OBJECTIVES: The purpose of this study was to estimate the costs of immune-related adverse events (irAEs) associated with the new anti-PD1 immuno-oncology therapies, with the anti-CTLA-4 immuno-oncology therapy and with the combined therapy (CTLA4 + anti-PD1) in patients affected by metastatic melanoma.

METHODS: A probabilistic cost of illness (COI) model has been developed to estimate the management costs of grade ≥ 3 adverse events associated with the new anti-PD1 therapies (pembrolizumab and nivolumab), the anti-CTLA-4 therapy (ipilimumab) and the combined therapy CTLA4 + anti-PD1 (nivolumab + ipilimumab) for the treatment of patients with metastatic melanoma from the National Health Service (NHS) perspective in Italy. The identification of the epidemiological and cost parameters to be included in the cost of illness model was carried out through a systematic literature review (SLR). Univariate and probabilistic sensitivity analyses were conducted to verify the sensitivity of the model results.

RESULTS: The model has estimated a cost associated with the management of grade ≥ 3 immune-related adverse events in patients with metastatic melanoma equal to €176.2 (95% CI: €63.5-€335.0) for anti-CTLA-4 therapy, €48.6 (95% CI: €40.1-€58.5) for the new anti-PDI therapies, and €276.8 (95% CI: €240.4-€316.2) for the combined therapy. Among the innovative therapies for the considered metastatic melanoma, the combined therapy was the most expensive innovative treatment in terms of event management of immune-related grade ≥ 3 adverse events.

CONCLUSIONS: This study may represent a useful tool to understand the economic burden associated with the management of irAEs associated with patients affected by metastatic melanoma.