10-K
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 10-K
(Mark One)
For the fiscal year ended December 31, 2024
OR
Forthe transition period from ___________________ to ___________________
Commission File Number 001-42121
Rapport Therapeutics, Inc.
(Exact name of registrant as specified in its charter)
(Address of principal executive offices) (Zip code)
Registrant’s telephone number, including area code: (857) 321-8020
Securities registered pursuant to Section 12(b) of the Act:
Title of each class Tradingsymbol(s) Name of each exchange on which registered
Common Stock, $0.001 par value per share RAPP The Nasdaq Global Market
Securities registered pursuant to Section 12(g) of the Act: None
Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. YES ☐No☒
Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 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, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth 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 provided 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 ☒
The aggregate market value of the voting and non-voting common equity held by non-affiliates of the registrant, based on the closing price of the shares of common stock on the Nasdaq Global Market on June 28, 2024 was $474,516,072.
The number of shares of registrant’s common stock outstanding as of March 1, 2025 was36,496,437.
DOCUMENTS INCORPORATED BY REFERENCE
Portions of the registrant’s definitive proxy statement for its 2025 Annual Meeting of Stockholders to be filed pursuant to Regulation 14A within 120 days of the end of the registrant’s fiscal year ended December 31, 2024 are incorporated by reference into Part III of this Annual Report on Form 10-K to the extent stated herein.
Table of Contents
Page
PART I
Item 1. Business 5
Item 1A. Risk Factors 46
Item 1B. Unresolved Staff Comments 100
Item 1C. Cybersecurity 100
Item 2. Properties 100
Item 3. Legal Proceedings 101
Item 4. Mine Safety Disclosures 101
PART II
Item 6. [Reserved] 102
Item 7A. Quantitative and Qualitative Disclosures About Market Risk 117
Item 8. Financial Statements and Supplementary Data 118
Item 9A. Controls and Procedures 150
Item 9B. Other Information 150
Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections 151
PART III
Item 10. Directors, Executive Officers and Corporate Governance 151
Item 11. Executive Compensation 151
Item 14. Principal Accounting Fees and Services 151
PART IV
Item 15. Exhibits and Financial Statement Schedules 152
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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS
This Annual Report on Form 10-K (this “Annual Report”) contains forward-looking statements. We intend such forward-looking statements to be covered by the safe harbor provisions for forward-looking statements contained in Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). All statements other than statements of historical facts, including statements regarding our future results of operations and financial position, business strategy, product candidates, planned preclinical studies and clinical trials, results of preclinical studies, clinical trials, research and development costs, regulatory approvals, commercial strategy, timing and likelihood of success, as well as plans and objectives of management for future operations, are forward-looking statements. These statements involve known and unknown risks, uncertainties, and other important factors that are in some cases beyond our control and may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements.
In some cases, forward-looking statements can be identified by terms such as “may,” “will,” “should,” “would,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “believe,” “estimate,” “predict,” “potential,” or “continue” or the negative of these terms or other similar expressions. Forward-looking statements contained in this Annual Report may include, but are not limited to, statements about:
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our ability to identify, develop, and commercialize current and future product candidates based on our RAP technology platform;
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the initiation, timing, progress, and results of our research and development programs, preclinical studies and clinical trials, including our ability to resolve the U.S. Food and Drug Administration’s clinical hold on our Phase 2a proof-of-concept trial of RAP-219 for the treatment of diabetic peripheral neuropathic pain;
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the translation of endpoints in our current and planned clinical trials to future registrational trials;
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our ability to replicate positive results from earlier preclinical studies or clinical trials conducted by us or third parties in current or future clinical trials;
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our ability to demonstrate that our current and future product candidates are safe and effective for their proposed indications;
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the number of patients with the diseases or disorders we elect to pursue with our product candidates, and the willingness of those patient populations to use and adhere to our product candidates if approved in the future;
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the implementation of our business model, and strategic plans for our business, programs, future product candidates, platform, and technology;
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our ability to advance any product candidates through applicable regulatory approval processes;
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our ability to obtain additional cash and the sufficiency of our existing cash, cash equivalents and short-term investments to fund our future operating expenses and capital expenditure requirements;
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the accuracy of our estimates regarding expenses, future revenue, capital requirements, and needs for additional financing;
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our ability to comply with our obligations under our intellectual property licenses with third parties, including Janssen Pharmaceutical NV;
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our ability to maintain, expand and protect our intellectual property portfolio;
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developments relating to our competitors and our industry;
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existing regulations and regulatory developments in the United States and other jurisdictions;
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our ability to identify and enter into future license agreements and collaborations;
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general economic, industry, and market conditions, including rising interest rates and inflation;
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our ability to attract, hire, and retain our key personnel and additional qualified personnel; and
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our anticipated use of our existing cash, cash equivalents and short-term investments.
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We have based these forward-looking statements largely on our current expectations and projections about our business, the industry in which we operate and financial trends that we believe may affect our business, financial condition, results of operations and prospects, and these forward-looking statements are not guarantees of future performance or development. These forward-looking statements speak only as of the date of this Annual Report and are subject to a number of risks, uncertainties and assumptions described in the section titled “Risk Factors” and elsewhere in this Annual Report. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified, you should not rely on these forward-looking statements as predictions of future events. The events and circumstances reflected in our forward-looking statements may not be achieved or occur and actual results could differ materially from those projected in the forward-looking statements. Except as required by applicable law, we do not plan to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events or otherwise.
You should read this Annual Report, the documents that we reference in this Annual Report and the other documents that we file with the Securities and Exchange Commission (“SEC”) with the understanding that our actual future results, levels of activity, performance and events and circumstances may be materially different from what we expect.
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SUMMARY RISK FACTORS
Our business is subject to numerous risks and uncertainties, which include, but are not limited to, the following:
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We are a clinical-stage biotechnology company with a limited operating history, which may make it difficult to evaluate our current business and predict our future success and viability. We have incurred significant financial losses since our inception and anticipate that we will continue to incur significant financial losses for the foreseeable future.
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We will require additional funding in order to finance operations. If we are unable to raise capital when needed, or on acceptable terms, we could be forced to delay, reduce or eliminate our product development programs or commercialization efforts.
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Our business is highly dependent on the success of our product candidates, particularly RAP-219 for focal epilepsy. If we are unable to successfully complete clinical development, obtain regulatory approval for or commercialize one or more of our product candidates, or if we experience delays in doing so, our business will be materially harmed.
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The successful development of pharmaceutical products involves a lengthy and expensive process and is highly uncertain.
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Due to the significant resources required for the development of our pipeline, and depending on our ability to access capital, we must prioritize the development of certain product candidates over others. Moreover, we may fail to expend our limited resources on product candidates or indications that may have been more profitable or for which there is a greater likelihood of success.
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The regulatory approval processes of the Food and Drug Administration (“FDA”), European Medicines Agency (“EMA”), Medicines and Healthcare products Regulatory Agency (“MHRA”) and other comparable regulatory authorities are lengthy, time-consuming and inherently unpredictable, and if we are ultimately unable to obtain regulatory approval for our product candidates, our business will be substantially harmed.
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We are dependent on a third party having accurately generated, collected, interpreted and reported data from certain preclinical studies and clinical trials that were previously conducted for our product candidates.
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If our clinical trials fail to replicate positive results from earlier preclinical studies or clinical trials conducted by us or third parties, we may be unable to successfully develop, obtain regulatory approval for or commercialize our product candidates.
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If we do not achieve our projected development and commercialization goals in the timeframes we announce and expect, the development and commercialization of our product candidates may be delayed, and our business and results of operations may be harmed.
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Our product candidates may cause undesirable side effects or have other properties that could delay or prevent their regulatory approval, limit the commercial profile of an approved label, or result in significant negative consequences following regulatory approval, if obtained.
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We have concentrated our research and development efforts on the treatment of disorders of the nervous system, a field that faces certain challenges in drug development.
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Even if any of our product candidates receives regulatory approval, it may fail to achieve the degree of market acceptance by physicians, patients, third-party payors and others in the medical community necessary for commercial success, in which case we may not generate significant revenues or become profitable.
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The number of patients with the diseases and disorders for which we are developing our product candidates has not been established with precision. If the actual number of patients with the diseases or disorders we elect to pursue with our product candidates is smaller than we anticipate, we may have difficulties in enrolling patients in our clinical trials, which may delay or prevent development of our product candidates. Even if such product candidates are successfully developed and approved, the markets for our product candidates may be smaller than we expect and our revenue potential and ability to achieve profitability may be materially adversely affected.
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We rely on third parties to assist in conducting our clinical trials. If they do not perform satisfactorily, we may not be able to obtain regulatory approval or commercialize our product candidates, or such approval or commercialization may be delayed, and our business could be substantially harmed.
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We depend on in-licensed intellectual property. If we fail to comply with our obligations under our intellectual property licenses with third parties, we could lose license rights that are important to our business.
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If we or our licensors are unable to obtain and maintain patent protection for our product candidates, or if the scope of the patent protection obtained is not sufficiently broad, our competitors could develop and commercialize products similar or identical to our product candidates and our ability to successfully commercialize our product candidates may be adversely affected.
The summary risk factors described above should be read together with the text of the full risk factors in the section titled “Risk Factors” and the other information set forth in this Annual Report, as well as in other documents that we file with the SEC. The risks summarized above or described in full elsewhere in this Annual Report are not the only risks that we face. Additional risks and uncertainties not presently known to us, or that we currently deem to be immaterial may also materially adversely affect our business, financial condition, results of operations, and future, growth prospects.
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PART I
Item 1. Business
Overview
We are a clinical-stage biotechnology company dedicated to discovering and developing small molecule precision medicines for patients with neurological or psychiatric disorders. Our foundational science has elucidated complexities of neuronal receptor biology and enables us to map and target certain neuronal receptor complexes. Neuronal receptors are complex assemblies of proteins, comprising receptor principal subunits and their receptor associated proteins (“RAPs”), the latter of which play crucial roles in regulating receptor expression and function. We believe that our deep expertise in RAP biology provides an opportunity for us to interrogate previously inaccessible targets and develop neurological and psychiatric drugs that are specific for receptor variants and neuroanatomical regions associated with certain diseases. Most neuroactive drugs lack this specificity, often resulting in undesired and intolerable side effects. Leveraging our expertise, we are developing a portfolio of precision product candidates that we believe has the potential to transform the standard of care of many neurological and psychiatric disorders.
Our founders have made pioneering discoveries related to the function of RAPs in the brain. Their findings form the basis of our RAP technology platform, which enables a differentiated approach to generate precision small molecule product candidates with the potential to overcome many limitations of conventional neurology drug discovery. RAP-219, our most advanced product candidate, is an AMPA receptor (“AMPAR”) negative allosteric modulator (“NAM”). RAP-219 is designed to achieve neuroanatomical specificity through its selective targeting of a RAP known as TARP8, which is associated with the neuronal AMPARs. Whereas AMPARs are distributed widely in the central nervous system (“CNS”), TARP8 is expressed only in discrete regions, including the hippocampus and neocortex, where focal seizures often originate. By contrast, TARP8 has minimal expression in the hindbrain, where drug effects are often associated with adverse events. As such, we believe RAP-219 has the potential for a differentiated profile as compared to traditional neuroscience medications. Due to the role of AMPA biology in various neurological disorders and our precision approach of selectively targeting TARP8, we believe RAP-219 has pipeline-in-a-product potential and we are evaluating it as a potentially transformational treatment for patients with focal epilepsy, bipolar disorder, and peripheral neuropathic pain.
A total of four Phase 1 trials in RAP-219 have been conducted to date in healthy adult volunteers: a single ascending dose (“SAD”) trial; a multiple ascending dose (“MAD”) trial; a second MAD trial (“MAD-2”), to assess dosing regimens that may accelerate time to reach therapeutic exposure; and a human positron emission tomography (“PET”) trial, which utilized a companion PET radiotracer to confirm brain target receptor occupancy and brain region specificity across a range of dosing and exposure levels. In January 2025, we announced results from our PET and MAD-2 trials of RAP-219. Data demonstrated that neuroanatomical specificity can be achieved through RAP-219’s selective targeting of TARPγ8. In Cohort 1 of the human PET trial, which used the dosing regimen utilized in our ongoing Phase 2a trial in patients with refractory focal epilepsy,RAP-219 achieved target receptor occupancy associated with maximal seizure protection in preclinical models within five days and was generally well tolerated, which we believe further supports the use of such dosing regimen in the Phase 2a trial.
We are currently conducting a Phase 2a proof-of-concept trial in adult patients with refractory focal epilepsy, for which we expect to report topline results in the third quarter of 2025. We believe RAP-219 also has therapeutic potential in bipolar disorder and peripheral neuropathic pain, and we intend to initiate a Phase 2a proof-of-concept trial in bipolar mania in the third quarter of 2025 with topline results expected in the first half of 2027. We were notified in the fourth quarter of 2024 by the U.S. Food and Drug Administration (“FDA”) that the Investigational New Drug (“IND”) submitted for the initiation of a Phase 2a proof-of-concept trial of RAP-219 for the treatment of diabetic peripheral neuropathic pain (“DPNP”) was placed on clinical hold. The FDA requested additional information and amendments specific to the protocol design. The clinical hold is specific to the IND for DPNP and has not impacted our ongoing Phase 2a trial in refractory focal epilepsy or planned proof-of-concept trial in bipolar mania. We believe in our ability to advance the clinical development of RAP-219 for DPNP and will provide an update on the anticipated timing of the Phase 2a trial initiation once available.
We have also identified another TARPγ8 targeted molecule with differentiated chemical and pharmacokinetic properties, RAP-199. However, with growing confidence in RAP-219 and a commitment to disciplined capital allocation, we are deferring further investment in RAP-199 and focusing our resources on execution of our three RAP-219 proof-of-concept clinical trials.
Beyond TARP8, we have two advanced discovery-stage nicotinic acetylcholine receptor (“nAChR”) programs stemming from our RAP technology platform. The first comprises modulators of 6 nAChRs that we are developing in chronic pain; and the second comprises modulators of 910 nAChRs that we are developing in hearing disorders. Third-party genetic data suggest that these nAChR subtypes could be attractive drug targets for these diseases. We continue to leverage our RAP technology platform to
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discover additional product candidates that we believe have the potential to provide a transformative benefit for large patient populations with neurological or psychiatric diseases with unmet needs.
Our Pipeline
Our current portfolio of programs from our RAP technology platform is summarized in the pipeline chart below:
* We have conducted four Phase 1 trials in healthy adult volunteers supportive of multiple RAP-219 indications.
