Cost-effectiveness of olaparib versus routine surveillance in the maintenance setting for patients with -mutated advanced ovarian cancer after response to first-line platinum-based chemotherapy in Singapore.

Objective: To evaluate the cost-effectiveness of olaparib as a maintenance treatment versus routine surveillance (RS) in patients with mutated (m) advanced ovarian cancer (OC) following response to first-line platinum-based chemotherapy in Singapore.

Methods: A 4-health state partitioned survival model was developed to simulate the lifetime (50 years) incremental cost-effectiveness ratio (ICER) of olaparib versus RS from a healthcare payer perspective. Progression-free survival, time to second disease progression, and overall survival were estimated using SOLO-1 data and extrapolated beyond the trial period using parametric survival models. Any patient who remained progression-free at year 7 was assumed to be no longer at risk of progression. Mortality rates were based on all-cause mortality, adjusted based on mutation. Health state utilities and adverse event frequencies were from SOLO-1. Drug costs were from local public healthcare institutions. Healthcare resource usage and costs were from local clinician input and publications. A 3% discount rate was applied to costs and outcomes. Deterministic and probabilistic sensitivity analyses (PSA) were performed to assess the robustness of results.

Results: The base-case analysis of olaparib maintenance therapy versus RS resulted in an ICER of Singapore dollar (SGD) 19,822 per quality-adjusted life-year (QALY) gained. The ICER was most sensitive to variations in the discount rate. PSA demonstrated that olaparib had an 87% probability of being cost-effective versus RS at a willingness-to-pay of SGD 60,000 per QALY gained.

Conclusion: Olaparib has a high potential of being a cost-effective maintenance treatment versus RS for patients with m advanced OC after response to first-line chemotherapy in Singapore.