Pfizer's Prostate Cancer Drug Combo Extends Progression-Free Survival
Pfizer announced positive top-line results from the Phase 3 TALAPRO-3 study, where the combination of TALZENNA and XTANDI demonstrated a statistically significant improvement in radiographic progression-free survival.
New York – Pfizer Inc. on Thursday announced positive top-line results from its Phase 3 TALAPRO-3 study evaluating the combination of TALZENNA® (talazoparib), an oral poly ADP-ribose polymerase (PARP) inhibitor, and XTANDI® (enzalutamide), an androgen receptor pathway inhibitor (ARPI), in people with homologous recombination repair (HRR) gene-mutated metastatic castration-sensitive prostate cancer (mCSPC).
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 significantly exceeded the pre-specified target hazard ratio, 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, 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."
An interim analysis also showed a strong trend toward improved overall survival (OS), a key secondary endpoint. Benefits were also observed in other secondary endpoints, including objective response rate, duration of response, and time to Prostate-Specific Antigen (PSA) progression. The safety of the TALZENNA plus XTANDI combination was consistent with the known safety profile of each medicine.
Pfizer plans to discuss these findings with global health authorities to potentially expand the indication for TALZENNA into this earlier stage of the disease. The combination is currently approved in 60 countries for the treatment of metastatic castration-resistant prostate cancer with HRR gene mutations.