OBJECTIVES: To estimate the cost per responder of recently approved FcRn inhibitors for the treatment of generalised myasthenia gravis (gMG), with responder defined as those who achieved at least a 3-point reduction in their baseline MG-ADL score.

METHODS: A systematic literature review identified relevant randomised controlled studies in gMG which allowed for a network meta-analysis (NMA) to be performed for rozanolixizumab 7mg/kg, rozanolixizumab 10mg/kg, and efgartigimod 10mg/kg. Assumptions for weight distribution and mean number of infusions (21.6 for rozanolixizumab, 20.6 for efgartigimod) were from a recent physician survey of gMG patients in the United States and clinical trial data, respectively. Cost per responder was estimated by dividing the drug wholesale acquisition price for the first year of treatment in the US per patient by the probability of MG-ADL response. Current evidence from the long-term extension studies for each drug suggests a similar responder rate across multiple cycles up to 52 weeks; thus the responder rate was assumed constant across cycles in the first year of treatment.

RESULTS: Two phase 3 studies were identified through the SLR, MycarinG and ADAPT comparing rozanolixizumab 7mg/kg and 10mg/kg to placebo and efgartigimod 10mg/kg to placebo respectively. While there were numerical differences between rozanolixizumab 10mg/kg, 7mg/kg and efgartigimod (0.77, 0.74 and 0.72 respectively), there were no statistically significant differences, thus an average responder rate of 0.74 was used. The cost per responder for the first year of treatment, was $365,827.82 for rozanolixizumab and $403,874.26 for efgartigimod.

CONCLUSIONS: While the FcRn inhibitor class were shown to have similar responder rates, rozanolixizumab showed lower cost per responder based on gMG patients’ weight distribution and clinical trial infusion data. Using products with lower cost per responder may result in cost savings for the healthcare system.