10-K
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United States
Securities and Exchange Commission
Washington, D.C. 20549
FORM 10-K
For the fiscal year ended December 31, 2025
OR
For the transition period from to
Commission File No. 001-33407
Perspective Therapeutics, Inc.
(Exact name of registrant as specified in its charter)
(State of incorporation) (I.R.S. EmployerIdentification No.)
(Address of principal executive offices) (Zip code)
Registrant’s telephone number, including area code: (206) 676-0900
Securities registered pursuant to Section 12(b) of the Act
Title of each class Trading Symbol(s) Name of exchange on which registered
Common Stock, $0.001 par value CATX NYSE American
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 Section 15(d) of the Act. Yes ☐No☒
Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes☒ No ☐
Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes☒ No ☐
Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “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 Act): Yes ☐ No ☒
As of June 30, 2025, the last business day of the registrant’s most recently completed second fiscal quarter, the approximate aggregate market value of voting and non-voting common equity held by non-affiliates of the registrant was $212,873,547 based on the closing price of the registrant’s common stock on June 30, 2025.
As of March 12, 2026, the number of shares outstanding of the registrant’s common stock, $0.001 par value per share, was 113,933,436.
INCORPORATION BY REFERENCE
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Part III of this Annual Report on Form 10-K incorporates certain information by reference from the registrant's proxy statement for the 2026 annual meeting of stockholders to be filed no later than 120 days after the end of the registrant's fiscal year ended December 31, 2025.
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PERSPECTIVE THERAPEUTICS, INC.
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PART I
ITEM 1 – BUSINESS 6
ITEM 1A – RISK FACTORS 39
ITEM 1B – UNRESOLVED STAFF COMMENTS 68
ITEM 1C – CYBERSECURITY 68
ITEM 2 – PROPERTIES 69
ITEM 3 – LEGAL PROCEEDINGS 70
ITEM 4 – MINE SAFETY DISCLOSURES 70
PART II
ITEM 6 – [RESERVED] 71
ITEM 7A – QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK 86
ITEM 8 – FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA 86
ITEM 9A – CONTROLS AND PROCEDURES 86
ITEM 9B – OTHER INFORMATION 86
ITEM 9C – DISCLOSURE REGARDING FOREIGN JURISDICTIONS THAT PREVENT INSPECTIONS 86
PART III
ITEM 10 – DIRECTORS, EXECUTIVE OFFICERS AND CORPORATE GOVERNANCE 87
ITEM 11 – EXECUTIVE COMPENSATION 87
ITEM 14 – PRINCIPAL ACCOUNTANT FEES AND SERVICES 87
PART IV
ITEM 15 – EXHIBITS AND FINANCIAL STATEMENT SCHEDULES 88
SIGNATURES 90
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CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS
In addition to historical information, this Annual Report on Form 10-K (“Annual Report” or “Form 10-K”), contains certain “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995 (PSLRA). This statement is included for the express purpose of availing Perspective Therapeutics, Inc. of the protections of the safe harbor provisions of the PSLRA.
This Form 10-K, including Management’s Discussion and Analysis of Financial Condition and Results of Operations in Part II, Item 7, contains forward-looking statements within the meaning of 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 contained in this Form 10-K other than statements of historical fact, including, without limitation, statements regarding our future financial condition, results of operations, business strategy and plans and objectives of management for future operations, industry trends and other future events are forward-looking statements. In some cases, you can identify forward-looking statements by terminology, such as “believe,” “expect,” “anticipate,” “intend,” “estimate,” “forecast,” “project,” “may,” “could,” “might,” “plan,” “should,” “will,” “would” or the negative of these terms and other similar expressions, although not all forward-looking statements contain these identifying terms. Forward-looking statements in this Form 10-K include, among other things:
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the timing, progress and results of our preclinical studies and clinical trials of our current and future product candidates, including statements regarding the timing of our planned regulatory communications, submissions and approvals, initiation and completion of studies or trials and related preparatory work and the period during which the results of the trials will become available, and our research and development programs;
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our ability to obtain and maintain regulatory approvals for our future product candidates, including our ability to obtain Fast Track designation from the U.S. Food and Drug Administration (FDA) under our Investigational New Drug application for our novel asset, PSV359;
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the potential impact of changes and disruptions at the FDA, including due to a lapse in appropriations and/or decreased funding for the FDA, on our business;
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our manufacturing infrastructure, capabilities and strategy, including the scalability and commercial viability of our manufacturing methods and processes, and the potential expansion of our regional network of drug product candidate finishing facilities;
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our expectation that our manufacturing infrastructure will have the capacity to meet future clinical trial and commercial demands at major treatment centers;
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our ability to expand our supply network and distribution capabilities;
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our ability to identify patients with the diseases treated by our product candidates and to enroll these patients in our clinical trials;
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the risk that unconfirmed responses reported in preliminary or interim data from our clinical trials may not ultimately result in confirmed responses to treatment after follow-up evaluations or audit and verification procedures;
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our expectations regarding the potential functionality, capabilities and benefits of our product candidates, if approved, for commercial use;
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the potential size of the commercial market for our product candidates and other programs;
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our expectations regarding the scope of any approved indication for any product candidate or other program;
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our ability to successfully commercialize our product candidates;
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our ability to leverage technology to identify and develop future product candidates;
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our estimates of our expenses, ongoing losses, future revenue, capital requirements and our need for or ability to obtain additional funding before we can expect to generate any revenue from product sales;
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our belief regarding the sufficiency of our cash resources to fund our current planned clinical milestones and operational investments into late 2027;
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our competitive position and expectations regarding developments and projections relating to our competitors or our industry;
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the potential impacts of U.S. and international trade policies, including tariffs, on our costs for supplies, equipment and materials used in the development and production of our targeted alpha therapy drug product candidates; and
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expectations, beliefs, intentions and strategies regarding the future.
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These statements are based on certain assumptions and analyses made by us in light of our experience and our assessment of historical trends, current conditions and expected future developments as well as other factors we believe are appropriate under the circumstances. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond our control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. Whether actual results will conform to the expectations and predictions of management is subject to a number of risks and uncertainties as updated in this Form 10-K in Item 1A under the heading “Risk Factors” below that may cause actual results to differ materially. Consequently, all of the forward-looking statements made in this Form 10-K are qualified by such risks and uncertainties, and there can be no assurance that the actual results anticipated by management will be realized or, even if substantially realized, that they will have the expected consequences to or effects on our business operations. Readers are cautioned not to place undue reliance on such forward-looking statements as they speak only of our views as of the date the statement was made (or any earlier date indicated in such statement). While we may update certain forward-looking statements from time to time, we undertake no obligation to do so, whether as a result of new information, future events or otherwise, except as required by applicable law. Our U.S. Securities and Exchange Commission (SEC) filings are available publicly on the SEC’s website at www.sec.gov.
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NOTE REGARDING COMPANY REFERENCES
Unless the context requires otherwise, references to “Perspective,” “the Company,” “our company,” “we,” “us” and “our” refer to Perspective Therapeutics, Inc., and, as the context requires, its subsidiaries. References to “Viewpoint” refer to Viewpoint Molecular Targeting, Inc., a wholly owned subsidiary, and references to “Isoray” refer to Isoray Medical, Inc., a wholly owned subsidiary.
BASIS OF PRESENTATION
On June 14, 2024, we filed a Certificate of Amendment to our Certificate of Incorporation with the Secretary of State of the State of Delaware to effect a 1-for-10 reverse stock split of our issued and outstanding shares of common stock, par value $0.001 per share (Reverse Split), which became effective on that date. All historical share and per share amounts reflected throughout this Annual Report on Form 10-K have been adjusted to reflect the Reverse Split. However, our periodic and current reports, and all other documents that were filed prior to June 14, 2024, do not give effect to the Reverse Split.
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SUMMARY OF RISK FACTORS
Investing in our common stock involves significant risks. Some of the principal risks related to our business include the following. These risks are discussed more fully under “Item 1A - Risk Factors” of this Annual Report.
Risks Related to Our Business, Financial Results and Need for Additional Capital
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We are a clinical-stage biopharmaceutical company and have a limited operating history upon which to base an investment decision.
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We will require substantial additional capital to fund our operations. Additional funds may be dilutive to shareholders or impose operational restrictions. Further, if additional capital is not available, we may need to delay, limit or eliminate our research, development and commercialization programs and modify our business strategy.
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We have incurred losses in nearly every year since our inception, and we anticipate that we will not achieve profits for the foreseeable future.
Risks Related to Our Business and Industry
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Our product candidates are in early stages of development and must go through clinical trials, which are very expensive, time consuming and difficult to design and implement. The outcomes of clinical trials are uncertain, and delays in the completion or termination of any clinical trial of our product candidates could harm our business, financial condition and prospects.
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We rely on single vendors to provide supplies and services used in the development and production of our alpha-particle therapies.
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If we encounter difficulties enrolling patients in our clinical trials, our clinical development activities could be delayed or otherwise adversely affected.
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Because the results of preclinical studies and early clinical trials are not necessarily predictive of future results, any product candidate we advance into clinical trials may not have favorable results in later clinical trials, if any, or receive regulatory approval.
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Delays in the commencement, execution or completion of our clinical trials could result in increased costs and delay our ability to pursue regulatory approval and commercialization of our product candidates.
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We may be required to suspend, repeat or terminate our clinical trials if they are not conducted in accordance with regulatory requirements, the results are negative or inconclusive, or the trials are not well designed.
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The approval processes of regulatory authorities are lengthy, time consuming, expensive and inherently unpredictable; if we experience unanticipated delays or are unable to obtain approval for our product candidates from applicable regulatory authorities, we will not be able to market and sell those product candidates in those countries or regions and our business will be substantially harmed.
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Disruptions at the FDA, including due to a lapse in appropriations and/or decreased funding for the FDA, could prevent the FDA from performing functions on which our business relies, which could negatively impact our business.
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We receive federal funding to conduct certain research on our product candidates and other programs, and recent federal policy changes could disrupt that funding.
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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 the approved labeling, or result in significant negative consequences following marketing approval, if any.
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If we are unable to execute our sales and marketing strategy for our product candidates, if commercialized, and are unable to gain market acceptance, we may be unable to generate sufficient revenue to sustain our business.
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Because we license technology underlying some of our product candidates from third parties, any dispute with our licensors or non-performance by us or by our licensors may adversely affect our ability to develop and commercialize the applicable product candidates.
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We may form or seek strategic alliances or enter into additional licensing arrangements in the future, and we may not realize the benefits of such alliances or licensing arrangements.
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We may rely partially on third parties to manufacture our clinical pharmaceutical supplies and could continue to rely on third parties to produce commercial supplies of any approved product candidate, and our dependence on third party suppliers could adversely impact our business.
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We may not be successful in managing the build-out of our manufacturing facilities and associated costs or satisfying manufacturing-related regulatory requirements.
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We rely on third parties to conduct our clinical trials, and if these third parties do not meet their deadlines or otherwise conduct the trials as required, our clinical development programs could be delayed or unsuccessful, and we may not be able to obtain regulatory approval for or commercialize our product candidates when expected or at all.
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We have in-sourced part of the research, development and clinical operations functions previously assigned to clinical research organizations, and we may not be able to efficiently execute those operations, or the cost savings expected from this transition may not materialize, which may adversely affect the financial performance of our business and our ability to advance our pipeline.
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We may seek orphan drug designation, rare pediatric disease designation or other FDA designations but may not receive such designation. Even if the FDA grants the designation, we may not receive orphan drug exclusivity or a priority review voucher if the product candidate does not meet the FDA requirements at the time of approval or licensure.
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We have received Fast Track designation for VMT-α-NET and VMT01, but such designation may not actually lead to a faster development or regulatory review or approval process. Additionally, the FDA may rescind the designation if it determines the applicable product candidate no longer meets the qualifying criteria for Fast Track.
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We will face intense competition and may not be able to compete successfully.
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We may rely on market exclusivity periods that may not be or remain available to us.
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If any product candidate that we successfully develop does not achieve broad market acceptance among physicians, patients, healthcare payors and the medical community, the revenues that it generates from their sales will be limited.
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Coverage and adequate reimbursement may not be available for our products, if commercialized, which could make it difficult for us to sell any future products profitably.
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Due to the significant resources required for the development of our drug candidates, we must prioritize development of certain drug candidates and/or certain disease indications and may expend our limited resources on candidates or indications that do not yield a successful program and fail to capitalize on drug candidates or indications that may be more profitable or for which there is a greater likelihood of success.
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If we fail to attract and retain key management, scientific and clinical development personnel, we may be unable to successfully develop or commercialize our product candidates.
Legal and Regulatory Risks Related to Our Operations
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Significant disruptions of information technology systems or cybersecurity incidents could materially adversely affect our business, results of operations and financial condition.
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Our employees and independent contractors, including principal investigators, consultants, commercial collaborators, service providers and other vendors, may engage in misconduct or other improper activities, including noncompliance with regulatory pricing standards and requirements, which could have an adverse effect on our results of operations.
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If we fail to comply with applicable healthcare regulations, we could face substantial penalties, and our business, operations and financial condition could be adversely affected.
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Healthcare reform measures could hinder our programs’ commercial success.
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Failure to comply with government regulations could harm our business.
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Our business exposes us to product liability claims.
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Our business involves environmental risks.
Risks Related to Intellectual Property Matters
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Our success will depend upon intellectual property, proprietary technologies and regulatory market exclusivity periods, and we may be unable to protect our intellectual property.
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Our ability to compete may be adversely affected if we do not adequately protect our proprietary rights.
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Potential patent litigation could be costly and disruptive and may have an adverse effect on our business, financial condition and results of operations.
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The value of our granted patents and our patents pending is uncertain.
Risks Related to Ownership of Shares of Common Stock and Public Company Status
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The concentration of our common share ownership will likely limit the ability of other shareholders to influence corporate matters.
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Our stock price has been and may continue to be volatile.
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The price of our common stock may be adversely affected by the future issuance and sale of shares of our common stock or other equity securities.
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PART I
ITEM 1 – BUSINESS
Overview
We are a radiopharmaceutical development company pioneering advanced treatments for cancers throughout the body. We have proprietary technology that utilizes the alpha-emitting isotope Lead-212 (212Pb) to deliver powerful radiation specifically to cancer cells via specialized targeting moieties. We are also developing complementary imaging diagnostics that incorporate the same targeting moieties, which provides the opportunity to personalize treatment and optimize patient outcomes. This theranostic approach enables the ability to see the specific tumor and then treat it to potentially improve efficacy and minimize toxicity.
Our neuroendocrine tumor (VMT-α-NET), melanoma (VMT01) and solid tumor (PSV359) programs are in Phase 1/2a imaging and therapy trials in the U.S. We are growing our regional network of drug product candidate finishing facilities, enabled by our proprietary 212Pb generator technologies, to deliver patient-ready product candidates for clinical trials and commercial operations.
