FDA approves Pfizer’s HRR mCRPC drug

James Spargo | June 21, 2023 | News story | Medical Communications |  FDA, Oncology, Pfizer, breast cancer, oncology, prostate cancer 

US-based pharmaceutical and biotechnology company Pfizer has announced that the US Food and Drug Administration (FDA) has approved its homologous recombination repair (HRR) gene-mutated metastatic castration-resistant prostate cancer (mCRPC) drug Talzenna (talazoparib) in combination with Xtandi (enzalutamide).

Talzenna is an oral inhibitor of poly ADP-ribose polymerase (PARP), which is involved in DNA damage repair. Talzenna blocks PARP enzyme activity and traps PARP at the site of the DNA damage, which leads to decreased cancer cell growth and cancer cell death. It is currently approved as a once-daily monotherapy for the treatment of deleterious or suspected deleterious germline breast cancer susceptibility gene (BRCA)-mutated (gBRCAm) human epidermal growth factor receptor 2 (HER2)-negative locally advanced or metastatic breast cancer.

The FDA approval is based on data from the phase 3 TALAPRO-2, two-part, two-cohort, multicentre, randomised, double-blind, placebo-controlled study. Cohort one included 805 all-comers, with cohort two comprising 399 patients with HRR mutations. The primary endpoint was radiographic progression-free survival (rPFS) and the secondary was overall survival (OS).

The data showed clinically meaningful and statistically significant rPFS in patients with mCRPC with prospectively identified HRR gene mutations treated with Talzenna plus Xtandi versus placebo plus Xtandi. The safety of Talzenna plus Xtandi was generally consistent with the known safety profile, with serious adverse reactions (Ars) occurring in around 30% of the patients. Discontinuation of Talzenna occurred in 10% of patients.

Angela Hwang, chief commercial officer, president of Global Biopharmaceuticals Business at Pfizer, stated: “Pfizer has a legacy of bringing medicines to patients with genitourinary cancers and helping improve outcomes for patients suffering from advanced prostate cancer. As a global standard of care, Xtandi has shown efficacy in three types of prostate cancer, and the addition of Talzenna demonstrated significant improvements in delaying or preventing rPFS or death in patients with this type of advanced prostate cancer. With today’s FDA approval of Talzenna plus Xtandi, we are proud to be able to offer this potentially practice-changing treatment to patients and add to their options in managing this aggressive disease.”

James Spargo