Olaparib in combination with bevacizumab compared to bevacizumab monotherapy for the first-line maintenance treatment of advanced ovarian cancer: a cost-effectiveness analysis

Abstract

<h3>Objectives:</h3> The addition of maintenance olaparib to bevacizumab (OLAP+BEV) demonstrated significant progression-free survival (PFS) benefit vs BEV alone in the randomized trial PAOLA-1 in advanced ovarian cancer patients with homologous recombination deficiency (HRD)-positive tumors. We aim to quantify the health and economic impact by evaluating the US cost-effectiveness of OLAP+BEV relative to BEV as a maintenance treatment for women with advanced ovarian cancer who had partial or complete response to first-line platinum-based chemotherapy and whose cancer is associated with HRD-positive status <h3>Methods:</h3> Our economic model was a cohort-level four state partitioned survival model with a lifetime horizon. States were progression-free, post first progression, post second progression, and death, modelled using first PFS (PFS1), second PFS (PFS2) and overall survival (OS) outcomes from the PAOLA-1 trial. This approach captured multiple progressions, and the differing health state utility after each progression. PFS1 was modelled through parametric mixture survival modeling to a landmark survival point at 5 years, beyond which, patients who have not progressed are assumed to experience all-cause mortality as the general population. PFS2 and OS were modelled by fitting standard parametric models, and time on treatment data was used directly from PAOLA-1, with a treatment cap of 24 months for OLAP and 15 months for BEV. The cost of HRD testing was calculated as unit cost divided by prevalence and was included as a one-time cost for OLAP+BEV arm. US-based health state utility values were analyzed by applying the methods developed by Pickard. The analyses were conducted from a US healthcare payer perspective, with an annual discount rate of 3%. We also explored the robustness of results using deterministic (DSA) and probabilistic sensitivity analysis. <h3>Results:</h3> At year 5, 45.1% and 16.9% patients remained PFS from OLAP+BEV and BEV arm, respectively. The results showed that compared with bevacizumab alone, OLAP+BEV led to a gain in quality-adjusted life years (2.89 QALYs gain) and life years (3.43 Lys gain) but resulted in higher costs, leading to a deterministic incremental cost-effectiveness ratio (ICER) of $75,276 per QALY. OLAP+BEV had an 87.5% probability of being cost-effective at a willingness-to-pay threshold of $100,000 per QALY. DSA identified efficacy (PFS and OS parameters), subsequent treatment and utility values as key model drivers. <h3>Conclusions:</h3> OLAP+BEV is associated with LY and QALY gain, and is cost effective for US payers relative to BEV monotherapy for the treatment of women with advanced, HRD-positive ovarian cancer