Our Strategy
Our goal is to advance innovative precision medicines for the treatment of cancer by developing and commercializing our precision targeted alpha therapies (TATs). The key elements of our strategy are to:
Discover and Develop a Broad Oncology Pipeline
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Advance our initial drug candidate, VMT-α-NET, through clinical development for the treatment of neuroendocrine tumors expressing somatostatin receptor type 2 (SSTR2).
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Expand the potential of our product candidates in additional indications and as combination therapies in current and additional indications.
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Advance our second drug candidate, VMT01, through clinical development for the treatment of melanoma tumors expressing melanocortin 1 receptor (MC1R).
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Advance our third drug candidate, PSV359, through clinical development for the treatment of solid tumors expressing fibroblast activation protein.
Deploy Our Innovative Platform Technology
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Continue to leverage our TAT platform to expand our pipeline of product candidates.
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Utilize a precision medicine approach by leveraging imaging diagnostics.
Build and Strengthen Our Manufacturing and Supply Infrastructure
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Continue to strengthen and scale our internal manufacturing capabilities.
Radiopharmaceuticals
Radiopharmaceuticals have been developed to precisely apply the tumor-killing power of radiation to a wider array of cancers, including for patients who have metastatic disease. Radiopharmaceuticals are drugs that contain medical isotopes, which are unstable elements that emit radiation and can be used to diagnose and treat cancers. To create radiopharmaceuticals, radiation-emitting medical isotopes are typically attached to targeting molecules and administered via intravenous injection. Once administered, the radiopharmaceuticals selectively target tumor antigens that are unique to, or preferentially expressed on, cancer cells throughout the body. Currently available targeted radiopharmaceuticals have demonstrated the ability to simultaneously bind to and kill multiple tumors. By precisely delivering alpha radiation directly to cancer cells, we believe the power of radiotherapy can be realized while reducing the off-target effects.
Targeted radiopharmaceuticals are drugs that contain a radionuclide payload, which are unstable elements that emit radiation and can be used to diagnose and treat cancers, and a targeting moiety. To create targeted radiopharmaceuticals, radiation-emitting medical isotopes are typically attached to targeting molecules, which are then administered via intravenous injection. Once administered, the radiopharmaceuticals selectively target tumor receptors that are unique to, or preferentially expressed on, cancer cells throughout the body. Targeted radiopharmaceuticals, as a class, have achieved clear clinical benefit over non-radioactive standard-of-care agents in the treatment of gastroenteropancreatic neuroendocrine tumors and castration-resistant metastatic prostate cancer, and they possess characteristics that many believe may improve upon the profiles of current antibody-drug conjugates.
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We are leveraging our proprietary TAT platform to build on the successes of currently available radiation therapies and create the next generation of precision oncology targeted radiopharmaceuticals. Our TATs are comprised of three components: (i) a targeting peptide, that is designed to selectively target receptors that are unique to, or preferentially expressed on, cancer cells throughout the body; (ii) the alpha-emitting medical isotope 212Pb, designed to kill cancer cells, that is encased in our proprietary lead-specific chelator; and (iii) our optimized proprietary chelator.
We believe that our TAT platform and current and future product candidates, if approved, could provide several potential advantages over currently available radiopharmaceuticals, including:
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enhanced tumor-killing power by using 212Pb alpha-particle radiation in an outpatient setting;
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ability to pursue multiple targets and use multiple classes of targeting molecules;
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broad applicability across multiple tumor types, including neuroendocrine, metastatic melanomas and others cancers;
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increased tolerability and therapeutic window associated with our lead-based TATs;
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exploitation of multiple mechanisms of action, including direct deoxyribonucleic acid (DNA) damage through double-stranded DNA breaks, and an alpha particle-mediated enhanced anti-tumor immune response;
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a scalable manufacturing process and supply chain using our proprietary generator technologies; and
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ability to use our 203Pb imaging diagnostics to enrich targeted patient populations and determine treatment therapeutic suitability.
We believe the multiple mechanisms of action of our TATs may give them the ability to treat hard-to-treat tumors and the potential to work synergistically with other approved oncology therapies. The primary mechanism of action of 212Pb is direct cell damage through the induction of multiple double-stranded DNA breaks. A secondary mechanism, which would likely expand the effective direct cell kill range of the alpha particles, is referred to as the Bystander Effect, which involves the propagation of alpha particle-induced cell death from irradiated dying cells to kill adjacent non-irradiated cells in a three-dimensional solid tumor model. The Bystander Effect has been shown to be as significant to the overall efficacy in killing cancer cells as the direct DNA breaks.
Alpha vs. Beta Radiopharmaceuticals
There are two main classes of therapeutic radiopharmaceuticals, which differ based on the types of particles that are emitted - beta-emitting isotopes and alpha-emitting isotopes. Historically, due to the readily available supply of beta-emitting isotopes and the better understanding of their chemistry and biology, they were more widely used than alpha-emitting isotopes. As a result, first-generation-targeted therapeutic radiopharmaceuticals were based on beta-emitting isotopes, which kill cancer cells primarily by creating free radicals that damage cellular machinery and cause single-stranded DNA breaks, which can be repaired by the cell. As a result, certain cancers are refractory to beta particle-based radiopharmaceutical treatment. Products based on beta-emitting isotopes have been developed successfully, but as the development of radiopharmaceuticals has continued to evolve, a deeper understanding of the potential of alpha-emitting isotopes for treating cancer has emerged.
Compared to beta particles, alpha particles can cause greater physical damage to cancer cells, including multiple double-stranded DNA breaks, which are very difficult for cancer cells to overcome, unlike in the case of single-stranded DNA breaks. Rather, double-stranded DNA breaks are highly lethal, with even a single double-stranded break being sufficient to cause cancer cell death. Alpha particles are over 7,000 times more massive than beta particles, resulting in a significantly higher energy transfer rate, providing alpha particles the advantage of depositing a high amount of tumor-killing energy over a short distance of one to two cells, compared to the relatively long distance of up to 12 mm for beta particles. The amount of energy produced by alpha particles is high enough such that only a small number of alpha particles are required to cause cell death. This feature, when combined with their short path length, enables alpha particles to cause damage only to cancer cells in close proximity, reducing the risk of off-target radiation and normal cell damage that can occur with beta particles. However, because of the short travel distance, alpha particles need to be delivered into or on the surface of tumor cells to achieve the desired therapeutic effect.
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Commercially Available Radiopharmaceuticals
Two of the earliest antibody-targeted radiopharmaceuticals, Bexxar, marketed by GlaxoSmithKline, and Zevalin, marketed by Acrotech Biopharma, LLC, are beta-emitting therapies whose market acceptance was hampered by several issues, including handling and administration difficulties, supply chain challenges and reimbursement complications. However, next-generation radiopharmaceuticals that have overcome the challenges faced by first-generation radiopharmaceuticals have since been developed and approved, and over the past decade the global radiopharmaceutical market has been growing rapidly. One such approved, next-generation targeted radiopharmaceutical therapy is Lutathera, a beta-emitting therapy marketed by Novartis. Novartis reported that fiscal year 2025 sales revenue from Lutathera was $816 million, up 12% from fiscal year 2024, despite only being approved for a subset of neuroendocrine cancers that affect the pancreas or gastrointestinal tract, known as GEP-NETs. Another radiopharmaceutical therapy, Pluvicto, a beta-emitting radioligand therapy marketed by Novartis, was initially approved to treat progressive prostate-specific membrane antigen (PSMA) positive metastatic castration-resistant prostate cancer and is being further developed by Novartis for other prostate cancer indications. Novartis reported that fiscal year 2025 sales revenue for Pluvicto was $2.0 billion, up 42% from fiscal year 2024.
Our TAT Platform
Through the use of proprietary, specialized targeting peptides, we are able to obtain patient images using Lead-203 (203Pb) and then deliver a powerful alpha-particle radiotherapy directly to the tumor using 212Pb labeled radiotherapies, potentially limiting damage to healthy tissue. Utilizing a radioactive imaging agent that emits gamma rays, 203Pb, connected to a specific targeting peptide, we have the ability to image tumors. Because 203Pb and 212Pb are elementally identical, we can use the imaging information to understand the biodistribution and pharmacokinetics of the 212Pb alpha-particle therapy using the same targeting peptide to treat and potentially kill cancerous cells. This two-step, personalized medicine approach, as depicted below, offers the ability to understand which patients may respond to our therapy and potentially improve efficacy while minimizing toxicity associated with many other types of cancer treatments.
Human Image: Cagle et al. European Association of Nuclear Medicine 2024, Presentation Number: OP-473
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Our image-guided TAT leverages a specialized targeting peptide to deliver cancer-killing 212Pb directly to the tumor. Our process for selecting cancer targets is designed to ensure that such targets are overexpressed in cancer cells and minimally expressed on normal healthy cells. When the peptide is radiolabeled with 203Pb, the patient can be imaged (i.e., single-photon emission computed tomography (SPECT) and computed tomography (CT)) to reveal cancer cells in the body. When the peptide is radiolabeled with 212Pb, the target-peptide binding can deliver powerful, yet locally deposited, cancer-killing alpha-particle radiation directly to cancer cells. This targeting mechanism allows for maximized therapeutic effects while minimizing off-target toxicities and may be used as a monotherapy or in combination with other precision treatments, such as targeted intracellular pathway inhibitors and immune checkpoint inhibitors.
Our TAT platform is highlighted by research and insights into the underlying biology of alpha-emitting radiopharmaceuticals as well as our differentiated capabilities in target identification, candidate generation, manufacturing and supply chain, and the development of imaging diagnostics. Our TAT platform was primarily developed over 15 years at the University of Iowa. We believe that our TATs have the potential to be broadly applicable across multiple targets and tumor types and transform the treatment landscape of radiopharmaceuticals for the treatment of cancer.
212Pb (Lead-212)
Although there are many beta- and alpha-emitting isotopes, we believe that the ideal therapeutic isotope should emit alpha particles at a high rate over a relatively short period of time in order to maximize damage to cancer cells and increase efficacy. Alpha particles kill tumors through multiple mechanisms. The primary mechanism of action is direct cell damage through the induction of multiple double-stranded DNA breaks. As alpha particles traverse the nucleus of a cell, they create a linear track of direct chromosomal damage, leaving behind multiple clusters of double-stranded DNA breaks. These direct alpha particles can kill cells up to a distance of 100 μm, which is equal to a depth of a few cells. A secondary mechanism, which would expand effective direct cell kill range of the alpha particle, is referred to as the Bystander Effect. This effect has been shown to be as significant to the overall efficacy in killing cancer cells as the direct DNA breaks. The Bystander Effect has been shown to propagate alpha particle-induced cell death from irradiated dying cells to kill adjacent non-irradiated cells up to 1,000 μm away in a three-dimensional solid tumor model. A third mechanism by which alpha-particle therapy enhances the body’s own anti-tumor immune response is less well understood but has been widely observed and reported. In our own preclinical studies, we have observed a vaccine-like effect that prevented the regrowth of tumors upon re-challenge. This is an area of ongoing investigation by us and the international scientific community. Our findings were reported by our Vice President of Discovery, Dr. Mengshi Li, et.al. in the peer-reviewed journal Cancers 2021, 13: 3676, 2021 and showed that the cooperative effect between [212Pb]VMT01 and immune checkpoint inhibitors were also observed in a heterogeneous preclinical melanoma model. Induction of this cooperative effect was found even with 2 Gy of alpha-ration in tumor.
We believe 212Pb is an optimal therapeutic isotope as compared to currently commercially available radiopharmaceuticals as well as other alpha therapies in development. With a half-life of 10.6 hours, 212Pb is ideally suited to deliver powerful alpha-particle therapy to cancerous tumors, while representing a lower risk for off-target unintended effects. The decay properties of the 212Pb isotope and the rapid excretion of drug that has not bound to the tumor target provide the potential for treatment on an outpatient basis.
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The graphic below provides our illustration of the comparison of the key differences between beta particles and alpha emitters.
*Daughter isotopes
USPI for 177Lu vipivotide tetraxetan.
Sgouros G. Alpha-particles for targeted therapy. Adv Drug Deliv Rev. 2008;60(12):1402-1406. doi:10.1016/j.addr.2008.04.007
212Pb is an alpha-emitting nuclide that acts as the therapeutic in our innovative theranostic approach. The higher linear-energy transfer of alpha particles, compared to beta particles, results in an increased incidence of double-stranded DNA breaks and improved localized cancer cell damage. We believe 212Pb half-life of 10.6 hours provides many significant advantages over other radiotherapies, including faster clearance and the potential for reduced off-site toxicity. Its decay chain includes the short-lived isotopes bismuth-212, polonium-212 and thallium-208, which all emit either alpha or beta during decay over about another hour. The end of the decay chain is the stable element lead-208.
To maximize the potential clinical benefit of radiopharmaceuticals to patients and minimize potential toxicity issues, we believe that TATs must selectively localize and remain within the tumor while the portions of the TAT that are not localized within the tumor are rapidly cleared from the body. Nearly 15 years of work by our co-founder, Dr. Michael Schultz, colleagues at the University of Iowa and our team members resulted in the development of our proprietary TAT, Pb-specific chelator (PSC) and peptide linker technology to enable the delivery of isotopes to tumor cells while simultaneously promoting enhanced clearance of the non-tumor localized isotopes.
Due to the short half-life of 212Pb and the small size of the compounds, when our TATs are not bound to targeted cancer cells, they rapidly clear from the body, primarily through the urinary system, along with any isotopes bound to the linker. This results in lower total body radiation exposure when compared to radiopharmaceuticals designed with longer lived isotopes or larger molecular weight targeting moieties, such as antibodies or antibody fragments. We believe that our TATs’ ability to promote clearance without compromising the tumor’s uptake of the alpha particle overcomes a longstanding challenge of radiopharmaceutical drug development.
Our Chemistry and Biology Expertise with 212Pb
We believe that our experience working with alpha-emitting radiopharmaceuticals positions us to build on the success of currently approved radiopharmaceuticals. By utilizing the advantages of 212Pb and our proprietary chelator, we have the ability to develop next-generation radiopharmaceutical therapies. 212Pb has complex chemistry and requires extensive experience and expertise to develop and properly characterize 212Pb radiopharmaceuticals with regard to the required tumor targeting, shelf-life, in vivo stability and potential for commercial-scale manufacturing. For example, the high energy emitted from 212Pb could cause product candidates to prematurely degrade. We believe we have the experience and know-how to develop molecules and formulations of 212Pb to maximize the shelf-life of our product candidates and allow for regional production and distribution. In addition to a deep understanding of the chemistry of 212Pb, we believe we have differentiated knowledge of the underlying biology of 212Pb and its mechanisms of directly damaging the DNA of tumors through single- and double-stranded DNA breaks, the Bystander Effect and use of the immune system’s adaptive response to attack non-target expressing tumors in order to stimulate a vaccine effect.
