Perspective Therapeutics Announces Clinical Collaboration and Supply Agreement with Merck to Evaluate [212Pb]PSV359 in Combination with Keytruda® (Pembrolizumab) in FAP-α Positive Solid Tumors

Perspective will add a Keytruda combination arm to its ongoing Phase 1/2a FAP-α–targeted radiopharmaceutical trial under a collaboration with Merck.

Rhea-AI Summary

Perspective Therapeutics (CATX) announced a clinical trial collaboration and supply agreement with Merck (MRK)/b) on September 14, 2026 to evaluate Perspective’s targeted alpha therapy in combination with Merck’s anti-PD-1 therapy Keytruda (pembrolizumab) in FAP-α–positive solid tumors.

The combination will be tested via an amendment to Perspective’s ongoing Phase 1/2a, multi-center, open-label, dose-finding and dose-expansion study (NCT06710756) in patients with certain non-small cell lung and colorectal cancers expressing FAP-α. The study has completed enrollment in the first three monotherapy dose cohorts. Perspective sponsors the trial, while Merck supplies pembrolizumab at no cost. PSV359 is designed to deliver the alpha-emitting isotope 212Pb to FAP-α–expressing tumors, with related imaging agents (203Pb/68Ga, PSV377) used to select patients and assess FAP-α expression.

Positive

• Collaboration with Merck to evaluate [212Pb]PSV359 plus Keytruda in FAP-α–positive solid tumors
• Merck will provide pembrolizumab at no cost for the Perspective-sponsored Phase 1/2a study
• Ongoing Phase 1/2a trial has completed enrollment in first three monotherapy dose cohorts
• Theranostic platform uses 212Pb therapy plus 203Pb/68Ga imaging to identify FAP-α–positive patients

Negative

• None.

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+3.56% vs previous close $2.91 last price 0.1x rel. volume Open Argus

Details

Market reaction after Phase 1/2a partnership: CATX +3.56%

$2.88 $3.47 Day Range

$332.18M Market Cap

Following this news, CATX has gained 3.56%, reflecting a moderate positive market reaction. Our momentum scanner has triggered 4 alerts so far, indicating moderate trading interest and price volatility. The stock is currently trading at $2.91.

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Market Context

6% was CATX’s 24-hour move after the Aug 10 2Q26 report, which identified PSV359 as continuing in Ph...

Analysis

6% was CATX’s 24-hour move after the Aug 10 2Q26 report, which identified PSV359 as continuing in Phase 1/2a; today’s Merck collaboration adds a combination-treatment amendment to that same program.

Key Figures

Monotherapy dose cohorts: 3 cohorts

Monotherapy dose cohorts

3 cohorts

Phase 1/2a PSV359 study; enrollment completed

Historical Context

1 past event · Latest: Aug 10

1 event

1. Aug 10

   2Q26 earnings report

   24h Move

   +6.0%

   Earlier report identified PSV359 continuing in Phase 1/2a development.

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Key Terms

fap-α, anti-pd-1, tumor microenvironment, theranostic

4 terms

fap-α medical

"patients with certain types of non-small cell lung cancer and colorectal cancer that express fibroblast activation protein alpha (FAP-α)"

FAP-α is a protein found on certain support cells that surround tumors; it acts like a neighborhood sign indicating where cancer-supporting activity is concentrated. Investors care because therapies or imaging tests that target FAP-α can help detect tumors, deliver drugs directly to the tumor environment, or slow tumor growth, so success or failure of such products influences clinical trial outcomes, regulatory approval prospects, and commercial value.

anti-pd-1 medical

"Merck’s anti-PD-1 therapy"

Anti-PD-1 is a type of drug that blocks a protein called PD-1 on immune cells, effectively releasing the immune system’s “brakes” so it can better recognize and attack cancer cells. For investors, these drugs matter because they can produce durable responses in multiple cancers, drive large sales if approved, and influence valuations through trial results, regulatory decisions, partnerships and competition in the oncology market.

