This study also emphasises the importance of molecular biomarker testing in prostate cancer.
The top line Phase III results announced by Pfizer showed that talazoparib with enzalutamide has a favourable overall survival (OS) trend compared to enzalutamide with placebo. Credit: YES Market Media / Shutterstock.com.
At the 2026 American Society of Clinical Oncology (ASCO) annual congress, Pfizer presented top line data for the Phase III TALAPRO-3 clinical trial, which is evaluating the poly(ADP-ribose) polymerase (PARP) inhibitor Talzenna (talazoparib) combined with Xtandi (enzalutamide), the standard of care (SOC) androgen receptor signalling inhibitor (ARSI). This dual-action regimen specifically targets patients with metastatic castration-sensitive prostate cancer (mCSPC) harbouring homologous recombination repair (HRR) gene alterations. The management of advanced prostate cancer is shifting toward early precision medicine, a more personalised treatment regimen that looks at patient molecular and biomarker profiles.
The top line Phase III results showed that talazoparib with enzalutamide has a favourable overall survival (OS) trend compared to enzalutamide with placebo. Importantly, the primary endpoint data showed that there was clinically meaningful improvement in radiographic progression-free survival (rPFS) in patients with HRR-altered mCSPC compared to enzalutamide with a placebo, with a 52% reduction in risk of progression and death. Moreover, when evaluating rPFS in patients who are BRCA positive (BRCAm) compared with patients who had other HRR gene alterations (non-BRCAm), both groups benefited from the combination therapy. The BRCAm arm had a 63% risk reduction, and the non-BRCAm arm had a 43% reduction. Due to the improved rPFS, this treatment could lead to wider use of the combination in metastatic prostate cancer management. It may also influence how clinicians sequence therapies, especially for patients who are candidates for both hormonal therapy and targeted agents. This study also emphasises the importance of molecular biomarker testing in prostate cancer, which would qualify some patients for more effective treatments earlier, improving prognosis.
