weighted average price prior to signing), with the approximately $15.7 million investment to be used by Santhera for Phase IV studies of AGAMREE® in DMD and future development of additional indications for AGAMREE®.

Intellectual Property Protections for AGAMREE®

AGAMREE® is protected by multiple patents with expiration dates from August 2028 to July 2040. The Orange Book listed patents granted by the USPTO are as follows:

U.S. Patent No. Indication Expiration Date

11,471,471 Aqueous oral pharmaceutical suspension compositions March 17, 2040

11,382,922 Aqueous oral pharmaceutical suspension compositions July 16, 2040

12,201,639 Aqueous oral pharmaceutical suspension compositions March 17, 2040

Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a genetic disorder characterized by progressive muscle degeneration and weakness due to the alterations of a protein called dystrophin that helps keep muscle cells intact. DMD is the most common of four conditions known as dystrophinopathies, with the others being Becker Muscular Dystrophy, or BMD, a mild form of DMD; an intermediate clinical presentation between BMD and DMD, and DMD-associated dilated cardiomyopathy (heart disease), with little or no clinical skeletal, or voluntary, muscle disease.

DMD symptom onset is in early childhood, usually between the ages of 2 and 3. The disease primarily affects boys, but in rare cases can affect girls. For girls who are carriers, about 2.5 to 20 percent may have mild symptoms. In the U.S., the incidence of DMD is estimated to be about 1 in 3,600 live male births.

DMD causes muscle weakness that worsens over time, and common symptoms include:

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Progressive muscle weakness and atrophy that begins in the legs and pelvis, occurring less severely in the arms, neck, and other areas of the body.

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Calf muscle hypertrophy (increase in muscle size).

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Difficulty climbing up stairs.

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Difficulty walking that gets worse over time.

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Frequent falls.

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Waddling gait (walk).

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Toe walking.

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Fatigue.

Other common symptoms of DMD include:

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Cardiomyopathy.

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Breathing difficulties and shortness of breath.

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Cognitive impairment and learning difficulty.

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Delayed speech and language development.

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Developmental delay.

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Scoliosis.

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Short stature.

DMD is caused by a mutation in the gene that gives instructions for a protein called dystrophin. Dystrophin is a critical part of the dystrophin-glycoprotein complex (DGC), which plays an important role as a structural unit of muscle. In DMD, both dystrophin and DGC proteins are missing, which ultimately leads to the death of muscle cells. People with DMD have less than 5% of the normal quantity of dystrophin needed for healthy muscles. As people with DMD age, their muscles can't replace dead cells with new ones, and connective and adipose (fat) tissue gradually replace muscle fibers.

DMD has X-linked recessive inheritance, but about 30% of cases happen spontaneously with no family history of the condition. X-linked diseases are located on the X chromosome. Recessive inheritance means that when there are two copies of the responsible gene, both copies must have a pathogenic variant or mutation in order for a person to have the condition. Since males only have one X chromosome, any mutation on that chromosome will cause DMD.

FYCOMPA® Product Overview

Epilepsy is a serious neurological condition that affects more than 50 million individuals globally, 80% of whom live in developing countries. An estimated 1.7% of U.S. adults have been diagnosed with the condition. From prominent historical figures to friends or family members, most people probably know someone affected by epilepsy.

The FDA approved FYCOMPA® in October 2012 as an adjunctive agent for the treatment of focal onset seizures with or without secondary generalization in patients with epilepsy at least 4 years of age. In June 2015, the agency approved a second indication for primary generalized tonic-clonic seizures in patients with epilepsy who are at least 12 years of age.

FYCOMPA® is a novel non-competitive selective antagonist at the postsynaptic ionotropic alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor. In the nervous system, glutamate is known to be a major excitatory neurotransmitter, but the exact antiepileptic mechanism of perampanel in humans is unknown. Studies suggest that AMPA receptor antagonism can lead to reduced overstimulation and anticonvulsant effects, as well as inhibiting seizure generation and spread. In addition, AMPA receptor antagonists may prevent neuronal death.

At the time of its approval, the FDA included specific significant warnings for FYCOMPA®, in the prescribing information, that it required to be included prominently in all communications about the product. Such warnings are known as boxed warnings because they are traditionally surrounded by a black box to emphasize their significance. For FYCOMPA®, the warning addresses rare but serious behavioral changes that occur in some patients using FYCOMPA® including aggression (up to and including homicidal behavior), hostility, anger, distrust and other extreme behavioral changes; visual and auditory hallucinations; and difficulty with memory. In addition, FYCOMPA® was classified as a Class III controlled substance prior to its approval due to evidence of prolonged use creating a physical dependence in some patients and the possibility of abuse.

Epilepsy

Epilepsy is a long-term (chronic) disease that causes repeated seizures due to abnormal electrical signals produced by damaged brain cells. A burst of uncontrolled electrical activity within brain cells causes a seizure. Epilepsy is generally diagnosed after an individual suffers two seizures within a 24-hour period. Generally, cells in the brain send messages to and receive messages from all areas of the body. These messages are transmitted via a continuous electrical impulse that travels from cell to cell. Epilepsy disrupts this rhythmic electrical impulse pattern. Instead, there are bursts of electrical energy — like an unpredictable lightning storm — between cells in one or more areas of your brain. This electrical disruption causes changes in awareness (including loss of consciousness), sensations, emotions and muscle movements. In the U.S., about 3.4 million people have epilepsy. Of this number, approximately 3 million are adults and 470,000 are children. There are approximately 150,000 new cases of epilepsy in the U.S. each year. Worldwide, about 65 million people have epilepsy.

Epileptic seizures (defined by two or more unprovoked seizures separated by more than 24 hours, or one unprovoked seizure with high probability of an additional seizure in the next 10 years, or as better defined by an epileptic syndrome) are separated into two broad categories: partial-onset seizures (POS) and generalized seizures, which affect one or both hemispheres of the brain, respectively. While many risk factors (e.g., infection, genetics, prenatal injury, or structural or metabolic abnormalities) have been elucidated, more than half of all cases of epilepsy are due to unknown causes. Regardless of the causative factor, epileptic seizures result from a persistent and uncontrolled increase in hypersynchronous neuronal excitability implicating various receptors (e.g., sodium, calcium, potassium, gamma-aminobutyric acid, or glutamate) involved in normal neurotransmission. Antiepileptic drugs (AEDs) target the various receptors to reduce neuronal excitability and control seizures, thus reducing the risk of seizure-related injuries and death. Although monotherapy is ideal for treating epileptic seizures, only about 49% of patients achieve seizure freedom while using their first appropriately selected AED. Subsequently, 62% to 66% of patients might only be able to achieve seizure freedom with a second or third appropriately selected AED, respectively, leaving up to one-third of patients with inadequate control of their seizures. In addition, patients may have a higher risk of

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toxicity if AEDs with similar mechanisms of action are used concomitantly. In the last two decades, the number of agents commercially available in the armamentarium against epilepsy has risen fourfold, few with a novel mechanism of action like FYCOMPA®.

