138P Cost-effectiveness of nivolumab and ipilimumab versus chemotherapy (with and without bevacizumab) in patients with unresectable malignant pleural mesothelioma in Switzerland

Malignant pleural mesotheliomas (MPMs) are aggressive and often unresectable. In the past, chemotherapy was standard for palliation. Recently, immunotherapy with nivolumab ipilimumab (nivo+ipi) approved. This study evaluated cost-effectiveness of nivo+ipi versus (with without bevacizumab) Swiss patients unresectable MPM, overall by histological subtype. We developed a three-state Markov cohort model cycle length one month, 30-year time horizon, discount rate 3% costs benefits. The included updated survival treatment-dependent utility results from Checkmate-743 MAPS registration trials. A statutory health insurance perspective considered unit 2022 both publicly available real-world sources. assumed willingness-to-pay (WTP) threshold CHF100’000. Model robustness explored in sensitivity analyses. Compared chemotherapy, incurred additional CHF104’100 0.48 quality-adjusted life years (QALYs), yielding an incremental ratio (ICER) CHF217’288/QALY gained. Chemotherapy+bevacizumab dominated strategy. Preference cisplatin over carboplatin led to ICER CHF175’057. For non-epithelioid subtype, decreased CHF124’612. Nivo+ipi may be cost-effective if priced at 43% all histologies 79% MPM their list price. Substantial discounts would necessary achieve prices. Accepting higher WTP threshold, more likely than histologies. is unlikely alternative. [Grant support: SUVA, Lucerne, Switzerland].