NEW YORK – Pfizer on Wednesday said that researchers have dosed the first metastatic castration-sensitive prostate cancer, or mCSPC, patient with a DNA damage response gene mutation in the Phase III TALAPRO-3 trial, which is exploring the activity of talazoparib (Talzenna) plus enzalutamide (Pfizer/Astellas' Xtandi).
TALAPRO-3 will enroll 550 men with DNA damage response-deficient mCSPC at 285 study sites around the world. Patients will be randomized to receive the PARP inhibitor talazoparib plus the androgen receptor inhibitor enzalutamide or placebo plus enzalutamide. Researchers will track patients for radiographic progression-free survival and overall survival. The study is slated to complete toward the end of 2024.
Around 25 percent of advanced prostate cancer patients harbor mutations in DNA damage response genes. In TALAPRO-2, another randomized Phase III trial of talazoparib, Pfizer is enrolling metastatic castration-resistant prostate cancer patients with and without DNA damage response gene defects.
Talazoparib is currently approved in the US for BRCA-mutated, HER2-negative advanced or metastatic breast cancer.