OBJECTIVES: TALAPRO-2, an international phase 3 trial (NCT03395197) comparing first-line (1L) treatment of adult patients with mCRPC unselected for DNA damage repair mutations (all comers) with talazoparib + enzalutamide (n=402) vs placebo + enzalutamide (n=403), showed a statistically significant improvement in the primary endpoint of radiographic progression free survival (rPFS) by blinded independent committee review (HR=0.627; 95% CI 0.506-0.777; P<0.0001). EQ-5D-5L was collected during the trial (baseline, every 4 weeks until week 53 or rPFS, every 8 weeks after week 53 until rPFS when no such progression had been documented, or every 12 weeks after progression until end of study). The aim of this research was to estimate pre-progression health-state utility values (HSUVs) suitable for use in cost-effectiveness analyses in 1L mCRPC.

METHODS: Data from all-comers in TALAPRO-2 were analyzed. Pre-progression HSUVs were estimated regardless of and by treatment arm using multivariate linear mixed effects regression analysis adjusted for covariates. Analyses employed value sets for US, UK, and Canada.

RESULTS: For US, mean (95% CI) pre-progression HSUV regardless of treatment arm was 0.847 (0.839-0.856). US treatment-specific pre-progression HSUVs for talazoparib + enzalutamide and placebo + enzalutamide were 0.851 (0.839-0.863) and 0.844 (0.831-0.856), respectively (difference not statistically significant, P=0.380). Consistent results were found for UK (regardless of treatment arm 0.827 (0.819-0.835); by treatment arm 0.831 (0.820-0.842) vs 0.823 (0.812-0.834); P=0.323) and Canada (regardless of treatment arm 0.858 (0.853-0.864); by treatment arm 0.861 (0.853-0.869) vs. 0.856 (0.847-0.864); P=0.376) for talazoparib + enzalutamide vs. placebo + enzalutamide, respectively.

CONCLUSIONS: This analysis generated pre-progression HSUVs suitable for use in cost-effectiveness analyses in 1L mCRPC.