Authors' objectives: The Academic Technology Assessment Group (ATAG) reviewed a report on the additional benefits and cost-effectiveness of efgartigimod in patients with generalized myasthenia gravis submitted by the manufacturer (Argenx Japan K.K). In the analysis scope determined by the Expert Committee of Cost-Effectiveness Evaluation (ECCEE), the populations are acetylcholine receptor antibody-positive and antibody-negative generalized myasthenia gravis (gMG) patients, respectively, and the comparators are prednisolone, immunosuppressive drug, acetylcholinesterase inhibitor. This report summarizes the results of the review and the re-analysis by the ATAG. To evaluate the additional benefits of efgartigimod, the manufacturer evaluated the additional benefits of efgartigimod alfa for all patients with gMG population without complying with the scope. Based on the results of the Quantitative Myasthenia Gravis (QMG) responder rate (defined as a score improvement rate of > 3 from the baseline) and the Myasthenia Gravis-Activities of Daily Living (MG-ADL) responder rates (defined as a score improvement rate of > 2 from the baseline) for all patients considered in the ADAPT trial, a randomized controlled trial for efgartigimod, the manufacturer concluded that efgartigimod had additional benefits in the whole gMG population. The ATAG considered that the evaluation should be conducted according to the scope; therefore, evaluated the additional benefits for each population based on the results of the ADAPT trial. For the acetylcholine receptor antibody-positive population, the QMG and MG-ADL responder rates were significantly higher for efgartigimod alfa; therefore, the ATAG concluded that efgartigimod alfa had additional benefits. However, as the sample of antibody-negative patients was small and the results had high uncertainty, it concluded that it could not be judged from the currently available evidence that efgartigimod had additional benefits for the acetylcholine receptor antibody-negative population. For the acetylcholine receptor antibody-positive population, the ATAG assessed the cost-effectiveness analysis that the manufacturer conducted. The manufacturer used a Markov model, which had the health states of efgartigimod alfa or the comparator as first-line treatment, intravenous immunoglobulin or plasma exchange as second-line treatment, eculizumab as third-line treatment, and the best supportive care. In the re-analysis by the ATAG, the rates of patients using eculizumab, drug cost, costs related to efgartigimod, and the assumption to include productivity loss were revised. Regarding the acetylcholine receptor antibody-negative population, cost-minimization analysis was performed for the one-month treatment costs. For the acetylcholine receptor antibody-positive population, efgartigimod incurred an additional cost of JPY26,531,123 and 0.238QALY, and the ICER was JPY111,660,260/QALY. For the acetylcholine receptor antibody-negative population, efgartigimod increased costs by JPY1,268,110

Project Status: Completed

URL for project: https://c2h.niph.go.jp/en/

Year Published: 2023

URL for published report: https://c2h.niph.go.jp/en/results/C2H2204.html

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: Japan

Organisation Name: Center for Outcomes Research and Economic Evaluation for Health

Contact Address: 2-3-6 Minami, Wako-shi, Saitama 351-0197 Japan

Contact Name: Takeru Shiroiwa

Contact Email: t.shiroiwa@gmail.com