Early cost-effectiveness of tumor infiltrating lymphocytes (TIL) for second line treatment in advanced melanoma: a model-based economic evaluation

BACKGROUND: An emerging immunotherapy is infusion of tumor infiltrating Lymphocytes (TIL), with objective response rates of around 50% versus 19% for ipilimumab. As an Advanced Therapeutic Medicinal Products (ATMP), TIL is highly personalized and complex therapy. It requests substantial upfront investments from the hospital in: expensive lab-equipment, staff expertise and training, as well as extremely tight hospital logistics. Therefore, an early health economic modelling study, as part of a Coverage with Evidence Development (CED) program, was performed. METHODS: We used a Markov decision model to estimate the expected costs and outcomes (quality-adjusted life years; QALYs) for TIL versus ipilimumab for second line treatment in metastatic melanoma patients from a Dutch health care perspective over a life long time horizon. Three mutually exclusive health states (stable disease (responders)), progressive disease and death) were modelled. To inform further research prioritization, Value of Information (VOI) analysis was performed. RESULTS: TIL is expected to generate more QALYs compared to ipilimumab (0.45 versus 0.38 respectively) at lower incremental cost (presently €81,140 versus €94,705 respectively) resulting in a dominant ICER (less costly and more effective). Based on current information TIL is dominating ipilimumab and has a probability of 86% for being cost effective at a cost/QALY threshold of €80,000. The Expected Value of Perfect Information (EVPI) amounted to €3 M. CONCLUSIONS: TIL is expected to have the highest probability of being cost-effective in second line treatment for advanced melanoma compared to ipilimumab. To reduce decision uncertainty, a clinical trial investigating e.g. costs and survival seems most valuable. This is currently being undertaken as part of a CED program in the Netherlands Cancer Institute, Amsterdam, the Netherlands, in collaboration with Denmark.