Access to FYCOMPA®

Despite the loss of patent exclusivity for FYCOMPA®, we continue to sell both FYCOMPA® tablets and the FYCOMPA® oral suspension version of the product, although we ceased marketing efforts for this product effective December 31, 2025.

Acquisition of U.S. rights to FYCOMPA®

On December 17, 2022, we entered into an Asset Purchase Agreement with Eisai, pursuant to which we acquired the U.S. rights to FYCOMPA®. Pursuant to the Asset Purchase Agreement entered into with Eisai for FYCOMPA®, we purchased Eisai’s regulatory approvals and documentation, product records, intellectual property, inventory, and other matters relating to the U.S. rights for FYCOMPA®, in exchange for an up-front cash payment of $160 million; and royalty payments on net sales post-expiration of the patents for FYCOMPA®, which royalty payments will be reduced upon generic equivalents to FYCOMPA® entering the market. Finally, we have agreed to pay Eisai an additional cash payment of $25 million if a patent extension for FYCOMPA®was approved by the USPTO (which did not occur).

In conjunction with the Asset Purchase Agreement, at the closing of our purchase on January 24, 2023 we entered into two additional agreements with Eisai:

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A Transition Services Agreement under which a U.S. subsidiary of Eisai provided us with certain services for certain periods, including but not limited to, FDA Post-Marketing study requirements for FYCOMPA® and Transitional Services pursuant to which Eisai’s U.S. subsidiary assisted us with the transition of commercial, market asset, finance, medical information, and supply issues; and

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A Supply Agreement under which Eisai has agreed to manufacture FYCOMPA® for us for at least seven years at prices to be updated on a yearly basis.

These additional agreements became effective upon the closing of the transaction with Eisai on January 24, 2023. The transition services under the Transition Services Agreement ended on December 31, 2023.

Clinical Trials Supporting FYCOMPA®

Partial Onset Seizures

The efficacy of FYCOMPA® in partial-onset seizures, with or without secondary generalization, was studied in patients who were not adequately controlled with 1 to 3 concomitant AEDs in 3 randomized, double-blind, placebo-controlled, multicenter trials (Studies 1, 2, and 3) in adult and pediatric patients (12 years of age and older). All trials had an initial 6-week Baseline Period, during which patients were required to have more than five seizures in order to be randomized. The Baseline Period was followed by a 19-week Treatment Period consisting of a 6-week Titration Phase and a 13-week Maintenance Phase. Patients in these 3 trials had a mean duration of epilepsy of approximately 21 years and a median baseline seizure frequency ranging from 9 to 14 seizures per 28 days. During the trials, more than 85% of patients were taking 2 to 3 concomitant AEDs with or without concurrent vagal nerve stimulation, and approximately 50% were on at least one AED known to induce CYP3A4, an enzyme critical to the metabolism of FYCOMPA® (i.e., carbamazepine, oxcarbazepine, or phenytoin), resulting in a significant reduction in FYCOMPA®’s serum concentration.

Each study evaluated placebo and multiple FYCOMPA® dosages. During the Titration period in all 3 trials, patients on FYCOMPA® received an initial 2 mg once daily dose, which was subsequently increased in weekly increments of 2 mg per day to the final dose. Patients experiencing intolerable adverse reactions were permitted to have their dose reduced to the previously tolerated dose.

The primary endpoint in Studies 1, 2, and 3 was the percent change in seizure frequency per 28 days during the Treatment Period as compared to the Baseline Period. The criterion for statistical significance was p<0.05. A statistically significant decrease in seizure rate was observed at doses of 4 to 12 mg per day. Dose response was apparent at 4 to 8 mg with little additional reduction in frequency at 12 mg per day.

Primary Generalized Tonic-Clonic Seizures

The efficacy of FYCOMPA® as adjunctive therapy in patients 12 years of age and older with idiopathic generalized epilepsy experiencing primary generalized tonic-clonic seizures was established in one multicenter, randomized, double-blind, placebo-controlled study (Study 4), conducted at 78 sites in 16 countries. Eligible patients on a stable dose of 1 to 3 AEDs experiencing at least 3 primary generalized tonic-clonic seizures during the 8-week baseline period were randomized to either FYCOMPA® or placebo. Efficacy was analyzed in 162 patients (FYCOMPA®N=81, placebo N=81) who received medication and at least one post-treatment seizure assessment. Patients were titrated over 4 weeks up to a dose of 8 mg per day or the highest tolerated

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dose and treated for an additional 13 weeks on the last dose level achieved at the end of the titration period. The total treatment period was 17 weeks. Study drug was given once per day.

The primary endpoint was the percent change from baseline in primary generalized tonic-clonic seizure frequency per 28 days during the treatment period as compared to the baseline period. The criterion for statistical significance was p<0.05. A statistically significant decrease in seizure rate was observed with FYCOMPA® compared to placebo.

Intellectual Property Protections for FYCOMPA®

Patent protection for FYCOMPA® is primarily from two patents listed in the Orange Book. The first, U.S. patent no. 6,949,571 (the '571 patent) expired on May 23, 2025. The second FYCOMPA® patent in the Orange Book is U.S. Patent No. 8,772,497 (the '497 patent), which expires on July 1, 2026.

Expiration of Patent Protection for FYCOMPA®

Following the expiration of the '571 patent and the '497 patent, three generic versions of the tablets and one generic version of the oral suspension have come onto the market.

Manufacturing and Supply

We are licensed in Florida as a virtual drug manufacturer, which means that we have no in-house manufacturing capacity and we are obligated to rely on contract manufacturers and packagers. We have no plans to build or acquire the manufacturing capability needed to manufacture any of our research materials or commercial products, and we expect that our drug products and drug substances will be prepared by contractors with suitable capabilities for these tasks and that we will enter into appropriate supply agreements with these contractors at appropriate times in the development and commercialization of our products. Because we will use contractors to manufacture and supply our products, we will be reliant on such contractors. Further, the contractors selected would have to be inspected by the FDA and found to be in substantial compliance with federal regulations in order for an application for one of our drug candidates to be approved, and there can be no assurance that the contractors we select would pass such an inspection.

FIRDAPSE®

We have entered into agreements with a supplier of the API contained in FIRDAPSE® for future requirements and we have contracted with third-party contract manufacturers who are manufacturing FIRDAPSE® tablets for us.