tumor microenvironment medical

"a tumor microenvironment historically characterized by poor drug penetration"

The tumor microenvironment is the immediate area surrounding a cancer cell, made up of nearby cells, blood vessels, and support structures that influence how the cancer grows and spreads. It functions like a bustling neighborhood that can either help or hinder the tumor’s development. For investors, understanding changes in this environment can signal the effectiveness of treatments and potential shifts in a cancer-related market.

theranostic medical

"This "theranostic" approach enables visualization of the specific tumor"

A theranostic is a single medical approach or agent that combines diagnosis and treatment—using a test or imaging step to find patients likely to benefit, then delivering a targeted therapy tied to that same marker. For investors, theranostics can speed development, lower the chance of failed trials and concentrate sales on the right patients, like a smart key that both locates the correct lock and opens it, potentially improving clinical and commercial success.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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SEATTLE, Sept. 14, 2026 (GLOBE NEWSWIRE) -- Perspective Therapeutics, Inc. (“Perspective,” the “Company,” “we,” “us,” and “our”) (NYSE AMERICAN: CATX), a radiopharmaceutical development company pioneering advanced treatments for cancers throughout the body, today announced a clinical trial collaboration agreement with Merck (NYSE: MRK), known as MSD outside of the United States and Canada.

The agreement supports the evaluation of Perspective’s targeted alpha-particle therapy [²¹²Pb]PSV359 in combination with Keytruda® (pembrolizumab), Merck’s anti-PD-1 therapy. This combination will be evaluated under an amendment to the Company’s ongoing Phase 1/2a study of [²¹²Pb]PSV359 in patients with certain types of non-small cell lung cancer and colorectal cancer that express fibroblast activation protein alpha (FAP-α) (clinicaltrials.gov identifier NCT06710756). The study has completed enrollment in the first three monotherapy dose cohorts.

Perspective is sponsoring the study, and Merck is providing pembrolizumab at no cost.

“FAP-α is associated with the majority of solid tumors and with a tumor microenvironment historically characterized by poor drug penetration and immune suppression or exclusion,” said Markus Puhlmann, Perspective’s Chief Medical Officer. “By combining targeted radiopharmaceutical treatment with a well-established immune checkpoint inhibitor, we aim to evaluate whether this approach can reshape the tumor environment and potentially improve treatment outcomes for patients with advanced FAP-α-positive solid tumors.”

About FAP-α

FAP-α is a protein abundantly expressed on the surface of cancer-associated fibroblasts (CAFs) in the stroma, a part of the tumor microenvironment (TME) in the majority of epithelial cancers. In addition to expression on CAFs, FAP-α is expressed on certain cancer cells themselves, including sarcomas and mesotheliomas.^1,2,3,4 Higher FAP-α expression has been found to be associated with poor prognosis in a number of solid tumors such as non-small cell lung cancer, colorectal cancer, pancreatic cancer, stomach cancer, mesothelioma, head and neck cancer, esophageal cancer, and ovarian cancer.^5,6,7,8,9,10 Expression of FAP-α in healthy tissues is usually low.^3,4

About PSV359

PSV359 was designed to target and deliver ²¹²Pb to tumor sites expressing FAP-α, associated with multiple highly prevalent solid tumors, with patients in need of additional treatment options. The targeting moiety may also be radiolabeled with ²⁰³Pb or ⁶⁸Ga (known as PSV377) to detect FAP-α expression in individual patients. Preclinical imaging and therapy as well as human imaging results suggest Perspective's proprietary targeting ligand has improved levels of target engagement and uptake in tumors, as well as reduced retention in healthy tissues, which may result in a desirable therapeutic index.

Perspective is conducting a multi-center, open-label, dose-finding and dose-expansion study (clinicaltrials.gov identifier NCT06710756) of [²¹²Pb]PSV359 in patients with advanced solid tumors that express FAP-α as determined by imaging with [²⁰³Pb]PSV359. The primary objective of the dose finding phase of the study is to assess the safety and tolerability of various doses of [²¹²Pb]PSV359 in order to determine the recommended Phase 2 dose to be used in the expansion phase of the study, where anti-tumor activities may be an additional primary outcome measure.

