OBJECTIVES : Tumor-Infiltrating Lymphocytes (TIL) therapy is a promising but complex therapy for advanced melanoma which is despite promising results (phase I/II studies) and its expected cost-effectiveness not yet implemented as a standard therapy. Scenario drafting can be used to systematically evaluate future dynamics surrounding an innovative treatment and thereby facilitate its adoption. This study aims to evaluate future perspectives related to the adoption of TIL-therapy in advanced melanoma in terms of various scenarios of cost-effectiveness.

METHODS : Using a Delphi approach, 14 adoption scenarios for TIL-therapy were drafted, incorporating factors related to e.g.: patients perspective, pharmaceutical influence, and research developments. The likelihood of the scenarios taking place within 5 years was evaluated among international experts using a web-based questionnaire. Based on the questionnaire, scenarios were labeled as “likely” and “unlikely”. The likely scenarios were incorporated in an existing cost-effectiveness model comparing TIL-therapy to ipilimumab.

RESULTS : Twenty-nine experts from 12 countries completed the questionnaire. The scenarios showed an average likelihood ranging from 29% to 58%, indicating that future developments of TIL-therapy are uncertain. Seven of the scenarios were labeled as “likely”, the other 7 were “unlikely”. Four of the 7 likely scenarios showed a high probability for TIL-therapy to be cost-effective (89%-99%). The three other likely scenarios: “commercialization of TIL production”, “pharmaceutical companies lowering the prices of ipilimumab” and “using TIL-therapy combined with ipilimumab” showed a smaller chance for TIL-therapy to become cost-effective (0%-56%).

CONCLUSIONS : Scenario drafting can be a useful tool to minimize uncertainty surrounding decisions on adoption and coverage. Moreover, when scenarios are not cost-effective, it can facilitate adoption by identifying crucial contextual factors influencing the adoption. In this analysis, TIL-therapy was cost-effective compared to ipilimumab in most of the “likely” future scenarios. However, the factors involved in the “likely” scenarios resulting in TIL-therapy not being cost-effective should be considered in the adoption process.