Pfizer has received FDA approval for Talzenna, a combination therapy with Xtandi, as a treatment for metastatic castration-resistant prostate cancer (mCRPC) with homologous recombination repair (HRR) gene mutations. Talzenna becomes the first and only PARP inhibitor approved for use in combination with Xtandi, offering new hope for patients. Sales projections indicate significant growth potential, making Talzenna a notable contender in the market, according to GlobalData, a leading data and analytics company.

GlobalData forecasts Talzenna sales to reach $644 million in 2029. Talzenna was approved in 2018 to treat patients with metastatic BRCA-positive, HER2-negative breast cancer. Xtandi, the blockbuster androgen receptor inhibitor that was approved for mCRPC a decade ago and has since become the standard of care, had its label expanded to include other prostate cancer subtypes.

Israel Stern, MSc, Oncology & Hematology Analyst at GlobalData, comments: “This approval is a win for Pfizer as it will now have the broadest PARP inhibitor label. Recently, AstraZeneca and Merck’s Lynparza (Olaparib) in combination with Johnson & Johnson’s (J&J) Zytiga (abiraterone) was approved for mCRPC but only for patients with BRCA mutations. Pfizer’s approval is for HRR mCRPC an umbrella mutation encompassing several gene mutations including BRCA.”

The approval was based on the Phase III TALAPRO-2 study, which found that HRR-mutant patients who received Talzenna-Xtandi had a 55% improvement in progression-free survival compared to those who received placebo plus Xtandi.

Stern continues: “While the approval is for HRR-mutant patients, data from TALAPRO-2 suggest that the combination treatment benefited all patients in the study, regardless of HRR mutational status. Long-term data will indicate whether the FDA will approve the treatment for all patients with mCRPC, significantly increasing the patient share, as HRR mutations only account for about a quarter of all mCRPC patients.”

An additional competitor for Pfizer is poised to hit the market, as J&J’s PARP inhibitor niraparib is seeking approval for use in combination with Zytiga, but only for BRCA-mutant patients.

Stern concludes: “Pfizer will now find itself competing for patient share with these new PARP-inhibitor combinations entering the market. The breadth of Talzenna’s approval, however, gives Pfizer a competitive advantage, as it is marketed for all HHR-mutated patients. In addition, the company is conducting a Phase llI trial evaluating the combination in another tumor subtype, DNA Damage Repair mutated metastatic castration-sensitive prostate cancer. Talzenna will gain another revenue stream if this indication is approved.”