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Imaging Diagnostics – 203Pb
For each of our product candidates, we create an imaging analogue that utilizes the same linker and targeting molecule but replaces 212Pb with the radioactive imaging isotope 203Pb. This allows us to assess uptake of the imaging analogue into the targeted tumor and to determine radiation doses to key organs. The imaging analogue versions of our product candidates are leveraged in both preclinical and clinical development and are used to enrich the patient population in our clinical trials by identifying the patients and tumor types more likely to respond to therapy.
203Pb is a gamma-emitting nuclide that acts as the diagnostic in our innovative theranostic approach. 203Pb has a long enough half-life to facilitate radiopharmaceutical preparation and gamma-ray imaging (e.g., SPECT or planar gamma camera) at time points up to 24 hours and, potentially, 48 hours post administration. The ability to collect data on the biodistribution of 203Pb over this period allows for a more detailed understanding of tumor and other organ accumulation, retention and clearance that can be used as part of a treatment planning process for determining appropriately administered radioactivity levels of 212Pb for alpha-particle therapy.
Our Pipeline
We are leveraging our TAT platform to advance a pipeline of alpha-based therapeutic programs to treat various cancers. The table below details our current pipeline of TATs, indicating the status of each of our three lead programs in clinic within our broad proprietary pipeline at March 12, 2026.
To date, we have retained global development and commercialization rights to all our product candidates. In January 2024, we announced we had entered into a strategic agreement with an affiliate of Lantheus Holdings, Inc. (Lantheus) whereby in exchange for an upfront payment of $28 million (less certain withholding amounts), Lantheus obtained an exclusive option to negotiate for an exclusive license to our [212Pb]VMT-α-NET and a right to co-fund the Investigational New Drug (IND)-enabling studies for early-stage therapeutic candidates targeting PSMA and gastrin-releasing peptide receptor (GRPR) and, prior to IND filing, a right to negotiate for an exclusive license to such candidates.
Programs
VMT-α-NET: A Targeted Alpha Therapy Targeting SSTR2
Overview
We designed VMT-α-NET to target and deliver 212Pb to cancer-specific receptors on tumor cells expressing SSTR2, a protein that is overexpressed in neuroendocrine tumors (NETs) and other cancers. [212Pb]VMT-α-NET is a TAT in development for patients with unresectable or metastatic SSTR2-expressing tumors who have not previously received peptide-targeted radiopharmaceutical therapy, such as Lutathera.
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NETs are a group of rare, heterogeneous tumors that develop in different organs of the body and arise from specialized cells in the neuroendocrine system. Both the incidence and prevalence of NETs have continued to rise globally over several decades, primarily due to improvements in the diagnosis and surveillance of disease. Earlier detection has not only given rise to an increase in localized disease diagnoses but also improvements in staging, disease classification, management and survival. Despite these advancements, delayed diagnosis is still common due to asymptomatic presentation or nonspecific symptoms. As noted by N. Patel and B. Benipal in Incidence of Neuroendocrine Tumors in the United States from 2001-2015: A United States Cancer Statistics Analysis of 50 States, gastroenteropancreatic NETs, or GEP NETs, represent the most common NET subtype, comprising 55–70% of all NETs, followed by lung (22-27%). In Epidemiologic trends of and factors associated with overall survival in patients with neuroendocrine tumors over the last two decades in the USA., P. Wu, D. He, H. Chang, and X. Zhang estimated that more than 12,000 people in the U.S. are diagnosed with a NET each year, and current prevalence of NETs in the U.S is approximately 170,000 patients per year. As NETs display a wide variety of biologic behavior, the prognosis differs immensely between indolent limited disease grade 1 tumors and widely spread grade 3 carcinomas.
The median overall survival rate also varies widely in the highly heterogeneous NET populations and is based on site, stage and grade of disease. It is estimated that 80% of NETs over-express SSTR2. For this reason, somatostatin analogues are a cornerstone of the treatment of most NETs. In addition to SSTR2 analogs, low-grade and/or localized disease is amenable to surgical intervention and carries a good prognosis in terms of five-year overall survival rate (>90%), but there remains recurrence risk. High-grade and/or distant disease is more difficult to treat and carries lower median survival rates, typically measured in months. Radioligand therapy has emerged as a promising therapeutic option for GEP NETs in late stage and is being evaluated for earlier lines of treatment. We believe there is additional opportunity for radioligand therapy in earlier lines of treatment and other somatostatin-expressing NET indications, such as meningioma, lung and pheochromocytoma/paraganglioma NETs, where there remains significant unmet medical need. In October 2024, Research and Markets Newswire reported worldwide sales for systemic NET treatments were valued at $3.6 billion in 2023 and are estimated to reach $6.9 billion by the end of 2030.
Using a specialized peptide, VMT-α-NET is designed to target and bind to the SSTR2 on tumor cells. As a diagnostic, we link 203Pb, a radioactive imaging agent that emits gamma rays, to its SSTR2-targeting peptide. Through the use of imaging scans, we are able to characterize the tumor to confirm the patient’s cancer expresses SSTR2. This confirms the patient may be a candidate for treatment. As a therapeutic, we link 212Pb, its alpha-particle radioactive isotope, to the same SSTR2 targeting peptide which has been shown to bind and kill cancerous cells.
In 2022, we received a “safe to proceed” decision on an IND application with the U.S. Food and Drug Administration (FDA) to evaluate [212Pb]VMT-α-NET therapy under IND #160357. The indication of the opening study is treatment of advanced SSTR2-positive NETs patients who are progressing on, symptomatic on, or intolerant of approved non-radiological therapies. Later in 2022, we received Fast Track Designation for this program based on preclinical data for the indication of SSTR2-positive NETs regardless of prior treatment response.
Additionally, we may pursue a priority review voucher (PRV) for [212Pb]VMT-α-NET for the rare pediatric disease of advanced neuroblastoma after review of additional trial data.
Preclinical Studies of [212Pb]VMT-α-NET
Our therapeutic [212Pb]VMT-α-NET has demonstrated positive clinical activity in preclinical studies using a mouse model of NETs, whereby [212Pb]VMT-α-NET significantly inhibited tumor growth and significantly improved survival compared to untreated mice controls.
Our diagnostic [203Pb]VMT-α-NET has produced strong SPECT/CT imaging and tumor contrast in multiple preclinical studies using mouse models of tumors expressing SSTR2, whereby [203Pb]VMT-α-NET has shown an 8-fold improved tumor uptake with decreased kidney retention as compared to 203Pb radiolabeled DOTATOC. DOTATOC is an established targeting compound for imaging SSTR2-expressing NETs and is FDA approved for use when radiolabeled to positron emission tomography (PET) isotopes for certain forms of neuroendocrine tumors.
At the Annual Congress of the European Association of Nuclear Medicine in September 2023, we presented mouse model data highlighting the efficacy of [203/212Pb]VMT-α-NET in treating metastatic neuroblastoma tumors. The study showed successful tumor uptake via sequential SPECT imaging and demonstrated a maximum tolerated dose (MTD) of [212Pb]VMT-α-NET as 2.22 MBq without acute toxicity, with a 100% overall survival rate at 90 days observed in the group receiving three fractionated doses of 740 kBq of [212Pb]VMT-α-NET.
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At the World Molecular Imaging Congress in September 2023, we presented data highlighting the effectiveness of [212Pb]VMT-α-NET in treating neuroendocrine tumors in a tumor xenograft mouse model. The results highlighted the significant therapeutic efficacy of treatment with three fractionated doses of [212Pb]VMT-α-NET, which resulted in a 70% complete response rate and 80% survival at 120 days.
Our first-in-human experience with [203Pb]VMT-α-NET imaging occurred under the supervision of the attending physician at the University of Ulm in Dresden, Germany in 2021 in a patient with metastatic and refractory gastrointestinal NET. Imaging from this study using [203Pb]VMT-α-NET revealed favorable properties, including rapid tumor accumulation, rapid renal clearance and excellent tumor retention as seen by SPECT/CT imaging at 22 hours with high tumor conspicuity. There were no adverse signs or symptoms attributed to the imaging tracer. The pharmacokinetic and biodistribution properties of the imaging agent, based on semi-quantitative medical physics analysis by the team at the University of Ulm, suggest the potential for the chemically identical therapeutic agent, [212Pb]VMT-α-NET, to be administered without concurrent renal protective amino acid infusion in radiotherapy naïve patients. This would be a clinically relevant point of differentiation from the current practice using approved radiopharmaceutical products for NETs.
Company-Sponsored Trials of [212Pb]VMT-α-NET
We have a multi-center open-label study (clinicaltrials.gov identifier NCT05636618) of [212Pb]VMT-α-NET, a targeted alpha-particle therapy, for patients with advanced SSTR2-positive neuroendocrine tumors. This protocol was amended in 2025 to use the Bayesian Optimal Interval Phase 1/2 design and to determine the optimal biologic dose (OBD) in adult patients with unresectable or metastatic NETs of gastrointestinal, lung, adrenal or neural tissue origin. The primary endpoints of this study are safety and tolerability, determination of a recommended dose for subsequent study and determination of pharmacokinetic properties. Secondary endpoints are overall response rate by response evaluation criteria in solid tumors (RECIST) v.1.1, progression-free survival by RECIST v.1.1 and overall survival. Patients with positive uptake on FDA-approved SSTR2 PET/CT will receive a fixed dose of [212Pb]VMT-α-NET IV administered at the recommended Phase 2 dose and schedule.
In November 2024, at the North American Tumor Society’s NANETS Multidisciplinary NET Medical Symposium, we announced initial results from this study and have announced further updates to these initial results in January 2025 at the 2025 American Society of Clinical Oncology Gastrointestinal Cancers Symposium, in May 2025 at the 2025 American Society of Clinical Oncology (ASCO 2025) Annual Meeting, in October 2025 at the European Society for Medical Oncology Congress 2025 (ESMO), and in January 2026 at the 2026 ASCO Gastrointestinal Cancers Symposium (ASCO-GI 2026).
We initially dosed two patients in Cohort 1 (treated at 2.5 mCi per dose) and seven patients in Cohort 2 (treated at 5.0 mCi per dose) of our Phase 1/2a study of [212Pb]VMT-α-NET in patients with unresectable or metastatic SSTR2-expressing NETs, regardless of body weight. Subsequent review for dose-limiting toxicity (DLT) during the safety observation period in the seven patients in Cohort 2 by the Safety Monitoring Committee (SMC) led the SMC to recommend escalating further in a third cohort and enrolling additional patients at 5.0 mCi to better understand efficacy and safety. During the second quarter of 2025, enrollment for Cohort 2 closed with an additional 39 patients having received at least one treatment, for a total of 46 patients including the seven who were enrolled for DLT observation.
In late June 2025, we announced the opening of Cohort 3 in which patients will receive up to four fixed administered doses of [212Pb]VMT-α-NET at 6.0 mCi every eight weeks if they weigh more than 60 kg (133 lb), or 100μCi/kg of body weight if they weigh less than or equal to 60 kg. Eight Cohort 3 patients then commenced treatment and contributed to the DLT assessment by the SMC. The DLT assessment is now complete, and we are cleared to treat more patients at this dose, with eight additional patients already treated as of February 28, 2026, for a total of 16 patients. By mid-2026, the eight DLT patients would have had the opportunity for at least 32 weeks of follow up since beginning treatment, which is sufficient time to have completed at least one scan following the full course of treatment.
During January 2026, updated interim results with a data cut-off date of December 10, 2025, were presented at ASCO-GI 2026. The 56 patients in the safety analysis comprised two patients in Cohort 1 (2.5 mCi), 46 patients in Cohort 2 (5.0 mCi) and eight patients in Cohort 3 (6.0 mCi), each of whom had received at least one treatment. There were no DLTs, no treatment-related discontinuations, and no serious renal complications, dysphagia or clinically significant treatment-related myelosuppression reported. Grade 3 or higher treatment-emergent adverse events were reported in 21 patients (37.5%). One of these patients, who was enrolled in Cohort 3, experienced a transient Grade 4 event (lymphocyte count decrease). This event was transient and resolved without medical intervention. The patient continues to receive [212Pb]VMT-α-NET treatment. There were no Grade 5 events. Serious adverse events were reported in five patients, with none deemed related to the study medication.
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In October 2025 at ESMO, we reported interim efficacy data for two patients in Cohort 1 and 23 patients in Cohort 2. At ASCO-GI 2026, we presented updated efficacy analysis for the same 25 patients from ESMO with an additional 13 weeks of follow up since the presentation at ESMO. Of the 25 patients, 19 (76%) were without progression and remained alive, including both of the patients in Cohort 1. Nine (39%) patients in Cohort 2 were observed to have response according to investigator-assessed RECIST v1.1. Eight (35%) of those responses were confirmed and previously reported at ESMO; one additional patient experienced an initial response in their most recent tumor assessment after the prior update at ESMO. As the patient remains on the study, the patient is expected to receive a subsequent tumor assessment. Seven patients were observed to have deepening of best response, including one patient with stable disease.
As of February 28, 2026, the first 23 patients in Cohort 2 would have had the opportunity for at least 48 weeks of follow up since beginning treatment, and by mid-2026, we expect all 46 patients in Cohort 2 would have had the opportunity for at least 48 weeks of follow up since beginning treatment.
We believe our clinical data package positions us for meaningful regulatory engagement in 2026 to align on the path forward.
During the dose finding phase of the study, we enrolled primarily NETs patients whose disease originated in the pancreas or the digestive track. We have allowance for enrollment of NETs patients whose disease originated in the lung (of which small cell lung cancer is a subset), and pheochromocytoma/paraganglioma NETs, as well as SSTR2+ meningioma.
1Change in sum of diameters from baseline per RECIST v1.1.
Data shown for Cohort 2; one patient had a non-evaluable scan post baseline scan and, therefore, it is not included in this chart.
Halfdanarson TR et al, Presentation at ASCO-GI 2026. Data cut-off date December 10, 2025.
Investigator-Initiated Clinical Research and Section 13-2(B) Usage of [212Pb/203Pb]VMT-α-NET
The National Institutes of Health (NIH) is conducting a prospective institutional review board (IRB)-approved, standard 3+3 dose escalation design phase 1 clinical trial (NCT06479811) using [212Pb]VMT-α-NET in radionuclide therapy naive patients. The first three patients enrolled were diagnosed with olfactory neuroblastoma, although the study allows for five different SSTR-tumor types. Four dose levels (2.5 mCi, 5.0 mCi, 7.5 mCi and 10 mCi) are included in the trial with each course consisting of four cycles of therapy eight weeks apart. The DLT period is 12 weeks after the first cycle of therapy and enrollment opened in August 2025. The investigators plan to report on their results during the Society of Nuclear Medicine and Molecular Imaging 2026 Annual Meeting (SNMMI 2026) taking place from May 30 - June 2, 2026.
