Retifanlimab vs Avelumab in Patients With Metastatic Merkel Cell Carcinoma: A Cost-Utility Analysis in Italy

OBJECTIVES: To assess the cost-utility of retifanlimab versus avelumab in patients with metastatic Merkel cell carcinoma (mMCC) in first line of treatment from the perspective of Italian National Healthcare Service (NHS).

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 of patients treated with retifanlimab or avelumab in Italy. Progression-free survival (PFS) and overall (OS) Kaplan-Meier curves were modelled independently and POD1UM-201 anonymized data were used to model retifanlimab efficacy. In the absence of a head-to-head trial, the efficacy of avelumab was estimated using hazard ratio (HR) from a matching-adjusted indirect comparisons (MAIC) of the JAVELIN Merkel 200 (avelumab pivotal trial) and POD1UM-201 data. Based on previous NICE submission, a time-to-death approach was considered for utility values, and states were defined as “>266 days to death”, “35-266 days to death”, and “<35 days to death”. Direct healthcare costs, including drug acquisition (ex-factory price published in Official Gazette) and administration, disease monitoring, adverse event management, post-progression therapy and end of life were collected from Italian formularies and tariff plan. Costs and health gains were discounted at 3% annually. Deterministic and probabilistic sensitivity analysis and scenario analysis evaluated the uncertainties on inputs.

RESULTS: Retifanlimab led to better long-term outcomes compared to avelumab (6.39 vs 3.42 LYs and 5.11 vs 2.68 QALYs) with an additional cost of € 12,228 per patient (ICER estimated at € 5,037 per QALY). All sensitivity analyses confirmed the robustness of the base case results.

CONCLUSIONS: Retifanlimab can be considered as a cost-effective option for Italian patients with mMCC in first line of treatment.