Cost-Effectiveness of Adjuvant Olaparib for Patients With Breast Cancer and Germline BRCA1/2 Mutations.

Importance: The OlympiA trial found that 1 year of adjuvant olaparib therapy can improve distant disease-free survival and overall survival from early-stage breast cancer in patients with a germline BRCA1/2 mutation. However, olaparib, an oral poly-adenosine diphosphate ribose polymerase inhibitor, is estimated to cost approximately $14 000 per month in the US. Objective: To estimate the incremental cost-effectiveness of adjuvant olaparib compared with no olaparib in eligible patients. Design, Setting, and Participants: In an economic evaluation from a health care system perspective, the cost-effectiveness of adjuvant olaparib was analyzed using a Markov state-transition model. The model simulated costs and lifetime health outcomes of 42-year-old women with high-risk early-stage breast cancer and a known BRCA1/2 mutation who completed definitive primary therapy and neoadjuvant or adjuvant systemic therapy. The study was conducted from August 2021 to July 2023. The effectiveness of olaparib was based on the findings of the OlympiA randomized clinical trial, and other model parameters were identified from the literature. The model was calibrated to the 1-, 2-, 3-, and 4-year distant disease-free and overall survival observed in the OlympiA trial, and olaparib was assumed to reduce the risk of distant recurrence only in the first 4 years. Exposure: One year of adjuvant olaparib or no adjuvant olaparib. Main Outcome and Measure: Incremental cost-effectiveness ratio (ICER) in 2021 US dollars per quality-adjusted life-year (QALY) gained. All outcomes were discounted by 3% annually. Results: In the base case, adjuvant olaparib was associated with a 1.25-year increase in life expectancy and a 1.20-QALY increase at an incremental cost of $133 133 compared with no olaparib. The resulting ICER was approximately $111 000 per QALY gained. At a willingness-to-pay threshold of $150 000 per QALY, olaparib was cost-effective at its 2021 price and in more than 92% of simulations in probabilistic sensitivity analysis. The results were sensitive to assumptions about the effectiveness of olaparib and quality of life for patients with no disease recurrence. Conclusions and Relevance: In this study, from a US health care system perspective, adjuvant olaparib was a cost-effective option for patients with high-risk, early-stage breast cancer and a germline BRCA1/2 mutation.