AGAMREE®

Under our License and Collaboration Agreement with Santhera, we are currently purchasing supplies of AGAMREE® from Santhera while we take the steps to add additional outside, third-party manufacturers for the manufacture and supply of AGAMREE®. In that regard, we expect to have an additional third-party manufacturer for the manufacture and supply of AGAMREE® before the end of 2026.

FYCOMPA®

Under our Supply Agreement with Eisai, Eisai has agreed to manufacture and supply to us finished bulk FYCOMPA®tablets for us for a seven-year period that will run through at least the end of 2029. In addition, Eisai has assigned to us third-party manufacturing contracts related to final packaging of bulk FYCOMPA® tablets and also the manufacture of the oral solution formulation.

Manufacturing Changes

Any significant change that we make for any of our drug products must be approved by the FDA in an sNDA. If the manufacturing plan and data are insufficient, any sNDA we submit will not be approved. Before an sNDA can be approved, our manufacturers must also demonstrate compliance with FDA’s current Good Manufacturing Practices (cGMP) regulations and policies. Further, even if we receive approval of any sNDAs for our drug product(s), if our manufacturers do not follow cGMPs in the manufacture of our products, it may delay product launches or shipments and adversely affect our business.

Since we contract with third parties to manufacture our products, our contract manufacturers are required to comply with all applicable environmental laws and regulations that affect the manufacturing process. As a result, we do not believe that we will have any significant direct exposure to environmental issues.

Competition

The pharmaceutical industry is intensely competitive, and any product candidate developed or licensed by us would likely compete with currently marketed and potentially new drugs and therapies even though they are not indicated for these conditions. We also may face generic competition upon the loss of exclusivity and/or patent protection for our products. There are many pharmaceutical companies, biotechnology companies, public and private universities, government agencies and

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research organizations that compete with us in developing various approaches to the treatment of orphan diseases. Many of these organizations have substantially greater financial, technical, marketing and manufacturing resources than we have.

FIRDAPSE®

Before the approval of FIRDAPSE®, LEMS was generally treated with unapproved drugs and therapies including steroids, azathioprine, other immunosuppressants and intravenous immunoglobulin, which work by suppressing the immune system, and pyridostigmine. Plasma exchange has also been used in an attempt to remove antibodies from the body. Further, one other product, guanidine HCl tablets, was approved many years ago (during a period when drugs were not required to be reviewed by the FDA for both safety and effectiveness) for use in the treatment of LEMS. However, this drug has significant side effects and is not currently believed to be an effective treatment for LEMS. Notwithstanding, drugs may be prescribed by physicians for the treatment of LEMS whether or not they are considered effective.

Finally, we are aware that amifampridine has been available in the past from compounding pharmacies and may remain available, even though FIRDAPSE® has been approved and is commercially marketed in the U.S.

AGAMREE®

The market for DMD treatment is highly competitive, with multiple lines of treatment and medications, both name brand and generic. The first-line treatment has long been and continues to be corticosteroids. On February 9, 2017, the FDA approved Emflaza (deflazacort), a corticosteroid marketed by PTC Therapeutics for the treatment of DMD in patients five years old and older. In March 2024, the FDA approved Duvyzat (Givinostat), a non-steroidal first-in-class medication intended for people six years of age and older. The product works by inhibiting histone deacetylase enzymes to reduce inflammation and slow muscle damage. Finally, a gene-therapy treatment, Elevidys, was approved in 2023 for the treatment of ambulatory DMD patients between the ages of four and five, with the exceptions of patients with specific deletions in exon eight or exon nine of the DMD gene.

After the submission of additional study data in June 2024, Sarepta received an expanded label for treatment of all DMD patients over the age four. After the evaluation of a number of safety reports of patients on Elevidys, the FDA announced a restriction of the label, in July 2025, to treatment of only ambulatory patients with DMD. On January 26, 2026, Sarepta announced positive results from a three-year global, randomized placebo-controlled Phase 3 study evaluating Elevidys in ambulatory individuals with DMD ages 4 to 7 (averaging nine years of age at the time of last assessment). Since the drug was only evaluated with co-treatment with prednisone as an immunosuppressant, we expect that DMD patients transitioning to Elevidys may (in the short-term) delay initiating use of AGAMREE® while waiting for access to such gene therapy or stop their AGAMREE® therapy during the course of their gene therapy treatment.

In addition, there are other companies which have announced plans for pre-clinical candidates and clinical development for the treatment of DMD, including gene transfer and/or gene editing therapies.

We believe that patients are likely to return to a differentiated steroid like AGAMREE® post the immunosuppression period due to its potential superior clinical profile. Additionally, we believe that in the long-term, corticosteroids like AGAMREE®, will continue to be the foundational therapy for the treatment of DMD. However, there can be no assurance that new therapies approved in the future for the treatment of DMD will require the use of steroids after administration of such new therapies.

FYCOMPA®

FYCOMPA® is the first and only AED that targets a specific receptor in the brain called “AMPA”. The receptor plays a role in allowing seizures to occur. Seizures have historically been treated with benzodiazepines such as clonazepam (Klonopin) and lorazepam (Ativan), GABA inhibitors such as gabapentin (Neurontin), phenobarbital (Luminal), and pregabalin (Lyrica), and sodium channel blockers such as carbamazepine (Tegretol) and lacosamide (Vimpat). Additionally, surgical options such as deep brain stimulation have been used in patients who have failed polypharmacy. Finally, there are multiple compounds that have been recently approved or are in late-stage development for focal epilepsy.

One or more generic manufacturers have approved ANDAs for FYCOMPA® and several are currently marketing their own generic versions of the product.

Factors affecting competition generally

In general, our ability to compete depends in large part upon:

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our ability to complete clinical development and obtain regulatory approvals for our drug candidates;

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the demonstrated efficacy, safety and reliability of our drug candidates;

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the timing and scope of regulatory approvals;

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product acceptance by physicians and other health care providers;

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the willingness of payors to reimburse for our product;

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protection of our proprietary rights and the level of generic competition;

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the speed at which we develop drug candidates;

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our ability to supply commercial quantities of a product to the market;

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our ability to obtain reimbursement from private and/or public insurance entities for product use in approved indications;

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our ability to recruit and retain skilled employees; and

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the availability of capital resources to fund our development and commercialization activities.

Business Development

We are continuing to work to broaden and diversify our product portfolio through acquisitions of early and/or late-stage products or companies or technology platforms in rare disease therapeutic categories. To accomplish these priorities, we are continuing to employ a disciplined approach to evaluating assets, and we believe that this strategic expansion will better position our company long-term to build out a broader more diversified portfolio of drug candidates (which should add greater value to our company over the near and long-term). In that regard, we are currently exploring several additional potential opportunities to acquire companies with commercial drug products and/or drug products in development or to in-license or acquire commercialized drug products or drug products in development. However, other than the recent License Agreement with KYE for AGAMREE®, no additional definitive agreements have been entered into to date and there can be no assurance that our efforts to continue to broaden and diversify our product portfolio will be successful.