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The NIH is also conducting a prospective IRB-approved, standard 3+3 dose escalation design phase 1 clinical trial (NCT06427798) using [212Pb]VMT-α-NET in patients diagnosed with metastatic pheochromocytoma/paraganglioma or gastrointestinal NETs who have been previously treated with at least one cycle of systemic radionuclide therapy. Three dose levels (2.5 mCi, 5.0 mCi and 7.5 mCi) are included with each course consisting of four cycles of therapy eight weeks apart. The trial opened for enrollment in February 2025 and the DLT period is 12 weeks after the first cycle of therapy. The investigators plan to report on their results during SNMMI 2026.
The University of Iowa is conducting an investigator-initiated Phase 1 trial (clinicaltrials.gov identifier NCT05111509) to investigate the feasibility of using [203Pb]VMT-α-NET to enable personalized, image-guided therapy dose calculations for [212Pb]VMT-α-NET therapy in patients with recurrent NETs after treatment with approved radiopharmaceutical therapy (RPT). In addition, in December 2023, we announced that the first patient was dosed at the University of Iowa in an investigator-initiated Phase 1 trial evaluating the safety of [212Pb]VMT-α-NET in patients with unresectable or metastatic SSTR2-expressing neuroendocrine tumors. The patients enrolled in the study had either progressed or relapsed after previous therapies, including currently approved PRRT. This is a single site safety study (clinicaltrials.gov identifier NCT06148636) of [212Pb]VMT-α-NET targeted alpha-particle therapy for patients with refractory or relapsed SSTR2-positive neuroendocrine tumors. The first part of this Phase 1 trial is imaging with a surrogate tracer, [203Pb]VMT-α-NET, using SPECT/CT imaging. Each participant is assigned a radiation dose to the kidneys that cannot be exceeded. The second part of the study is a sequential 3+3 dose escalation phase of four cohorts based on the maximum allowed injected dose for an individual while keeping kidney exposure to less than a predetermined threshold. The study involves two treatments, about eight to 10 weeks apart. The drug will be given by infusion once per treatment. Participants will also receive an infusion of amino acids to help protect the kidneys as well as medications to help protect against nausea. A participant who is administered [212Pb]VMT-α-NET will be monitored for at least six months for safety assessments. Participants will also have imaging at six months post treatment to measure how their tumors responded to therapy and will have lifelong follow up for this study. An independent SMC reviewed the trial in August 2025 and recommended expansion of Cohort 2 to include three more subjects for a total of six at the same renal dose level and approved continuation of the trial. The investigator informed us that they plan to submit their results at SNMMI 2026.
We supported diagnostic and therapeutic dosing of [203/212Pb]VMT-α-NET at the Technical University of Dresden under provisions in Section 13-2(B) of Germany’s Medicinal Products Act supporting patients that lack further treatment options. This is a single-site retrospective evaluation of imaging with [203Pb]VMT-α-NET and subsequent single administration of [212Pb]VMT-α-NET in patients with progressive metastatic GEP-NET after exhausting all current therapies, including radiopharmaceuticals. The investigator published a manuscript in September 2025 (Michler E, Kästner D, Pretze M, Hartmann H, Freudenberg R, Schultz MK, Bundschuh RA, Kotzerke J, Brogsitter C. [203/212Pb]Pb-VMT-α-NET as a novel theranostic agent for targeted alpha radiotherapy-first clinical experience. Eur J Nucl Med Mol Imaging. 2025 Sep;52(11):4171-4183. doi: 10.1007/s00259-025-07269-0. Epub 2025 Apr 9. PMID: 40202686; PMCID: PMC12397198). Eight patients were treated with a single dose of [212Pb]VMT-α-NET at mean activity level of 2.7 mCi (100 MBq). Progression was defined by new SSTR-positive tumor lesions on Gallium-68 (68Ga) DOTATATE-PET/CT imaging or by increasing blood tumor markers, namely Chromogranin A. Certain preliminary results were presented at the 2025 Society of Nuclear Medicine and Molecular Imaging Mid-Winter Meeting.
VMT01: A Targeted Alpha Therapy Targeting MC1R
Overview of VMT01and VMT02
We are also leveraging our TAT platform with our product candidate, VMT01, which is currently in Phase 1/2a clinical trials. We designed VMT01 to target and deliver 212Pb to tumor sites expressing MC1R, a protein that is overexpressed in melanoma cancers. [212Pb]VMT01 is a TAT in development for second-line or later treatment of patients with progressive MC1R-positive metastatic melanoma. Review of market research prepared by Research and Markets Newswire in January 2026 indicates metastatic melanoma could represent over a $13.8 billion market opportunity by 2031.
Using a specialized peptide, VMT01 is designed to target MC1R on tumor cells. As a diagnostic, we either link 203Pb or 68Ga to its MC1R-targeting peptide. MC1R is a G-protein-coupled receptor that has been investigated as a target for metastatic melanoma drug delivery due to its overexpression on the surface of melanoma cells and relative absence in normal cells. MC1R-targeted radiolabeled peptides have been used as delivery vehicles for delivering radiometals to melanoma tumors in preclinical models for diagnostic imaging and therapy, as well as in clinical imaging studies that demonstrated the ability to identify MC1R-positive tumors by PET imaging.
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We also designed two imaging surrogates, the chemically identical [203Pb]VMT01 for SPECT imaging and dosimetric calculations and [68Ga]VMT02, a PET imaging tracer, for patient selection. [68Ga]VMT02 utilizes the same targeting peptide as VMT01 but differs in having a chelator optimized for PET radiotracers. Through the use of the imaging scans, we are able to characterize whether the patient’s cancer expresses MC1R and, thus, is a candidate for treatment. As a therapeutic, we link 212Pb to the same MC1R targeting peptide which has been shown to bind and kill cancerous cells. The melanoma program focuses primarily on development of the therapeutic compound. The rationale for the development of two imaging tracers is to provide flexibility in imaging a molecular target for which a validated and approved imaging tracer does not exist. Further commercialization of one or both of these imaging tracers would follow a separate regulatory path from the therapeutic compound and would proceed based on the potential for utility after a therapeutic efficacy signal is identified.
VMT01 and VMT02 bind with high affinity and specificity to MC1R-expressing melanoma tumors and do not bind to healthy cells (where MC1R is absent). Thus, the radioactive nuclide carried by the peptide is delivered primarily to tumor cells, while nonspecific binding to healthy cells is minimal. Treatment is carried out in two stages. In the first stage (i.e., the diagnostic stage), [203Pb]VMT01 or [68Ga]VMT02 is administered for SPECT or PET imaging, respectively. The decay of radionuclides 203Pb and 68Ga result in gamma radiation that can be detected by the imaging device. This detection can be used to pinpoint the presence of cancerous tumors expressing MC1R and illuminate the pharmacokinetic properties and biodistribution of the radiopharmaceutical. This information can be used to guide the second therapeutic stage with [212Pb]VMT01, in which the radionuclide 212Pb replaces 203Pb and 68Ga. [212Pb]VMT01 is designed to deliver alpha (α) radiation efficiently to melanoma tumors that express the MC1R receptor. This two-stage process is commonly referred to as image-guided receptor-targeted alpha-particle radionuclide therapy for cancer and is also referred to as a “theranostic” approach.
We conducted nonclinical pharmacology, pharmacokinetics and toxicology studies utilizing in vitro and in vivo assays, SPECT and PET imaging and histopathology to support the first-in-human Phase 1/2a clinical development of [212Pb]VMT01 per recommendations in the FDA’s guidance document titled “Oncology Therapeutic Radiopharmaceuticals: Nonclinical Studies and Labeling Recommendations Guidance for Industry.” Promising results have demonstrated an increase in progression-free survival, improvement in overall survival and, in some cases, complete remission in mice bearing murine and human melanoma tumors. We have also observed significant synergy with checkpoint inhibitors in animal models that are resistant to immunotherapy alone, and a subset of animals receiving the combination therapy demonstrated resistance to re-inoculation with naive melanoma cells.
Management believes that there are currently no FDA-approved radiopharmaceutical peptide-based receptor targeting approaches for the treatment of metastatic melanoma. The goal of the theranostic approach with [203Pb]VMT01 or [68Ga]VMT02 (diagnosis) and [212Pb]VMT01 (therapy) is to establish a new methodology to treat patients with MC1R-expressing tumors that has the potential to improve long-term outcomes.
Role of VMT01 in Advanced Melanoma Treatment
Melanoma is a cancer of the skin arising from uncontrollable growth of melanocytes, the melanin producing cells of the body. Melanoma generally originates on the epidermis (the outermost layer of skin). In rare instances, melanoma can originate in the eyes or mucosal membranes, as these are other locations where melanocytes are present. Metastatic melanoma is the result of melanoma that has progressed through the layers of skin, infiltrated the blood stream or lymphatic system and traveled to other areas of the body to metastasize.
According to projections from the World Health Organization, the number of worldwide cases of cutaneous melanoma will increase from approximately 325,000 in 2020 to over 500,000 in 2040 with the number of melanoma deaths increasing by almost 70%. The International Agency for Research on Cancer Global Cancer Observatory states that the risk of melanoma increases as people age, with the average age of diagnosis being early to mid 60s. Melanoma is a global disease affecting all populations around the world. The risk of developing melanoma increases significantly in areas of high ultraviolet exposure and for people with fair complexion. Particularly high incidences are observed in North America, Northern Europe and New Zealand. The highest occurs in Australia, where annual rates are more than twice that of North America. The American Cancer Society reported that, in the U.S., there will be an estimated 112,000 new diagnoses of invasive melanoma in 2026 and approximately 8,510 are expected to die from the disease.
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The National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) Program estimates 77% of all melanoma cases in the United States are local disease, receiving surgical treatment followed by watchful waiting. Melanoma that has regional spread (stage III) indicates spreading to nearby lymph nodes and accounts for 10% of cases, with a five-year survival rate of approximately 70%. Metastatic melanoma is classified as stage IV, where melanoma metastasizes to distant organs, such as the brain, lungs or liver, and contains any T or N value in the TNM staging system. SEER also noted that metastatic melanoma accounts for 5% of cases and carries a poor prognosis with a one-year survival rate of 50% and five-year survival rate of 29%-35%. The majority of metastatic melanoma patients will receive some form of immunotherapy; however, more than 50% ultimately progress. Patients with tumors positive for the BRAF mutation who progress on immunotherapy can receive targeted therapy; however, these patients ultimately acquire resistance. Thus, the majority of metastatic melanoma patients who eventually progress on immunotherapy (and targeted therapy if BRAF positive) are left with very limited options and represent the patient population with the greatest unmet need in melanoma (source: https://www.sciencedirect.com/science/article/pii/S1040842824000192). This segment of the melanoma population is the intended entry market for VMT01. Grandview Research has reported that the market size for global melanoma therapeutics is estimated to reach approximately $10.3 billion by 2030, growing at a compound annual growth rate of 9.9% from 2025 to 2030.
Leading treatments for metastatic melanoma are typically not curative. Treatments include immunotherapy to help the immune system recognize evading cancer cells, targeted therapy to interfere with known cancer processes, radiation therapy to kill cancer cells via high-energy X-ray or proton beams and chemotherapy to attack rapidly dividing cancer cells. Immune checkpoint inhibitors, targeted mitogen-activated protein kinase inhibitors and cell therapies have improved outcomes but also low response rates and acquired drug resistance, and adverse side effects have limited quality of life for metastatic melanoma patients. The most dramatic improvements in response have often been reported to lead to grade 3/4 adverse events and therapy discontinuation. Recurrence is common, with complex mechanisms of resistance that include altered oncogenic pathways, tumor heterogeneity and enhanced DNA repair. We believe [212Pb]VMT01 has the potential to overcome many of these resistance pathways. Our intent is to test the safety and tolerability of [212Pb]VMT01 in previously treated patients who are experiencing progression or recurrence of disease as monotherapy as well as in combination with first-line immunotherapies.
Clinical Studies of [203/212Pb]VMT01
We have a multi-center, open-label, dose-finding study (clincialtrials.gov identifier NCT5655312) of [212Pb]VMT01 in patients with histologically confirmed melanoma and MC1R-positive imaging scans. In September 2024, we received Fast Track designation for the development of [212Pb]VMT01. The first part of the study is a dose finding phase to determine the MTD, maximum feasible dose (MFD) or OBD following a single administration of [212Pb]VMT01. In July 2024, we submitted a protocol amendment to explore the combination of the checkpoint inhibitor nivolumab with [212Pb]VMT01 in patients with histologically confirmed melanoma and positive MC1R imaging scans in our ongoing Phase 1/2a study of [212Pb]VMT01. The supply of nivolumab was secured in March 2024, when we entered into a clinical trial collaboration agreement with Bristol Myers Squibb. As such, the second part of the study is a combination therapy dose finding in which [212Pb]VMT01 and nivolumab are administered in escalating doses to determine MTD, MFD or OBD. The third part of the study is expected to entail the enrollment of patients in monotherapy and combination therapy expansion cohorts based on the identified MTD, MFD or OBD. Patients may be eligible to receive up to three administrations of [212Pb]VMT01 approximately eight weeks apart or they may be eligible to receive nivolumab every four weeks for up to 24 months. A dosimetry sub-study is included to assess biodistribution, tumor uptake and correlation of uptake with observed toxicities and efficacy.
In October 2024, we announced initial results from the first two dosing cohorts of the Phase 1/2a clinical study of [212Pb]VMT01 in patients with progressive MC1R-positive metastatic melanoma. Three patients were enrolled in Cohort 1 and received 3.0 mCi of [212Pb]VMT01, while seven patients were enrolled in Cohort 2 and received 5.0 mCi of [212Pb]VMT01. Patients in each cohort received a median of five prior lines of systematic therapy, including a median of three prior lines of immunotherapy. No DLTs were observed among any patients, and no adverse events (AEs) led to treatment discontinuation. Treatment emergent AEs were mostly grades 1 and 2. None of the four cases of grade 3 treatment emergent AEs were deemed to be treatment related. There were no grade 4 or 5 treatment emergent AEs. No renal toxicities had been reported as of October 11, 2024 (there were no clinically significant changes in blood urea nitrogen or serum creatinine) in spite of dosimetry estimated renal radiation that approached the higher end of conventional dosing.
All patients in Cohort 1 completed three treatments, with one patient experiencing an unconfirmed RECIST version 1.1 objective response after completion of treatment, and two patients experiencing stable disease at 9 and 11 months from the start of treatment, respectively, as reported in October 2024 at the 21st International Congress of the Society of Melanoma Research. In Cohort 2, patients progressed after either the first cycle (three patients) or the second cycle (four patients). These findings are consistent with published and ongoing preclinical studies showing immunostimulatory effects at lower radiation doses.