Introduction to RAP-219
RAP-219 is an investigational small molecule that is designed to inhibit TARP8-containing AMPARs with picomolar (“pM”) affinity, which implies tight binding. Given RAP-219’s mechanism of action, neuroanatomical specificity and target potency observed to date in preclinical studies, we believe it has the potential to be a differentiated therapy for focal epilepsy and other neurological and psychiatric disorders, including bipolar disorder and peripheral neuropathic pain.
Epilepsy is estimated to affect 50 million people worldwide, including approximately 3.0 million adults in the United States (“United States” or “U.S.”). In 2022, the total branded market for epilepsy was approximately $2.8 billion, and this is expected to grow to approximately $3.6 billion by 2028. There are an estimated 1.8 million people in the United States who suffer from focal epilepsy, accounting for approximately 60 percent of patients with epilepsy. Focal epilepsy is characterized by seizures caused by intermittent abnormal electrical activity originating in specific areas of the brain. The hippocampus, located within the temporal lobe, is commonly associated with focal epilepsy, with approximately 50 percent of all seizures originating in or around this area. The cerebral cortex is another common site of focal onset seizure initiation, originating up to 50 percent of all seizures. However, the hippocampus often plays a role in these seizures as well, with the abnormal electrical brain activity that arises in the cerebral cortex often traveling to and being perpetuated by the hippocampus.
Epilepsy has profound negative impacts on a patient’s quality of life, including limitations on social engagement, physical activity and independence. Recent studies have also found that epilepsy can result in cognitive impairment. The treatment goal for all patients with epilepsy, including focal epilepsy, is complete freedom from seizures. Despite there being more than 20 antiseizure medications (“ASMs”) approved by the FDA, 30 to 40 percent of patients with epilepsy continue to experience recurring seizures despite taking two or more ASMs. This is termed “refractory epilepsy.” In addition to providing sub-optimal efficacy, ASMs are commonly associated with risks of intolerable and debilitating adverse events (“AEs”). These side effects, such as cognitive impairment, sedation, ataxia and dizziness, are believed to result from drug actions in brain regions unrelated to epilepsy. These AEs often lead to dosing adjustments and patient nonadherence, both of which can limit efficacy. We believe tolerability, adherence and clinical benefit can be improved with RAP-219, an investigational therapy that is designed to precisely modulate only diseased brain regions.
Patients with epilepsy commonly take ASM combinations, which is referred to as polypharmacy. Drug-drug interactions make polypharmacy complex and add a further challenge to managing persistent seizures in epilepsy. When a physician adds a drug to a patient’s regimen, they typically prioritize one with a differentiated mechanism of action, an approach referred to as rational
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polypharmacy. Therefore, there is a critical need for therapies with new mechanisms of action, fewer AEs and a mitigated risk of drug-drug interaction for the treatment of focal epilepsy.
AMPAR inhibition is a clinically validated approach in treating epilepsy, with perampanel (marketed as FYCOMPA) approved by the FDA in 2012 for both focal and generalized epilepsy. Whereas perampanel binds to AMPARs throughout the CNS and periphery, RAP-219’s actions on AMPARs are restricted to those few specific regions where TARP8 is expressed, most notably the hippocampus. This leads us to believe that the tolerability profile of RAP-219 could be significantly differentiated from that of perampanel and other currently available ASMs.
TARP8 is expressed in specific brain regions, being most enriched in the hippocampus and other forebrain structures that are key sites associated with focal onset seizures. As brain regions with TAPR8 expression closely overlay with the brain sites most often involved with the pathophysiology of focal epilepsy, we believe that RAP-219 has potential to provide a differentiated profile. Furthermore, TARP8 expression is enriched in the hippocampus, amygdala, and cerebral cortex and has minimal expression in certain other areas that are critical for normal brain functions, including the cerebellum and brainstem. In contrast to the precision mechanism of RAP-219, the majority of ASMs, including perampanel, bind their target receptors throughout the brain, and we believe this lack of anatomical specificity may contribute to their side effect profiles. We believe that RAP-219, as compared to currently available ASMs, has the potential to have a greater therapeutic index, meaning a wider range of doses at which it is likely to be effective without causing unacceptable AEs. If RAP-219 is approved, this could have important clinical utility for the management of focal epilepsy.
We observed RAP-219 to be generally well tolerated in the four phase 1 trials evaluating RAP-219 in healthy adult volunteers we have conducted to date. The plasma concentrations of RAP-219 measured during those trials suggested that once-daily oral administration with a simple dosing schedule could achieve our targeted therapeutic exposures (3 ng/mL to 7 ng/mL). For our ongoing Phase 2a proof-of-concept trial, we are enrolling adult patients with refractory focal epilepsy who have an implanted responsive neurostimulation (“RNS”) system, an FDA approved device for refractory focal onset epilepsy. The RNS system includes an electrode that continually monitors intracranial brain waves and detects the magnitude, duration and frequency of spectrographic activity, which are recorded as intracranial electroencephalography (“iEEG”) data. We are using these iEEG data as the biomarker-based primary endpoint in our proof-of-concept trial. We believe these data could be translatable to a clinical seizure endpoint in future registrational trials. We expect to release topline results from this Phase 2a proof-of-concept trial in refractory focal epilepsy in the third quarter of 2025.
Introduction to Our Discovery-Stage Nicotinic Acetylcholine Receptor Programs
In addition to RAP-219, we have two discovery-stage programs stemming from our RAP technology platform. Our 6 nAChR and 910 nAChR programs were both enabled by our discovery of RAPs that drive the assembly of functional versions of these receptors in cell lines. Based on third-party genetic data, we believe each of these nAChR subtypes could be attractive drug targets. However, it was not until our identification of these RAPs that it became possible to create cell lines for in vitro compound screening and optimization against these important targets.
We are pursuing agonists and positive allosteric modulators (“PAMs”) of the 6 nAChR in chronic pain. Gain-of-function variants in the gene encoding the 6 subunit can attenuate pain levels. A previous third-party investigational pan-nAChR agonist demonstrated clinical activity in a randomized placebo controlled study in painful diabetic neuropathy but this experimental therapeutic was associated with intolerable side effects, which led to the discontinuation of its development. We believe that these side effects were primarily due to the non-selective nature of that agonist. Through our ability to functionally express and pharmacologically screen for 6 nAChR modulators, we have identified small molecule agonists and PAMs that showed 6 nAChR selectivity as well as beneficial activity in a preclinical model of peripheral neuropathic pain. We are optimizing these molecules in anticipation of selecting candidates to advance into the clinic.
Our 910 nAChR program focuses on the discovery of small molecule modulators of this receptor as potential therapies for hearing disorders. Third-party studies observed a loss-of-function mutation of the gene for the 9 subunit in mice associated with increased sensitivity to noise-induced hearing loss. Conversely, we observed a gain-in-function mutation in 9 protected against hearing loss. We have identified small molecule modulators of 910 nAChR and are now optimizing these molecules in anticipation of selecting candidates to advance into the clinic.
Our Company’s History and Our Team
Rapport was formed in February 2022, with founding support from Third Rock Ventures and Johnson & Johnson Innovation-JJDC, to advance the discovery and development of RAP-targeted precision neuromedicines. Our scientific founder and Chief
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Scientific Officer, David Bredt, M.D., Ph.D., pioneered the discovery of RAPs and their targeting by small molecules at Janssen Pharmaceutical NV (“Janssen”).
In August 2022, we entered into a license agreement with Janssen (the “Janssen License”) for the research, development and commercialization of certain TARP8 products, including RAP-219 and nAChR projects created by Dr. Bredt and his colleagues at Janssen. We are furthering development of these assets and extending discovery efforts into novel areas. Under the terms of the Janssen License, certain TARP8 and nAChR patents, materials and know-how were transferred to us. All discovery and development efforts related to our pipeline programs are herein referred to as “ours,” although some of these preclinical efforts were completed at Janssen prior to the Janssen License. In many cases, these efforts were made by certain of the same personnel who have since joined Rapport.
In addition to Dr. Bredt, we have a seasoned leadership team with deep expertise in building novel therapeutic platforms, bringing therapeutics to market and supporting the growth of public biopharmaceutical and biotechnology companies, such as Abraham N. Ceesay, M.B.A., our Chief Executive Officer and a member of our board of directors, Troy Ignelzi, our Chief Financial Officer, Jeffrey Sevigny, M.D., our Chief Medical Officer, Cheryl Gault, our Chief Operating Officer, Swamy Yeleswaram, Ph.D., our Chief Development Officer, Kathy Wilkinson, our Chief People Officer and Karina Chmielewski, our Chief Information Officer.
Our Strategy
Leveraging our RAP technology platform, we strive to become a leader in precision neuroscience through the discovery and development of transformational small molecule medicines for patients with neurological or psychiatric disorders. As key elements of our strategy, we intend to:
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Advance RAP-219 clinical development in focal epilepsy. RAP-219 is designed as a highly potent and selective NAM of TARP8-AMPAR which has demonstrated antiseizure activity in preclinical epilepsy models without evidence of motoric impairment or sedation characteristic of many approved ASMs.
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Expand the potential of RAP-219 in additional neurological and psychiatric indications. We believe that RAP-219’s ability to precisely modulate the activity of AMPARs within specific CNS regions, provides the potential for clinical applications in neurological indications beyond focal epilepsy.
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Extend the life cycle of RAP-219 and expand the TARP8 franchise. We are exploring a long- acting injectable formulation of RAP-219, which we believe will expand the potential clinical utility across RAP-219’s indications and potentially extend the molecule’s lifecycle.
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Advance development of our RAP-enabled nAChR programs. Our RAP platform has enabled identification of small molecules specific for nAChR drug targets we find compelling. We believe that our 6 nAChR program may deliver clinical benefits in chronic pain while avoiding the AEs associated with non-selective nAChR agonists. We believe that compounds specific to the 910 receptor could provide therapeutic benefit in hearing disorders. We are optimizing molecules for both programs, in anticipation of selecting lead candidates to advance into the clinic.
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Fortify our leadership position in RAP-enabled drug discovery to expand our pipeline of transformative precision neuroscience therapies for patients. We believe the science underpinning our RAP technology platform can serve as the foundation for a broad portfolio of precision neuroscience product candidates that have the potential to transform the current treatment armamentarium for many neurological and psychiatric disorders. We are committed to leveraging our expertise in RAP biology to develop a portfolio of small molecule therapies to deliver potentially more effective, better tolerated and safer treatments to large and underserved neurological and psychiatric patient populations.
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Pursue strategic partnerships opportunistically. We currently have exclusive global rights to use our technology platform and to commercialize our product candidates. If we believe that partnerships can accelerate the development or maximize the market potential of our product candidates, we will consider entering into product, target and/or geographic specific strategic partnerships on an opportunistic basis.
Our RAP Technology Platform
Our founders are pioneers of RAP biology who have made key discoveries related to RAP function. Their findings form the basis of our RAP technology platform, which can potentially provide a differentiated approach to generate precision small molecule product candidates.
Due to the complexities of studying drug activity in the brain, a standard approach to discovery and optimization of neurology drugs is through in vitro cellular assays involving recombinant receptors. This approach often fails to replicate the function of
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relevant targets in their natural contexts and has resulted in the approval of neurology drugs that are not designed to be selective for specific forms of their targets, which can contribute to unwanted toxicities and limit therapeutic indexes.
We believe that leveraging RAPs can overcome many limitations of conventional neurology drug discovery. RAPs have defining characteristics that we believe make them ideal tools in the development of precision neuromedicines. First, because RAPs play critical roles in modulating receptor assembly and function, understanding RAP biology provides powerful insights into neuronal signaling. Second, because RAPs can be differentially expressed in specific brain regions, we believe they can serve as drug targets with neuroanatomical specificity.
Using two distinct strategies, we are leveraging our expertise in RAP biology to develop a portfolio of precision neuroscience product candidates that we believe will transform the treatment of many neurological and psychiatric disorders. One strategy uses a RAP as a direct target, which can be more precise than drugging a receptor itself. RAP-219 exemplifies this, as it has been shown in preclinical studies to bind to an AMPA RAP, TARP8, which is enriched in brain regions that initiate or perpetuate seizures in focal epilepsy.
A second strategy uses RAPs to “unlock” receptors for potentially first-in-class drug discovery programs. Many receptors cannot function without their RAPs, and such receptors have therefore been inaccessible to study in vitro. Our discovery platform integrates cutting-edge genetics with functional proteomics to discover RAPs that are regionally localized and involved in disease-related signaling. We have designed our platform to prosecute a wide range of validated therapeutic targets. This second strategy enabled our discovery stage nAChR programs, which focus on 6 and 910.
RAP-219, Our TARP8 Specific Product Candidate
Ionotropic receptors for glutamate (“iGluR”) are ligand gated ion channels activated by the neurotransmitter glutamate. These receptors mediate most excitatory synaptic transmission throughout the CNS. iGluRs comprise four subtypes based on their ligand binding properties: AMPARs, kainate receptors, N-methyl-D-aspartate (“NMDA”) receptors and delta receptors. The glutamate signaling pathway is targeted by FDA approved drugs for indications such as epilepsy, schizophrenia, Alzheimer’s disease and Parkinson’s disease. However, these medicines are associated with numerous side effects, such as sedation, ataxia, cognitive impairment and neuropsychiatric symptoms. These undesired effects may be exacerbated by the impact of these drugs on glutamate receptors throughout the brain.
AMPARs are cation, or positively charged ion, channels that open to permit the influx of sodium ions (Na+) to depolarize postsynaptic membranes. Our lead asset, RAP-219, is an investigational small molecule designed to potently and specifically inhibit TARP8-containing AMPARs. Because TARP8 expression is restricted to specific brain regions such as the hippocampus, which are often involved in focal epilepsies, we believe RAP-219 has the potential to provide a differentiated clinical profile, including improved activity and tolerability. In preclinical epilepsy models, RAP-219 reduced seizures without inducing sedation or motoric impairment, which are side effects that plague most existing ASMs. Owing to pharmacology studies in animal models as well as expression of TARP8 in spinal cord and limbic system, we believe RAP-219 may treat bipolar disorder and peripheral neuropathic pain. The initial formulation of RAP-219 is planned to be a once-per-day oral tablet. We are also developing a long-acting injectable formulation for once a month or even less frequent dosing, which we believe will result in better compliance and patient outcomes.
