The Cost-Effectiveness of Anti-IL17 Biologic Therapies for Moderate-to-Severe Plaque Psoriasis Treatment in Italy and Germany: A Sequential Treatment Analysis

Objective: The objective of this study was to optimise the cost-effectiveness of different anti-IL17 treatment sequences used in the treatment of moderate-to-severe plaque psoriasis in Italy and Germany over a five-year time horizon. Methods: We adjusted a previously published treatment sequence model for biologic drugs used in psoriasis treatment to an Italian and German setting, respectively. The model included all anti-IL17 biologics currently available in the treatment of moderate-to-severe plaque psoriasis in the markets of scope (secukinumab, ixekizumab, brodalumab and bimekizumab). Real-world discontinuation rates were used to model switches between the four anti-IL17 biologics included in the study. The treatment costs were based on label dosing recommendations for each drug, including induction and maintenance therapy, and the manufacturer prices of each drug in Italy and Germany, respectively. We used long-term Psoriasis Area and Severity Index 100 (PASI100) measures to inform the model on the efficacy for each treatment. The cost-effectiveness in the analysis was evaluated based on the cost per PASI100-responder. Results: We found that the most cost-effective treatment sequence was achieved by using brodalumab as first-line treatment, bimekizumab as second-line treatment, ixekizumab as third-line treatment and secukinumab as fourth-line treatment in both Italy and Germany, which resulted in a total cost per responder of euro128,200 and euro138,212, respectively, over a five-year period. Several scenario analyses were also conducted and ensured that the results were robust to changes in key input parameters. Conclusion: Our study showed that using brodalumab as a first-line therapy to treat moderate-to-severe psoriasis in both Italy and Germany leads to the most cost-effective treatment sequence, when compared to all possible combinations of anti-IL17s over a fiveyear time horizon. In addition, we found that treatment discontinuation and switching are important factors when assessing the costeffectiveness of biologic therapies.