FDA approves Pfizer's Talzenna with Xtandi for earlier-stage prostate cancer with HRR mutations

The approval rests on the Phase 3 TALAPRO-3 trial of 599 patients. Adding talazoparib to enzalutamide cut the risk of radiographic progression or death by 52% compared with enzalutamide plus placebo, with a hazard ratio of 0.48, the FDA said. Median progression-free survival was not reached in the combination arm, against 45.8 months in the placebo arm, and overall survival data were still immature.

The label carries warnings for myelodysplastic syndrome and acute myeloid leukemia, low blood counts and harm to a fetus. Pfizer said anemia was the most common severe side effect, reported in 51% of patients on the combination against 3% in the control group.

Why it matters: Pfizer said the expansion makes the combination available earlier in the course of the disease, for patients with both BRCA and non-BRCA HRR mutations.