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Primary endpoint met in Phase 3 TALAPRO-3 study demonstrating a statistically significant and clinically meaningful reduction in risk of disease progression or death in HRR gene-mutated metastatic hormone sensitive prostate cancer
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Consistent rPFS efficacy benefit was observed in patients whose tumors harbored BRCA and non-BRCA HRR gene alterations
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Interim analysis showed a strong trend toward improvement in overall survival
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These results will be discussed with global health authorities to potentially expand TALZENNA indication in this earlier stage disease
March 19, 2026 --NEW YORK--(BUSINESS WIRE)-- Pfizer Inc. (NYSE: PFE) today announced positive topline results from the Phase 3 TALAPRO-3 study of TALZENNA® (talazoparib), an oral poly ADP-ribose polymerase (PARP) inhibitor, in combination with XTANDI® (enzalutamide), an androgen receptor pathway inhibitor (ARPI), in people with homologous recombination repair (HRR) gene-mutated metastatic castration-sensitive prostate cancer (mCSPC), also known as metastatic hormone-sensitive prostate cancer (mHSPC).
The study met its primary endpoint, with TALZENNA plus XTANDI demonstrating a statistically significant and clinically meaningful improvement in radiographic progression-free survival (rPFS), compared to placebo plus XTANDI. The results markedly exceeded the pre-specified target hazard ratio of 0.63, with the majority of patients remaining progression-free at the time of analysis. Consistent efficacy benefit was also observed in patients whose tumors harbored BRCA and non-BRCA HRR gene alterations.
“Current treatment approaches leave many patients with HRR gene-mutated metastatic castration-sensitive prostate cancer vulnerable to early disease progression,” said Neeraj Agarwal, M.D., FASCO, Professor and Presidential Endowed Chair of Cancer Research at Huntsman Cancer Institute at the University of Utah, and global lead investigator for TALAPRO-3. “The TALAPRO-3 results demonstrate that treatment with TALZENNA in combination with XTANDI earlier in the disease course significantly extends the time patients can live without their cancer worsening.”
At the time of the interim analysis, results showed a strong trend toward improved overall survival (OS), a key secondary endpoint. Benefits were also observed in other secondary endpoints, including overall response rate, duration of response, and time to Prostate-Specific Antigen (PSA) progression. The safety of TALZENNA plus XTANDI was consistent with the known safety profile of each medicine, and no new safety signals were identified.
Prostate cancer is the second most common cancer in men worldwide, with an estimated 1.4 million new cases diagnosed globally in 20221 and 330,000 new cases anticipated in the United States in 2026.2 mCSPC, is a form of advanced prostate cancer that has spread beyond the prostate but is still sensitive to androgen inhibition.3 Despite recent treatment advances, 50% to 65% of patients with mCSPC progress to metastatic castration-resistant prostate cancer (mCRPC) within two years, with increased risk in HRR gene-mutated patients.4-6
“Alterations in DNA damage repair genes, such as HRR genes, are found in approximately 25% of metastatic prostate cancers and associated with a worse prognosis and are less responsive to current standards of care, representing a group with a high unmet need,” said Jeff Legos, Chief Oncology Officer, Pfizer. “TALZENNA plus XTANDI is already a standard of care in HRR gene-mutated metastatic castration-resistant prostate cancer, and these unprecedented results demonstrate the potential to deliver benefit earlier in the disease course. These findings underscore Pfizer’s leadership in precision medicine and commitment to bringing more personalized treatment options to people living with prostate cancer.”
TALZENNA plus XTANDI in HRR gene-mutated mCSPC is an investigational treatment regimen. The TALAPRO-3 results will be submitted for presentation at an upcoming medical congress and will be discussed with global health authorities for potential regulatory submissions.
TALZENNA plus XTANDI is currently approved in 60 countries, including in the United States for adults with HRR gene-mutated mCRPC and in the European Union for adults with mCRPC in whom chemotherapy is not clinically indicated.
About TALAPRO-3
The Phase 3 TALAPRO-3 trial is a multicenter, randomized, double-blind, placebo-controlled study that enrolled 599 patients with mCSPC [with ≤3 months of ADT (chemical or surgical) with or without an approved ARPI in the mCSPC setting] at sites in the U.S., Canada, Europe, South America, and the Asia-Pacific region. Patients with histologically/cytologically confirmed adenocarcinoma of the prostate without neuroendocrine differentiation, small cell, or signet cell features and with alterations in one or more HRR genes (as per HRR12 gene panel) in the trial were randomized to receive TALZENNA 0.5 mg/day plus XTANDI 160mg/day, or placebo plus XTANDI 160mg/day.
The primary endpoint of the trial is investigator-assessed radiographic progression-free survival (rPFS), defined as the time from the date of randomization to radiographic progression in soft tissue per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1), or in bone per Prostate Cancer Working Group 3 (PCWG3) criteria by investigator assessment, or death, whichever occurs first. Secondary endpoints include overall survival (OS), objective response rate (ORR), duration of response (DOR), prostate-specific antigen (PSA) response, and patient-reported outcomes.