Regulatory Matters

Government Regulation and Product Approval

Government authorities in the U.S., at the federal, state and local level, and in other countries extensively regulate, among other things, the research, development, testing, manufacture, labeling, record-keeping, promotion, storage, advertising, distribution, marketing and export and import of products such as those we are developing. Our drugs must be approved by the FDA through the NDA process before they may be legally marketed in the U.S.

In the U.S., drugs are subject to rigorous regulation by the FDA under the FDCA and implementing regulations, as well as other federal and state statutes. The process of obtaining regulatory approvals and the subsequent compliance with appropriate federal, state, local, and foreign statutes and regulations require the expenditure of substantial time and financial resources. Failure to comply with the applicable U.S. requirements at any time during the product development process, approval process, or after approval, may subject an applicant to administrative or judicial sanctions. These sanctions could include the FDA’s refusal to approve pending applications, license suspension or revocation, withdrawal of an approval, a clinical hold, warning letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines, civil penalties or criminal prosecution. Any agency or judicial enforcement action could have a material adverse effect on us.

The process required by the FDA before a drug may be marketed in the U.S. generally involves the following: completion of pre-clinical laboratory tests, animal studies and formulation studies according to the FDA’s good laboratory practice (GLP) regulations:

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submission of an investigational new drug application (IND) which must become effective before human clinical trials may begin and which must include approval by an institutional review board, or IRB, at each clinical site before the trials are initiated;

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performance of adequate and well-controlled human clinical trials to establish the safety and efficacy of the proposed drug for its intended use conducted in compliance with federal regulations and good clinical practice (GCP), an international standard meant to protect the rights and health of patients and to define the roles of clinical trial sponsors, administrators, and monitors;

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submission to, and filing by, the FDA of an NDA;

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satisfactory completion of an FDA inspection of the manufacturing facility or facilities at which the drug is produced to assess compliance with cGMP regulations to assure that the facilities, methods and controls are adequate to preserve the drug’s identity, strength, quality and purity;

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potential FDA audit of the non-clinical and clinical trial sites that generated the data in support of the NDA; and

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FDA review and approval of the NDA.

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The testing and approval process requires substantial time, effort and financial resources, and the receipt and timing of any approval is uncertain.

U.S. Drug Development Process

Once a pharmaceutical candidate is identified for development, it enters the pre-clinical testing stage. Pre-clinical tests include laboratory evaluations of product chemistry, toxicity and formulation, as well as animal studies. Prior to beginning human clinical trials, an IND sponsor must submit an IND to the FDA. The IND sponsor must submit the results of the pre-clinical tests, together with manufacturing information and analytical data, to the FDA as part of the IND. Some pre-clinical or non-clinical testing may continue even after the IND is submitted. In addition to including the results of the pre-clinical studies, the IND will also include a protocol detailing, among other things, the objectives of the clinical trial, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated, if the trial lends itself to an efficacy evaluation. The IND automatically becomes effective 30 days after receipt by the FDA, unless the FDA, within the 30–day time period, raises concerns or questions about the conduct of the trial. In such a case, the IND sponsor and the FDA must resolve any outstanding concerns before the clinical trial can begin. The FDA may, at any time, impose a clinical hold on ongoing clinical trials. If the FDA imposes a clinical hold, clinical trials cannot commence or recommence without FDA authorization and then only under terms authorized by the FDA.

Clinical trials involve the administration of the investigational new drug to healthy volunteers or patients under the supervision of one or more qualified investigators in accordance with federal regulations and GCP.

Clinical trials must be conducted under protocols detailing the objectives of the trial and the safety and effectiveness criteria to be evaluated. Each protocol must be submitted to the FDA as part of the IND. Further, an Institutional Review Board (IRB) at each institution participating in the clinical trial must review and approve each protocol before any clinical trial commences at that institution. All research subjects must provide informed consent, and informed consent information must be submitted to the IRB for approval prior to initiation of the trial. Progress reports detailing the results of the clinical trials must be submitted at least annually to the FDA and more frequently if adverse events or other certain types of other changes occur.

Human clinical trials are typically conducted in three phases. A fourth, or post-approval, phase may include additional clinical studies. These phases generally include the following, and may be sequential, or may overlap or be combined:

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Phase 1 clinical trials involve the initial introduction of the drug into human subjects. These studies are designed to determine the safety of usually single doses of the compound and determine any dose limiting intolerance, as well as evidence of the metabolism and pharmacokinetics of the drug in humans.

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Phase 2 clinical trials usually involve studies in a limited patient population to evaluate the safety and efficacy of the drug for specific, targeted indications, to determine dosage tolerance and optimal dosage, and to identify possible adverse effects and safety risks.

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In Phase 3, if a compound is found to be potentially effective and to have an acceptable safety profile in Phase 2 (or occasionally Phase 1) studies, the Phase 3 studies will be conducted to further confirm clinical efficacy, optimal dosage and safety within an expanded population which may involve geographically diverse clinical trial sites. Generally, but not always, two adequate and well-controlled Phase 3 clinical trials are required by the FDA for approval of an NDA.

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Phase 4 clinical trials are studies required of or agreed to by a sponsor that are conducted after the FDA has approved a product for marketing. These studies are used to gain additional experience from the treatment of patients in the intended therapeutic indication and to document a clinical benefit in the case of drugs approved under accelerated approval regulations. If the FDA approves a product while a company has ongoing clinical trials that were not necessary for approval, a company may be able to use the data from these clinical trials to meet all or part of any Phase 4 clinical trial requirement. Failure to promptly conduct Phase 4 clinical trials where necessary could result in withdrawal of approval for products approved under accelerated approval regulations.

While Phase 1, Phase 2, and Phase 3 tests are generally required for approval of an NDA, certain drugs may not require one or more steps in the process depending on other testing and the situation involved. Additionally, the FDA, an IRB, or the sponsor may stop testing at any time if results show patients being exposed to unnecessary health risks or overly dangerous side effects.

In addition, the manufacturer of an investigational drug in a Phase 2 or Phase 3 clinical trial for a serious or life-threatening disease is required to make available, such as by posting on its website, its policy on evaluating and responding to requests for expanded access to such investigational drug.