Background to Focal Epilepsy
Epilepsy is a chronic neurological disorder characterized by spontaneous recurrence of sudden abnormal bursts of brain electrical activity that disrupt brain function and cause seizures. Epilepsy is estimated to affect 50 million people worldwide including 3.0 million adults in the United States. Epilepsy is the third most common neurological disorder, with almost 10 percent of people experiencing a seizure during their lives. The annual direct costs, including outpatient, inpatient, emergency care and treatment costs, of epilepsy in the United States are estimated to be $28 billion.
Epilepsy can be divided into subgroups defined by the types of seizures that occur:
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Generalized epilepsy is characterized by seizures affecting broad areas of the brain. The most severe type is known as tonic-clonic seizures, which involve sudden loss of consciousness, body stiffening, twitching and shaking. In other cases, these patients can experience subsets of these symptoms. Generalized seizures account for 40 percent of all epilepsies.
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Focal epilepsy is characterized by seizures affecting more restricted areas of the brain. Focal epilepsy, which sometimes results in loss of consciousness or awareness, can lead to changes in the way things look, smell, feel, taste or sound. These seizures may be accompanied by involuntary jerking of a body part or by repetitive movements such as hand
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rubbing, chewing, or swallowing. Focal epilepsies account for 60 percent of all epilepsies. Figure 1 below illustrates the prevalence of focal epilepsy in the United States.
Figure 1. The prevalence of focal epilepsy in the United States is estimated to be 1.8 million patients.
The unpredictable nature of epilepsy has a profound negative impact on patient quality of life. Patients often limit their social engagement and physical activity for fear of seizures. Epilepsy also limits patients’ ability to function independently. For instance, in some U.S. states, individuals with epilepsy are required to have a record of being seizure-free for 3 to 12 months in order to drive. Epilepsy is often associated with depression, anxiety and psychosis and doubles the incidence of mental health disorders. Furthermore, epilepsy also presents serious mortality risk with approximately one percent of patients suffering sudden unexpected death in epilepsy (“SUDEP”). Having uncontrolled seizures increases the risk of SUDEP. Both treatment and indirect costs for individuals with uncontrolled epilepsy are significantly higher than for those with stable epilepsy.
Current Standard of Care and Limitations
Treatment strategies for focal epilepsy can include both medical and surgical options, which strive to achieve seizure control with minimal AEs. Although there are over 20 FDA approved ASMs, 30 to 40 percent of patients have refractory epilepsy and continue to experience uncontrolled seizures despite taking two or more ASMs. First-line treatment for focal epilepsy is monotherapy, prescribing one ASM which is selected based on a patient’s seizure type, medical history and their physician’s experience with a drug’s efficacy, tolerability and convenience.
Approved ASMs have many mechanisms of action, and most work by either inhibiting neuronal excitation or augmenting neuronal inhibition. Some ASMs blunt excitation by inhibiting voltage sensitive sodium or calcium channels or by blocking excitatory AMPA or NMDA receptors. Alternatively, some ASMs augment inhibition by enhancing -aminobutyric acid type A (“GABAA”) receptors or voltage-gated potassium channels. In addition, there are some ASMs for which the precise mechanism of action is not known and some which engage multiple targets. Most ASMs bind to targets expressed throughout the brain, and we believe this broad pharmacology can drive their side effects.
If a single ASM fails to prevent seizures, physicians often prescribe a different ASM or begin polypharmacy. When a prescribing physician decides which ASM to add to a refractory patient’s drug regimen, one important factor is the desire to add a new ASM with a different mechanism of action from those ASMs the patient is already taking. The process of polypharmacy involves trial and error which can elevate risk of AEs and drug-drug interactions. Tolerability issues can lead patients to take suboptimal doses to minimize side effects or can lead to treatment discontinuation, which occurs in 30 to 40 percent of patients. AEs commonly reported with ASMs include systemic effects such as nausea and vomiting, neurologic effects such as sedation, cognitive effects, ataxia and dizziness. In addition, some ASMs are associated with severe medical safety risks, for example, rare idiosyncratic reactions such as the life- threatening multi-organ hypersensitivity reaction known as Drug Rash with Eosinophilia and Systemic Symptoms (DRESS), serious skin reactions such as Stevens-Johnson syndrome and toxic epidermal necrolysis, bone marrow suppression, significant liver and kidney abnormalities, and cardiac arrhythmias.
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Antiseizure Therapy Through Modulation of Glutamate Signaling
Glutamate is the major excitatory neurotransmitter in the brain. Glutamate releases from presynaptic nerve terminals and the activation of postsynaptic receptors are critical for neurotransmission. Correspondingly, processes associated with glutamate release and its downstream signaling are highly regulated. Elevation in extracellular glutamate levels can lead to seizures, and many ASMs target this pathway.
ASMs can blunt glutamate-dependent signaling through diverse mechanisms. Drugs such as phenytoin, carbamazepine, lamotrigine and lacosamide molecule voltage-gated sodium channels and inhibit action potentials from reaching the glutamate release machinery within the presynaptic nerve terminal. Other drugs such as ethosuximide and ezogabine modulate voltage-gated calcium and potassium channels, respectively, which also can prevent the presynaptic release of glutamate. Figure 2 below shows the mechanisms of currently approved ASMs, including many that modulate glutamate signaling.
Source: Created with Biorender.com. Bialer M, White HS. (2010). Key factors in the discovery and development of new antiepileptic drugs. Nature Reviews Drug Discovery, 9(1):68–82. doi: 10.1038/nrd2997. Löscher W, Klein P. (2021). The Pharmacology and Clinical Efficacy of Antiseizure Medications: From Bromide Salts to Cenobamate and Beyond. CNS Drugs (2021) 35:935 -963. doi: 10.1007/s40263-021-00827- 8.
Figure 2. Mechanistic cartography of currently approved ASMs acting on the excitatory synapse (Left) and the inhibitor synapse (Right).
After being released into the synaptic cleft, glutamate can bind to AMPARs on postsynaptic neurons. This process permeates sodium and other cations, triggering a series of events that can ultimately lead to the generation of an action potential and the propagation of neuronal signals. Perampanel directly blocks the gating of all AMPARs, while other drugs, such as phenobarbital and tiagabine, oppose glutamate signaling by increasing the activity of inhibitory synaptic signaling driven by the GABAA receptors. Figure 2 above shows the mechanistic cartography of existing ASMs, including many that modulate glutamate signaling in the excitatory synapse.
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Validation of AMPAR as a Target in Epilepsy
Perampanel, developed by Eisai Co. Ltd. and currently marketed as FYCOMPA by Catalyst Pharmaceuticals, Inc., is an FDA approved ASM that directly antagonizes all AMPARs throughout the brain. In three clinical trials of patients with refractory focal epilepsy, perampanel reduced the frequency of partial onset (focal) seizures by 31 to 34 percent compared to 10 to 21 percent in the placebo group. However, perampanel’s efficacy was accompanied by frequent AEs consistent with its pan-AMPAR activity. At the highest recommended dose of perampanel (12 mg per day), over 40 percent of patients experienced dizziness, 18 percent reported somnolence, and at least 10 percent reported headaches, irritability, fatigue and falls. Perampanel’s FDA approval label is accompanied by a black box warning for serious psychiatric and behavioral reactions, including aggression, hostility and homicidal ideation and threats. Furthermore, significant drug-drug interactions were reported for perampanel. The concomitant use with the other ASMs carbamazepine, phenytoin and oxcarbazepine decreased plasma levels of perampanel by approximately 50 to 67 percent. In addition, perampanel at a dose of 12 mg per day reduced exposure of levonorgestrel, an oral contraceptive, by approximately 40 percent.
We believe there are at least three critical differences between perampanel and RAP-219. First, their chemical structures are completely different. Second, perampanel and RAP-219 have entirely distinct binding sites. Whereas perampanel binds directly to AMPAR GluA subunits, RAP-219 is designed to interact with 8, but not other TARP subtypes, and only when TARP8 is associated with GluA proteins. Third, whereas perampanel blocks AMPARs throughout the brain and body, RAP-219 activity on AMPARs has been observed to be restricted to those specific neurons that express TARP8, which are primarily located in the select forebrain regions. As such, we believe the tolerability profile of RAP-219 will be differentiated from that of perampanel, and may not induce the intolerable side effects associated with perampanel, such as dizziness, somnolence, fatigue, falls and vertigo.
Preclinical Studies Supportive of RAP-219
Preclinical studies have demonstrated RAP-219’s pharmacology and pharmacodynamic properties, as summarized below. In addition, preclinical studies have been conducted with third-party and earlier generation TARP8 NAMs by us and third-parties, the results of which we believe are supportive of RAP-219 because these third-party and earlier generation TARP8 NAMs share the same binding site and have similar pharmacological effects as RAP-219.
TARP8 Expression is Localized
TARP8 is expressed in specific brain regions, being most enriched in the hippocampus, and also present in the amygdala and cortex. In a study completed by Janssen, radiolabeled TARP8 ligands, such as [3H]JNJ-56022486 (an earlier generation TARP8 NAM), were shown to bind selectively to regions of the mouse brain in a distribution that overlapped TARP8 protein expression. The highest density radioactive [3H]JNJ-56022486 binding occurred in the hippocampus, which is also the region where the majority of focal seizures originate and the brain region where focal seizures originating in the cortex often spread. Radioligand binding of [3H]JNJ-56022486 also occurred in other brain regions that contain TARP8, including the amygdala, cerebral cortex and striatum, which can also be involved in seizure initiation and propagation. Importantly, the spread of seizures from the hippocampus into the amygdala has been shown in a third-party study to increase the risk of SUDEP in patients.
Figure 3 below illustrates the enrichment of TARP8 in mouse hippocampus. The left image derives from the Allen Brain Atlas, a publicly available database of gene expression in the brain, and depicts in red high levels of TARP8 messenger ribonucleic acid detected by in situ hybridization. The right image depicts with yellow and orange high levels of [3H]JNJ-56022486 binding detected by autoradiography.
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Figure 3. TARP8 is expressed in the mouse hippocampus.
TARP8 Ligands are Highly Selective Inhibitors of AMPAR
Structural analyses performed by a third party using cryogenic electron microscopy (“Cryo-EM”) have shown that a TARP8 AMPAR NAM, JNJ-55511118 (an earlier generation TARP8 NAM), binds to an interface between TARP8 and AMPAR, which leads to alterations in the structure of the AMPAR, thereby negatively modulating receptor function and its ability to respond to glutamate. Third-party structural studies indicated that all TARP8 AMPAR NAMs tested bind in a similar mode, suggesting the potential for RAP-219 to also bind in this pocket between GluA and TARP8. Figure 4 illustrates TARP8 ligands binding to the interface between TARP8 and AMPAR.
Figure 4. TARP8 ligands bind to the interface between TARP8 and AMPAR.
RAP-219 Was Observed to Be a Potent TARP8-Specific Inhibitor of AMPAR
Janssen tested RAP-219’s effect on recombinant human GluA1-TARP8 complexes in mice and rats. The study found that RAP-219 inhibited the function of GluA1-TARP8 receptors with half maximal effect, referred to as the IC50, at a concentration of approximately 100 pM, demonstrating RAP-219’s potency. By contrast, as exemplified in Figure 5 below, RAP-219 was found to be far less potent on complexes of GluA1 with other relevant TARP isoforms, including 2, 3, 4 or 7 or on other receptor types, such as NMDA receptors, G protein-coupled receptors (“GPCRs”), enzymes or and kinases.
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Figure 5. RAP-219 observed to be a highly selective inhibitor of TARP8 AMPAR.
RAP-219 Was Observed to Be Bioavailable and CNS Penetrant in Animal Models
Oral doses of RAP-219 were rapidly absorbed with over 80 percent bioavailability in mice, rats, dogs and non-human primates. In these animal studies, completed by Janssen, RAP-219 had a half-life of 17.8 to 38.3 hours and was observed to distribute into the brain with a brain-to-plasma ratio of 0.96 in rats. Figure 6 below shows that oral doses of 0.02 mg/kg in the mouse and 0.01 mg/kg in the rat resulted in 50 percent TARP8- receptor/AMPAR occupancy for RAP-219 in the hippocampus, referred to as “ED50.”
Figure 6. Dose dependent receptor occupancy of RAP-219. Following oral dosing of RAP-219, AMPAR occupancy was quantified in the hippocampus of the mouse (A) at 24 hours and rat (B) at 4 hours after dosing using ex-vivo autoradiography.
RAP-219 has the Potential for Reduced Drug-Drug Interactions Versus Approved ASMs
RAP-219 is neither a substrate nor an inhibitor of cytochrome P450 (“CYP”) enzymes. CYPs comprise a large and diverse family of enzymes, responsible for the detoxification of many drugs, including ASMs. Drug- drug interactions with CYPs can decrease or increase ASM blood levels, which can reduce drug effectiveness or increase relevant drug side effects, respectively. RAP-219 has not been observed to induce or inhibit or be metabolized by any evaluated CYPs at clinically relevant concentrations. The systemic clearance of RAP-219 in humans appears to be predominantly via phase 2 conjugation. We believe that RAP-219’s lack of interaction with the CYP pathway has the potential to reduce drug-drug interactions, which would serve as an advantage given the widespread use of polypharmacy in focal epilepsy, bipolar disorder and peripheral neuropathic pain.
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RAP-219 Preclinical Trials in Focal Epilepsy
Multiple preclinical epilepsy models were used by Janssen to assess the potential of ASMs. In the pentylenetetrazol (“PTZ”) infusion mouse model of acute seizures, RAP-219 administration was associated with an increased seizure threshold. PTZ is a GABAA receptor antagonist, which causes acute severe seizures in animals when infused at a high dose. As shown in Figure 7 below, RAP-219 led to a dose-dependent increase in the threshold concentration required to trigger both twitch and clonus in the Metrazol mouse model. Significant differences compared to vehicle treatment were detected in 0.1 and 1 mg/kg doses (P<0.01) for both twitch and clonus. ED50 values were 0.02 mg/kg for both twitch and clonus responses.
Figure 7. RAP-219 led to a dose dependent increase in the threshold concentration required to trigger both twitch and clonus responses in the IV Metrazol model.
The corneal kindling induced seizure model in mice is considered to be a valid model in focal epilepsy. In this model studied by Janssen, repeated application of an electrical stimulus, which is initially subconvulsive, resulted in alterations in brain function that led to progressive sensitization to seizures. As illustrated in Figure 8 below, in fully kindled mice, oral administration of a single dose of RAP-219 at doses of 0.02 mg/kg to 3 mg/kg prevented seizures with an estimated half maximal effective concentration (“EC50”) occurring at 2.3 ng/mL plasma concentration. Immediately prior to the corneal kindling test, the same mice were assessed with a rotarod test. This is a performance test widely used to assess motor impairment and sedation in rodents. The lack of motoric
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impairment with RAP-219, even at approximately 100-fold higher exposures, is consistent with the lack of expression of TARP8 in brain regions involved in motor coordination and sedation, such as the hindbrain.
