Retifanlimab Vs Avelumab in Patients with Metastatic Merkel Cell Carcinoma: A Cost Utility Analysis in Italy

OBJECTIVE: Merkel cell carcinoma (MCC) is a very rare and aggressive neuroendocrine skin cancer, characterized by a 5-year survival rate of 13.5% in patients with distant metastases. This study aimed to evaluate the cost-utility of retifanlimab compared to avelumab in the treatment of metastatic MCC patients who had not received prior systemic therapies, from the perspective of the Italian National Health Service (SSN).METHODS: A 7-day cycles partitioned survival model with three mutually exclusive health-states—progression-free, post-progression and death—was developed to compare lifetime clinical outcomes and costs for patients treated with retifanlimab versus avelumab in the Italian context. Progression-free survival and overall survival curves were modelled independently, with POD1UM-201 trial data used for retifanlimab efficacy. In the absence of direct head-to-head clinical trial data, avelumab efficacy was estimated using the hazard ratio obtained from a matching-adjusted indirect comparison. Following a previous National Institute for Health and Care Excellence submission, utility values were derived using a timeto-death approach, with health states defined as “>266 days to death”, “35-266 days to death”, and “<35 days to death”. Direct healthcare costs, including drug acquisition and administration, disease monitoring, adverse event management, post-progression therapy, and end-of-life care, were sourced from Italian data. Costs and health outcomes were discounted at an annual 3% rate. Deterministic and probabilistic sensitivity analyses, along with scenario analysis, were conducted to assess the uncertainty of input parameters.RESULTS: In the base case, retifanlimab demonstrated greater efficacy compared to avelumab, with 6.39 vs 3.42 life-years and 5.11 vs 2.68 quality-adjusted life-years (QALYs), at an additional cost of €12,228. The incremental cost-utility ratio was estimated at €5,037 per QALY gained. Sensitivity analyses confirmed the robustness of the base case results.CONCLUSIONS: Retifanlimab can be considered a cost-effective option for Italian patients with metastatic MCC who have not received prior systemic therapies.