Concurrent with clinical trials, companies usually complete additional animal studies and must also develop additional information about the chemistry and physical characteristics of the drug and finalize a process for manufacturing the product in accordance with cGMP requirements. The manufacturing process must be capable of consistently producing quality batches

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of the drug candidate and, among other requirements, the manufacturer must develop methods for testing the identity, strength, quality and purity of the final drug. Additionally, appropriate packaging must be selected and tested, and stability studies must be conducted to demonstrate that the drug candidate does not undergo unacceptable deterioration over its shelf life.

U.S. Review and Approval Process

FDA approval of an NDA is required before marketing of the product may begin in the U.S. The NDA must include the results of product development, pre-clinical studies and clinical studies, together with other detailed information, including information on the chemistry, manufacture and composition of the product. The FDA has 60 days from its receipt of the NDA to review the application to ensure that it is sufficiently complete for substantive review before filing it. The FDA may request additional information rather than file an NDA. In this event, the NDA must be resubmitted with the additional information. The resubmitted application also is subject to review before the FDA files it. Once the submission is filed, the FDA begins an in-depth substantive review. The submission of an NDA is also subject to the payment of a substantial application fee (for FDA fiscal year 2026 this fee is $4,682,003), although a waiver of such fee may be obtained under certain limited circumstances, including when the drug that is subject of the application has received Orphan Drug Designation for the indication sought. Further, the sponsor of an approved NDA is subject to an annual program fee, which for FDA fiscal year 2026 is $442,213per prescription drug product. User fees typically increase annually. The approval process is lengthy and difficult, and the FDA may refuse to approve an NDA if the applicable regulatory criteria are not satisfied or may require additional clinical or other data and information. Even if such data and information is submitted, the FDA may ultimately decide that the NDA does not satisfy the criteria for approval. The FDA may also refer applications for novel drug products or drug products which present difficult questions of safety or efficacy to an advisory committee, typically a panel that includes clinicians and other experts, for review, evaluation and a recommendation as to whether the application should be approved. The FDA is not bound by the recommendation of an advisory committee. The FDA reviews an NDA to determine, among other things, whether a product is safe and effective for its intended use. Before approving an NDA, the FDA will inspect the facility or facilities where the product is manufactured to determine whether its manufacturing is cGMP–compliant to assure and preserve the product’s identity, strength, quality, purity and stability.

If the FDA’s evaluation of the NDA submission or manufacturing facilities is not favorable, the FDA will issue a complete response letter. The complete response letter outlines the deficiencies in the submission and often requires additional testing or information in order for the FDA to reconsider the application. Even after submitting this additional information, the FDA ultimately may decide that the application does not satisfy the regulatory criteria for approval. With limited exceptions, the FDA may withhold approval of an NDA regardless of prior advice it may have provided or commitments it may have made to the sponsor.

Once an NDA is approved, changes to the conditions of approval, including additional indications, are made by the submission of a supplement to the NDA. The sNDA must contain all of the information necessary to support the change. In the case of a new indication, that information usually consists of at least one clinical trial, and often more. Like an NDA, FDA determines whether the sNDA is sufficiently complete to permit review before it files the sNDA. FDA then reviews the sNDA. Like an NDA, FDA can either approve the sNDA or issue a complete response letter outlining the deficiencies in the sNDA.

Post-approval requirements

Once an NDA is approved, a product will be subject to certain post-approval requirements. For instance, the FDA closely regulates the post-approval marketing and promotion of drugs, including standards and regulations for direct-to-consumer advertising, off-label promotion, industry-sponsored scientific and educational activities and promotional activities involving the internet. As a condition of NDA approval, the FDA may also require a risk evaluation and mitigation strategy (REMS), to help ensure that the benefits of the drug outweigh the potential risks. REMS can include medication guides, communication plans for healthcare professionals, and other Elements To Assure Safe Use (ETASU). ETASU can include, but are not limited to, special training or certification for prescribing or dispensing, dispensing only under certain circumstances, special monitoring, and the use of patient registries. The requirement for a REMS can materially affect the potential market and profitability of the drug.

Drugs may be marketed only for the approved indications and in accordance with the provisions of the approved labeling. Changes to some of the conditions established in an approved application, including changes in indications, labeling, or manufacturing processes or facilities, require submission and FDA approval of a new NDA or sNDA before the change can be implemented. An sNDA for a new indication typically requires clinical data similar to that in the original application, and the FDA uses the same procedures and actions in reviewing NDA supplements as it does in reviewing NDAs.

Adverse event reporting and submission of periodic reports is required following FDA approval of an NDA. The FDA also may require post-marketing testing, known as Phase 4 testing, and surveillance to monitor the effects of an approved product or place conditions on an approval that could restrict the distribution or use of the product. In addition, quality control as well as drug manufacture, packaging, and labeling procedures must continue to conform to cGMPs after approval. Drug manufacturers and certain of their subcontractors are required to register their establishments with the FDA and certain state

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agencies and are subject to periodic unannounced inspections by the FDA during which the agency inspects manufacturing facilities to assess compliance with cGMPs. Accordingly, manufacturers must continue to expend time, money and effort in the areas of production and quality control to maintain compliance with cGMPs. Regulatory authorities may withdraw product approvals or request product recalls if a company fails to comply with regulatory standards, if it encounters problems following initial marketing, or if previously unrecognized problems are subsequently discovered.

Controlled Substance Regulations

A drug product approved by FDA may be subject to scheduling as a controlled substance under the Controlled Substances Act (CSA) depending on the drug’s potential for abuse. Controlled substances that are pharmaceutical products are subject to a high degree of regulation under the CSA, which establishes, among other things, certain registration, manufacturing quotas, security, recordkeeping, reporting, import, export and other requirements administered by the U.S. Drug Enforcement Administration (DEA). The DEA classifies controlled substances into five schedules. Schedule I substances by definition have a high potential for abuse, have no currently “accepted medical use” in the U.S., lack accepted safety for use under medical supervision, and may not be prescribed, marketed or sold in the U.S. Pharmaceutical products approved for use in the U.S. may be listed as Schedule II, III, IV or V, with Schedule II substances considered to present the highest potential for abuse or dependence and Schedule V substances the lowest relative risk of abuse. FYCOMPA® is a Schedule III drug (DEA Controlled Substance Code 2261), which means that the DEA has determined that (i) it has a potential for abuse less than the drugs or other substances in Schedules I and II, (ii) it has a currently accepted medical use in treatment in the U.S., and (iii) abuse may lead to moderate or low physical dependence or high psychological dependence.

Schedule III drugs are subject to certain DEA import volume limits and state regulations relating to manufacturing, storage, distribution and physician prescription procedures, including limitations on prescription refills. In addition, the third parties who perform our clinical and commercial manufacturing, distribution, and dispensing for FYCOMPA® are required to maintain necessary DEA registrations and state licenses. The DEA periodically inspects facilities for compliance with its rules and regulations.