Figure 8. RAP-219 had an estimated EC50 of 2.3 ng/mL in the corneal kindling mouse model of focal epilepsy.
Maximal seizure protection, based on the percentage of responding animals, was observed at a plasma concentration of approximately 10 ng/mL, and significant seizure reduction was seen at a plasma concentration of approximately 7 ng/mL. This corresponds to a projected receptor occupancy of approximately 50 to 70 percent based on data generated in rats as measured by ex-vivo autoradiography, as shown in Figure 9 below.
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Figure 9. A plasma concentration of 7 ng/mL of RAP-219 corresponded to approximately a 70 percent receptor occupancy in rats.
Data from a separate study completed by us, in fully kindled mice, suggests that oral administration of RTX-1738 (a TARP8 NAM licensed to us under the same patent as RAP-219) at 3 mg/kg prevented seizures after either a single administration or after seven consecutive days of dosing, indicating that antiseizure activity was maintained with repeat dosing, i.e. no tolerance to the antiseizure activity was observed.
We believe that one potential advantage of the precision targeting observed with RAP-219 in preclinical models is a wide therapeutic index that may be achieved by avoiding AMPAR modulation in the hindbrain. The therapeutic index measures the general tolerability of a drug, reflecting the range of doses at which a medication is effective without causing unacceptable adverse effects. Drugs with narrow therapeutic indexes have a lesser difference between doses that produce therapeutic effects and doses that cause adverse effects. In preclinical animal studies, we found the ratio between doses of RAP-219 that did not produce a toxic effect in 50 percent of the population (“TD50”) on the rotarod test were greater than 150 higher than those with ED50 for beneficial activity in the corneal kindling test. This compares favorably to that same ratio derived from preclinical animal models for other approved and widely prescribed ASMs which range from 1.3 for phenytoin to greater than 44 for levetiracetam. Thus, we believe RAP-219’s potentially wider therapeutic index could translate to patients, providing sustained therapeutic benefit without intolerable side effects, improving upon the traditional ASMs.
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RAP-219 Preclinical Toxicity Studies
In vivogood laboratory practice(“GLP”) and non-GLP toxicology studies have also been conducted with RAP-219. In a 28-day GLP toxicology study in rats completed by Janssen, once-daily administration of RAP-219 was generally well- tolerated and no adverse effects were observed at any dose. Non-adverse effects including clinical signs were observed, and all non-adverse findings appeared to be reversible following completion of the 28-day recovery period. In a 28-day GLP toxicology study in dogs, once-daily administration of RAP-219 at doses of up to 10 mg/kg per day yielded overall exposures approximately 100-fold higher than those required to inhibit seizures in the mouse corneal kindling model. RAP-219 was generally well-tolerated and no adverse effects were observed at any dose. The non-adverse effects included CNS-related clinical signs, minor changes in a limited number of clinical pathology parameters, as well as minimal microscopic changes in the adrenal gland and thymus. All drug related RAP-219 effects observed either reversed completely or were in the process of reversing following the 28-day recovery period. Similar results were observed in 13-week toxicology studies in rats and dogs completed by us. Based on the preclinical toxicology data collected to date across these models, we believe RAP-219 has a low genotoxic potential and a favorable tolerability profile. These data supported further development through clinical investigation for once-daily oral dosing of RAP-219 up to 3 months.
Additional toxicology studies including a chronic (6-months in rats and 9-months in dogs) study as well as reproduction toxicology studies (in rats and rabbits) are ongoing to support longer-term dosing and dosing women of childbearing potential in subsequent clinical trials. In these ongoing studies, convulsion was observed in two instances. A female rabbit dosed at 40 mg/kg per day showed convulsion on the last day of the 10-day pilot tolerability or range finding study to enable GLP reproduction toxicology study. This dose level was considered not tolerated. The no observed effect level (“NOEL”) dose for convulsion was 30 mg/kg per day.
A male dog in the ongoing 9-month chronic toxicology study developed convulsion following the first dose of 20 mg/kg. As demonstrated in the 28-day GLP toxicology study in dogs, the highest dose level tested in dogs and the NOEL dose for convulsion was 10 mg/kg per day. The margins for the mean maximum exposures (Cmax) from the Phase 2a proof-of-concept trial in refractory focal epilepsy dose (0.75 mg per day for 5 days followed by 1.25 mg per day) over that from the NOEL in rabbits and dogs were greater than 700-fold and 500-fold, respectively. To deal with convulsion in nonclinical studies, we plan to use one-tenth of the exposure from the no-effect dose level for convulsion as the highest exposure for clinical trials. Using this approach, we expect the margins will be greater than 70-fold and 50-fold in rabbits and dogs, respectively. Therefore, we believe the potential for convulsion risk to patients is low.
RAP-219 Phase 1 Trials in Healthy Adult Volunteers
A total of four Phase 1 trials with RAP-219 have been conducted to date to assess the safety, tolerability, pharmacodynamics and pharmacokinetics of RAP-219 in 100 healthy adult volunteers: a SAD trial; a first MAD trial; a MAD-2 trial; and a human PET trial. Final results are available for the SAD, first MAD, and MAD-2 trials and a final study report is in progress for the PET trial. In all of these trials, RAP-219 was generally well tolerated with no serious adverse events ("SAEs"). There were three treatment discontinuations (3%) that were attributed to treatment emergent adverse events ("TEAEs"), with no TEAEs greater than Grade 2. No clinically significant laboratory, electrocardiogram (ECG), or vital sign abnormalities were reported in the SAD or two MAD trials. While the final study report is in progress, TEAEs observed in the PET trial are generally consistent with other Phase 1 trials. The results of these trials indicate a safety and tolerability profile supporting continued clinical development of RAP-219.
The SAD trial had two parts. Part 1 was randomized, double-blind and placebo-controlled; and evaluated doses from 0.25 mg to 3 mg; and Part 2 was an open label single cohort evaluation of the effect of a high-fat meal on the pharmacokinetics of a 1 mg single dose of RAP-219. There were five cohorts in the Phase 1 SAD trial Part 1 and each cohort consisted of six subjects who received RAP-219 and two subjects who received placebo. The pharmacokinetics of RAP-219 in the SAD Part 1 trial were consistent with the observations from the nonclinical studies, and were characterized by low clearance and a long terminal elimination half-life of approximately 8 to 14 days. The maximum exposures (Cmax) at the 2 mg and 3 mg doses corresponded to approximately 50 percent projected receptor occupancy, based on data from preclinical studies. In Part 1 of the SAD trial, all doses were generally well tolerated with no SAEs, and all drug related TEAEs were rated as mild (grade 1) or moderate (grade 2). All moderate drug-related TEAEs observed were at the two highest doses (2 mg and 3 mg) and were generally consistent with the effects seen in nonclinical toxicology studies with RAP-219; included agitation and amnesia, each reported in two subjects, and anxiety, dizziness, visual hallucination, sinus tachycardia and hypertension, each reported in one subject. In Part 2 of the SAD trial, there were six subjects who all received 1 mg of RAP-219. A modest increase in overall exposure (25 percent increase in area under the curve) and maximum exposure (42 percent increase in Cmax) were observed when RAP-219 was dosed with a high-fat, high-calorie meal. Based on the emerging safety profile and the observed food effect, we believe RAP-219 can be dosed without regard to food.
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The first MAD trial was a randomized, double-blind and placebo-controlled trial and evaluated once-daily doses ranging from 0.25 mg to 1.25 mg over two or four weeks. There were five cohorts in the first MAD trial. Each cohort for the first MAD trial consisted of six subjects receiving RAP-219 and two subjects receiving a placebo. In the first MAD trial, all doses were generally well tolerated with no SAEs, all drug related TEAEs were rated as mild (grade 1), and no dose response was observed with regards to drug-related TEAEs.
The MAD-2 trial was a randomized, double-blind, placebo-controlled trial in healthy volunteers and was designed to assess dosing regimens that may accelerate the time to reach therapeutic exposure more quickly than in our first MAD trial, and to further evaluate the safety and tolerability of RAP-219 with continued dose escalation. The MAD-2 trial evaluated once-daily doses ranging from 0.5 mg to 1.75 mg. There were three cohorts in the MAD-2 trial. Each cohort for the MAD-2 trial consisted of six subjects receiving RAP-219 and two subjects receiving a placebo. In the MAD-2 trial, all doses were generally well tolerated with no SAEs, all drug-related TEAEs were rated as mild (grade 1) or moderate (grade 2) and no dose or exposure-related response was observed with regards to the incidence of TEAEs. Data from the MAD-2 trial demonstrated that dose titration was feasible after just two days of dosing at the starting dose, and that the higher dose of 1.75 mg once daily was generally well tolerated. Target exposures (those trough concentrations associated with target projected receptor occupancy in pre-clinical models) were achieved within 5 days of dosing across various dosing regimens.
Among the 48 participants exposed to RAP-219 in the two MAD trials, the most common TEAEs were headache (n=5), sinus tachycardia (n=4), and brain fog, insomnia, bowel movement irregularity, dry mouth, and medical device site reaction (n=3 each). Among the 16 participants exposed to placebo, the most common TEAEs were abdominal pain, brain fog, constipation, cough, decreased appetite, dizziness, medical device site reaction, and second-degree atrioventricular block (n=1 each).
Figure 10 below shows the pharmacokinetic profile of RAP-219 following the two highest single doses from the SAD trial, the last dose (Day 28) of the two highest dose levels (Cohorts 4 and 5) in the first MAD trial, and following the last dose (Day 28) of the highest dose level (Cohort 3) in the MAD-2 trial, along with preliminary receptor occupancy concentrations based on data from the human PET trial. Cohort 4 of the first MAD trial was dosed at 0.75 mg per day for 28 days and exceeded the preliminary human receptor occupancy level of 70% at day 28 trough. Cohort 5 of the first MAD trial was dosed at 0.75 mg per day for 5 days followed by 1.25 mg per day for 23 days. Data from Cohort 5 showed maximum exposures (Cmax) up to 3-fold higher than those achieved following the highest single dose (3 mg) in the Phase 1 SAD trial and were approximately at the human receptor occupancy level of 85% at day 28 trough. Cohort 3 of the MAD-2 trial was dosed at 0.5 mg per day for 2 days, 1.0 mg per day for 2 days, and 1.75 mg per day for 24 days. Preliminary data from this cohort suggest an approximate 4-fold increase in Cmax compared to the highest single dose (3 mg) in the SAD trial and exceeded the preliminary human receptor occupancy level of 85% (see Figure 10 below).
Figure 10. SAD Exposures vs. MAD Exposures.
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The human PET trial was an open label trial in healthy volunteers which utilized a companion PET radiotracer to confirm brain region selectivity and brain target receptor occupancy across a range of dosing and exposure levels, and was designed to confirm neuroanatomical distribution of TARPγ8 and establish the relationship between plasma concentration and brain receptor occupancy after 14 days of dosing with RAP-219 under different dosing regimens. This trial was conducted in Belgium at a site experienced with the radiotracer. There were three cohorts in the Phase 1 PET trial: Cohort 1 was given the same dosing regimen currently being used in the Phase 2a trial in refractory focal epilepsy (0.75 mg daily for 5 days, followed by 1.25 mg daily for 9 days), and lower doses were used in the other two cohorts to better characterize the plasma concentration versus receptor occupancy relationship. Cohort 2 was given 0.25 mg daily for 14 days and Cohort 3 was given 0.25 mg daily for 7 days, followed by 0.5 mg daily for 7 days. The preliminary PET data demonstrated that Cohort 1 (the dosing regimen utilized in the ongoing Phase 2a trial in refractory focal epilepsy) exceeded the projected target receptor occupancy range associated with maximal seizure protection in preclinical models (50%-70%) within five days of dosing, while maintaining a tolerability profile generally consistent with prior Phase 1 trial findings. The trial confirmed that the expression of TARP-γ8-containing AMPA receptors is enriched in the hippocampus and cerebral cortex and is minimal in the cerebellum and brain stem.
Clinical Development Plan of RAP-219 in Refractory Focal Epilepsy
For the Phase 2a proof-of-concept, open label trial of RAP-219, we expect to enroll approximately 20 participants who have previously been implanted with an intracranial RNS system, marketed by NeuroPace, Inc. (“NeuroPace”), to monitor and manage their epilepsy. Additional key participant eligibility criteria include implantation of the RNS system at least 15 months before screening, stable device configuration, stimulation and detection settings (including the duration of “long episodes” (“LEs”) recorded by the RNS system) for at least eight weeks before screening, at least an average of eight LEs per 4-week interval and at least one clinical seizure in the 8-week retrospective eligibility period, treatment with a maximum of four concomitant medications and no generalized onset seizures in the past ten years. Participants in this trial will receive a dose of 0.75 mg per day for 5 days, followed by 1.25 mg per day for the remainder of the treatment period. Our Phase 2a proof-of-concept trial design is further detailed in Figure 11 below.
Figure 11. Phase 2a Proof-of-Concept Trial Schema.
The primary endpoint of our Phase 2a proof-of-concept trial is a reduction in frequency of LEs recorded by the RNS system, specifically the change in LE frequency during the second 4-week interval of the treatment period (weeks 5-8) compared to baseline frequency (frequency per 28 days determined across 8-week retrospective and 4-week prospective baseline intervals). One focus of this analysis will be a responder analysis to determine the proportion of participants who experience a greater than or equal to 30% decrease in long episode frequency per 28 days. The key secondary endpoints of this proof-of-concept trial include change in clinical seizure frequency (measured using patient-recorded paper diaries), change in electrographic biomarkers (including detection frequency, spike frequency, frequency of long episode with saturation, and other RNS system data outputs) and number and percent of participants who achieve any improvement as assessed by the investigator (measured by Clinical Global Impression of Change scores of minimally, much or very much improved).
In November 2023, we established a collaboration with NeuroPace to leverage the RNS system’s data to track responses of patients receiving RAP-219 in our Phase 2a proof-of-concept trial. This collaboration has allowed us to more rapidly identify study sites and efficiently screen appropriate patients in the recruitment of our Phase 2a proof-of-concept trial. In addition, we believe access to NeuroPace’s data collection and analysis capabilities will enable us to efficiently prepare our proof-of-concept data package.
