Pfizer has announced positive topline results from a Phase 3 study of Talzenna plus Xtandi in patients with metastatic castration-resistant prostate cancer (mCRPC).
Talzenna (talazoparib) is an oral poly ADP-ribose polymerase (PARP) inhibitor, and Xtandi (enzalutamide) is an androgen receptor pathway inhibitor (ARPI).
TALAPRO-2 is a multicentre, randomised, double-blind, placebo-controlled Phase 3 study in 1,035 patients, at sites in the US, Canada, Europe, South America, and the Asia-Pacific region.
In the study, Talzenna plus Xtandi combination resulted in a statistically significant improvement in overall survival (OS) compared to Xtandi alone.
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.”
The Phase 3 study included two patient cohorts, all-comers and those with HRR gene mutations, and the primary endpoint was radiographic progression-free survival (rPFS).
rPFS is the time from the date of randomisation to the first objective evidence of radiographic progression by blinded independent review, or death, whichever is first.
The secondary endpoints of the study include OS, objective response rate (ORR), duration of response (DOR), and prostate-specific antigen (PSA) response.
In the final analysis, the clinically meaningful improvement in rPFS was maintained in both cohorts from the prior primary analysis that was published in The Lancet.
In addition, Talzenna plus Xtandi showed a safety profile that was generally consistent with the known safety profile of each medicine.
TALAPRO-2 study global lead investigator Neeraj Agarwal said: “These overall survival results indicate potentially practice-changing efficacy for Talzenna in combination with Xtandi for men with metastatic castration-resistant prostate cancer.
“Metastatic castration-resistant prostate cancer is the most advanced and aggressive stage of the disease, and the TALAPRO-2 results provide much-needed hope to patients who remain in high unmet need for effective treatment options.”
Talzenna plus Xtandi was approved by the US Food and Drug Administration (FDA) in June last year, for the treatment of adult patients with HRR gene-mutated mCRPC.
The combination was also approved by the European Commission (EC) in January this year, for the treatment of adult patients with mCRPC in whom chemotherapy is not clinically indicated.