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Lighter portions of each bar signify transition of the patient to follow-up period (begins approximately 24 weeks after first dose). Patient 03-104 discontinued follow up (without progressive disease). Morris ZS et al, Poster Presentation at ASCO 2025. Data cut-off date April 21, 2025.
1See https://www.sec.gov/Archives/edgar/data/728387/000119312525303895/catx-ex99_1.htm, Slide 61.
The SMC reviewed these findings and recommended exploring a lower dose level of 1.5 mCi per dose, both as a single agent and in combination with the anti-PD-1 antibody, nivolumab. The SMC’s recommendation allows for the monotherapy and combination cohorts to proceed concurrently. An amendment to further explore lower dose levels for monotherapy was approved, and Cohort 3 at 1.5 mCi per dose was opened for enrollment. The combination cohort at 1.5 mCi per dose with nivolumab was also opened for enrollment. The first patients in the combination and monotherapy cohorts received their first treatments in March and April 2025, respectively. As of July 31, 2025, a total of five patients had received their initial monotherapy treatments of VMT01 at 1.5 mCi per dose, once every eight weeks for up to three doses. Additionally, two patients had received VMT01 1.5 mCi with nivolumab.
In September 2025, we announced that the first patient received [212Pb]VMT01 at 3.0 mCi in combination with nivolumab, as part of a new cohort. Additionally, the [212Pb]VMT01 3.0 mCi monotherapy cohort reopened for enrollment. The SMC recommended evaluating [212Pb]VMT01 at a higher dose based on its review of five patients dosed with [212Pb]VMT01 at 1.5 mCi in the monotherapy cohort and two patients dosed with [212Pb]VMT01 at 1.5 mCi together with nivolumab.
As of February 28, 2026, a total of 10 patients had received VMT01 treatment following the re-opening of the [212Pb]VMT01 3.0 mCi monotherapy cohort and the opening of the cohort in which patients are receiving [212Pb]VMT01 at 3.0 mCi in combination with nivolumab. Six patients had received VMT01 at 3.0 mCi in combination with nivolumab. Four patients had received 3.0 mCi of VMT01 as monotherapy, in addition to the three patients who received this monotherapy dose in late 2023. Both cohorts are now closed for enrollment.
By late 2026, the 10 patients who had received VMT01 3.0 mCi treatment since the initiation or re-opening of these cohorts in September 2025 would have had the opportunity for at least 24 weeks of follow up after their initial doses, which is sufficient time to receive at least one scan after their full treatment (up to three doses every eight weeks).
PSV359 – A Targeted Alpha Therapy Targeting Fibroblast Activation Protein (FAP) alpha
Tumor stroma cells do not typically express cancer-specific markers like SSTR2 or MC1R. FAP-α is primarily expressed on tumor stroma cells, but also on some cancer cells. FAP-α is a pan-cancer target that is highly expressed in many cancers. Our in-house discovery team discovered PSV359, a novel cyclic peptide targeting human FAP-α, via various drug discovery methods. We believe PSV359 is an optimized peptide with potential best-in-class characteristics that has been demonstrated in preclinical models. In March 2024, we released the first-in-human clinical SPECT/CT imaging which suggested favorable tumor targeting and retention by the PSV359 compound while clearing from normal organs rapidly and completely.
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In October 2024, we announced first-in-human SPECT/CT images of [203Pb]PSV359 from an independent investigator revealed strong tumor uptake, fast clearance through the renal system, low accumulation in normal organs, and long tumor retention in three patients with FAP-α expressing cancers.
Preclinical results for PSV359 were presented during the Society of Nuclear Medicine and Molecular Imaging 2024 Annual Meeting and the 37th Annual Congress of the European Association of Nuclear Medicine meetings in June and October 2024, respectively. Researchers presented a novel cyclic peptide targeting human FAP-α, which was discovered by us via phage display methods. FAP-α is a protein abundantly expressed in certain cancer cells as well as cancer-associated fibroblasts in tumor lesions and involved in promoting disease progression. The peptide was conjugated to a lead-specific chelator via a molecular linker to form a novel construct, PSV359. The purpose of this study was to evaluate the in vitro and in vivo performance of [203/212Pb]PSV359 in preclinical xenograft models. As depicted below, PSV359 demonstrated superior binding affinity and specificity against human FAP-α (Kd=1.8 nM, Ki=0.4 nM) as compared to other FAP-targeted drugs and remained stable in serum for 96 hours. Overall, strong anti-tumor clinical activity of [212Pb]PSV359 was found in both HT1080-human FAP-α (FAP-α on cancer cells) and U87MG (FAP-α in stromal tissues) xenograft models.
Source: Cagle et al. European Association of Nuclear Medicine 2024, Presentation Number: OP-473.
The FAP-α PSV359 program is a significant addition to our clinical pipeline of targeted alpha therapeutics. We filed an IND application for this asset in December 2024, and we received a “study may proceed” letter (i.e., approval to conduct the trial) from the FDA in the first quarter of 2025. In April 2025, we announced the first patient was treated with [212Pb]PSV359. As of February 28, 2026, two patients had been treated with [212Pb]PSV359 at 2.5 mCi (Cohort 1), and six patients had been treated with [212Pb]PSV359 at 5.0 mCi (Cohort 2), for a total of eight patients. By late 2026, these patients would have had the opportunity for at least 32 weeks of follow up after their initial doses, which is sufficient time to have completed at least one scan after the full course of treatment (up to four doses every eight weeks). Activation activities are underway for additional sites.
Pre-Targeting Theranostic Targeting Platform - The Next Generation of TAT
In January 2024, we entered into an exclusive, worldwide license agreement with Stony Brook University for the global intellectual property rights to its Cuburbit[7]uril-admantane (CB7-Adma) pre-targeting platform and were awarded the Phase 1 tranche of a 2.5-year Fast-Track Small Business Innovation Research grant (Phase 1 $0.4 million; total $2.4 million) from the NIH National Cancer Institute in support of our CB7-Adma host-guest pre-targeting program for the diagnosis and treatment of cancer.
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Pre-targeting utilizing the CB7-Adma platform involves two steps. First, an antibody that binds with high specificity to a cancer-specific protein is administered via intravenous injection. This antibody is chemically modified to include the CB7 chemical entity and accumulates over time at the tumor site. Then, a radionuclide held tightly by our proprietary chelator attached to an Adma group is administered. The Adma group binds to the CB7 group that was previously attached to the cancerous cells with specificity, delivering radiation dose selectively to the tumor sites.
Central to this innovation is CB7-Adma (host-guest) complex formation, driving the interaction between the antibody and radioligand. The chosen host-guest pair, CB7-Adma, has demonstrated promising in vivo stability, modularity and low immunogenicity. The platform’s potential was validated through in vivo profiling of ligands, employing a CB7-modified carcinoembryonic antigen targeting antibody.
We are currently working through preclinical optimization of this platform and working to identify initial targeting antibodies for further investigation.
Manufacturing and Supply
We have developed a proprietary isotope delivery system, colloquially called a “generator,” VMT-α-GEN, to allow for delivery of our preferred therapeutic isotope, 212Pb, for supply to patients. In January 2021, we entered into a 10-year feedstock contract with the National Isotope Development Center (NIDC) of the Department of Energy’s (DOE) Isotope Program. We receive feedstock shipments of Thorium-228 (a precursor to 212Pb) from the NIDC. We also have contracts with various manufacturers to produce certain components of our VMT-α-GEN system. This has allowed us to scale manufacturing of VMT-α-GEN for research purposes that we believe will facilitate our alpha therapy clinical trials. We believe that by controlling our own therapeutic isotope supply, we can solve the many supply chain risks that have slowed alpha-particle therapy clinical adoption to date.
We assemble and manufacture our finished radiopharmaceutical candidates by chelating or trapping an atom of 212Pb within a specialized chelator or chemical “cage” and connecting the 212Pb within its cage to the targeting peptide with our linker technology. For clinical supply, we intend to use a combination of third-party contract manufacturing organizations, or CMOs, and our own manufacturing sites complying with the FDA’s current good manufacturing practices, or CGMP, to manufacture and distribute our doses.
For the drug precursors and isotopes that comprise our TAT platform, a variety of clinical phase manufacturers have been engaged and utilized. We procure chelator-modified peptide precursors from peptide manufacturers who are capable of producing clinical phase precursor material. The imaging isotope 203Pb is procured from manufacturers with appropriate radiation handling licensing and shipped to our production sites, such as our facility in Coralville, IA, while 68Ga is produced on site at PET radiopharmacies that have access to this isotope and are capable of producing finished product. The therapeutic isotope 212Pb is supplied via our proprietary 224Ra/212Pb generators, which are manufactured by a CMO. These isotope delivery systems can be shipped globally to enable final finished radiopharmaceutical production for clinical trials. We have received “safe to proceed” designations for three therapeutic IND applications in which our isotope delivery system was presented to the FDA for use in clinical trial manufacturing. Quality and stability testing for all of our precursors is an ongoing process, and we are focused on continuing to enhance the robustness and reliability of our supply chain to date.
In September 2024, we entered into a Master Equipment and Services Agreement (MESA) and statements of work (SOWs) thereunder with Comecer SpA (Comecer), pursuant to which we agreed to purchase from Comecer manufacturing equipment for the production of our radiopharmaceutical products including, but not limited to, isotope processing hot cells and production suites and related equipment (collectively, the Deliverables) and services for installation and validation of the Deliverables at several of our production facilities in the United States. The first set of production equipment is completing Factory Acceptance Testing at Comecer and is on track to ship by mid-2026, supporting the installation of initial production lines at our Illinois facility in 2026.
We are also actively strengthening our current manufacturing capabilities to support the clinical supply of radiopharmaceuticals through the expansion of clinical production lines at our locations in Coralville, IA, and Somerset, NJ. The Coralville facilities comprise approximately 4,000 square feet of wet laboratory facilities and a small, finished product facility equipped with air and temperature handling and monitoring designed to comply with applicable clinical drug regulatory requirements. Additionally, we have built a second production suite that became operational in 2025. We have staff experienced in finished radiopharmaceutical manufacturing and shipping who will not only supply drug product for our near-term activities but will also perform technology transfer to any CMOs where the finished production of radiopharmaceuticals will be accomplished. We have obtained radiation handling licenses to enable us to provide clinical doses for our Phase 1/2 clinical trials. In addition, we are capable of synthesizing peptides, chelators and linkers in our Coralville facilities, and this capability enables us to independently perform research for pipeline development.
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In March 2024, we acquired the assets and associated lease of Lantheus’ radiopharmaceutical manufacturing facility in Somerset, NJ. Soon after the acquisition, we began the onboarding and operationalization processes and, in October 2024, we achieved the first shipment and patient dosing from our Somerset facility. With three manufacturing suites that can meet CGMP requirements, the Somerset facility is expected to have the capacity to meet future clinical trial and commercial demands at major cancer treatment centers throughout the Northeastern U.S. An existing production suite in Somerset is being upgraded to support Phase 3 activities, with installation targeted for completion by mid-2026. A fourth production suite has also been installed and completed, and we expect it to be operational in 2026.
Also in 2024, we purchased buildings located in the metropolitan areas of Houston, TX, Chicago, IL, and Los Angeles, CA, which we intend to use for the manufacture of our product candidates upon completion of modifications and installation of equipment. In October 2025, we entered into an agreement with a general contractor to begin building modifications at our facility in the Chicago, IL metropolitan area along with preparations for the eventual installation of some of the Comecer manufacturing equipment and associated clean rooms. While we are currently successfully shipping products long distances and meeting patient demands from both our Coralville, IA, and Somerset, NJ sites, we intend to continue to expand our manufacturing and supply network in the future as we anticipate increasing our clinical trial activities and ultimately pursue commercialization.
In addition, CMOs have locations that are strategically placed locally to major metropolitan areas that are within reach for delivery of our radiopharmaceuticals for trials and ultimately for commercialization. We are currently reviewing various CMOs across the United States to determine the potential to transfer know-how and technology to these CMOs to allow broader potential geographic coverage of radioactive products across our potential clinical trial sites.
Commercialization
None of our current product candidates has received the regulatory approvals required to begin commercialization.
Competition
The life sciences and pharmaceutical industries are known to have rapid advancement of novel technologies, intense competition and a strong emphasis on intellectual property. While we believe that our technology and intellectual property provide us with competitive advantages, we face potential competition from multiple sources, including large pharmaceutical companies, specialty pharmaceutical and biotechnology companies, academic institutions, government agencies and public and private research organizations.
Commercial and academic clinical trials are being pursued by a number of parties in the field of radiopharmaceuticals. Early results from these trials have fueled continued interest in radiopharmaceuticals, which are being pursued by several biotechnology companies, as well as by large pharmaceutical companies, including both commercial and academic clinical trials. Results from these trials, combined with recent product approvals, have garnered continued interest in the space by both large pharmaceutical companies and specialized biotechnology companies, which are developing both early-stage and later-stage candidates.
There are also several companies developing alpha-based radiopharmaceuticals for the treatment of cancer, including Bayer, Novartis, Bristol Myers Squibb (through its acquisition of RayzeBio), Eli Lilly (through its acquisition of POINT Biopharma), Sanofi, Lantheus (through its acquisition of Evergreen), Telix Pharmaceuticals, Actinium Pharmaceuticals, RadioMedix, AdvanCell, Orano Med, Aktis Oncology, AstraZeneca (through its acquisition of Fusion Pharmaceuticals), Convergent Therapeutics, Johnson & Johnson, ARTBIO and Abdera. These companies use various alpha-emitting isotopes such as 223Ra, 225Ac, 212Pb and 211At. Most alpha-based radiopharmaceuticals are in clinical development, with Bayer’s Xofigo® being the only approved alpha particle-based therapy. Xofigo® was approved in 2013 for the treatment of symptomatic bone metastases in people with castration-resistant prostate cancer.
There are also companies with beta-based radiopharmaceuticals, both in development and already approved. There are multiple companies, including Lantheus, Novartis and Q BioMed Inc., with approved beta-based radiopharmaceutical products using isotopes such as 131I, 177Lu, 89Sr and 90Y. Novartis’ Lutathera® and Pluvicto® are prominent beta-based radioligands, and other beta-based radiopharmaceuticals are in various stages of clinical development by companies including Novartis, Curium SAS, Telix Pharmaceuticals, Cellectar Biosciences, ITM, Actinium Pharmaceuticals, Lantheus, Blue Earth Therapeutics and Clarity Pharmaceuticals.
