Pfizer Inc. ( PFE ) shares are up during Thursday’s trading session after the company shared data from Talzenna plus Xtandi’s investigational treatment regimen for HRR gene-mutated metastatic castration-sensitive prostate cancer (mCSPC).

Pfizer Talzenna Plus Xtandi Hit Primary Goal

On Thursday, the U.S. drug giant reported topline data from the TALAPRO-3 Phase 3 study of Talzenna (talazoparib) in combination with Xtandi (enzalutamide) for metastatic hormone-sensitive prostate cancer.

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 prespecified target hazard ratio of 0.63, with the majority of patients remaining progression-free at the time of analysis.

Broad Efficacy Across HRR Gene Mutations

Consistent efficacy benefit was also observed in patients whose tumors harbored BRCA and non-BRCA HRR gene alterations.

The TALAPRO-3 results will be submitted for presentation at an upcoming medical congress and discussed with global health authorities for potential regulatory submissions.

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.

Existing Approvals Support Expansion Potential

Currently, 60 countries, including the U.S., have approved Talzenna plus Xtandi for adults with HRR gene-mutated castration-resistant prostate cancer (mCRPC), and the European Union has approved it for adults with mCRPC for whom chemotherapy is not clinically indicated.

Pfizer Breast Cancer Study Also Meets Endpoint

On Tuesday, Pfizer ( PFE ) shared topline results from the Phase 2 FOURLIGHT-1 study evaluating atirmociclib plus fulvestrant in pretreated metastatic breast cancer patients.

The study met its primary endpoint, showing a significant improvement in progression-free survival (PFS), consistent across all prespecified subgroups.

Over 90% of patients started atirmociclib within three months of their last CDK4/6 inhibitor treatment.

PFE Price Action: Pfizer ( PFE ) shares were up 0.13% at $27.35 at the time of publication on Thursday. The stock is approaching its 52-week high of $27.94, according to Benzinga Pro data.

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