The Hatch-Waxman Amendments

Orange Book Listing

In seeking approval for a drug through an NDA, applicants are required to list with the FDA each patent with claims covering the applicant’s product or approved methods of using the product. Upon approval of a drug, each of the patents listed in the application for the drug are then published in the FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations, commonly known as the Orange Book. Drugs listed in the Orange Book can, in turn, be cited by potential generic competitors in support of approval of an ANDA. An ANDA provides for marketing of a drug product that has the same active ingredients in the same strengths and dosage form as the listed drug and has been shown to be bioequivalent to the listed drug. Other than the requirement for bioequivalence testing, ANDA applicants are not required to conduct, or submit results of, pre-clinical or clinical tests to prove the safety or effectiveness of their drug product. Drugs approved in this way are commonly referred to as “generic equivalents” to the listed drug and can often be substituted by pharmacists under prescriptions written for the original listed drug.

The ANDA applicant is required to certify to the FDA concerning any patents listed for the approved product in the FDA’s Orange Book. Specifically, the applicant must certify that: (i) the required patent information has not been filed; (ii) the listed patent has expired; (iii) the listed patent has not expired but will expire on a particular date and approval is sought after patent expiration; or (iv) the listed patent is invalid or will not be infringed by the new product. The ANDA applicant may also elect to submit a section viii statement certifying that its proposed ANDA label does not contain (or carves out) any language regarding the patented method-of-use rather than certify to a listed method-of-use patent. If the applicant does not challenge the listed patents, the ANDA application will not be approved until all the listed patents claiming the referenced product have expired.

A certification that the new product will not infringe the already approved product’s listed patents, or that such patents are invalid, is called a Paragraph IV certification. If the ANDA applicant has provided a Paragraph IV certification to the FDA, the applicant must also send notice of the Paragraph IV certification to the NDA and patent holders once the ANDA has been accepted for filing by the FDA. The NDA and patent holders may then initiate a patent infringement lawsuit in response to the notice of the Paragraph IV certification. The filing of a patent infringement lawsuit within 45 days of the receipt of a Paragraph IV certification automatically prevents the FDA from approving the ANDA until the earlier of 30 months, expiration of the patent, settlement of the lawsuit, or a decision in the infringement case that is favorable to the ANDA applicant.

The ANDA application also will not be approved until any applicable non-patent exclusivity listed in the Orange Book for the referenced product has expired.

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Exclusivity

Upon NDA approval of a new chemical entity (NCE), which is a drug product that contains an active moiety that has never been approved by FDA in any other NDA, that drug receives five years of marketing exclusivity during which FDA cannot receive any ANDA seeking approval of a generic version of that drug. A drug may obtain a three-year period of exclusivity for a particular condition of approval, or change to a marketed product, such as a new formulation for the previously approved product, if one or more new clinical studies (other than bioavailability or bioequivalence studies) was essential to the approval of the application and was conducted/sponsored by the applicant. During this period of exclusivity, FDA cannot approve an ANDA for a generic drug that includes the change.

An ANDA may be submitted one year before NCE exclusivity expires if a Paragraph IV certification is filed. If there is no listed patent in the Orange Book, there cannot be a Paragraph IV certification, and, thus, no ANDA can be filed before the expiration of the exclusivity period.

Section 505(b)(2) NDAs

Most drug products obtain FDA marketing approval pursuant to an NDA or an ANDA. A third alternative is a special type of NDA, commonly referred to as a Section 505(b)(2), or 505(b)(2), NDA, which enables the applicant to rely, in part, on FDA’s previous approval of a similar product, or published literature, in support of its application.

505(b)(2) NDAs often provide an alternate path to FDA approval for new or improved formulations or new uses of previously approved products. Section 505(b)(2) permits the filing of an NDA where at least some of the information required for approval comes from studies not conducted by, or for, the applicant and for which the applicant has not obtained a right of reference. If the Section 505(b)(2) applicant can establish that reliance on FDA’s prior findings of safety and effectiveness or published literature is scientifically appropriate, it may eliminate the need to conduct certain pre-clinical or clinical studies of the new product.

The FDA may also require companies to perform additional studies or measurements to support the change from the approved product. The FDA may then approve the new product candidate for all, or some, of the label indications for which the referenced product has been approved, as well as for any new indication sought by the Section 505(b)(2) applicant.

To the extent that the Section 505(b)(2) applicant is relying on studies conducted on previously approved drug product, the Section 505(b)(2) applicant must submit patent certifications with respect to any patents for the approved product on which the application relies that are listed in the FDA’s publication, Approved Drug Products with Therapeutic Equivalence Evaluations, commonly referred to as the Orange Book. Specifically, the applicant must certify for each listed patent that either: (1) the required patent information has not been filed; or (2) the listed patent has expired; or (3) the listed patent has not expired but will expire on a particular date, and approval is not sought until after patent expiration; or (4) the listed patent is invalid, unenforceable or will not be infringed by the proposed new product. A certification that the new product will not infringe the previously approved product’s listed patent or that such patent is invalid or unenforceable is known as a Paragraph IV certification.

If the applicant does not challenge one or more listed patents through a Paragraph IV certification, the FDA will not approve the Section 505(b)(2) NDA application until all the listed patents claiming the referenced product have expired. Further, the FDA also will not approve, as applicable, a Section 505(b)(2) NDA application until any non-patent exclusivity has expired, for example: five-year exclusivity period for obtaining approval of an NCE; or three-year exclusivity period for an approval based on new clinical trials; or pediatric exclusivity, listed in the Orange Book for the referenced product.

A section 505(b)(2) NDA applicant must send notice of the Paragraph IV certification to the owner of the referenced NDA for the previously approved product and relevant patent holders within 20 days after the Section 505(b)(2) NDA has been accepted for filing by the FDA. If the relevant patent holder elects to initiate litigation, the Section 505(b)(2) applicant may invest a significant amount of time and expense in the development of its product, only to be subject to significant delay and patent litigation before its product may be commercialized. Alternatively, if the NDA applicant or relevant patent holder does not file a patent infringement lawsuit within the specified 45-day period, the FDA may approve the Section 505(b)(2) application at any time.

ANDAs

Generic drugs may enter the market after the approval of an ANDA. The ANDA development process typically does not require new pre-clinical or clinical studies, but it does typically require one or more bioequivalence studies to show that the ANDA drug is bioequivalent to the previously approved brand name reference listed drug. Bioequivalence studies compare the bioavailability of the proposed drug product with that of the approved listed product containing the same active ingredient. Bioavailability is a measure of the rate and extent to which the active ingredient or active moiety is absorbed from a drug product and becomes available at the site of action. A demonstration of bioequivalence means that the rate and extent of

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absorption of the ANDA drug is not significantly different from the rate and extent of absorption of the brand name reference listed drug when administered at the same molar dose under similar experimental conditions.

