Cost-effectiveness of perioperative pembrolizumab plus enfortumab vedotin for cisplatin-ineligible or cisplatin-declining patients with muscle-invasive bladder cancer in the United States

AIMS: In the KEYNOTE 905/EV 303 study, perioperative enfortumab vedotin plus pembrolizumab (EV+Pem) improved event-free survival (EFS), overall survival (OS), and pathological complete response in a predominantly cisplatin-ineligible muscle-invasive bladder cancer (MIBC) population, compared with surgery alone with or without adjuvant nivolumab, as indicated (surgery ± adjuvant nivolumab). This study assessed the cost-effectiveness of perioperative EV+Pem for cisplatin-ineligible or declining patients with MIBC from a US third-party payer perspective. METHODS: This cost-utility analysis used a state-transition Markov model with event-free (EF), progressed or recurrent disease (PRD), and death health states. The target population included cisplatin-ineligible or cisplatin-declining adults with MIBC. Transitions from EF were estimated using parametric multistate survival models based on trial data, with extrapolation beyond follow-up. Survival following PRD was modeled using a treatment-mix approach reflecting US clinical practice. Costs were derived from US sources, and utilities from KEYNOTE-905 EQ-5D-5L data. Scenario analyses explored alternative extrapolations and structural assumptions, and sensitivity analyses assessed parameter uncertainty. RESULTS: In the base case, EV+Pem increased life-years by 3.08 (7.70 vs 4.62) and quality-adjusted life-years (QALYs) by 2.56 (6.19 vs 3.62) versus surgery ± adjuvant nivolumab. EV+Pem was associated with higher initial treatment costs, increasing total costs by $133,661 ($546,831 vs $413,171), partially offset by lower costs of treatment for PRD ($34,636 vs $129,813), yielding an incremental cost-effectiveness ratio (ICER) of $52,117 per QALY gained. Across scenario analyses, ICERs ranged from $50,363 to $69,703 per QALY gained. Probabilistic sensitivity analysis showed that EV+Pem had a 99.1% probability of being cost-effective at a $100,000 per QALY threshold. LIMITATIONS: Results are subject to uncertainty in long-term survival extrapolation and evolving treatment patterns following PRD. CONCLUSIONS: EV+Pem is cost-effective versus surgery ± adjuvant nivolumab for cisplatin-ineligible or cisplatin-declining patients with MIBC from a US third-party payer perspective at a willingness-to-pay threshold of $100,000 per QALY.