Cenegermin for Treating Neurotrophic Keratitis: An Evidence Review Group Perspective of a NICE Single Technology Appraisal

As part of the Single Technology Appraisal (STA) process, the National Institute for Health and Care Excellence (NICE) invited the manufacturer of cenegermin (OXERVATE(®), Dompé) to submit evidence for the clinical and cost effectiveness of cenegermin for neurotrophic keratitis (NK). The Liverpool Reviews and Implementation Group (LRiG) at the University of Liverpool was commissioned to act as the Evidence Review Group (ERG). This article summarises the ERG’s review of the evidence submitted by the company and provides a summary of the Appraisal Committee’s (AC) final decision. Clinical-effectiveness evidence from two phase II randomised controlled trials (RCTs) of cenegermin found cenegermin to improve corneal healing after 8 weeks compared with vehicle, considered a proxy for artificial tears. Longer-term data and comparisons with other relevant comparators were insufficient to draw conclusions. The company developed a de novo economic model that found cenegermin to be dominant when compared with artificial tears, except in one of seven scenarios. However, the ERG considered that the model had a major structural flaw in that it failed to allow patients to enter a ‘sustained healing’ state from ‘standard of care (SoC) non-healing’ and ‘SoC deteriorating’ states, or to move into an ‘SoC deteriorating’ state from an ‘SoC non-healing’ state. Following the first AC meeting, the company submitted a revised model with a revised model structure that removed the ‘SoC deteriorating’ state and introduced an ‘SoC healed’ state to sit alongside the existing ‘sustained healing’ and ‘SoC non-healing’ states from the original model. However, the ERG continued to express concerns, which included (1) extrapolation of the treatment effect of cenegermin over a patient’s lifetime; (2) the assumption that patients had two specialist visits a month; (3) the assumption that artificial tears, autologous serum eye drops and contact lenses continued for a lifetime after healing; (4) the simplified modelling of costs and utilities; and (5) the underlying uncertainty in the utility values. The ERG therefore considered the company’s model could not produce a robust incremental cost-effectiveness ratio (ICER) per quality-adjusted life-year (QALY) gained. The ERG did however present an alternative ICER by amending the use and cost of autologous serum eye drops, contact lenses and artificial tears in the ‘healed’ and ‘non-healed’ states. Applying these changes produced an ICER of £302,717 per QALY gained. Because of uncertainties with the clinical- and cost-effectiveness evidence, the AC concluded that cenegermin cannot be recommended within its marketing authorisation for NK.