A Study to Evaluate the Efficacy and Safety of ABC008 for Inclusion Body Myositis

A Phase II/III Randomized, Double-blind, Placebo-controlled, Multicenter Study to Determine the Efficacy and Safety of ABC008 in the Treatment of Subjects with Inclusion Body Myositis Detailed Description: A Phase II/III Randomized, Double-blind, Placebo-controlled, Multicenter Study to Determine the Efficacy and Safety of ABC008 in the Treatment of Subjects with Inclusion Body Myositis Detailed Description: This is a Phase II/III randomized, double-blind, placebo-controlled, parallel multicenter study with 3 parts. The study will include a sentinel cohort (Part A) of 30 subjects who will receive first three doses of the study drug. Safety data from subjects in the sentinel cohorts will be evaluated by a Data and Safety Monitoring Board (DSMB) before further dosing of the sentinel cohort, as well as initiation of enrollment in the double-blind safety and efficacy cohort (Part B). After completion of Part A or Part B, subjects have the option of enrolling in an open-label long-term extension study or progressing to the pharmacodynamics (PD) recovery cohort (Part C), to evaluate the recovery of the depletion of killer cell lectin-like receptor G1 (KLRG1)+ cells after the end of treatment with ABC008. Efficacy, safety, HRQoL, and HRU assessments will be conducted. Blood samples will be obtained to evaluate the serum PK, PD, and immunogenicity of ABC008 throughout the study.