For our product candidate [212Pb]VMT-α-NET, we are aware of several competing therapies targeting neuroendocrine tumors. Novartis’ Lutathera®, which was approved in 2018, uses 177Lu for the treatment of individuals with somatostatin receptor-positive gastroenteropancreatic neuroendocrine tumors. We are aware of the following companies with neuroendocrine tumor, radioligand preclinical and clinical development programs: ITM, Bristol Myers Squibb (through its acquisition of RayzeBio), Eli Lilly (through its acquisition of POINT Biopharma) and Sanofi. We also face potential competition from other treatments targeting neuroendocrine tumors such as Sandostatin® and Afinitor® (Novartis), Somatuline® (Ipsen) and Sutent® (Pfizer). While we believe [212Pb]VMT-α-NET has significant advantages compared to conventional approaches to neuroendocrine tumors, we may still face competition from these more established treatments.
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Many of our current or potential competitors, either alone or with their collaboration partners, have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining regulatory approvals and marketing approved products than we do. Mergers and acquisitions in the pharmaceutical and biotechnology industries may result in even more resources being concentrated among a smaller number of our competitors. Smaller or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. These competitors also compete with us in recruiting and retaining qualified scientific and management personnel and establishing clinical trial sites and patient enrollment in clinical trials, as well as in acquiring technologies complementary to, or necessary for, our programs.
We could see a reduction or elimination in our commercial opportunity if our competitors develop and commercialize drugs that are safer, more effective, have fewer or less severe side effects, are more convenient to administer, are less expensive or with a more favorable label than our drug candidates. Our competitors also may obtain FDA or other regulatory approval for their drugs more rapidly than we may obtain approval for ours, which could result in our competitors establishing a strong market position before we are able to enter the market. The key competitive factors affecting the success of all our drug candidates, if approved, are likely to be efficacy, safety, convenience, price, availability of the relevant isotope, the effectiveness of imaging diagnostics, the level of generic competition and the availability of reimbursement from government and other third-party payors.
Intellectual Property
Our success depends, in part, on our ability to obtain, maintain and enforce intellectual property protection for our platform technologies, product candidates and other programs and know-how to defend against third-party challenges to our intellectual property rights, to preserve the confidentiality of our know-how and trade secrets and to operate without infringing, misappropriating or otherwise violating the intellectual property rights of others. We seek to protect our proprietary product candidates and other programs and technologies by, among other methods, filing patent applications in the U.S. and in foreign jurisdictions covering our inventions and improvements that are important to the development and future commercialization of our business. We also rely on trade secrets, know-how, ongoing technological innovation and the in-licensing of third-party intellectual property to establish and maintain our proprietary position. We and, in certain cases, our collaborators and licensors, file patent applications directed to our product candidates and other programs and related radiopharmaceutical technologies in an effort to build and preserve intellectual property positions covering the composition, manufacture and use of such candidates and technologies, including their use for the prevention, diagnosis and/or treatment of diseases.
Patent Rights
Patents provide us with the right to exclude others from practicing the inventions claimed therein and, in the U.S., generally permit us, subject to certain statutory exceptions, to prevent others from making, using, selling, offering for sale, or importing products or methods covered by our patents without authorization. Patent rights are territorial in nature and must be obtained, maintained and enforced in each jurisdiction in which protection is sought. To obtain and maintain patent protection, an invention must satisfy applicable legal requirements in the relevant jurisdiction, including novelty, non-obviousness, adequate written description and enablement, and proper inventorship. The scope of protection afforded by a patent is defined by its claims. A third party may infringe a patent by practicing each element of one or more asserted claims without authorization, including through indirect infringement, such as inducement or contributory infringement, where recognized. Patents are granted for limited terms, generally 20 years from the earliest non-provisional filing date to which priority is claimed, subject to potential patent term adjustment to account for certain administrative delays and, in limited circumstances, patent term extension to compensate for a portion of the time required for product development and regulatory review.
From time to time, we may elect to discontinue the prosecution or maintenance of certain patent applications or issued patents within our portfolio based on strategic, commercial, financial or other considerations. In addition, during prosecution, post-grant proceedings or litigation, or in response to evolving business strategies, we may amend, narrow, disclaim or otherwise modify the scope of claims in pending patent applications or issued patents, which could materially affect the scope of protection afforded by such patent applications or patents. Accordingly, there can be no assurance that any claims included in our pending patent applications, whether in-licensed or developed internally, will be allowed in their current form, if at all, or that the scope of any claims in our issued patents, whether in-licensed or developed internally, will be maintained.
Intellectual Property Protection on Selected Assets
As of March 10, 2026, we owned three issued U.S. patents and one issued European patent and had one allowed U.S. patent application, two allowed European patent applications, one allowed Chinese patent application and 55 other pending U.S. and foreign patent applications. Collectively, these patents and patent applications relate to, among other things, radionuclide generation technologies, FAP-α-targeting compounds and their uses, pre-targeting technologies and antibody-conjugated radiopharmaceutical compounds.
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As of March 10, 2026, we licensed certain patents and patent applications from academic collaborators, including the University of Iowa and Stony Brook University. The licensed intellectual property portfolio includes 14 issued patents, two allowed patent applications and 31 pending U.S. and foreign patent applications.
The following is the patent status for our selected assets:
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VMT-α-NET. As of March 10, 2026, we have exclusively in-licensed from the University of Iowa patents and patent applications comprising two issued U.S. patents, three issued foreign patents and seven pending patent applications in seven foreign jurisdictions directed to this asset. Composition of matter patents have been issued in the U.S., China, Australia and Japan, and a method of use patent is issued in the U.S. The issued patents and the pending patent applications, if issued, are currently expected to expire in 2041, subject to any applicable patent term extensions.
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VMT01. As of March 10, 2026, we have exclusively in-licensed from the University of Iowa patents and patent applications comprising two issued U.S. patents, one issued foreign patent, one allowed foreign patent application, one pending U.S. patent application and one pending foreign patent application directed to this asset. Composition of matter patents directed to this compound have been issued in the U.S. and Australia. The issued patents and pending patent applications, if issued, are currently expected to expire in 2037, subject to any applicable patent term extensions.
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PSV359. As of March 10, 2026, we owned one issued U.S. patent, one issued foreign patent, three pending U.S. patent applications, five pending Patent Cooperation Treaty patent applications and three pending patent applications in three foreign jurisdictions directed to this asset. Composition of matter patents directed to this compound have been issued in the U.S. and Europe. The issued patents and the pending patent applications, if issued, are currently expected to expire in 2043 and 2044, subject to any applicable patent term adjustments and extensions.
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VMT-α-GEN. As of March 10, 2026, we owned one issued U.S. patent, one allowed European patent application, two pending U.S. patent applications and seven pending patent applications in seven foreign jurisdictions directed to this 212Pb radionuclide generation technology. The issued U.S. patent and pending patent applications, if issued, are currently expected to expire in 2043.
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AlphaPRIMETM. As of March 10, 2026, the Company owned one issued U.S. patent, one allowed European patent application, one pending U.S. patent application and eight pending patent applications in eight foreign jurisdictions directed to this 212Pb radionuclide generation technology. The issued U.S. patent and pending patent applications, if issued, are currently expected to expire in 2044.
We maintain an active research and development program that may result in the creation of additional intellectual property, and we file patent applications, as appropriate, directed to such additional intellectual property that is developed internally or in collaboration with third parties. Our collaborations are governed by agreements that are intended to protect our intellectual property rights and to define ownership, confidentiality and licensing arrangements. However, such agreements may not adequately protect our intellectual property, and we cannot assure that any patent applications will result in issued patents or that any issued patents will provide meaningful protection or competitive advantage.
Agreements and Collaborations
Lantheus Agreements
Investment Agreement
On January 8, 2024, we entered into an investment agreement (Lantheus Investment Agreement) with Lantheus Alpha Therapy, LLC, a Delaware limited liability company and wholly owned subsidiary of Lantheus Holdings, Inc. (Lantheus), pursuant to which we agreed to sell and issue to Lantheus in a private placement transaction certain shares (Lantheus Shares) of our outstanding common stock, par value $0.001 per share (Common Stock). The closing of the purchase and sale of the Lantheus Shares to Lantheus by us (Lantheus Closing) was subject to us raising at least $50.0 million of gross proceeds (excluding Lantheus’ investment) in a qualifying third-party financing transaction, which occurred on January 22, 2024. The number of Lantheus Shares sold was 5,634,235, representing 19.99% of the outstanding shares of Common Stock as of January 8, 2024. Pursuant to the Lantheus Investment Agreement, we agreed to cooperate in good faith to negotiate and enter into a registration rights agreement with Lantheus, obligating us to file a registration statement on Form S-3 with the U.S. Securities and Exchange Commission (SEC) to register for resale the Lantheus Shares issued at the Lantheus Closing. We filed such Form S-3 on March 29, 2024, and the SEC declared it effective on April 9, 2024 (File No. 333-278362). The Lantheus Investment Agreement also contains agreements between us and Lantheus whereby Lantheus is provided certain board observer and information rights, subject to certain exceptions.
The Lantheus Investment Agreement also provides Lantheus with certain pro rata participation rights to maintain its ownership position in us in the event that we make any public or non-public offering of any equity or voting interests in us or any securities that are convertible or exchangeable into (or exercisable for) equity or voting interests in us, subject to certain exceptions.
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Pursuant to the Lantheus Investment Agreement, we are required to notify Lantheus within 10 business days of the end of a fiscal quarter in which we issued shares of Common Stock pursuant to “at the market” sales programs, including the 2024 ATM Agreement (as defined below), of (i) the number of shares of Common Stock issued during such fiscal quarter pursuant to such agreement and (ii) the average price per share received by us before commissions (ATM Average Price). Upon receipt of such notice, Lantheus may elect, at its option, to purchase all or a portion of its Pro Rata Portion (as defined in the Lantheus Investment Agreement) of such shares at an aggregate price equal to the number of shares purchased multiplied by the ATM Average Price for such quarter (ATM Participation Right). Pursuant to the Lantheus Investment Agreement, Lantheus may not exercise the ATM Participation Right more than two times per calendar year.
Asset Purchase Agreement
On January 8, 2024, we entered into an Asset Purchase Agreement (Progenics APA) with Progenics Pharmaceuticals, Inc., a Delaware corporation (Progenics) and affiliate of Lantheus, pursuant to which we acquired certain assets and the associated lease of Progenics’ radiopharmaceutical manufacturing facility in Somerset, NJ, for a purchase price of $8.0 million in cash. The transactions contemplated by the Progenics’ APA closed on March 1, 2024.
Option Agreement
On January 8, 2024, we entered into an option agreement (Option Agreement) with Lantheus whereby Lantheus was granted an exclusive option to negotiate an exclusive, worldwide, royalty- and milestone-bearing right and license to [212Pb]VMT-α-NET, our clinical-stage alpha therapy developed for the treatment of neuroendocrine tumors, and a right to co-fund the IND application, enabling studies for early-stage therapeutic candidates targeting PSMA and GRPR and, prior to IND filing, a right to negotiate for an exclusive license to such candidates. In consideration of the rights granted by us to Lantheus pursuant to the Option Agreement, Lantheus paid to us a one-time payment of $28.0 million, subject to certain withholding provisions associated with the closing of the Progenics APA.
Under the terms of the Option Agreement, Lantheus also had a right of first offer and last look protections for any third-party merger and acquisition transactions involving us for a 12-month period, which expired on January 8, 2025.
Equity Financings
2026 Registered Offering
On February 2, 2026, we entered into an underwriting agreement with Piper Sandler & Co. and UBS Securities LLC, as representatives of the underwriters named therein, in connection with our previously announced underwritten offering (2026 Offering) of 39,576,088 shares (2026 Offering Shares) of our Common Stock, and, in lieu of 2026 Offering Shares to certain investors, pre-funded warrants (2026 Pre-funded Warrants) to purchase 6,598,046 shares of Common Stock. The price to the investors for the 2026 Offering Shares was $3.79 per 2026 Offering Share, and the price to the investors for the 2026 Pre-funded Warrants was $3.789 per 2026 Pre-funded Warrant, which represents the per share price for the 2026 Offering Shares less the $0.001 per share exercise price for each such 2026 Pre-funded Warrant. The 2026 Offering closed on February 3, 2026.
Our gross proceeds from the 2026 Offering were approximately $175.0 million, before underwriting discounts and commissions and other offering-related expenses.
The exercise price and the number of shares of Common Stock issuable upon exercise of each 2026 Pre-funded Warrant are subject to appropriate adjustment in the event of certain stock dividends and distributions, stock splits, stock combinations, reclassifications or similar events affecting the Common Stock as well as upon any distribution of assets, including cash, stock or other property, to our stockholders. The 2026 Pre-funded Warrants will not expire and are exercisable in cash or by means of a cashless exercise. A holder of the 2026 Pre-funded Warrants may not exercise such 2026 Pre-funded Warrants if the aggregate number of shares of Common Stock beneficially owned by such holder, together with its affiliates, would be more than 4.99% or 9.99%, as elected by such holder, of the issued and outstanding shares of Common Stock following such exercise, as such percentage ownership is determined in accordance with the terms of the 2026 Pre-funded Warrants. A holder of the 2026 Pre-funded Warrants may increase or decrease this percentage not in excess of 19.99% by providing at least 61 days’ prior notice to us.
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2024 At-the-Market (ATM) Agreement
On August 13, 2024, we entered into a Controlled Equity OfferingSM Sales Agreement (2024 ATM Agreement) with Cantor Fitzgerald & Co. and RBC Capital Markets, LLC (each, an ATM Agent, and together, the ATM Agents) pursuant to which we, from time to time, may offer and sell shares (2024 ATM Shares) of our Common Stock, through or to the ATM Agents having an aggregate sales price of up to $250.0 million.
Subject to the terms and conditions of the 2024 ATM Agreement, each ATM Agent is required to use its commercially reasonable efforts to sell the ATM Shares from time to time, based upon our instructions. We have provided the ATM Agents with customary indemnification rights, and the ATM Agents will be entitled to a commission of up to 3.0% of the gross proceeds from each sale of the ATM Shares effectuated through or to the applicable ATM Agent selling the ATM Shares.
Sales of the 2024 ATM Shares under the 2024 ATM Agreement may be made in transactions that are deemed to be “at the market offerings” as defined in Rule 415 under the Securities Act of 1933, as amended. We have no obligation to sell any of the 2024 ATM Shares and may at any time suspend offers under the 2024 ATM Agreement or terminate the 2024 ATM Agreement.
Any Common Stock sold under the 2024 ATM Agreement will be issued and sold pursuant to our shelf registration statement on Form S-3 (File No. 333-279692) (the May 2024 Registration Statement), which initially became effective upon filing with the SEC on May 24, 2024, and which was subsequently amended on March 26, 2025 and April 4, 2025, with Post-Effective Amendment #3 being declared effective with the SEC on April 8, 2025. On August 13, 2024, we initially filed a prospectus supplement to the May 2024 Registration Statement with the SEC in connection with the offer and sale of up to $250.0 million of the 2024 ATM Shares pursuant to the 2024 ATM Agreement. We re-filed the ATM prospectus supplement with each of the post-effective amendments to the May 2024 Registration Statement.