About TALZENNA® (talazoparib)
TALZENNA is an oral inhibitor of poly ADP-ribose polymerase (PARP), which plays a role in DNA damage repair. Preclinical studies have demonstrated that TALZENNA blocks PARP enzyme activity and traps PARP at the site of DNA damage, leading to decreased cancer cell growth and cancer cell death.
TALZENNA was initially approved in the U.S., EU, and multiple other regions as a single agent for the treatment of adult patients with deleterious or suspected deleterious gBRCAm HER2-negative locally advanced or metastatic breast cancer.
TALZENNA in combination with XTANDI was approved by the U.S. Food and Drug Administration (FDA) for the treatment of adult patients with HRR gene-mutated mCRPC in June 2023. The combination was also approved by the European Commission in January 2024 for the treatment of adult patients with mCRPC in whom chemotherapy is not clinically indicated. TALZENNA in combination with XTANDI is approved in 60 countries, indications vary by country.
About XTANDI® (enzalutamide)
XTANDI (enzalutamide) is an androgen receptor pathway inhibitor. XTANDI is a standard of care and has received regulatory approvals in one or more countries around the world for use in people with metastatic hormone-sensitive prostate cancer (mHSPC), metastatic castration-resistant prostate cancer (mCRPC), non-metastatic castration-resistant prostate cancer (nmCRPC) and non-metastatic hormone-sensitive prostate cancer (nmHSPC) with high-risk biochemical recurrence (BCR). XTANDI is currently approved for one or more of these indications in more than 80 countries, including in the United States, European Union and Japan. Over 1.5 million patients have been treated with XTANDI globally.7
About Pfizer Oncology
At Pfizer Oncology, we are at the forefront of a new era in cancer care. Our industry-leading portfolio and extensive pipeline includes three core mechanisms of action to attack cancer from multiple angles, including small molecules, antibody-drug conjugates (ADCs), and multispecific antibodies, including other immune-oncology biologics. We are focused on delivering transformative therapies in some of the world’s most common cancers, including breast cancer, gastrointestinal cancers, genitourinary cancers, hematology-oncology, and thoracic cancers, which includes lung cancer. Driven by science, we are committed to accelerating breakthroughs to help people with cancer live better and longer lives.
About Pfizer: Breakthroughs That Change Patients’ Lives
At Pfizer, we apply science and our global resources to bring therapies to people that extend and significantly improve their lives. We strive to set the standard for quality, safety and value in the discovery, development and manufacture of health care products, including innovative medicines and vaccines. Every day, Pfizer colleagues work across developed and emerging markets to advance wellness, prevention, treatments and cures that challenge the most feared diseases of our time. Consistent with our responsibility as one of the world's premier innovative biopharmaceutical companies, we collaborate with health care providers, governments and local communities to support and expand access to reliable, affordable health care around the world. For 175 years, we have worked to make a difference for all who rely on us.
About the Pfizer/Astellas Collaboration
In October 2009, Medivation, Inc., which is now part of Pfizer (NYSE: PFE), and Astellas (TSE: 4503) entered into a global agreement to jointly develop and commercialize XTANDI® (enzalutamide). The companies jointly commercialize XTANDI in the United States, and Astellas has responsibility for manufacturing and all additional regulatory filings globally, as well as commercializing XTANDI outside the United States.
References
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American Cancer Society. Key statistics for prostate cancer. Prostate Cancer Facts. Available at: https://www.cancer.org/cancer/types/prostate-cancer/about/key-statistics.html.Last accessed: March 2026
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Troy SP, Jakubowski CD, Gartrell BA. Packing the Punch: Current and Emerging Treatment Strategies in Metastatic Castration-Sensitive Prostate Cancer. Curr Urol Rep. 2025;26(1):50. Published 2025 Jun 21. doi:10.1007/s11934-025-01272-6
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Bilen MA, Burbage S, Rossi C, Khilfeh I, Diaz L, Wang Y, Pilon D, Brown G, Shore N, Lowentritt B, Lin DW. Comparison of Real-World Outcomes between Patients with BRCA1/2-Positive and Homologous Recombination Repair-Negative Metastatic Castration-Sensitive Prostate Cancer. Adv Ther. 2025;42:3945–3959. Published 2025 Jun 17. doi:10.1007/s12325-025-03270-z
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Wenzel M, Preisser F, Hoeh B, Schroeder M, Würnschimmel C, Steuber T, Heinzer H, Banek S, Ahrens M, Becker A, Karakiewicz PI, Chun FKH, Kluth LA, Mandel P. Impact of Time to Castration Resistance on Survival in Metastatic Hormone Sensitive Prostate Cancer Patients in the Era of Combination Therapies. Front Oncol. 2021;11:659135. Published 2021 Apr 23. doi:10.3389/fonc.2021.659135
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Shore N. Real‑World Time‑to‑Next‑Treatment and Time‑to‑Castration‑Resistance Among Patients With Metastatic Castration‑Sensitive Prostate Cancer Using Androgen Receptor Pathway Inhibitors With and Without Homologous Recombination Repair Alterations. UroToday. Presented at: American Urological Association (AUA) 2025 Annual Meeting; April 26–29, 2025; Las Vegas, NV.
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Data on file. Northbrook, IL: Astellas Inc.