Value Assessment and Quantitative Benefit-Risk Modelling of Biosimilar Infliximab for Crohn's Disease

Regulatory approval of biosimilars often depends on extrapolating evidence from one clinical indication to all of those of the originator biologic. We aimed to develop a quantitative benefit-risk analysis to assess whether the resulting increase in the uncertainty in the clinical performance of biosimilars (i.e. risk) may be countered by their lower pricing (benefit).

A 1-year decision-analytic model was developed for the biosimilar infliximab (Inflectra^®) for Crohn's disease. The perspective was that of the National Health Service in the UK and costs were valued to 2015/16. A hypothetical cohort of biologic-naïve patients with moderate-to-severe Crohn's disease was simulated through the model. Immunogenicity to infliximab was a key modifier, influencing rates of non-response and infusion reactions. Net health benefit was estimated based on quality-adjusted life-years. A range of sensitivity analyses tested the robustness of the results and explored how the biosimilar price must respond to varying immunogenicity to remain the preferred option.

The base-case analysis predicted a positive incremental net health benefit of 0.04 (95% central range 0.00-0.09) favouring the biosimilar, based on 0.803 quality-adjusted life-years, and costs of £18,087 and £19,176 for the biosimilar and originator, respectively. Two-way sensitivity analyses suggested that if 50% of patients developed antibodies, the value-based price of £410 per vial must be lower than that of the originator (£420), but remain higher than the actual market price (£378).

The model supports the use of Inflecta^® for Crohn's disease in the UK, and provides a framework for the quantitative evaluation of biosimilars in the context of a health technology assessment. Value-based pricing using this methodology could protect health systems from the potential risks of biosimilars where they are untested in the approved populations.