As noted above, generic drug products are generally introduced to the marketplace at the expiration of patent protection and non-patent market exclusivity for the reference listed drug. However, if an ANDA applicant is the first ANDA applicant to submit an ANDA containing a Paragraph IV certification, that ANDA may be eligible for a period of generic marketing exclusivity on approval. This exclusivity, which under certain circumstances must be shared with other ANDA applicants with Paragraph IV certifications, lasts for 180 days, during which the FDA cannot grant final approval to other ANDA sponsors of an application for a generic equivalent to the same reference drug. Under certain circumstances, eligibility for 180-day exclusivity may be forfeited.

Various types of changes to an approved ANDA must be requested in a prior approval supplement. In addition, some changes may only be approved after new bioequivalence studies are conducted or other requirements are satisfied. In addition, the ANDA applicant must demonstrate that manufacturing procedures and operations conform to FDA cGMP requirements. Facilities, procedures, operations, and/or testing of products are subject to periodic inspection by the FDA and other authorities. In addition, the FDA conducts pre-approval and post-approval reviews and inspections to determine whether the systems and processes are in compliance with cGMP and other FDA regulations.

There are also user fees for ANDA applicants, sponsors, and manufacturers. For fiscal year 2026, the application fees are $358,247per ANDA application and the facility fees are $238,943per domestic finished dosage form facility, $253,943per foreign finished dosage form facility, $43,549per domestic API facility, and $58,549per foreign API facility. In addition, there is a new annual program fee based on the size of the generic drug applicant. These user fees typically increase each fiscal year.

National Priority Vouchers

In June 2025, the FDA announced the creation of Commissioner's National Priority Voucher, a pilot program designed to accelerate the review of products with the potential to address one or more of what it refers to as "key national priorities": addressing a U.S. public health crisis, delivering more innovative cures for the American people, addressing a large unmet medical need, promoting domestic drug development and manufacturing to advance the health interests of Americans and strengthen U.S. supply chain resiliencies, and increasing the accessibility and affordability of drugs and biologics. Voucher recipients receive enhanced communications with review staff throughout the development process, and review decisions are targeted for completion within 1-2 months following submission of an application. The first vouchers were awarded in December 2025.

Other Regulatory Requirements

In addition to regulation by the FDA and certain state regulatory agencies, we are also subject to a variety of foreign regulations governing clinical trials and the marketing of other products. Outside of the U.S., our ability to market a product depends upon receiving a marketing authorization from the appropriate regulatory agencies. The requirements governing the conduct of clinical trials, marketing authorization, pricing and reimbursement vary widely from country to country. In any country, however, we will only be permitted to commercialize our products if the appropriate regulatory agency is satisfied that we have presented adequate evidence of safety, quality and efficacy. Whether or not FDA approval has been obtained, approval of a product by the comparable regulatory authorities of foreign countries must be obtained prior to the commencement of marketing of the product in those countries. The regulatory approval and oversight process in other countries includes all of the risks associated with regulation by the FDA and certain state regulatory agencies as described above.

Under the European Union regulatory system, applications for drug approval may be submitted either in a centralized or decentralized manner. Under the centralized procedure, a single application to the European Medicines Agency leads to an approval granted by the European Commission which permits marketing of the product throughout the European Union. The decentralized procedure provides for mutual recognition of nationally approved decisions and is used for products that do not comply with requirements for the centralized procedure. Under the decentralized procedure, the holders of national marketing authorization in one of the countries within the European Union may submit further applications to other countries within the European Union, who will be requested to recognize the original authorization based on an assessment report provided by the country in which marketing authorization is held.

Pharmaceutical pricing and reimbursement

In both the U.S. and foreign markets, our ability to commercialize our products successfully, and to attract commercialization partners for our products, depends in significant part on the availability of adequate financial coverage and reimbursement from third-party payors, including, in the U.S., governmental payors such as Medicare and Medicaid, managed care organizations, private commercial health insurers and PBMs. Third-party payors are increasingly challenging the prices charged for medicines and examining their cost effectiveness, in addition to their safety and efficacy. We may need to conduct expensive pharmacoeconomic or other studies in order to further demonstrate the value of our products. Even with the availability of such

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studies, our products may be considered less safe, less effective or less cost-effective than alternative products, and third-party payors may not provide coverage and reimbursement for our drug candidates, in whole or in part.

Political, economic and regulatory influences are subjecting the health care industry in the U.S. to fundamental changes. There have been, and we expect there will continue to be, legislative and regulatory proposals to change the healthcare system in ways that could significantly affect our business, including the Patient Protection and Affordable Care Act of 2010 (the Affordable Care Act), the Inflation Reduction Act of 2022 (IRA) and Most Favored Nation (MFN) pricing.

We anticipate that in the U.S., Congress, state legislatures, and private sector entities will continue to consider and may adopt healthcare policies intended to curb rising healthcare costs. These cost-containment measures could include:

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public transparency on qualifying price increases and/or discounting to better inform purchasers;

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additional controls on government-funded reimbursement for drugs;

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controls on healthcare providers;

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challenges to the pricing of drugs or limits or prohibitions on reimbursement for specific products through other means;

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reform of drug importation laws;

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entering into contractual agreements with payors; and

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expansion of use of managed-care systems in which healthcare providers contract to provide comprehensive healthcare for a fixed cost per person.

We are unable to predict what additional legislation, regulations or policies, if any, relating to the healthcare industry or third-party coverage and reimbursement may be enacted in the future or what effect such legislation, regulations or policies would have on our business. Any cost containment measures, including those listed above, or other healthcare system reforms that are adopted may have a material adverse effect on our business prospects.

Further, the pricing of pharmaceutical products generally, and particularly the pricing of orphan drugs, has received scrutiny from the press, and from members of Congress in both parties. Some members of the medical community and some politicians have also made statements in the press on the potential pricing of orphan drugs generally and on the pricing of our product specifically. The impact of this scrutiny on us and on the pricing of orphan drugs and other pharmaceutical products generally cannot be determined at this time.