The RNS system is FDA approved for the treatment of refractory focal epilepsy. The RNS system involves a surgeon implanting a small battery-powered device called a responsive neurostimulator in the patient’s skull. The neurostimulator is connected to thin wires, or electrodes, that the surgeon places in areas of the brain where the patient’s seizures originate. The device continuously records the brain’s electrical activity for abnormal epileptiform patterns. Abnormal brain electrical activity detected by
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the RNS system that could likely lead to a seizure is referred to as a LE. When abnormal activity is detected, the device delivers a pulse of electrical stimulation that may halt the seizure and prevent it from spreading to other brain regions. As of December 31, 2024, over 6,500 patients have been implanted with the RNS system.
Patients with the implanted RNS system typically also receive ASMs, and additional oral therapies may be prescribed to optimize treatment since many patients continue to have seizures after implantation of the device. Two retrospective studies published in peer reviewed epilepsy journals have demonstrated that when new ASMs are added to an RNS system patient’s treatment regimen, LE changes detected by the RNS system within one to four weeks of new ASM treatment initiation are predictive of long-term clinical response (i.e., a clinically meaningful reduction in focal seizures) to the new ASM. In addition, other iEEG measures obtained from the RNS system have also been shown to be predictive of clinical response, such as detections or episode starts, spike frequency and spectral power, and will be used as secondary or exploratory endpoints in this trial.
Testing RAP-219 in patients with the RNS system provides the opportunity to objectively quantify changes in LE frequency as a potential biomarker of efficacy. Because LEs have been shown to provide an early and objective indicator of clinical response to an ASM, and because the population of patients with the RNS system is representative of the refractory focal epilepsy population that will be the focus of future registrational trials, quantifying LEs after the addition of RAP-219 may provide a clearer perspective on the potential of RAP-219 to provide clinical benefit in future focal epilepsy trials. We are enrolling patients who have been treated with an RNS system for at least 15 months, have stable device configuration settings, stimulation and detection settings (including LE duration) for at least eight weeks before screening and continue to have seizures while also on a stable ASM regimen. Due to an increasing number of patients in the United States implanted with an RNS system for their focal epilepsy, the support from NeuroPace in identifying patients eligible for our Phase 2a proof-of-concept trial and RAP-219’s minimal drug-drug interactions observed to date, we expect to report topline results from this Phase 2a proof-of-concept trial in the third quarter of 2025 and, if the trial is positive, would provide translatable proof-of-concept for RAP-219.
The RNS proof-of-concept protocol was chosen after discussions with key opinion leaders, consultants, and clinical advisory boards, and it was determined that it provided the best chance of translatability to registrational trial outcomes in focal epilepsy. We considered other clinical models commonly used in proof-of-concept studies in epilepsy. We also considered the photosensitive epilepsy proof-of-concept model, where patients with known visually evoked epileptiform discharges are purposely provoked using a strobe light. We believe the photosensitivity model is sub-optimal because it is a single-dose study and its relevance to focal epilepsy is limited since photosensitive discharges are found in patients with generalized epilepsy. We also considered transcranial magnetic stimulation (“TMS”), where healthy volunteers are subjected to TMS and changes in TMS-evoked potentials are measured to assess cortical excitability. We believe the TMS model has limited relevance to focal epilepsy since it does not evaluate patients with epilepsy.
Assuming a successful outcome of our Phase 2a proof-of-concept clinical trial, we plan to discuss these results with the FDA and initiate registrational clinical trials to assess RAP-219 in adults with focal epilepsy. We anticipate the design of these registrational trials and patient population to be studied will be similar to those conducted for other approved therapies and, if RAP-219 is eventually approved, that RAP-219’s indication will be similar to currently approved ASMs.
Opportunities to Expand the Potential for RAP-219 in Epilepsy
The ultimate goal of antiseizure therapy is complete freedom from seizures and improvement in patient quality of life. We believe that RAP-219 has the potential to significantly reduce or possibly eliminate focal epilepsy seizures while avoiding many of the common intolerable AEs associated with many approved ASMs. The differentiated target and mechanism of action of RAP-219 in combination with its neuroanatomical precision within the most common seizure onset-zones as demonstrated in preclinical models provides the opportunity for potentially superior clinical activity compared to currently approved ASMs. Certain patients who are refractory to treatment with other ASMs have been found to respond favorably to combination therapies, especially when rational polypharmacy is employed. We believe that the unique proposed mechanism of RAP-219 and its potential for reduced drug-drug interactions, if approved, would make it a drug of choice for rational polypharmacy by improving clinical benefit without changing drug levels of other ASMs.
We are also exploring the development of a long-acting injectable formulation of RAP-219 with the goal of reducing dosing frequency to once every one or two months, thereby helping to improve adherence. We envision patients would first be stabilized on an oral dose of RAP-219 and then transitioned to the long-acting injectable formulation. For many patients, nonadherence to prescribed ASMs is a major issue in optimizing benefit from pharmacotherapy. This nonadherence rate can be up to approximately 50 percent. One study found that patients who were not adherent to their ASMs had less seizure control as compared with patients who were adherent. We believe that, in addition to the potential reduced side effect profile of RAP-219, its high potency and long half-life, each observed to date in our Phase 1 studies, provide additional opportunities to improve patient adherence. In addition, we believe the potential to dose RAP-219 once per day would be preferred by patients and should improve adherence. A long-acting
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formulation of RAP-219 has the potential to be the first long-acting injectable ASM. We intend to advance such a formulation into clinical development if and when we establish a tolerable and efficacious once-daily oral formulation.
Other Potential Clinical Applications for RAP-219 and TARP8 Modulators
Many ASMs blunt excitatory neurotransmission in the CNS and some have been shown to provide clinical benefit in other indications, including peripheral neuropathic pain and psychiatric diseases. However, the same issues that are problematic in ASMs used to treat epilepsy, such as intolerable AEs and drug-drug interactions, are also present when treating these other indications. Because monotherapy also commonly fails in the treatment of peripheral neuropathic pain and psychiatric conditions, polypharmacy is a widespread practice.
Bipolar Disorder Background and TARPg8 as a Potential Treatment
Bipolar disorder is characterized by alternating episodes of depression and either mania (bipolar I) or hypomania (bipolar II). Bipolar Mania is characterized by discrete periods of elevated or irritable mood, increased energy, and heightened activity that represent a noticeable change from previous behavior. In bipolar I, manic symptoms are sufficient to require inpatient treatment whereas bipolar II typically involves milder hypomanic episodes that don’t require inpatient treatment. Depressive symptoms in patients with bipolar depression include symptoms such as persistent sad or irritable mood, loss of interest or pleasure in nearly all activities, feelings of worthlessness or excessive guilt, diminished ability to think or concentrate, and recurrent thoughts of death or suicide. Previous manic or hypomanic symptoms in a patient with depressive symptoms defines the diagnosis of bipolar disorder; with some patients experiencing both manic and depressive symptoms in the same episode.
Bipolar disorder affects 2.8 percent of the adult population in the United States, or approximately 7.2 million adults. The global bipolar disorder market was approximately $1.4 billion in 2022, and sales are expected to grow to over $4 billion by 2028. Bipolar disorder is often treated with antipsychotic medications as a monotherapy or in combination with mood stabilizers. The side effects and safety risks associated with antipsychotic drugs in patients with bipolar disorder include dizziness, sedation, weight gain, movement disorders and agitation.
We believe that RAP-219 has the potential to provide a clinical benefit to patients with bipolar disorder for multiple reasons. First, there are several ASMs, including valproate, lamotrigine, and carbamazepine, that have shown clinical benefit in epilepsy and bipolar disorder and are FDA approved for both indications. The corneal kindling model of epilepsy is also believed by some experts to be predictive of bipolar treatments. Second, third- party functional neuro-imaging studies in patients with bipolar disorder typically show that the hippocampus, a brain region where TARP8 is expressed, exhibits abnormal activation and hyperactivity as well as elevated responses to emotional stimuli, attentional activities and memory tasks. Finally, a third-party genome-wide association study of 40,000 patients with bipolar disorder reported that bipolar disorder risk alleles were enriched in genes in synaptic signaling pathways and brain-expressed genes, particularly those with high specificity of expression in neurons of the prefrontal cortex and hippocampus. We believe that by selective targeting TARP8 and blunting abnormal hippocampal activity, RAP-219 may normalize these responses and thereby improve the symptoms of bipolar disorder.
Background of Peripheral Neuropathic Pain
Neuropathic pain is a chronic condition caused by dysfunctional or damaged nerves, classified either as peripheral or central, depending on whether the primary dysfunction or damage is in the peripheral nervous system or in the CNS. Peripheral neuropathic pain is a common condition estimated to affect up to 17 percent of the global population. Peripheral neuropathic pain is a large market, estimated at $6.6 billion globally in 2021 and forecasted to grow at over four percent annually. Peripheral neuropathic pain indications reflect large patient populations in the United States, including, for example, painful diabetic peripheral neuropathy at approximately 2.8 million, post- herpetic neuralgia at approximately 1.8 million and trigeminal neuralgia at approximately 1.0 million diagnosed patients.
It is generally accepted that peripheral neuropathic pain often begins with an injury to or dysfunction of a peripheral nerve resulting in abnormal, spontaneous activity, known as ectopic discharges, akin to epileptic activity in the brain, that results in abnormal spontaneous pain and abnormal painful and uncomfortable sensations. The ectopic discharges from peripheral nerves travel to the dorsal horn of the spinal cord and then to the brain and can cause sensitization and hyperexcitability in both the spinal cord and the brain. It is hypothesized that inflammation associated with the injury also drives chronic stimulation of neurons, leading to prolonged sensations of pain. Although peripheral neuropathic pain may start with dysfunction or damage in the peripheral nervous system, aberrant signaling into the spinal cord generally progresses with functional chronic changes to the CNS, both in the spinal cord and brain.
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There is significant unmet need in the treatment of peripheral neuropathic pain, with most available treatments only having moderate efficacy and all having side effects that limit their use. First-line therapy with gabapentin or pregabalin is associated with lethargy, vertigo, cognitive issues and peripheral swelling. Opioid analgesics are typically not efficacious in peripheral neuropathic pain and are associated with nausea, lethargy, cognitive slowing and constipation. Opiates also have abuse potential that limits widespread use. Nonsteroidal anti-inflammatory drugs are often prescribed but rarely have meaningful efficacy and are associated with gastrointestinal, renal and cardiovascular AEs.
Evidence for the Importance of AMPARs and TARP8 in Pain
TARP8 is expressed in areas of the CNS associated with pain including the anterior cingulate cortex and the dorsal horn of the spinal cord. It is hypothesized that the anterior cingulate cortex registers affective aspects of pain while the dorsal horn processes nociceptive inputs from peripheral nerves. TARP8 inhibition has demonstrated preclinical activity in third party pain models. For instance, a TARP8 AMPAR selective inhibitor, LY3130481, was found by third-party researchers to suppress excitatory synaptic transmission in pain pathways and significantly reduce pain-related behaviors in mouse models of neuropathic and inflammatory pain without impairing motor function. This study also reported that the magnitude of improved pain behavioral effects were positively correlated with occupancy of TARP8 containing AMPARs in the CNS and were lost in TARP8 knock-out mice, supporting the dependence of the antinociceptive action of LY3130481 on TARP8.
Our preclinical studies with RTX-1738 have demonstrated pain behavior improvements in animal models of acute, inflammatory and neuropathic pain. In the rat formalin induced pain model, we observed that RTX-1738 administered 60 minutes before formalin attenuated nocifensive behavior during both phase 1 (acute pain, 0-10 minutes after formalin injection) and phase 2 (persistent pain, 20-60 minutes after formalin injection). In another study, RTX-1738 showed attenuation of tactile allodynia in the spinal nerve ligation (“SNL”) rat model of neuropathic pain. In this test, RTX-1738 was administered daily 7 days after nerve ligation, and pain behavior was assessed 90 minutes post-dose. Starting at day 16 after surgery, which corresponds to day three of dosing with RTX-1738, paw withdrawal threshold was elevated, reflecting a decrease in pain behavior.
There has also been encouraging evidence from prior clinical trials of perampanel in neuropathic pain associated with diabetic neuropathy and post-herpetic neuralgia. While the randomized placebo-controlled studies failed to show a significant reduction in pain scores, subjects that tolerated perampanel reported moderate but meaningful pain relief in the subsequent open-label study. We believe that the trial’s failure to show reduction in pain in the overall population was likely driven by perampanel’s intolerable AEs.
Our nAChR Programs
We have a portfolio of discovery projects that leverage RAPs for nAChRs that we believe have potential for generating product candidates. Neuronal AChRs are transmembrane ligand-gated ion channels composed of five subunits of / subtypes. These receptors are excitatory acetylcholine gated ion channels and are expressed throughout the CNS as well as the periphery. They have critical roles in diverse aspects of neuronal signaling in the central and autonomic nervous system. We are optimizing nAChR modulators in anticipation of selecting candidates to advance into the clinic.
Our 6 nAChR Program
We are developing agonists and PAMs of the 6 nAChR in chronic pain, which may include neuropathic pain, inflammatory pain and nociceptive pain. Pan-nAChR agonists have been shown to significantly reduce pain in third-party clinical trials, but these agonists were associated with side effects that have limited their development potential. We believe that our RAP platform technology, which allows identification of agonists and PAMs that are selective for 6 nAChR, has the potential enable the discovery of molecules with clinical activity in pain and improved tolerability.
6 nAChR as a Potential Target in Chronic Pain
Nicotine and certain nAChR agonists have analgesic properties, but their development for chronic pain has been unsuccessful. Epibatidine, a naturally occurring compound, is a pan-nAChR agonist with high affinity for 42 and 34 nAChRs, the most widely expressed subtypes in the mammalian nervous system. Epibatidine has potent analgesic properties. However, it is associated with toxic side effects that have precluded its development. ABT-594, an investigational third-party pan-nAChR agonist, demonstrated significant improvements in patients with neuropathic pain in a Phase 2 randomized placebo-controlled study, but up to 66 percent of patients withdrew from the trial due to AEs such as nausea, dizziness, vomiting, abnormal dreams and asthenia (weakness or lack of energy). Following these results, further development of ABT-594 was discontinued. There are currently no approved drugs for pain that specifically target nAChRs.
