Background: Through phase III clinical trials, (poly(adenosine diphosphate–ribose) polymerase inhibitors) (PARPI) have demonstrated outcome improvements in metastatic castration-resistant prostate cancer (mCRPC) patients with alterations of breast cancer 1 or 2 genes (BRCA1/2). While improving outcomes, PARPI contribute to the ever-growing economic burden of prostate cancer. The objective of this project is to evaluate the cost-effectiveness of PARPI (olaparib, rucaparib or talazoparib) versus the standard of care (docetaxel or androgen-receptor pathway inhibitors (ARPI)) for mCRPC patients with BRCA1/2 mutations from the Canadian healthcare system perspective.

Methods: Partitioned survival models were created to represent mCRPC disease after progression until death. Survival inputs were extracted from PROfound, TRITON3 and TALAPRO-1 clinical trials, while Canadian-specific costs are presented in 2023 dollars. Outcomes are discounted at 1.5% per year.

Results: PARPI provide better survival benefit in terms of quality-adjusted life years (QALY) than the current standard of care, but at a higher additional cost (incremental cost-utility ratio of $572,009/QALY). PARPI required price reductions of up to 83% to meet local willingness-to-pay thresholds (WTP). Results were most sensitive to PARPI acquisition costs and health state utility parameters.

Conclusions: While providing survival benefits to mCRPC patients presenting deleterious BRCA1/2 gene mutations, PARPI are not as cost-effective and require major price reductions to reach local WTP thresholds.