OBJECTIVES: Two poly-ADP ribose polymerase (PARP) inhibitors, olaparib and rucaparib have been approved for patients with Metastatic Castration-Resistant Prostate Cancer (mCRPC) by US Food and Drug Administration (FDA) in May 2020. These PARP inhibitors have been approved in men with gene mutated mCRPC and have progressed following prior treatment. We performed cost-effectiveness analysis of olaparib compared to rucaparib in the treatment of mCRPC state from a US payer perspective.

METHODS: We used a partition survival model to project disease progression and survival that included costs over the lifetime. Efficacy and adverse event data for olaparib and rucaparib were informed from the PROfound and TRITON2 trials, respectively. Transition probabilities were estimated from the overall survival (OS), and progression-free survival (PFS) curves reported from these trials. Cost and utility data were derived from the literature. The primary outcome was the incremental cost-effectiveness ratio (ICER) using a willingness to pay threshold of $150,000. One-way and probabilistic sensitivity analyses were performed to explore parameter uncertainty.

RESULTS: Discounted quality-adjusted life-years (QALYs) over a lifetime time horizon were higher for rucaparib than olaparib (12.90 vs. 11.34 QALYs). For both olaparib and rucaparib, the majority of the QALYs were accrued in the pre-progression state. Discounted costs were also higher for rucaparib ($288,624) than olaparib ($242,988). These values translated to an ICER of $29,323/QALY for rucaparib vs. olaparib. One-way sensitivity analyses revealed that incremental cost results were most sensitive to the cost of rucaparib and the utility of progression-free state. In the probabilistic sensitivity analyses, 76% of the Monte Carlo simulations rucaparib was cost-effective compared to olaparib.

CONCLUSIONS: Rucaparib appears to be cost-effective compared to olaparib for men suffering from mCRPC who have specific germline mutations