About Perspective Therapeutics, Inc.

Perspective Therapeutics, Inc. is a radiopharmaceutical development company pioneering advanced treatments for cancers throughout the body. The Company has proprietary technology that utilizes the alpha-generating isotope ²¹²Pb to deliver powerful radiation specifically to cancer cells via specialized targeting moieties. The Company is also developing complementary imaging techniques that incorporate the same targeting moieties, which provides the opportunity to personalize treatment and optimize patient outcomes. This "theranostic" approach enables visualization of the specific tumor and subsequent treatment, potentially improving efficacy and minimizing toxicity.

The Company is advancing a portfolio of clinical-stage programs in the U.S., including bamzireotide navoxetan (VMT-α-NET, neuroendocrine tumors), lapemelanotide zapixetar (VMT01, melanoma), and PSV359 (solid tumors).

The Company is expanding its regional finished drug product candidate supply network, enabled by its proprietary ²²⁴Ra/²¹²Pb generator platform used to manufacture clinical drug product candidates, to support the delivery of patient-ready drug product candidates for clinical trials and, if approved, commercial operations.

For more information, please visit the Company's website at www.perspectivetherapeutics.com.

Safe Harbor Statement

This press release contains forward-looking statements within the meaning of the United States Private Securities Litigation Reform Act of 1995. Statements in this press release that are not statements of historical fact are forward-looking statements. Words such as "may," "will," "should," "expect," "plan," "anticipate," "could," "intend," "target," "project," "estimate," "believe," "predict," "potential," or "continue" or the negative of these terms or other similar expressions are intended to identify forward-looking statements, though not all forward-looking statements contain these identifying words. Forward-looking statements in this press release include statements concerning, among other things, the Company’s preclinical and clinical development plans and the expected timing for the release of additional data from its clinical programs; the Company’s beliefs that its product candidates address certain unmet medical needs; the Company’s expectations regarding regulatory pathways for its product candidates; the Company’s expectations regarding its interactions with regulatory agencies and the expected timing thereof; the Company’s regional distribution and manufacturing capabilities; and other statements that are not historical fact.

The Company may not actually achieve the plans, intentions, or expectations disclosed in the forward-looking statements, and you should not place undue reliance on the forward-looking statements. These forward-looking statements involve risks and uncertainties that could cause the Company's actual results to differ materially from the results described in or implied by the forward-looking statements. Known risk factors include that the Company’s clinical trials may be more costly or take longer to complete than anticipated, or may never be completed, or may not generate results that warrant future development of the tested product candidate; the Company may elect to change its strategy regarding its product candidates and clinical development activities; economic and market conditions may worsen; and risks related to the sufficiency of the Company’s cash resources for its future operating expenses and capital expenditures. A more complete discussion of the risks and uncertainties facing the Company appears under the heading “Risk Factors” in the Company’s most recent Annual Report on Form 10-K filed with the Securities and Exchange Commission (the “SEC”), in the Company’s other filings with the SEC, and in the Company’s future reports to be filed with the SEC and available at www.sec.gov. Forward-looking statements contained in this news release are made as of this date. Unless required to do so by law, we undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events, or otherwise.

KEYTRUDA® is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.

Media and Investor Relations Contacts:

