OBJECTIVES

Olaparib is a poly ADP-ribose polymerase (PARP) inhibitor recently approved for patients with metastatic castration resistant prostate cancer (mCRPC), alterations in homologous recombination repair genes, and disease progression following prior treatment with abiraterone or enzalutamide. It is the first medication in this new class of drugs approved for mCRPC, and represents a significant advancement for patients. This study sought to assess the value of olaparib versus the novel hormonal therapies, abiraterone and enzalutamide.

METHODS

We developed a partitioned survival model using progression-free survival (PFS) and overall survival (OS) curves from the olaparib phase 3 clinical trial program. The model consisted of three health states: progression-free, progressed disease, and death. We simulated a cohort of 1,000 male patients with mCRPC, at least one alteration in the BRCA1, BRCA2, or ATM genes, and disease progression while receiving a novel hormonal therapy. The model analysis took a healthcare system perspective and a life-time time horizon, with all costs and outcomes discounted at 3%. We performed one-way and probabilistic sensitivity analyses to evaluate the influence of individual model parameters and overall uncertainty, respectively.

RESULTS

Over a 12-year time horizon for 1,000 patients, the total cost of olaparib was $219,970,200 for 894 quality-adjusted life years (QALYs) gained while the cost of novel hormonal therapy was $30,008,232 for 635 QALYs gained. The incremental cost of olaparib was $189,961,968 for 259 QALYs gained, resulting in a discounted incremental cost-effectiveness ratio (ICER) of $734,903 per QALY gained. One-way sensitivity analysis found pre-progression, progressed utility, and olaparib cost were the most influential model parameters.

CONCLUSIONS

Using common willingness-to-pay thresholds in the U.S., olaparib does not appear to be cost-effective compared to continuing novel hormonal therapies in mCRPC patients with genetic alterations and prior disease progression. Future research should evaluate the evolving PARP inhibitor class and comparative effectiveness data.