OBJECTIVES : The development of an anti-FVIII inhibitor is the most serious complication of haemophilia A. Since February 7^th 2019, emicizumab is reimbursed in France for the prevention of bleeding episodes in patients with haemophilia A with FVIII inhibitor. The purpose of this analysis is to evaluate the Cost-Effectiveness of emicizumab compared to the current management by Bypassing Agents (BPAs) in France, taking into account the final public price granted.

METHODS : The analysis is based on a Markov model with two health states over a 5-year time horizon. Emicizumab is compared with BPAs (aPCC and rFVIIa) in prophylaxis or on-demand, according to their real-life use in the FranceCoag Network cohort (RFC). The ICER is expressed in euros per QALY (Quality-Adjusted Life Year). Bleeding rates are derived from the HAVEN 1 clinical trial for emicizumab and BPA on-demand, and an indirect comparison for BPA prophylaxis. Quality of life data are derived from the HAVEN 1 trial. The costs of treatment, adverse events and hospitalizations were included. Various sensitivity analyses were performed to evaluate the uncertainty around the result.

RESULTS : Emicizumab prophylaxis is a dominant strategy: it is more effective and less costly than BPAs. Over 5 years, the mean total cost per patient was 2,3 M€ in patients treated with emicizumab, versus 2,6 M€ with BPA, associated to 3,3 and 2,4 QALYs respectively. Thus, emicizumab brings 0,9 additional QALYs per patients for a saving of 283 642€. Exploration of uncertainty does not alter these results.

CONCLUSIONS : The health economic analysis shows the cost-effectiveness of emicizumab versus BPA in France. The methodology used was accepted by the CEESP in its Opinion of October 9, 2018. The limitations of this analysis are mainly based on the lack of data to model the consequences of the reduction of bleeding on the long-term evolution of arthropathy and disability.