The FDA approved Foundation Medicine CDx assays as companion diagnostics for Pfizer’s Talzenna (talazoparib) plus Xtandi (enzalutamide) in metastatic castration-resistant prostate cancer (mCRPC) with homologous recombination repair (HRR) gene mutations. The move links treatment eligibility to genomic testing via FoundationOne CDx. For diagnostics companies and oncologists, the decision clarifies which patients can access the PARP inhibitor and anchors use of a standardized HRR biomarker workflow. It also increases the commercial demand signal for integrated test-and-treat strategies in prostate cancer. The key near-term operational question for laboratories is ensuring assay readiness, workflow alignment, and payer coverage—especially for HRR reporting consistency across testing sites.