The MIGHT Trial - an Exploratory Clinical Trial of IVIG in Anti-HMGCR Immune Mediated Necrotizing Myopathy

This is a randomized, placebo-controlled, double blinded phase 2 exploratory clinical trial of intravenously administered pooled human immunoglobulin (IVIG) in anti-3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) immune mediated necrotizing myopathy (IMNM). Planned enrollment is 12 individuals with active anti-HMGCR IMNM meeting inclusion and exclusion criteria. Assuming 20% drop-out, the investigators anticipate 10 participants will complete all study assessments. Enrolled participants will be randomized 1:1 to either IVIG 2g/kg or placebo (0.9% sodium chloride at equivalent volume) at weeks 0, 4, and 8. The primary efficacy and co-primary safety and tolerability endpoints will be assessed at week 12. After the randomized phase of the trial, all participants, except those who were randomized to IVIG and met the clinical deterioration criteria, will be offered to continue on to an open-label extension phase in which participants will receive IVIG at weeks 12, 16, and 20. Participants will then return at week 24 for a final non-infusion visit to reassess safety, tolerability, and efficacy outcome.