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Third-party animal and human studies have implicated the 6 nAChR as a potential target for chronic pain. This nAChR subtype is enriched in sensory neurons of dorsal root ganglia (“DRG”), and 6 nAChR activity is associated with reduced pain. Mouse strains with increased levels of 6 in DRG showed reduced pain in a spared nerve injury (“SNI”) model of neuropathic pain. Conversely, complete inactivation of the gene for 6 in mice blocked the analgesic effects of nicotinic compounds. In humans, genetic variants with reduced 6 nAChR activity showed increased levels of postoperative pain.
Although the potential for selective 6 agonists as a therapeutic agent for pain has been acknowledged, discovery efforts have been hampered by challenges in establishing functional assays for 6 containing nAChRs in cell lines. Recombinant 6 does not assemble into functional multi-subunit nAChRs; therefore, 6 activity could not be measured in cell lines used for drug discovery. Our Chief Scientific Officer, Dr. Bredt, and his colleagues, overcame this impediment through the identification of RAPs, which serve as chaperones and auxiliary subunits that drive the assembly of functional 6-containing nAChRs. This has enabled us to functionally express 6 nAChR and discover a series of 6 selective PAMs and agonists. We believe that these 6 selective nAChR PAMs and agonists have the potential to alleviate chronic pain while avoiding the AEs that have precluded development of earlier non-selective nAChRs agonists.
Preclinical Validation of Our Approach
We plan to advance our discovery-stage 6 nAChR program into further development. Janssen conducted high-throughput screen of cells engineered to express 6 nAChRs and identified PAMs that were selective for this nAChR subtype. These PAMs were further characterized in patch clamp assays where they were shown to be selective modulators of 64 compared to nAChRs that did not contain the 6 subunit, including the more ubiquitously expressed 42 and 34 nAChRs. One of these PAMs, RTX-2621, was a potentiator of 64 and had low activity on 42 and 34 nAChR subtypes.
We tested RTX-2621 in the rat SNI model for neuropathic pain. In this model, damage to the sciatic nerve results in hypersensitivity of the rat paw to stimuli. This is generally recognized to be a robust model of neuropathic pain, as it replicates many of the neuronal signaling changes and physiological responses observed in humans. It was observed that RTX-2621 mitigated this hypersensitivity. We believe this demonstrates the potential for 6 to be a therapeutic target in chronic pain.
Our 910 nAChR Program
Another program involves the 910 nAChR. We are developing an agonist to the 910 nAChR in hearing disorders, which may include age-related hearing loss, acoustic trauma and tinnitus, as well as vestibular disorders. Third-party genetic studies in mice have shown that augmenting the 9 nAChR pathway can help prevent hearing loss associated with aging, acoustic trauma and that this pathway also be relevant to vestibular disorders. Despite this genetic validation, discovery of selective 910 nAChR agonists has been challenging because recombinant nAChRs containing 910 in cell lines fail to create a functional receptor. Our ability to identify agonists that are selective for 910 nAChR was made possible by the application of our RAP platform technology. We are currently developing an oral therapeutic targeting the 910 nAChR, which we believe has a high potential target in hearing disorders. We also believe the 910 nAChR is a potential target in vestibular disorders, and we may develop an oral product candidate for this indication in the future.
Background to Hearing Disorders
Hearing disorders impact a large percentage of the population. For example, approximately one third of people aged 65 to 74 and nearly half aged 75 and older have age-related hearing loss. Acoustic trauma effects approximately five percent of the global population, and surveys estimate that 10 to 25 percent of adults in the United States have tinnitus. Many hearing disorder patients start their treatment by using a hearing aid, with cochlear implantation given to the most severely affected patients. Despite this high prevalence, there are few pharmacotherapeutic treatments to prevent or reverse hearing disorders.
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910 nAChR as a Potential Target in Hearing Disorders
In the inner ear, the cochlea converts mechanical sound vibrations into nerve signals, which are transmitted to the brain. Sound vibrations are detected by a combination of outer hair cells, which amplify sound, and inner hair cells (“IHCs”), which receive the amplified sound signals. The IHCs, in turn, translate the incoming signals into release of neurotransmitters, which traverse the synapse to stimulate neurons that send electrochemical signals to the brain. One of the key receptors in this process is the 910 nAChR, which is highly enriched in cochlear hair cells.
The role of the 910 nAChR in hearing loss has been demonstrated by third-party genetic experiments. Gain and loss of function mutations to the gene encoding 9 demonstrated its role in experimentally induced hearing loss. In these experiments, the thresholds to elicit auditory brain stem responses (“ABR”) to various frequencies of sound were found to be elevated one day after auditory trauma, consistent with hearing loss. In wild-type mice, this effect of auditory trauma was temporary and after seven days, the ABR profile returned to that observed prior to the insult. In mice with a null mutation of the gene encoding 9, the ABR threshold was increased at day one, and this increase persisted at day seven, demonstrating increased vulnerability to hearing loss. By contrast, mice with a gain-of-function mutation in the gene for 9 were protected from any significant change in ABR on either day one or day seven.
We believe that a selective modulator of the a9a10 nAChR may help treat hearing disorders while avoiding many of the side effects that have limited the clinical application of other nAChR compounds.
Preclinical Validation of Our Approach
In vitro studies of 910 nAChR physiology have been challenging because this receptor could not be functionally expressed in recombinant cell lines in the absence of it RAPs. Through a genome-wide screen using our discovery platform, RAPs that drive the assembly of functional 910 nAChRs were identified by Janssen. Expression of these RAPs along with the 9 and 10 subunits enabled functional 910 nAChR expression in cell lines that we believe are suitable for drug discovery.
Janssen conducted a high throughput screen of cells engineered to express 910 nAChR and identified a number of small molecule agonists of 910. Through our medicinal chemistry efforts, 910 agonists with low nanomolar potency, inner ear penetration and high selectivity versus other nAChR family members have been identified and are being optimized. The use of these orally administered molecules in physiological hearing models may demonstrate the potential of 910 agonists to address hearing disorders.
Manufacturing and Supply
We do not own or operate, and currently have no plans to establish, any manufacturing facilities. We have engaged, and expect to continue to rely on, well-established third-party contract manufacturing organizations (“CMOs”) to supply our product candidates for use in our preclinical studies and clinical trials. Because we rely on contract manufacturers, we employ personnel with extensive technical, manufacturing, analytical, and quality experience to oversee contract manufacturing and testing activities, and to compile manufacturing and quality information for our regulatory submissions. We believe our current manufacturers have the scale, systems, and experience to supply our currently planned clinical trials.
Additionally, we intend to rely on third-party CMOs for later-stage development and commercial manufacturing, if our product candidates receive marketing approval. As our lead product candidates advance through clinical development, we expect to enter into longer-term commercial supply agreements to fulfill and secure our production needs. While the drug substances used in our product candidates are manufactured by more than one supplier, the number of manufacturers is limited. In the event it is necessary or advisable to acquire supplies from an alternative supplier, we might not be able to obtain them on commercially reasonable terms, if at all. It could also require significant time and expense to redesign our manufacturing processes to work with another company. If we need to change manufacturers during the clinical or development stage for product candidates or after commercialization for our product candidates, if approved, the FDA and corresponding foreign regulatory agencies must approve these new manufacturers in advance, which will involve testing and additional inspections to ensure compliance with FDA regulations and standards and may require significant lead times and delay.
To adequately meet our projected commercial manufacturing needs, our CMOs will need to scale-up production, or we will need to secure additional suppliers. Processes for producing drug substances and drug product for commercial supply are currently being developed, with the goal of achieving reliable, reproducible, and cost-effective production. We believe the drug substance and drug product processes for our current product candidates can be appropriately scaled.
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Competition
The biotechnology and pharmaceutical industries are characterized by rapidly advancing technologies, intense competition and a strong emphasis on proprietary products. While we believe our product candidates, platform, knowledge, experience and scientific personnel provide us with competitive advantages, we face potential competition from many different sources, including large and small pharmaceutical and biotechnology companies, academic institutions and governmental agencies as well as public and private research institutions. Any product candidates that we successfully develop and commercialize, including RAP-219, may compete with existing therapies and new therapies that may become available in the future.
Our competitors may have significantly greater financial resources, established presence in the market, expertise in research and development, manufacturing, preclinical and clinical testing, obtaining regulatory approvals and reimbursement and marketing approved products than we do. Mergers and acquisitions in the biotechnology and pharmaceutical industries may result in even more resources being concentrated among a smaller number of competitors. These competitors also compete with us in recruiting and retaining qualified scientific, sales, marketing and management personnel, establishing clinical trial sites and patient registration for clinical trials, as well as in acquiring technologies complementary to, or necessary for, our programs. Smaller or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies.
The key competitive factors affecting the success of RAP-219, and any other product candidates that we develop to address focal epilepsy and other neurological and psychiatric disorders, if approved, are likely to be efficacy, safety, convenience, price, the level of generic competition and the availability of reimbursement from government and other third-party payors.
Focal Epilepsy
In the field of focal epilepsy, we face competition from a variety of currently marketed therapies such as generic anticonvulsants, ASMs, sodium channel modulators and benzodiazepines, devices such as deep brain stimulation like the RNS system as well as brain surgeries in patients who have failed polypharmacy. RAP-219 may face competition from currently marketed therapies such as XCOPRI (cenobamate), which was developed by SK Life Science Inc. and approved by the FDA in November 2019 and FYCOMPA (perampanel), which was developed by Eisai Co. Ltd. and approved by the FDA in 2012. Our competition for RAP-219 may also include therapies in clinical development, such as XEN1101 being developed by Xenon Pharmaceuticals Inc., BHV-7000 being developed by Biohaven Ltd. (“Biohaven”), PRAX-628 being developed by Praxis Precision Medicines, Inc., darigabet being developed by Cerevel Therapeutics Holdings, Inc., ES-481 being developed by ES Therapeutics Australia Pty Ltd., SPN-817 being developed by Supernus Pharmaceuticals, Inc. and ADX71149 being developed by Addex Therapeutics Ltd. in partnership with Janssen Pharmaceuticals, Inc.
Bipolar Disorder
In the field of bipolar disorder, RAP-219 faces competition from mood stabilizers (e.g. lithium and Lamictal) and antidepressants (e.g. selective serotonin reuptake inhibitors and serotonin and norepinephrine reuptake inhibitors). Our competition may also include other programs in clinical development for the treatment of disorder in bipolar disorder, such as BHV-7000 being developed by Biohaven.
Peripheral Neuropathic Pain
In the field of peripheral neuropathic pain, our principal competition is from existing therapies, which include antidepressants (e.g., duloxetine, venlafaxine, amitriptyline and other tricyclic drugs), gabapentinoids (e.g., gabapentin, pregabalin), and opioids (e.g., tapentadol hydrochloride). We are also aware that various therapies are used off-label to treat peripheral neuropathic pain. Our competition may also include other programs in clinical development in peripheral neuropathic pain, such as VX-548 being developed by Vertex, Inc., LX9211 being developed by Lexicon Pharmaceuticals, Inc. and BHV-2100 being developed by Biohaven.
Intellectual Property
We strive to protect and enhance the proprietary technology, inventions and improvements that are commercially important to the development of our business, including seeking, maintaining and defending patent rights, whether developed internally or licensed from third parties. We may also rely on trademarks, copyrights and trade secrets relating to our proprietary technology platform and on know-how, continuing technological innovation and in-licensing opportunities to develop, strengthen and maintain our proprietary and intellectual property position. We additionally may rely on regulatory and other protections afforded through data exclusivity, market exclusivity and patent term extensions, where available.
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Our commercial success depends in part upon our ability to obtain and maintain patent and other proprietary protection for commercially important technologies, inventions and trade secrets related to our business, defend and enforce our intellectual property rights, particularly our patent rights, preserve the confidentiality of our trade secrets and operate without infringing valid and enforceable intellectual property rights of others.
The patent positions for biotechnology and pharmaceutical companies like us are generally uncertain and can involve complex legal, scientific and factual issues. In addition, the coverage claimed in a patent application can be significantly reduced before a patent is issued, and its scope can be reinterpreted and even challenged after issuance. As a result, we cannot guarantee that any of our product candidates will be protectable or remain protected by enforceable patents. We cannot predict whether the patent applications we are currently pursuing will issue as patents in any particular jurisdiction or whether the claims of any issued patents will provide sufficient proprietary protection from competitors. Any patents that we hold may be challenged, circumvented or invalidated by third parties.
TARP8 Program
We own six patent families directed to TARP8 modulators. A first patent family is directed to compositions of matter of certain TARP8 modulators, including RAP-219, and methods of use and expires in 2036, without taking a potential patent term extension into account. As of March 1, 2025, this patent family has one U.S. patent, one European patent, validated in 40 states, over 25 patents in various other foreign jurisdictions, two U.S. pending application, and over 10 applications pending in foreign jurisdictions. A second patent family is directed to compositions of matter of certain TARP8 modulators and methods of use and expires in 2037, without taking a potential patent term extension into account. As of March 1, 2025, this patent family has one U.S. patent. A third patent family is directed to compositions of matter of certain TARP8 modulators and methods of use and expires in 2037, without taking a potential patent term extension into account. As of March 1, 2025, this patent family has one U.S. patent, one European patent, validated in eight states, over 10 patents in various other foreign jurisdictions, and one application pending in a foreign jurisdiction. A fourth patent family is directed to compositions of matter of certain TARP8 modulators and methods of use and expires in 2037, without taking a potential patent term extension into account. As of March 1, 2025, this patent family has one U.S. patent, one European patent, validated in six states, more than 10 patents in various other foreign jurisdictions, and three applications pending in foreign jurisdictions. A fifth patent family is directed to crystalline forms of a TARP8 modulator and methods of use and expires in 2045, if granted, without taking a potential patent term extension into account. As of March 1, 2025, this patent family has one pending international application filed under the Patent Cooperation Treaty. A sixth patent family is directed to methods of use and oral doses of a TARP8 modulator and expires in 2045, if granted, without taking a potential patent term extension into account. As of March 1, 2025, this patent family has one pending US provisional application.
nAChR Program
We own one patent family directed to nAChR modulators. This patent family is directed to compositions of matter of certain nAChR modulators and methods of use and expires in 2046, if granted, without taking a potential patent term extension into account. As of March 1, 2025, this patent family has one pending US provisional application.
We have also non-exclusively in-licensed from Janssen Pharmaceutica NV three patent families directed to recombinant cells for the expression of nAChRs. A first patent family is directed to expression systems for the 910 nicotinic acetylcholine receptor and methods of use and expires in 2040, without taking a potential patent term extension into account. As of March 1, 2025, this patent family has one U.S. pending application and three applications pending in foreign jurisdictions. A second patent family is directed to expression systems for the 252 nicotinic acetylcholine receptor and methods of use and expires in 2042, if granted, without taking a potential patent term extension into account. As of March 1, 2025, this patent family has one U.S. pending application and multiple applications in foreign jurisdictions. A third patent family is directed to 64 nicotinic acetylcholine receptor and methods of use and expires in 2042, if granted, without taking a potential patent term extension into account. As of March 1, 2025, this patent family has one U.S. pending application and multiple applications in foreign jurisdictions.