Sales of pharmaceutical products depend in significant part on the availability of coverage and adequate reimbursement by third-party payors, such as state and federal governments, including Medicare and Medicaid, managed care providers, private commercial insurance plans and pharmacy benefit management (PBM) plans. There is significant uncertainty related to the insurance coverage and reimbursement of newly approved products. In the United States, the principal decisions about reimbursement for new products are typically made by the Centers for Medicare & Medicaid Services (CMS). Private payors tend to follow CMS to a substantial degree. However, no uniform or consistent policy of coverage and reimbursement for drug products exists among third-party payors. Therefore, coverage and reimbursement for drug products can differ significantly from payor to payor as well as from state to state. Consequently, the coverage determination process is often a time-consuming and costly process that must be played out across many jurisdictions and different entities. Further, a payor’s decision to provide coverage for a drug product does not imply that an adequate reimbursement rate will be approved. Particularly given the rarity of LEMS and DMD, our experience has been that securing coverage and appropriate reimbursement from third-party payors requires targeted education and highly skilled insurance navigation experts that have experience with rare disease launches and medical exception processes at insurance companies to provide patient coverage for important rare disease therapies. To that end, we have engaged a dedicated team of field-based market access account managers and reimbursement experts as well as a patient service center staffed with experienced personnel focused on ensuring that clinically-qualified patients have access to our products.

There can be no assurance, however, as to whether payors will continue to cover our products, and if so, at what level of reimbursement. In that regard, we have advised payors that we will provide free medication to support titration and confirm patient therapeutic benefit. Further, when necessary and in compliance with applicable laws, we provide patients with access to therapy at no charge while those patients are awaiting coverage decisions.

Orphan Drug Exclusivity

Some jurisdictions, including the U.S. and Europe, may designate drugs for relatively small patient populations as orphan drugs. Under the Orphan Drug Act of 1983 (ODA), the FDA may grant Orphan Drug Designation to drugs intended to treat a rare disease or condition that affects fewer than 200,000 individuals in the U.S., or more than 200,000 individuals in the U.S. and for which there is no reasonable expectation that the cost of developing and making available in the U.S. a drug for this

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type of disease or condition will be recovered from sales in the U.S. for that drug. In the U.S., Orphan Drug Designation must be requested before submitting an application for marketing approval. An Orphan Drug Designation does not shorten the duration of the regulatory review and approval process. The grant of an Orphan Drug Designation request does not alter the standard regulatory requirements and process for obtaining marketing approval. Safety and efficacy of a compound must be established through adequate and well-controlled studies. If a product which has been granted Orphan Drug Designation subsequently receives the first FDA approval for the indication or use for which it has such designation, the product is entitled to an orphan drug exclusivity period, which means the FDA may not approve any other application to market the same drug for the same indication or use for a period of seven years, except in limited circumstances, such as where an alternative product demonstrates clinical superiority to the product with orphan exclusivity. In addition, holders of exclusivity for orphan drugs are expected to assure the availability of sufficient quantities of their orphan drugs to meet the needs of patients. Failure to do so could result in the withdrawal of marketing exclusivity for the drug.

The orphan drug exclusivity contained in the ODA has been the subject of recent scrutiny from the press, from some members of Congress and from some in the medical community. There can be no assurance that the exclusivity granted in the ODA to orphan drugs approved by the FDA will not be modified in the future, and as to how any such change might affect our products, if approved.

The European Orphan Drug Regulation is considered for drugs intended to diagnose, prevent or treat a life-threatening or very serious condition afflicting five or fewer per 10,000 people in the EU, including compounds that for serious and chronic conditions would likely not be marketed without incentives due to low market return on the sponsor’s development investment. The medicinal product considered should be of significant benefit to those affected by the condition. Benefits of being granted Orphan Medicinal Product Designation are significant, including eight years of data exclusivity, two years of marketing exclusivity and a potential one-year extension of both. The EU Community and Member States may not accept or grant for ten years a new marketing authorization or application for another drug for the same therapeutic indication as the orphan drug, although the ten-year period can be reduced to six years if, after the end of the fifth year, available evidence establishes that the product is sufficiently profitable not to justify maintenance of the marketing exclusivity. A supplementary protection certificate may extend the protection six months beyond patent expiration if that is later than the orphan drug exclusivity period. To apply for the supplementary protection, a pediatric investigation plan, or PIP, must be included in the market application. In Europe all drugs now seeking marketing authorization need to have a PIP agreed with the European Medicines Agency (EMA) before it can be approved, even if it is a drug being developed specifically for a pediatric indication. If a product is developed solely for use in the pediatric population, then a Pediatric Use Marketing Authorization, or PUMA, may provide eight years of data exclusivity and ten years of marketing exclusivity.

Breakthrough Therapy Designation

Breakthrough therapy designation was introduced in an effort to encourage innovation and expedite the development and review of drugs for serious or life-threatening conditions. The criteria for breakthrough therapy designation are preliminary clinical evidence that demonstrates the drug may have substantial improvement on at least one clinically significant endpoint over available therapy. A breakthrough therapy designation conveys all of the fast-track program features (see below for more details on fast-track designation), as well as more intensive FDA guidance on an efficient drug development program. The FDA also has an organizational commitment to involve senior management in such guidance. Actions taken to expedite development may include the following actions, as appropriate holding meetings with the sponsor and review team throughout the development of the drug;

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providing timely advice to, and interactive communication with, the sponsor regarding the development of the drug to ensure that the development program to gather the non-clinical and clinical data necessary for approval is as efficient as possible;

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taking steps to ensure that the design of the clinical trials is as efficient as practicable, when scientifically appropriate, such as by minimizing the number of patients exposed to a potentially less efficacious treatment;

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assigning a cross-disciplinary project lead for the FDA review team to facilitate an efficient review of the development program and to serve as a scientific liaison between the cross-discipline members of the review team (i.e., clinical, pharmacology-toxicology, chemistry, manufacturing and control (CMC), compliance) for coordinated internal interactions and communications with the sponsor through the review division’s Regulatory Health Project Manager; and

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involving senior managers and experienced review staff, as appropriate, in a collaborative, cross-disciplinary review.

Pediatric Studies and Exclusivity

An NDA or supplement thereto must contain data that are adequate to assess the safety and effectiveness of the drug product for the claimed indications in all relevant pediatric subpopulations, and to support dosing and administration for each pediatric

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subpopulation for which the product is safe and effective. Additionally, sponsors must also submit pediatric study plans prior to the assessment data. Those plans must contain an outline of the proposed pediatric study or studies the applicant plans to conduct, including study objectives and design, any deferral or waiver requests, and other information. The applicant, the FDA, and the FDA’s internal review committee must then review the information submitted and agree upon a final plan. The FDA or the applicant may request an amendment to the plan at any time.

The FDA may, on its own initiative or at the request of the applicant, grant deferrals for submission of some or all pediatric data until after approval of the product for use in adults, or full or partial waivers from the pediatric data requirements.

CPRX US Equity

CPRX · 10-K · period ended 2025-12-31

Item 1. Business

CPRX US Equity☆

CPRX · 10-K · period ended 2025-12-31

Item 1. Business

CPRX US Equity