On February 18, 2025, we sold 3,379,377 shares of our Common Stock under the 2024 ATM Agreement at an average price of approximately $3.02 per share of Common Stock, resulting in gross proceeds of approximately $10.2 million.
May 2024 Registered Offering
On May 24, 2024, we entered into an underwriting agreement with BofA Securities, Inc., as representative of the underwriters named therein, in connection with our previously announced underwritten offering (Registered Offering) of 5,151,588 shares (Registered Offering Shares) of our Common Stock and, in lieu of Registered Offering Shares to certain investors, pre-funded warrants (May 2024 Pre-funded Warrants) to purchase 146,425 shares of Common Stock. The price to the investors for the Registered Offering Shares was $15.10 per Registered Offering Share, and the price to the investors for the May 2024 Pre-funded Warrants was $15.09 per May 2024 Pre-funded Warrant, which represents the per share price for the Registered Offering Shares less the $0.01 per share exercise price for each such May 2024 Pre-funded Warrant. The Registered Offering closed on May 29, 2024. BofA Securities, Inc., Oppenheimer & Co. Inc. and RBC Capital Markets, LLC acted as joint book-running managers for the Registered Offering and B. Riley Securities, Inc. acted as a co-manager for the Registered Offering. JonesTrading Institutional Services LLC acted as a financial advisor for the Registered Offering.
Our gross proceeds from the Registered Offering were approximately $80.0 million, before underwriting discounts and commissions and other offering-related expenses.
The May 2024 Pre-funded Warrants became exercisable subsequent to the filing and effectiveness of an amendment to our Amended and Restated Certificate of Incorporation with the Secretary of State of the State of Delaware on June 14, 2024. The exercise price and the number of shares of Common Stock issuable upon exercise of each May 2024 Pre-funded Warrant were subject to appropriate adjustment in the event of certain stock dividends and distributions, stock splits, stock combinations, reclassifications or similar events affecting the Common Stock as well as upon any distribution of assets, including cash, stock or other property, to our stockholders. The May 2024 Pre-funded Warrants did not have an exercise date and were exercisable in cash or by means of a cashless exercise. A holder of the May 2024 Pre-funded Warrants could not exercise such May 2024 Pre-funded Warrants if the aggregate number of shares of Common Stock beneficially owned by such holder, together with its affiliates, would have been more than 4.99% or 9.99%, as elected by such holder, of the issued and outstanding shares of Common Stock following such exercise, as such percentage ownership is determined in accordance with the terms of the May 2024 Pre-funded Warrants. A holder of May 2024 Pre-funded Warrants could increase or decrease this percentage not in excess of 19.99% by providing at least 61 days’ prior notice to us. The holders of the pre-funded warrants exercised all of the May 2024 Pre-funded Warrants during the second quarter of 2025 by means of the cashless exercise provision and within the other constraints noted above.
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March 2024 Private Placement with Institutional Investors
On March 4, 2024, we entered into an investment agreement with certain accredited institutional investors pursuant to which we agreed to issue and sell, in a private placement (March 2024 Private Placement), 9,200,998 shares of our Common Stock, for a purchase price of $9.50 per share, representing the closing price of the Common Stock on March 1, 2024. The closing of the March 2024 Private Placement occurred on March 6, 2024. The gross proceeds to us from the March 2024 Private Placement were approximately $87.4 million, before deducting fees and other estimated transaction expenses.
January 2024 Public Offering
On January 17, 2024, we entered into an underwriting agreement (Underwriting Agreement) with Oppenheimer & Co. Inc., as representative of the underwriters named therein (Underwriters), in connection with our underwritten public offering (Public Offering) of 13,207,521 shares (Public Shares) of our Common Stock and in lieu of Public Shares to certain investors, pre-funded warrants (Jan. 2024 Pre-funded Warrants) to purchase 3,008,694 shares of Common Stock. The price to the public for the Public Shares was $3.70 per Public Share, and the price to the public for the Jan. 2024 Pre-funded Warrants was $3.69 per Jan. 2024 Pre-funded Warrant, which represents the per share price for the Public Shares less the $0.01 per share exercise price for each such Jan. 2024 Pre-funded Warrant. Under the terms of the Underwriting Agreement, we granted the Underwriters an option, exercisable for 30 days, to purchase up to an additional 2,432,432 shares of Common Stock at the same price per share as the Public Shares, which such option was fully exercised by the Underwriters on January 18, 2024. The Public Offering closed on January 22, 2024.
The gross proceeds to us from the Public Offering were approximately $69.0 million, before underwriting discounts and commissions and other offering-related expenses.
The Public Offering was made pursuant to our shelf registration statement on Form S-3 (File No. 333-275638), declared effective by the SEC on December 14, 2023, a base prospectus dated December 14, 2023, and the related prospectus supplement dated January 17, 2024.
The Jan. 2024 Pre-funded Warrants were exercisable at any time after the date of issuance. The exercise price and the number of shares of Common Stock issuable upon exercise of each Jan. 2024 Pre-funded Warrant were subject to appropriate adjustment in the event of certain stock dividends and distributions, stock splits, stock combinations, reclassifications or similar events affecting the Common Stock as well as upon any distribution of assets, including cash, stock or other property, to our stockholders. The Jan. 2024 Pre-funded Warrants did not have an expiration date and were exercisable in cash or by means of a cashless exercise. A holder of Jan. 2024 Pre-funded Warrants could not exercise such Jan. 2024 Pre-funded Warrants if the aggregate number of shares of Common Stock beneficially owned by such holder, together with its affiliates, would have been more than 4.99% of the issued and outstanding shares of Common Stock following such exercise, as such percentage ownership is determined in accordance with the terms of the Jan. 2024 Pre-funded Warrants. A holder of Jan. 2024 Pre-funded Warrants could increase or decrease this percentage not in excess of 19.99% by providing at least 61 days’ prior notice to us. The holder of the Jan. 2024 Pre-funded Warrants exercised all the Jan. 2024 Pre-funded Warrants during the fourth quarter of 2024 by means of the cashless exercise provision and within the other constraints noted above.
2023 ATM Agreement
On April 11, 2024, we sold shares of our Common Stock pursuant to that certain At Market Issuance Sales Agreement (2023 ATM Agreement), dated as of November 17, 2023, by and among us, Oppenheimer & Co. Inc., B. Riley Securities, Inc. and JonesTrading Institutional Services LLC. The sales resulted in gross proceeds to us of approximately $49.5 million. For additional information regarding the 2023 ATM Agreement, see our Form S-3 filed on November 17, 2023 and Form S-3/A filed on December 7, 2023.
Brachytherapy Divestiture
On April 12, 2024 (GT Medical Closing Date), we completed the sale of substantially all of the assets (GT Medical Closing) of Isoray Medical, Inc. (Isoray), our wholly owned subsidiary, to GT Medical Technologies, Inc. (GT Medical). As previously disclosed, on December 7, 2023, we entered into an Asset Purchase Agreement (the GT Medical APA) with Isoray and GT Medical. Pursuant to the GT Medical APA, Isoray sold to GT Medical, and GT Medical purchased from Isoray, all of Isoray’s right, title and interest in and to substantially all of the assets of Isoray related to Isoray’s commercial Cesium-131 business including equipment, certain contracts and leases, inventory and intellectual property. Subject to limited exceptions set forth in the GT Medical APA, GT Medical did not assume the liabilities of Isoray.
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Pursuant to the terms of, and subject to the conditions specified in, the GT Medical APA, at the GT Medical Closing, (i) GT Medical issued to Isoray 279,516 shares of GT Medical’s common stock, par value $0.0001 per share, representing 0.5% of GT Medical’s issued and outstanding capital stock on a fully diluted basis as of the GT Medical Closing Date and (ii) Isoray has the right to receive, and GT Medical is obligated to pay, certain cash royalty payments during each of the first four years beginning upon the GT Medical Closing Date (each such year, a Measurement Period), as summarized below:
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with respect to GT Medical’s net sales of Cesium-131 brachytherapy seeds for cases that do not utilize GT Medical’s GammaTile Therapy: (a) if such net sales for a Measurement Period are $10.0 million or less, 3.0% of such net sales; (b) if such net sales for a Measurement Period are greater than $10.0 million and less than $15.0 million, 4.0% of such net sales; and (c) if such net sales for a Measurement Period are $15.0 million or more, 5.0% of such net sales; and
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with respect to GT Medical’s net sales of GT Medical’s GammaTile Therapy utilizing Cesium-131 brachytherapy seeds: 0.5% of such net sales for a Measurement Period.
During the second quarter of 2025, we recognized $0.2 million in royalties received pursuant to the GT Medical APA for the period from April 2024 to April 2025. Additionally, during the second quarter of 2025, we reduced our estimated reserve for environmental waste disposal by $0.3 million based on an estimate received from the hazardous waste disposal vendor.
For additional information regarding our brachytherapy divestiture, see our Forms 8-K filed with the SEC on December 12, 2023, April 3, 2024 and April 16, 2024.
Collaborations
License Agreement with the University of Iowa
On June 5, 2018, we entered into a license agreement, as amended in August 2018, November 2019, January 2020, and June 2020, with the University of Iowa Research Foundation (UIRF) for certain patent rights relating to the composition and use of peptide radiopharmaceutical drugs for the treatment of cancer alone or in combination with approved therapies (collectively, the Patent Rights). We hold a worldwide exclusive license, with the right to sublicense, import, make, have made, use, provide, offer to sell and sell all products derived from technology covered by the Patent Rights (the Licensed Products and/or Process(es)).
The UIRF License is a royalty-bearing license obligating us to pay a percentage of proceeds received from sales of Licensed Products and/or Licensed Process(es) at a rate that we believe is within market parameters for a newly organized preclinical development stage company. We also agreed to share a percentage of our proceeds that we derive from other agreements, like sublicense agreements, relating to Licensed Products and/or Licensed Process(es) that we may enter into in amounts that we also believe is within market parameters for a newly organized preclinical development stage company. We are also obligated to pay for past and ongoing intellectual property expenses.
The UIRF License commenced on June 5, 2018 and expires on the date of the last-to-expire Patent Rights, unless terminated earlier under the provisions thereof. We have the right to terminate the UIRF License at any time upon 90 days’ written notice to UIRF and the payment of a $10,000 termination fee. Each party has the right to terminate the UIRF License if the other party is in default or breach of any condition of the UIRF License with a right to cure any such breach within 90 days from receipt of notice of such default or breach. Either party can also terminate the UIRF License if the other party voluntarily files for bankruptcy or other similar insolvency proceedings, makes a general assignment for the benefit of creditors, or is the subject of an involuntary bankruptcy petition. If we fail to pay any sum that is due and payable to UIRF within 90 days after receiving written notice of our default from UIRF, then UIRF has the option of terminating the UIRF License. UIRF may also terminate the UIRF License in the event we, or any sublicensee, brings any action against UIRF, unless such suit is for an uncured material breach or imminent threatened breach of the UIRF License Agreement.
The UIRF License also obligates us to meet certain performance and financial milestones. If we fail to meet these milestones, UIRF will have the right to terminate the UIRF License upon notice as provided in the UIRF License.
License Agreement with Stony Brook University
In January 2024, we entered into an exclusive in-licensing of Stony Brook University’s CB7-Adma pre-targeting platform which covers global intellectual property rights. The agreement with Stony Brook University will expire on the later of the expiration date of the last to expire licensed patents or 20 years from the date of the first sale of a product utilizing the intellectual property.
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Facilities
Our corporate headquarters are located at 2401 Elliott Avenue, Suite 320, Seattle, WA 98121. In addition, we lease laboratory and office space in Coralville, IA and Somerset, NJ. In December 2022, we completed the purchase of a 20,000 square-foot building in Coralville, IA that has laboratory space.
Our facilities in Coralville, IA include a radiopharmaceutical manufacturing laboratory for radiopharmaceutical production for our clinical trials. Additionally, we have built a second production suite, which became operational in 2025. The wet labs have bench, hood and radiochemistry equipment and a separate cell-culture room for discovery lab pipeline development. In November 2025, we entered into a lease for approximately 5,000 square feet of office space, also in Coralville, IA.
In July 2024, August 2024 and October 2024, we purchased buildings located in the metropolitan areas of Houston, TX, Chicago, IL, and Los Angeles, CA, respectively, which we intend to use for the manufacture of our product candidates upon completion of modifications and installation of equipment. The square footage of these buildings range between 27,375 square feet and 41,588 square feet.
In March 2024 and August 2024, we acquired the sub-lease of a Lantheus radiopharmaceutical manufacturing facility and assumed a lease from Progenics for office space, respectively, both of which are located in Somerset, NJ. With three manufacturing suites that can meet CGMP requirements, the Somerset facility is expected to have the capacity to meet future clinical trial and commercial demands at major cancer treatment centers throughout the Northeastern U.S. An existing production suite in Somerset is being upgraded to support Phase 3 activities, with installation targeted for completion by mid-2026. A fourth production suite has also been installed and completed, and we expect it to be operational in 2026.
In April 2024, we completed the divestiture of the brachytherapy division which included the leased production facility located at the Applied Process Engineering Laboratory in Richland, WA. The facility lease transferred to GT Medical at that time.
We believe that our current facilities and CMO relationships are adequate to meet our existing needs.
Suppliers
We currently obtain nearly all our supply of Thorium-228 (a precursor to 212Pb) from a single supplier, the DOE. The amount of 228Th available to us under our agreement with the DOE was sufficient to support our clinical trials in 2025. In May 2025, we entered into a supply agreement with the DOE under which we will purchase Thorium-228 from the DOE during 2025 and early 2026. The supply agreement includes a “take-or-pay” provision pursuant to which we are committed to purchasing approximately $8.4 million of Thorium-228 during the term of the agreement.
We have identified additional suppliers both domestically and internationally for Thorium-228 who have represented that they are able to meet our quality requirements and purity standards. We are in the process of validating additional suppliers to further support our supply chain.
We currently utilize one vendor for the manufacture of resin chromatography columns that are used in our 212Pb generators, and we rely on a single vendor to assemble and load isotopes into the generators that are used to extract 212Pb for use in the doses for our clinical trials.
Other Agreements
For information related to in-licensing and patent licensing agreements, see the section entitled “Intellectual Property.”
Financial Information About Segments
We previously presented our results in two segments: Drug Operations and Brachytherapy. Due to the sale of our brachytherapy segment to GT Medical in the second quarter of 2024 and the classification of the assets and operations of the brachytherapy segment as discontinued operations in our consolidated financial statements, we have now determined that we operate in only one segment as we report operating results on an aggregate basis to our chief operating decision maker.
Financial Information About Geographic Areas
All of our long-lived assets are located in the United States.
