PRM142 - QUANTITATIVE BENEFIT-RISK MODELLING OF BIOSIMILARS: A CASE STUDY OF INFLIXIMAB IN CROHN’S DISEASE.

Abstract

Biosimilars are promoted as less expensive alternatives to originator biologic products. Similarity in one indication can be extrapolated to others. However, the extrapolation process involves uncertainties including immunogenicity, which can reduce efficacy and increase the risk of adverse events. Aim: To model whether the cost savings justify the increased uncertainties regarding efficacy and safety. A quantitative benefit-risk analysis of biosimilar versus originator infliximab in Crohn’s disease was developed. A hypothetical cohort of 100,000 patients was modelled for one-year using a decision-analytic model. The development of antibodies to infliximab was a key modifier in the model, influencing rates of non-response, loss of response and the likelihood of infusion reactions. Net health benefit was estimated based on QALYs. One-way sensitivity analyses tested the limits of the biosimilarity assumption and probabilistic sensitivity analysis tested the robustness of the results. Two-way sensitivity analyses explored how the biosimilar price would need to respond to varying immunogenicity to remain the preferred option. The base-case analysis predicted annual QALYs of 0.803 for each biologic, and costs of £18,087 and £19,176 for biosimilar and originator, respectively. The incremental net health benefit of 0.04 (95% Central Range 0.00-0.09) favoured the biosimilar. Two-way sensitivity analyses suggested that if 50% of patients were to develop antibodies, the value-based price would need to be lower than that of the originator, but remain higher than the actual market price. In the absence of trial evidence, the model provides a basis for the quantitative evaluation of biosimilars to support the health technology appraisal process. Value-based pricing using this methodology would be possible to protect health systems such as the NHS in the UK from the potential risks of biosimilars where they are untested in the populations for which they have been approved.