The term of individual patents depends upon the legal term of the patents in the countries in which they are obtained. In most countries in which we file, the patent term is 20 years from the earliest date of filing a non-provisional patent application.
In the United States, the term of a patent covering an FDA-approved drug may be eligible for a patent term extension under the Hatch-Waxman Act as compensation for the loss of patent term during the FDA regulatory review process. The period of extension may be up to five years beyond the expiration of the patent, but cannot extend the remaining term of a patent beyond a total of 14 years from the date of product approval. Only one patent among those eligible for an extension may be extended, and a given patent may only be extended once. Similar provisions are available in Europe and in certain other jurisdictions to extend the term of a patent that covers an approved drug. If our product candidates receive FDA approval, we intend to apply for patent term extensions, if available, to extend the term of patents that cover the approved product candidates. We also intend to seek patent term
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extensions in any jurisdictions where they are available, however, there is no guarantee that the applicable authorities, including the FDA, will agree with our assessment of whether such extensions should be granted, and even if granted, the length of such extensions.
In addition to patent protection, we also rely on know-how and trade secret protection for our proprietary information to develop and maintain our proprietary position. However, trade secrets can be difficult to protect. Although we take steps to protect our proprietary information, including restricting access to our premises and our confidential information, as well as entering into agreements with our employees, consultants, advisors and potential collaborators, third parties may independently develop the same or similar proprietary information or may otherwise gain access to our proprietary information. As a result, we may be unable to meaningfully protect our know-how, trade secrets, and other proprietary information.
In addition, we plan to rely on regulatory protection based on drug exclusivities, data exclusivities, and market exclusivities. See the section titled “—Government Regulation” for additional information.
License and collaboration agreements
Option and License Agreement with Janssen Pharmaceutical NV
In August 2022, we entered into an option and license agreement with Janssen Pharmaceutical NV, as amended on April 3, 2023, April 18, 2023, May 2, 2023, October 2, 2023, and April 9, 2024 (collectively, the “Janssen License”), under which we received an exclusive option to obtain from Janssen (a) a worldwide exclusive license for the research, development, and commercialization of transmembrane TARP8 AMPAR products for the diagnosis, treatment, prophylaxis or palliation of any disease or condition in humans or other animals (the “Field”) and (b) an assignment of certain patents related to TARP8, in each case of (a)-(b), subject to certain retained rights by Janssen. Pursuant to the Janssen License, we also received a worldwide, royalty-free, non-exclusive license (exclusive under certain joint patents) for the research, development, and commercialization of certain neuronal nicotinic acetylcholine (“nACh”) products in the Field.
We made a non-refundable, non-creditable upfront payment of $1.0 million to Janssen after we entered into the Janssen License. In October 2022, we exercised the option and paid a non-refundable, non-creditable option fee of $4.0 million to Janssen. If we succeed in developing and commercializing TARP8 products, Janssen will be eligible to receive (i) up to $76.0 million in development milestone payments and up to $40.0 million in sales milestone payments for the product containing the lead TARP8 development candidate, and (ii) up to $25.0 million in development milestone payments and up to $42.0 million sales milestone payments for other TARP8 products containing a non-lead TARP8 development candidate.
Janssen is also eligible to receive (a) royalties ranging from mid to high-single digit percentages on worldwide net sales of any products containing a TARP8 development candidate and (b) royalties ranging from low to mid-single digit percentages for other TARP8 products that do not contain a TARP8 development candidate, in each case of (a) and (b), subject to potential reductions following the expiration of valid claims and regulatory exclusivity covering such TARP8 products, the launch of certain generic products and the application of certain anti-stacking reductions for third party intellectual property payments, subject to a customary reduction floor. The royalties for any TARP8 product will expire on a country-by-country basis upon the latest to occur of (i) the expiration of all valid patent claims covering such product in such country, (ii) the expiration of all regulatory exclusivities in such country, and (iii) a specified number of years following the first commercial sale of such product in such country. The Janssen License provides us with certain other exclusive rights with respect to small molecules with activity against TARP8 and nACh.
We have the right to terminate the Janssen License for any or no reason upon providing prior written notice to Janssen upon ninety (90) days’ prior written notice to Janssen. Either party may terminate the license agreement in its entirety for the other party’s material breach if such party fails to cure the breach or upon certain insolvency events involving the other party.
NeuroPace Master Services Agreement and Statement of Work
In November 2023, we entered into a master services agreement (the “NeuroPace Agreement”) with NeuroPace Inc. (“NeuroPace”), the manufacturer and distributor of the responsive neurostimulation (“RNS”) system. Pursuant to the NeuroPace Agreement and in accordance with statement of work agreements entered into from time to time, NeuroPace provides us with certain services with respect to data from the RNS systems used in our clinical trials. The NeuroPace Agreement also grants us a royalty-free, worldwide, exclusive, non-transferable license to all data collected by the RNS systems in our Phase 2a clinical trial and the outcomes of algorithms that are applied to such data, as well as the ability to publish the outcomes of algorithms, subject to certain conditions. The consideration we will pay to NeuroPace for such services is set out in each statement of work agreement.
The NeuroPace Agreement contains an exclusivity provision providing that, at any time while providing services under the NeuroPace Agreement and for a period after the final clinical study report, NeuroPace may not perform any services that are the same as the services covered by the NeuroPace Agreement to any business that directly competes with us, subject to the specific
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terms of the NeuroPace Agreement. The NeuroPace Agreement also contains standard representations and warranties, confidentiality and intellectual property protective provisions and indemnification terms.
The NeuroPace Agreement expires on the later of three years from the effective date or the completion of all services under all statement of work agreements entered into prior to the third anniversary of the effective date. Either party may terminate the NeuroPace Agreement or any statement of work agreement (i) without cause by giving written notice to the other party within a specified period of time, (ii) by giving written notice upon a curable material breach that is not remediated within a specified period of time, or (iii) immediately upon written notice in the event of a material breach that cannot be cured.
Concurrently with the execution of the NeuroPace Agreement, the parties also entered into an initial statement of work, as amended in March 2024 (the “NeuroPace SOW”), under the NeuroPace Agreement, pursuant to which NeuroPace agreed to provide services related to our Phase 2a clinical trial of RAP-219, including, among other things, clinical trial readiness support, identification of potential patients satisfying the enrollment criteria and RNS system data reporting and data analysis. Pursuant to the payment schedule set out in the NeuroPace SOW, we will pay NeuroPace an aggregate of up to $3.7 million over a period of approximately two years in connection with NeuroPace’s provision of services and achievement of certain patient enrollment and deliverable milestones.
Government Regulation
Government authorities in the United States, at the federal, state and local level, and in other countries and jurisdictions, including the European Union (“EU”), extensively regulate, among other things, the research, development, testing, manufacture, quality control, approval, packaging, storage, recordkeeping, labeling, advertising, promotion, distribution, marketing, post-approval monitoring and reporting, and import and export of pharmaceutical products. The processes for obtaining regulatory approvals in the United States and in foreign countries and jurisdictions, along with subsequent compliance with applicable statutes and regulations, require the expenditure of substantial time and financial resources.
Review and Approval of Drugs in the United States
In the United States, the FDA regulates drugs under the U.S. Federal Food, Drug, and Cosmetic Act (“FDCA”) and its implementing regulations. The failure to comply with applicable U.S. requirements at any time during the product development process, approval process or after approval may subject an applicant and/or sponsor to a variety of administrative or judicial sanctions, including refusal by the FDA to approve pending applications, withdrawal of an approval, imposition of a clinical hold, issuance of warning letters and other types of letters, product seizures, total or partial suspension of production or distribution, injunctions, fines, refusals of government contracts, restitution, disgorgement of profits, or civil or criminal investigations and penalties brought by the FDA and the U.S. Department of Justice or other governmental entities. In addition, an applicant may need to recall a product.
An applicant seeking approval to market and distribute a new drug product in the United States must typically undertake the following:
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completion of nonclinical, or preclinical, laboratory tests, animal studies and formulation studies in compliance with the FDA’s GLP regulations;
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submission to the FDA of an investigational new drug application (“IND”) which must take effect before human clinical trials may begin;
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approval by an institutional review board (“IRB”) representing each clinical site before each clinical trial may be initiated at that site;
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performance of adequate and well-controlled human clinical trials in accordance with good clinical practices (“GCPs”) to establish the safety and efficacy of the proposed drug product for each indication;
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preparation and submission to the FDA of a New Drug Application (“NDA”) and payment of user fees;
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review of the product by an FDA advisory committee, where appropriate or if applicable;
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satisfactory completion of one or more FDA inspections of the manufacturing facility or facilities at which the product, or components thereof, are produced to assess compliance with current Good Manufacturing Practices (“cGMP”) requirements and to assure that the facilities, methods and controls are adequate to preserve the product’s identity, strength, quality and purity;
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satisfactory completion of FDA audits of clinical trial sites to assure compliance with GCPs and the integrity of the clinical data;
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FDA review and approval of the NDA; and
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compliance with any post-approval requirements, including risk evaluation and mitigation strategies (“REMS”) and post-approval studies required by the FDA.
Preclinical Studies
Before an applicant begins testing a compound in humans, the drug candidate enters the preclinical testing stage. Preclinical studies include laboratory evaluation of the purity and stability of the manufactured drug substance or active pharmaceutical ingredient (“API”) and the formulated drug or drug product, as well as in vitro and animal studies to assess the safety and activity of the drug for initial testing in humans and to establish a rationale for therapeutic use. The conduct of preclinical studies is subject to federal regulations and requirements, including GLP regulations. Some long-term preclinical testing, such as animal tests of reproductive adverse effects and carcinogenicity, may continue after the IND is submitted.
The IND and IRB Processes
An IND is an exemption from the FDCA that allows an unapproved drug to be shipped in interstate commerce for use in an investigational clinical trial and a request for FDA authorization to administer such investigational drug to humans. Such authorization must be secured prior to interstate shipment and administration of the investigational drug. In an IND, applicants must submit a protocol for each clinical trial and any subsequent protocol amendments. In addition, the results of the preclinical tests, manufacturing information, analytical data, any available clinical data or literature and plans for clinical trials, among other things, are submitted to the FDA as part of an IND. An IND automatically becomes effective 30 days after receipt by the FDA, unless before that time, the FDA raises concerns or questions related to one or more proposed clinical trials and places the trial on clinical hold. The FDA also may impose a clinical hold or partial clinical hold after commencement of a clinical trial under an IND. A clinical hold is an order issued by the FDA to the sponsor to delay a proposed clinical investigation or to suspend an ongoing investigation. A partial clinical hold is a delay or suspension of only part of the clinical work requested under the IND. No more than 30 days after imposition of a clinical hold or partial clinical hold, the FDA will provide the sponsor a written explanation of the basis for the hold. Following issuance of a clinical hold or partial clinical hold, an investigation (or full investigation in the case of a partial clinical hold) may only resume after the FDA has notified the sponsor that the investigation may proceed. The FDA will base that determination on information provided by the sponsor correcting the deficiencies previously cited or otherwise satisfying the FDA that the investigation can proceed.
A sponsor may choose, but is not required, to conduct a foreign clinical trial under an IND. When a foreign clinical trial is conducted under an IND, all FDA IND requirements must be met unless waived. When the foreign clinical trial is not conducted under an IND, the sponsor must ensure that the study is conducted in accordance with GCP, including review and approval by an independent ethics committee (“IEC”) and informed consent from subjects. The GCP requirements are intended to help ensure the protection of human subjects enrolled in non-IND foreign clinical trials, as well as the quality and integrity of the resulting data. FDA must also be able to validate the data from the study through an on-site inspection if necessary.
In addition to the foregoing IND requirements, an IRB representing each institution participating in the clinical trial must review and approve the plan for any clinical trial before it commences at that institution, and the IRB must conduct continuing review of the study at least annually. The IRB must review and approve, among other things, the study protocol and informed consent information to be provided to study subjects. An IRB must operate in compliance with FDA regulations. An IRB can suspend or terminate approval of a clinical trial at its institution, or an institution it represents, if the clinical trial is not being conducted in accordance with the IRB’s requirements or if the product candidate has been associated with unexpected serious harm to patients.
Additionally, some trials are overseen by an independent group of qualified experts organized by the trial sponsor, known as a data safety monitoring board or committee. This group provides authorization for whether or not a trial may move forward at designated check points based on access that only the group maintains to available data from the study. The FDA or the sponsor may suspend or terminate a clinical trial at any time on various grounds, including a finding that the research subjects are being exposed to an unacceptable health risk. Other reasons for suspension or termination may be made by us based on evolving business objectives and/or competitive climate.
Information about certain clinical trials must be submitted within specific timeframes to the National Institutes of Health (“NIH”) for public dissemination on its ClinicalTrials.gov website.
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Human Clinical Trials in Support of an NDA
Clinical trials involve the administration of the investigational product to human subjects under the supervision of qualified investigators in accordance with GCP requirements, which include, among other things, the requirement that all research subjects, or their legal representative, provide their informed consent in writing before their participation in any clinical trial. Clinical trials are conducted under written study protocols detailing, among other things, the inclusion and exclusion criteria, the objectives of the study, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated.
Human clinical trials are typically conducted in three sequential phases, which may overlap or be combined:
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Phase 1. The drug is initially introduced into healthy human subjects or, in certain indications such as cancer, patients with the target disease or condition and tested for safety, dosage tolerance, absorption, metabolism, distribution, excretion and, if possible, to gain an early indication of its effectiveness and to determine maximal dosage.
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Phase 2. The drug is administered to a limited patient population to identify possible AEs and safety risks, to preliminarily evaluate the efficacy of the product for specific targeted diseases and to determine dosage tolerance and optimal dosage.
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Phase 3. The drug is administered to an expanded patient population, generally at geographically dispersed clinical trial sites, in well-controlled clinical trials to generate enough data to evaluate the efficacy and safety of the product for approval, to establish the overall risk-benefit profile of the product and to provide adequate information for the labeling of the product.
Post-approval studies, often referred to as Phase 4 studies, may be conducted after initial regulatory approval. These studies are used to gain additional experience from the treatment of patients in the intended therapeutic indication.