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Government Regulation
Our present and future intended activities in the development, manufacture and sale of cancer therapy programs are subject to extensive laws, regulations, regulatory approvals and guidelines. In the United States, we must comply with laws, such as the U.S. Federal Food, Drug and Cosmetic Act (FFDCA), regulations, guidance documents and standards promulgated by the FDA, which govern, among other things, the testing, development, manufacturing, quality control, safety, purity, potency, efficacy, approval, labeling, packaging, storage, record keeping, distribution, marketing, sales, import, export, post-approval monitoring and reporting, advertising and other promotional practices involving pharmaceutical programs. We cannot market a product candidate in the United States until the pharmaceutical program has received FDA approval or licensure.
The FFDCA provides several distinct pathways for the approval of new drugs. A new drug application (NDA) under Section 505(b)(1) of the FFDCA is a comprehensive application to support approval of a product candidate that includes, among other things, data and information to demonstrate that the proposed drug is safe and effective for its proposed uses, that production methods are adequate to ensure the identity, strength, quality and purity of the drug, and that proposed labeling is appropriate and contains all necessary information. A 505(b)(1) NDA generally contains results of the full set of preclinical studies and clinical trials conducted by or on behalf of the applicant to characterize and evaluate the product candidate. Alternatively, Section 505(b)(2) of the FFDCA permits the filing of an NDA where at least some of the information required for approval comes from studies not conducted by or for the applicant and for which the applicant has not obtained a right of reference. The applicant may rely to some extent upon the FDA’s findings of safety and effectiveness for an approved product that acts as the reference drug and submit its own product-specific data, which may include data from preclinical studies or clinical trials conducted by or on behalf of the applicant, to address differences between the product candidate and the reference drug. Drug manufacturers may also submit an abbreviated new drug application (ANDA) under section 505(j) of the FFDCA to market a generic version of an approved branded drug product if the manufacturer shows the generic version is “therapeutically equivalent” or expected to have the same clinical effect and safety profile as the branded drug product when administered to patients under the conditions specified in the labeling.
The process of obtaining regulatory approvals and the subsequent compliance with appropriate federal, state, local and foreign statutes and regulations require the expenditure of substantial time and financial resources. In addition, the laws, rules and regulations that apply to our business are subject to change and it is difficult to foresee whether, how or when such changes may affect our business.
In addition to the FFDCA, our operations and properties are subject to a variety of other federal and state laws and regulations, including laws and regulations relating to occupational safety and environmental laws, including laws with respect to any air emissions, wastewater discharges, waste disposal and the management of hazardous substances.
Development and Approval
Drug Development Process. The process to develop and obtain approval for pharmaceutical products for commercialization in the United States and many other countries is lengthy, complex and expensive, and the outcome is far from certain. Although foreign requirements for conducting clinical trials and obtaining approval may differ in certain respects from those in the United States, there are many similarities, and they often are equally rigorous, and the outcome cannot be predicted with confidence.
The process required before a pharmaceutical product may be marketed in the United States generally include the following:
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Completion of extensive non-clinical laboratory tests and animal studies in accordance with the FDA’s Good Laboratory Practices (GLP) regulations, applicable requirements for the humane use of laboratory animals, such as the Animal Welfare Act or other applicable regulations;
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Filing an IND with the FDA for human clinical testing, which must become effective before human clinical trials may begin;
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Approval by an independent IRB or ethics committee overseeing each clinical site before each trial may be initiated at that site;
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Designing and conducting adequate and well-controlled human clinical trials in accordance with applicable FDA regulations and guidance for clinical trials (including human subject protection and IRB requirements) and, where applicable, Good Clinical Practices (GCP) guidelines issued by the International Council for Harmonisation of Technical Requirements for Pharmaceuticals in Human Use, and any additional requirements for the protection of human research subjects and their health information, to establish the safety and efficacy of the drug for each proposed indication;
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Submission to the FDA of an application for marketing approval that includes substantial evidence of safety and effectiveness from results of clinical trials, as well as the results of preclinical testing, detailed information about the chemistry, manufacturing and controls (CMC), and proposed labeling and packaging for the product candidate;
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Consideration by an FDA Advisory Committee, if applicable;
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Satisfactory completion of potential FDA inspections of the preclinical study and clinical trial sites that generated the data in support of the marketing application;
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Determination by the FDA within 60 days of its receipt of a marketing application to accept and file the application for substantive review;
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Satisfactory completion of FDA inspections of manufacturing facilities and, as applicable, clinical and nonclinical sites at which the active pharmaceutical ingredient, and finished drug product are produced and tested to assess compliance with CGMP;
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Payment of applicable user fees;
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FDA review and approval of the marketing application, including prescribing information, labeling and packaging of the drug program, agreement on post-marketing commitments, if applicable, prior to any commercial marketing or sale of the drug in the United States; and
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If required, implementation of a Risk Evaluation & Mitigation Strategies (REMS) program, and conduct of any required Phase 4 studies, and compliance with post-approval requirements, including ongoing monitoring and reporting of adverse events related to the product.
Prior to initiating human testing of any pharmaceutical product, the product undergoes preclinical testing. Nonclinical tests include laboratory evaluations of product chemistry, pharmacology, toxicity and formulation, as well as animal studies to assess the potential safety and activity of the product candidate. Adherence to federal regulations, such as GLPs and the Animal Welfare Act enforced by the Department of Agriculture, is required during the conduct of these tests.
The sponsor of a clinical study is required to submit the results of nonclinical tests, along with manufacturing details, analytical data, any available clinical data or literature, and a proposed clinical protocol, to the FDA as part of an IND application before clinical testing may begin. Some nonclinical testing typically continues even after IND submission. An IND provides an exemption from the FFDCA, allowing the shipment of an unapproved product for investigational use in clinical trials, subject to FDA authorization. The IND becomes effective 30 days after FDA receipt, unless concerns are raised by the FDA about the proposed clinical trial, including whether subjects will be exposed to unreasonable risks, within that period, in which case outstanding issues must be resolved before the clinical trial can proceed.
Clinical trials may involve the administration of the product candidate to healthy volunteers or patients under the supervision of qualified investigators, generally physicians not employed by or under the study sponsor’s control. Clinical trials involving some products for certain diseases may begin with testing in patients with the disease. Clinical trials are conducted under protocols detailing, among other things, the objectives of the clinical trial, dosing procedures, subject selection and exclusion criteria and the parameters to be used to monitor subject safety, including stopping rules that assure a clinical trial will be stopped if certain adverse events should occur. Each protocol and any amendments to the protocol must be submitted to the FDA as part of the IND. Clinical trials must be conducted and monitored in accordance with the FDA’s regulations comprising the GCP requirements, including the requirement that all research subjects or his or her legal representative provide informed consent. Further, each clinical trial must be reviewed and approved by an independent IRB at, or servicing, each institution at which the clinical trial will be conducted. IRBs are charged with protecting the welfare and rights of study participants and consider such items as whether the risks to individuals participating in clinical trials are minimized and are reasonable in relation to anticipated benefits. The IRB also approves the form and content of the informed consent that must be signed by each clinical trial subject or his or her legal representative and must monitor the clinical trial until completed. 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.
A sponsor conducting clinical trials outside the United States may conduct such studies under an IND, but is not required to do so; however, the FDA may accept foreign clinical data in support of an application only if the studies meet applicable requirements. Foreign study conducted under an IND must meet the same requirements that apply to studies being conducted in the United States. If a foreign clinical trial is not conducted under an IND, the sponsor may submit data from the clinical trial to the FDA in support of an application if the clinical trial is conducted in compliance with GCP, including review and approval by an independent ethics committee and compliance with informed consent principles, and the FDA is able to validate the data from the study through an onsite inspection if deemed necessary.
Clinical trials are typically conducted in sequential phases, although they may overlap or be combined. The four phases are as follows:
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Phase 1. Phase 1 includes the initial introduction of an investigational product candidate into humans. Phase 1 trials generally are conducted in healthy volunteers but in some cases are conducted in patients with the target disease or condition. These trials are designed to evaluate the safety, metabolism, pharmacokinetic properties and pharmacologic actions of the investigational product candidate in humans, the side effects associated with increasing doses, and if possible, to gain early evidence on effectiveness. During Phase 1 trials, sufficient information about the investigational product candidate’s pharmacokinetic properties and pharmacological effects may be obtained to permit the design of Phase 2 trials. The total number of participants included in Phase 1 trials varies but is generally in the range of 20 to 80.
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Phase 2. Phase 2 includes the controlled clinical trials conducted in patients with the target disease or condition, to determine dosage tolerance and optimal dosage, to identify possible adverse side effects and safety risks associated with the product candidate, and to obtain initial evidence of the effectiveness of the investigational product candidate for a particular indication. Phase 2 trials are typically well controlled, closely monitored, and conducted in a limited subject population, usually involving no more than several hundred participants.
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Phase 3.Phase 3 trials are controlled clinical trials conducted in an expanded subject population at geographically dispersed clinical trial sites. They are performed after preliminary evidence suggesting effectiveness of the investigational product candidate has been obtained and are intended to further evaluate dosage, clinical effectiveness and safety, to establish the overall benefit-risk relationship of the product candidate, and to provide an adequate basis for drug approval. Phase 3 trials usually involve several hundred to several thousand participants. In most cases, the FDA requires two adequate and well-controlled Phase 3 trials to demonstrate the efficacy and safety of the drug; however, the FDA may find a single Phase 2 or Phase 3 trial with other confirmatory evidence to be sufficient in rare instances, particularly in an area of significant unmet medical need and if the trial design provides a well-controlled and reliable assessment of clinical benefit.
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Phase 4. Post-approval studies, sometimes referred to as Phase 4 clinical trials, may be conducted after initial marketing approval. These studies may be required by the FDA as a condition of approval or licensure and are used to gain additional experience from the treatment of patients in the intended therapeutic indication. The FDA has express statutory authority to require post-market clinical studies to address safety issues.
During all phases of clinical development, regulatory agencies require extensive monitoring and auditing of all clinical activities, clinical data and clinical trial investigators. Annual progress reports detailing the results of the clinical trials must be submitted to the FDA. Written IND safety reports must be promptly submitted to the FDA and the investigators for serious and unexpected adverse events, any findings from other studies, tests in laboratory animals or in vitro testing and other sources that suggest a significant risk for human subjects, or any clinically important increase in the rate of a serious suspected adverse reaction over that listed in the protocol or investigator brochure. The sponsor must submit an IND safety report within 15 calendar days after the sponsor determines that the information qualifies for reporting. 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.
Clinical trials may not be completed successfully within a specified period of time, if at all. The decision to terminate development of an investigational product may be made by a health authority (such as the FDA), an IRB/ethics committee, or by a company for various reasons. At any time before or during clinical trials, the FDA may order the temporary or permanent discontinuation of a clinical trial, which is referred to as a clinical hold, or impose other sanctions, if the agency believes the clinical trial is not being conducted in accordance with FDA requirements or presents an unacceptable risk to the clinical trial patients. If the FDA imposes a clinical hold, trials may not recommence without FDA authorization and then only under terms authorized by the FDA. Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution if the clinical trial is not being conducted in accordance with the IRB’s requirements or if the investigational product has been associated with unexpected serious harm to patients.
There are requirements for the registration of ongoing clinical trials of product candidates on public registries and the disclosure of certain clinical trial results and other trial information after completion within timeframes to the NIH for public dissemination on its clinicaltrials.gov website. In addition, sponsors or distributors of investigational products for the diagnosis, monitoring or treatment of one or more serious diseases or conditions must have a publicly available policy on evaluating and responding to requests for expanded access requests.
Assuming successful completion of all required testing in accordance with all applicable regulatory requirements, detailed investigational product candidate information is submitted to the FDA in the form of a marketing application to request market approval for the product in specified indications.
Marketing Application. After completing the clinical studies required to support an application, a sponsor seeking approval to market a product candidate in the United States submits to the FDA an NDA (or, for biologics, a Biologics License Application). The NDA is a comprehensive application intended to demonstrate the product candidate’s safety and effectiveness and includes, among other things, preclinical and clinical data, information about the product candidate’s composition, and detailed CMC information, including manufacturing processes, controls and specifications. When an application is submitted, the FDA makes an initial determination as to whether the application is sufficiently complete to be filed for review. If the application is not complete, the FDA may refuse to file the application and request additional information. A refusal to file, which requires resubmission of the application with the requested additional information, delays review of the application.
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The FDA reviews the application to determine, among other things, whether the proposed product is safe and effective for its intended use, and whether the product is being manufactured in accordance with CGMP. Before approving an application, the FDA may inspect one or more clinical sites (and related records) to assess compliance with applicable clinical trial requirements and the reliability of the data. FDA Advisory Committee meetings may be held for New Chemical Entities, novel indications, or for applications that otherwise present scientific, technical or policy questions on which the agency believes it would benefit from the perspectives of outside experts. An advisory committee meeting includes a panel of independent experts, including clinicians and other scientific experts, who review, evaluate and make 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.
After review of an NDA, the FDA may grant marketing approval, request additional information, or issue a complete response letter (CRL) communicating the reasons for the agency’s decision not to approve the application. The CRL may request additional information, including additional preclinical or clinical data, for the FDA to reconsider the application. An application may be resubmitted with the deficiencies addressed, but resubmission does not guarantee approval. Data from clinical trials are not always conclusive, and the FDA’s interpretation of data may differ from the sponsor’s. Obtaining approval can take years, requires substantial resources and depends on a number of factors, including the severity of the targeted disease or condition, the availability of alternative treatments, and the risks and benefits demonstrated in clinical trials. Additionally, as a condition of approval, the FDA may impose restrictions that could affect the commercial prospects of a product and increase costs, such as a REMS, and/or post-approval commitments to conduct additional clinical trials or non-clinical studies or to conduct surveillance programs to monitor the product’s effects. Under the Pediatric Research Equity Act, certain applications for approval must also include an assessment, generally based on clinical study data, of the safety and effectiveness of the subject product in relevant pediatric populations, unless a waiver or deferral is granted.
Expedited Programs. The FDA maintains certain expedited programs to facilitate the development and review processes for certain qualifying pharmaceutical product candidates, including Fast Track designation, breakthrough therapy designation, priority review designation and accelerated approval pathway. A pharmaceutical product candidate may be granted Fast Track designation if it is intended for the treatment of a serious or life-threatening condition and demonstrates the potential to address unmet medical needs for such condition. With Fast Track designation, the sponsor may be eligible for more frequent opportunities to obtain the FDA’s feedback, and the FDA may review completed sections of the marketing application on a rolling basis, subject to FDA agreement. This rolling review is available if the applicant provides, and the FDA approves, a schedule for the remaining information. Even if a product receives Fast Track designation, the designation can be rescinded and provides no assurance that a product will be reviewed or approved more expeditiously than would otherwise have been the case, or that the product will be approved at all.