Perspective Therapeutics IR:
Annie J. Cheng, CFA
ir@perspectivetherapeutics.com

ENTENTE Network of Companies
Katie Morris, PhD
katiemorris@ententeinc.com

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¹ Garin-Chesa P, Old LJ, Rettig WJ. Cell surface glycoprotein of reactive stromal fibroblasts as a potential antibody target in human epithelial cancers. Proc Natl Acad Sci U S A. 1990;87(18):7235-7239. doi:10.1073/pnas.87.18.7235
² Dziadek S, Kraxner A, Cheng WY, et al. Comprehensive analysis of fibroblast activation protein expression across 23 tumor indications: insights for biomarker development in cancer immunotherapies. Front Immunol. 2024;15:1352615. Published 2024 Mar 15. doi:10.3389/fimmu.2024.1352615
³ Kratochwil C, Flechsig P, Lindner T, et al. 68Ga-FAPI PET/CT: Tracer Uptake in 28 Different Kinds of Cancer. J Nucl Med. 2019;60(6):801-805. doi:10.2967/jnumed.119.227967
⁴ Fitzgerald AA, Weiner LM. The role of fibroblast activation protein in health and malignancy. Cancer Metastasis Rev. 2020;39(3):783-803. doi:10.1007/s10555-020-09909-3
⁵ Cords L, Engler S, Haberecker M, et al. Cancer-associated fibroblast phenotypes are associated with patient outcome in non-small cell lung cancer. Cancer Cell. 2024;42(3):396-412.e5. doi:10.1016/j.ccell.2023.12.021
⁶ Coto-Llerena M, Ercan C, Kancherla V, et al. High Expression of FAP in Colorectal Cancer Is Associated With Angiogenesis and Immunoregulation Processes. Front Oncol. 2020;10:979. Published 2020 Jul 8. doi:10.3389/fonc.2020.00979
⁷ Henry LR, Lee HO, Lee JS, et al. Clinical implications of fibroblast activation protein in patients with colon cancer. Clin Cancer Res. 2007;13(6):1736-1741. doi:10.1158/1078-0432.CCR-06-1746
⁸ Wang S, Zheng Y, Yang F, et al. The molecular biology of pancreatic adenocarcinoma: translational challenges and clinical perspectives. Signal Transduct Target Ther. 2021;6(1):249. Published 2021 Jul 5. doi:10.1038/s41392-021-00659-4
⁹ Cohen SJ, Alpaugh RK, Palazzo I, et al. Fibroblast activation protein and its relationship to clinical outcome in pancreatic adenocarcinoma. Pancreas. 2008;37(2):154-158. doi:10.1097/MPA.0b013e31816618ce
¹⁰ Ma C, Xi S, Sun, H, et al. Identifying the oncogenic roles of FAP in human cancers based on systematic analysis. Aging 2023;15(14):7056-7083. doi: 10.18632/aging.204892

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What cancers are being studied with [212Pb]PSV359 and Keytruda in this collaboration?

The amended Phase 1/2a study will evaluate the combination in patients with certain types of non-small cell lung cancer and colorectal cancer that express fibroblast activation protein alpha (FAP-α).

Who sponsors the trial and what is Merck’s role?

Perspective Therapeutics is sponsoring the multi-center, open-label Phase 1/2a trial of [212Pb]PSV359. Under the collaboration and supply agreement, Merck is providing its anti-PD-1 therapy pembrolizumab (Keytruda) at no cost for use in the study.

How does PSV359 target FAP-α–positive tumors?

PSV359 was designed to deliver the alpha-generating isotope 212Pb to tumor sites expressing FAP-α. Its targeting moiety can also be radiolabeled with 203Pb or 68Ga (PSV377) to image FAP-α expression in individual patients, supporting selection and evaluation of FAP-α–positive tumors.

What is the primary objective of the current Phase 1/2a study?

In the dose-finding phase of the Phase 1/2a trial (NCT06710756), the primary objective is to assess the safety and tolerability of various doses of [212Pb]PSV359 and determine the recommended Phase 2 dose. In the expansion phase, anti-tumor activity may be an additional primary outcome measure.

What broader pipeline is Perspective Therapeutics advancing?

Perspective is advancing several U.S. clinical-stage programs using its 212Pb-based platform, including bamzireotide navoxetan (VMT-α-NET) for neuroendocrine tumors, lapemelanotide zapixetar (VMT01) for melanoma, and PSV359 for solid tumors. The company is also building a regional supply network enabled by its proprietary 224Ra/212Pb generator platform for clinical and potential future commercial drug product candidates.