The Societal Impact Of Natalizumab Treatment In The Italian Relapsing-Remitting Multiple Sclerosis Clinical Practice: The Tysabri® Pharmacoeconomics (Type) Study

Objectives: Recently, long-term treatment effects of GA and interferons-ß (IFNs) observed in the UK multiple sclerosis Risk Sharing Scheme (RSS) have become available. Using a UK National Health Service perspective, we evaluated the costeffectiveness of GA for RRMS using either randomised controlled trial (RCT) or RSS data. Methods: A discrete Markov model comparing GA (20 mg qd or 40 mg tiw) to BSC, IFN-1a 44µg, IFN-1a 22µg, IFN-1a 30µg and IFN-1b was developed. The model has 21 health states defined by Expanded Disability Status Scale and a 50-year time horizon. It also incorporates adverse events, treatment discontinuation, various second-line treatments and neutralising antibodies. Relapse rates and disability progression transition probabilities were obtained from natural history studies in RRMS patients. Treatment effects were informed by a de novo network metaanalysis using results of RCTs and outputs were compared to a scenario in which real-world data from the RSS was used. Univariate and probabilistic sensitivity analyses were performed. Results: GA dominated IFN-1a 22µg and IFN-1a 30µg as it represented lower overall costs and QALY gains of 0.226 and 0.067, respectively. GA is cost-effective compared to BSC at an incremental cost-effectiveness ratio (ICER) of £14,789 per QALY gained. Albeit a reversed ICER was observed, GA remained cost-effective against IFN-1a 44µg and IFN-1b. The model was most sensitive to the treatment-specific hazard ratio (HR) for disability progression. Other influential factors included the proportion of patients switching to second-line treatments, discount rates, treatment waning and health-state costs. Scenario analyses using treatment-specific HR from the RSS confirmed the robustness of the base case findings and compared well with the 6-year RSS results. Conclusions: Different modelling approaches and data sources consistently show that GA is a cost-effective option for treating RRMS. GA was shown to be more effective than predicted at the outset of the RSS