Progress reports detailing the results of the clinical trials must be submitted at least annually to the FDA. In addition, within 15 calendar days after the sponsor determines that the information qualifies for reporting, IND safety reports must be submitted to the FDA for any of the following: serious and unexpected suspected adverse reactions; findings from other studies or animal or in vitro testing that suggest a significant risk in humans exposed to the drug; and any clinically important increase in the case of a serious suspected adverse reaction over that listed in the protocol or investigator brochure. The sponsor also must notify the FDA of any unexpected fatal or life-threatening suspected adverse reaction within seven calendar days after the sponsor’s initial receipt of the information. Phase 1, Phase 2 and Phase 3 clinical trials may not be completed successfully within any specified period, or at all. The FDA will typically inspect one or more clinical sites to assure compliance with GCP and the integrity of the clinical data submitted.
Concurrent with clinical trials, companies often complete additional animal studies and must also develop additional information about the chemistry and physical characteristics of the drug as well as finalize a process for manufacturing the product in commercial quantities in accordance with cGMP requirements. The manufacturing process must be capable of consistently producing quality batches of the drug candidate and, among other things, the applicant must develop methods for testing the identity, strength, quality, purity, and potency 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.
Review of an NDA by the FDA
Assuming successful completion of required clinical testing and other requirements, the results of the preclinical studies and clinical trials, together with detailed information relating to the product’s chemistry, manufacture, controls and proposed labeling, among other things, are submitted to the FDA as part of an NDA requesting approval to market the drug product for one or more indications. Under federal law, the submission of most NDAs is additionally subject to a significant application user fee as well as annual prescription drug product program fees. These fees are typically increased annually. Certain exceptions and waivers are available for some of these fees.
The FDA conducts a preliminary review of an NDA within 60 days of its receipt, before accepting the NDA for filing, to determine whether the application is sufficiently complete to permit substantive review. The FDA may request additional information rather than accept an NDA for filing. In this event, the application must be resubmitted with the additional information. The resubmitted application is also subject to review before the FDA accepts it for filing. Once the submission is accepted for filing, the FDA begins an in-depth substantive review. The FDA has agreed to specified performance goals in the review process of NDAs. Applications for drugs containing new molecular entities are meant to be reviewed within 10 months from the date of filing, and applications for “priority review” products containing new molecular entities are meant to be reviewed within 6 months of filing.
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The review process may be extended by the FDA for three additional months to consider new information or clarification provided by the applicant to address an outstanding deficiency identified by the FDA following the original submission.
During its review of an NDA, the FDA typically will inspect the facility or facilities where the product is or will be manufactured. These pre-approval inspections may cover all facilities associated with an NDA, including drug component manufacturing (such as APIs), finished drug product manufacturing, and control testing laboratories. The FDA will not approve an NDA unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications.
In addition, as a condition of approval, the FDA may require an applicant to develop a REMS. REMS use risk minimization strategies beyond the professional labeling to ensure that the benefits of the product outweigh the potential risks. To determine whether a REMS is needed, the FDA will consider the size of the population likely to use the product, seriousness of the disease, expected benefit of the product, expected duration of treatment, seriousness of known or potential AEs, and whether the product is a new molecular entity. REMS can include medication guides, physician communication plans for healthcare professionals, and elements to assure safe use (“ETASU”). ETASU may 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 FDA may require a REMS before approval or post-approval if it becomes aware of a serious risk associated with use of the product.
The FDA is required to refer an application for a novel drug to an advisory committee or explain why such referral was not made. Typically, an advisory committee is a panel of independent experts, including clinicians and other scientific experts, that reviews, evaluates and provides a recommendation as to whether the application should be approved and under what conditions. The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions.
Fast Track, Breakthrough Therapy, and Priority Review
The FDA has a number of programs intended to facilitate and expedite development and review of new drugs if they are intended to address an unmet medical need in the treatment of a serious or life-threatening disease or condition. Three of these programs are referred to as Fast Track Designation, Breakthrough Therapy Designation, and priority review designation.
Specifically, the FDA may designate a product for Fast Track review if it is intended, whether alone or in combination with one or more other products, for the treatment of a serious or life-threatening disease or condition, and it demonstrates the potential to address unmet medical needs for such a disease or condition. For Fast Track products, sponsors may have greater interactions with the FDA and the FDA may initiate review of sections of a Fast Track product’s application before the application is complete. This rolling review may be available if the FDA determines, after preliminary evaluation of clinical data submitted by the sponsor, that a Fast Track product may be effective. The sponsor must also provide, and the FDA must approve, a schedule for the submission of the remaining information and the sponsor must pay applicable user fees. However, the FDA’s time period goal for reviewing a Fast Track application does not begin until the last section of the application is submitted. In addition, the Fast Track Designation may be withdrawn by the FDA if the FDA believes that the designation is no longer supported by data emerging in the clinical trial process.
Second, a product may be designated as a Breakthrough Therapy if it is intended, either alone or in combination with one or more other products, to treat a serious or life-threatening disease or condition and preliminary clinical evidence indicates that the product may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. The FDA may take certain actions with respect to Breakthrough Therapies, including holding meetings with the sponsor throughout the development process; providing timely advice to the product sponsor regarding development and approval; involving more senior staff in the review process; assigning a cross-disciplinary project lead for the review team; and taking other steps to design the clinical trials in an efficient manner.
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Third, the FDA may designate an NDA review for a priority review if it is for a product that treats a serious or life-threatening disease or condition and, if approved, would provide a significant improvement in safety or effectiveness. The FDA determines, on a case-by-case basis, whether the proposed product represents a significant improvement when compared with other available therapies. Significant improvement may be illustrated by evidence of increased effectiveness in the treatment of a condition, elimination or substantial reduction of a treatment-limiting product reaction, documented enhancement of patient compliance that may lead to improvement in serious outcomes, and evidence of safety and effectiveness in a new subpopulation. A priority designation is intended to direct overall attention and resources to the evaluation of such applications, and to shorten the FDA’s goal for taking action on a marketing application from 10 months to 6 months.
Accelerated Approval Pathway
The FDA may grant accelerated approval to a product for a serious or life-threatening condition that provides meaningful therapeutic advantage to patients over existing treatments based upon a determination that the product has an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit or on an intermediate clinical endpoint that can be measured earlier than an effect on irreversible morbidity or mortality (“IMM”), and that is reasonably likely to predict an effect on IMM or other clinical benefit, taking into account the severity, rarity, or prevalence of the condition and the availability or lack of alternative treatments. Products granted accelerated approval must meet the same statutory standards for safety and effectiveness as those granted traditional approval.
For the purposes of accelerated approval, a surrogate endpoint is a marker, such as a laboratory measurement, radiographic image, physical sign, or other measure that is thought to predict clinical benefit, but is not itself a measure of clinical benefit. Surrogate endpoints can often be measured more easily or more rapidly than clinical endpoints. An intermediate clinical endpoint is a measurement of a therapeutic effect that is considered reasonably likely to predict the clinical benefit of a product, such as an effect on IMM. The FDA has limited experience with accelerated approvals based on intermediate clinical endpoints, but has indicated that such endpoints generally may support accelerated approval where the therapeutic effect measured by the endpoint is not itself a clinical benefit and basis for traditional approval, if there is a basis for concluding that the therapeutic effect is reasonably likely to predict the ultimate clinical benefit of a product.
The accelerated approval pathway is most often used in settings in which the course of a disease is long and an extended period of time is required to measure the intended clinical benefit of a product, even if the effect on the surrogate or intermediate clinical endpoint occurs rapidly.
The accelerated approval pathway is contingent on a sponsor’s agreement to conduct, in a diligent manner, additional post-approval confirmatory studies to verify and describe the product’s clinical benefit. As a result, a product candidate approved on this basis is subject to rigorous post-marketing compliance requirements, including the completion of Phase 4 or post-approval clinical trials to confirm the effect on the clinical endpoint. Under the Food and Drug Omnibus Reform Act of 2022 (“FDORA”), the FDA is now permitted to require, as appropriate, that such trials be underway prior to approval or within a specific time period after the date of approval for a product granted accelerated approval. Sponsors are also required to send updates to the FDA every 180 days on the status of such studies, including progress toward enrollment targets, and the FDA must promptly post this information publicly. Under FDORA, the FDA has increased authority for expedited procedures to withdraw approval of a drug or indication approved under accelerated approval if, for example, the sponsor fails to conduct such studies in a timely manner and send the necessary updates to the FDA, or if a confirmatory trial fails to verify the predicted clinical benefit of the product. In addition, the FDA generally requires, unless otherwise informed by the agency, pre-approval of promotional materials for product candidates approved under accelerated regulations, which could adversely impact the timing of the commercial launch of the product.
The FDA’s Decision on an NDA
On the basis of the FDA’s evaluation of the NDA and accompanying information, including the results of the inspection of the manufacturing facilities and select clinical trial sites, the FDA may issue an approval letter or a complete response letter. An approval letter authorizes commercial marketing of the product with specific prescribing information for specific indications. A complete response letter generally outlines the deficiencies in the submission and may require substantial additional testing or information in order for the FDA to reconsider the application. If a complete response letter is issued, the applicant may resubmit the NDA to address all of the deficiencies identified in the letter, withdraw the application, or request a hearing. If the applicant resubmits the NDA, the FDA will issue an approval letter only when the deficiencies have been addressed to the FDA’s satisfaction. The FDA has committed to reviewing such resubmissions in 2 or 6 months depending on the type of information included. Even with submission of this additional information, the FDA ultimately may decide that the application does not satisfy the regulatory criteria for approval.
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If the FDA approves a product, it may limit the approved indications for use for the product, require that contraindications, warnings or precautions be included in the product labeling, require that post-approval studies, including Phase 4 clinical trials, be conducted to further assess the drug’s safety or effectiveness after approval, require testing and surveillance programs to monitor the product after commercialization, or impose other conditions, including distribution restrictions or other risk management mechanisms, including REMS, which can materially affect the potential market and profitability of the product. The FDA may prevent or limit further marketing of a product based on the results of post-market studies or surveillance programs.
Post-Approval Requirements
Drugs manufactured or distributed pursuant to FDA approvals are subject to pervasive and continuing regulation by the FDA, including, among other things, requirements relating to recordkeeping, periodic reporting, product sampling and distribution, advertising and promotion, reporting of adverse experiences with the product and applicable product tracking and tracing requirements. After approval, many changes to the approved product, such as adding new indications or other labeling claims, are subject to prior FDA review and approval. There also are annual prescription drug product program fee requirements for certain marketed products.
In addition, drug manufacturers and other entities involved in the manufacture and distribution of approved drugs are required to register their establishments with the FDA and state agencies, and are subject to periodic unannounced inspections by the FDA and these state agencies for compliance with cGMP requirements. Changes to the manufacturing process are strictly regulated and often require prior FDA approval before being implemented. FDA regulations also require investigation and correction of any deviations from cGMP and impose reporting and documentation requirements upon the NDA holder and any third-party manufacturers that the NDA holder may decide to use. Accordingly, manufacturers must continue to expend time, money, and effort in the area of production and quality control to maintain cGMP compliance.
Once an approval is granted, the FDA may withdraw the approval if compliance with regulatory requirements and standards is not maintained or if problems occur after the product reaches the market. Later discovery of previously unknown problems with a product, including AEs of unanticipated severity or frequency, or with manufacturing processes, or failure to comply with regulatory requirements, may result in revisions to the approved labeling to add new safety information; imposition of post-market studies or clinical trials to assess new safety risks; or imposition of distribution or other restrictions under a REMS program. Other potential consequences include, among other things:
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restrictions on the marketing or manufacturing of the product, complete withdrawal of the product from the market or voluntary product recalls;
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fines, warning or untitled letters or holds on post-approval clinical trials;
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refusal of the FDA to approve pending NDAs or supplements to approved NDAs, or suspension or revocation of product approvals;
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product seizure or detention, or refusal to permit the import or export of products; or
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injunctions or the imposition of civil or criminal penalties.
The FDA strictly regulates marketing, labeling, advertising and promotion of products that are placed on the market. Drugs may be promoted only for the approved indications and in accordance with the provisions of the approved label. However, companies may share truthful and not misleading information that is otherwise consistent with a product’s FDA approved labeling. The FDA and other agencies actively enforce the laws and regulations prohibiting the promotion of off-label uses, and a company that is found to have improperly promoted off-label uses may be subject to significant liability.
In addition, the distribution of prescription pharmaceutical products is subject to the Prescription Drug Marketing Act (“PDMA”), which regulates the distribution of drugs and drug samples at the federal level, and sets minimum standards for the registration and regulation of drug distributors by the states. Both the PDMA and state laws limit the distribution of prescription pharmaceutical product samples and impose requirements to ensure accountability in distribution.
From time to time, legislation is drafted, introduced, passed in Congress and signed into law that could significantly change the statutory provisions governing the approval, manufacturing, and marketing of products regulated by the FDA. In addition to new legislation, FDA regulations, guidance, and policies are often revised or reinterpreted by the agency in ways that may significantly affect the manner in which pharmaceutical products are regulated and marketed.
Hatch-Waxman Amendments
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Section 505 of the FDCA describes three types of marketing applications that may be submitted to the FDA to request marketing authorization for a new drug. A Section 505(b)(1) NDA is an application that contains full reports of investigations of safety and efficacy. A 505(b)(2) NDA is an application that contains full reports of investigations of safety and efficacy but where at least some of the information required for approval comes from investigations that were not conducted by or for the applicant and for which the applicant has not obtained a right of reference or use from the person by or for whom the investigations were conducted. This regulatory pathway enables the applicant to rely, in part, on the FDA’s prior findings of safety and efficacy for an existing product, or published literature, in support of its application. Section 505(j) establishes an abbreviated approval process for a generic version of approved drug products through the submission of an Abbreviated New Drug Application (“ANDA”). An ANDA provides for marketing of a generic drug product that has the same active ingredients, dosage form, strength, route of administration, labeling, performance characteristics and intended use, among other things, to a previously approved product, known as a reference listed drug (“RLD”). ANDAs are termed “abbreviated” because they are generally not required to include preclinical (animal) and clinical (human) data to establish safety and efficacy. Instead, generic applicants must scientifically demonstrate that their product is bioequivalent to, or performs in the same manner as, the innovator drug through in vitro, in vivo, or other testing. The generic version must deliver the same amount of active ingredients into a subject’s bloodstream in the same amount of time as the innovator drug and can often be substituted by pharmacists under prescriptions written for the reference listed drug.
Non-Patent Exclusivity