Pfizer has announced positive topline data from the Phase III TALAPRO-2 study of TALZENNA (talazoparib) plus XTANDI (enzalutamide) in patients with mCRPC.

TALZENNA is an oral poly ADP-ribose polymerase (PARP) inhibitor while XTANDI is an androgen receptor pathway inhibitor (ARPI).

The international, double-blind, multicentre, placebo-controlled trial involved 1,035 mCRPC patients across various regions including the US, Canada, Europe, South America and Asia-Pacific.

Participants were divided into two cohorts: an all-comers group and those with homologous recombination repair (HRR) gene mutations.

Radiographic progression-free survival (rPFS) was the trial’s primary endpoint while secondary endpoints comprised OS, objective response rate (ORR), duration of response (DOR) and prostate-specific antigen (PSA) response.

The study's findings revealed a statistically significant and clinically meaningful improvement in OS for both the all-comers cohort and the HRR gene-mutated mCRPC patients when treated with the TALZENNA plus XTANDI combination regimen versus XTANDI alone.

This improvement in rPFS, initially observed in the primary analysis, was maintained at the time of the final analysis, the company noted.

Moreover, the safety profile of the combination treatment regimen was found to be in line with the known profiles of the individual medications.

In June last year, Pfizer’s TALZENNA plus XTANDI combination therapy received approval from the US Food and Drug Administration for treating adult patients with HRR gene-mutated mCRPC.

Pfizer Oncology chief development officer Roger Dansey said: “The TALAPRO-2 results showed that TALZENNA plus XTANDI is the first and only PARP inhibitor in combination with an ARPI to significantly improve survival in patients with metastatic castration-resistant prostate cancer, regardless of mutation status.

“Pfizer is dedicated to advancing scientific breakthroughs in genitourinary cancers, and these exciting TALAPRO-2 results further highlight our long-standing commitment to improving survival for men with prostate cancer.”

In August this year, the company announced positive results from a late-stage study of its respiratory syncytial virus (RSV) vaccine, Abrysvo, in adults who are immunocompromised and at risk of developing severe RSV-associated lower respiratory tract disease (LRTD).