Phase 3 Myasthenia Gravis Inebilizumab Trial (MINT): Minimal Symptom Expression Achievement with Inebilizumab

ObjectiveTo determine the proportion of MINT participants who achieved minimal symptom expression (MSE) with inebilizumab. BackgroundInebilizumab’s efficacy in generalized myasthenia gravis (gMG) was demonstrated in MINT, which met its primary endpoint (change from baseline in Myasthenia Gravis Activities of Daily Living [MG-ADL] score). Design/MethodsMINT (NCT04524273) enrolled participants with anti-acetylcholine receptor antibody-positive (AChR+; n=190) or anti-muscle-specific kinase antibody-positive (MuSK+; n=48) gMG who underwent a protocol-specified steroid taper and were randomized 1:1 to inebilizumab or placebo for 26 (MuSK+) or 52 (AChR+) weeks (Ws) (randomized controlled phase). The proportion of participants who achieved MSE (MG-ADL score 0 or 1) without rescue therapy (RT) and those who achieved ≥3-point improvements in MG-ADL or Quantitative MG (QMG) scores were examined. ResultsA greater proportion of participants receiving inebilizumab vs placebo achieved MSE without RT at W26 (combined, 29% vs 20%; AChR+, 27% vs 20%; MuSK+, 38% vs 17%) and W52 (AChR+, 46% vs 25%). Higher proportion of participants achieved ≥3-point improvements in MG-ADL scores without RT in the inebilizumab vs placebo group at W26 (combined, 69% vs 48%; AChR+, 68% vs 49%; MuSK+, 71% vs 46%) and W52 (AChR+, 72% vs 45%). Higher proportion of inebilizumab-treated participants achieved ≥3-point improvements in QMG scores without RT vs placebo at W26 (combined, 60% vs 41%; AChR+, 61% vs 40%; MuSK+, 57% vs 46%) and W52 (AChR+, 69% vs 42%). Data from the open-label phase will also be reported. ConclusionsInebilizumab is associated with notable improvements in disease severity and function in patients with gMG.