US biopharmaceutical company Pfizer Inc (NYSE:PFE) on Thursday announced positive topline results from the Phase 3 TALAPRO-3 study evaluating TALZENNA (talazoparib) in combination with XTANDI (enzalutamide) in patients 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, demonstrating a statistically significant and clinically meaningful improvement in radiographic progression-free survival versus placebo plus XTANDI.

The combination therapy showed consistent efficacy across patients with both BRCA and non-BRCA HRR gene alterations, with a strong trend toward improved overall survival observed at interim analysis. Additional secondary endpoints, including overall response rate, duration of response, and time to prostate-specific antigen progression, also showed favourable outcomes, while safety remained consistent with known profiles and no new safety signals were identified.

These results will be discussed with global health authorities to evaluate potential expansion of TALZENNA's indication into earlier-stage disease. TALZENNA plus XTANDI is currently approved in 60 countries, including for HRR gene-mutated metastatic castration-resistant prostate cancer in the United States and in the European Union for patients where chemotherapy is not clinically indicated.