Pfizer Reports Breakthrough in Survival Rates for mCRPC Patients with Talzenna and Xtandi Combination

On February 13, Pfizer announced significant results from the Phase III TALAPRO-2 study, indicating that the combination of Talzenna (talazoparib, a PARP inhibitor) and Xtandi (enzalutamide, an androgen receptor inhibitor) markedly improves overall survival (OS) in patients with metastatic castration-resistant prostate cancer (mCRPC) compared to the standard treatment of enzalutamide plus placebo.

This combination therapy is the first to demonstrate a significant OS benefit for mCRPC patients in a randomized controlled trial, regardless of whether patients carry homologous recombination repair (HRR) gene mutations.

The TALAPRO-2 study included two patient cohorts: those not selected based on HRR mutation status (Cohort 1) and those with HRR mutations (Cohort 2). OS was a key secondary endpoint of the study. With a median follow-up of over 4 years (52.5 months):

In Cohort 1, patients receiving Talzenna plus Xtandi had a median OS of 45.8 months, compared to 37.0 months in the control group (HR 0.80; 95% CI 0.66-0.96; p=0.015), resulting in a nearly 9-month increase in OS and a 20% reduction in mortality risk.

In Cohort 2, the median OS for the Talzenna and Xtandi group was 45.1 months, while the control group had 31.1 months (HR 0.62; 95% CI 0.48-0.81; p=0.0005), indicating a 14-month increase in OS and a 38% reduction in mortality risk.

These findings will be presented as an oral report at the American Society of Clinical Oncology Genitourinary Cancers Symposium (ASCO GU) (abstract number LBA18).

Pfizer's Chief Medical Officer, Roger Dansey, stated, "Since the approval of Talzenna in combination with Xtandi, the treatment standard for mCRPC patients with HRR mutations has been redefined. The latest data from the TALAPRO-2 study is compelling, showing that this combination significantly extends OS in both selected and unselected HRR mutation status patients, potentially changing the treatment paradigm for all mCRPC patients."

He added, "While definitive conclusions cannot be drawn across different studies, these results appear to represent the longest median OS reported in randomized controlled Phase III studies in the mCRPC space. We look forward to working with global regulatory authorities to update the labeling for Talzenna."