US-based pharmaceutical giant Pfizer (NYSE: PFE) has announced positive results from the Phase III TALAPRO-2 study for its oral poly ADP ribose polymerase (PARP) inhibitor, Talzenna (talazoparib). The study evaluated the drug in combination with Xtandi (enzalutamide) for the treatment of metastatic castration-resistant prostate cancer (mCRPC) with or without homologous recombination repair (HRR) gene mutations. The combination therapy achieved its primary endpoint, demonstrating a statistically and clinically significant improvement in radiographic progression-free survival (rPFS) compared to a placebo combined with enzalutamide. The results exceeded the preset risk ratio of 0.696.
Positive Trends in Overall Survival and Secondary Endpoints
The study also showed promising trends in overall survival, a key secondary endpoint, although the data are not yet mature. Additional secondary endpoints, including investigator-assessed radiographic progression-free survival (rPFS), prostate-specific antigen (PSA) response, PSA progression time, and overall response rate, also demonstrated benefits. Further analysis of other secondary endpoints is ongoing. The safety profile of the combination therapy was consistent with the known safety characteristics of the individual drugs.
Global Scope and Future Studies
The TALAPRO-2 study is being conducted across 364 clinical centers in 26 countries, including 34 sites in China, according to ClinicalTrials.gov. Currently, talazoparib alone or in combination with enzalutamide has not been approved for the treatment of mCRPC anywhere in the world. However, the combination is also being evaluated in another Phase III study, the global randomized, double-blind, placebo-controlled TALAPRO-3 study, targeting HRR-deficient metastatic castration-sensitive prostate cancer (mCSPC) patients.-Fineline Info & Tech
