Clinical effectiveness of efgartigimod in a broad population of patients with generalized myasthenia gravis: subgroup analyses from a randomized, double‑blind, placebo‑controlled, phase 3 trial (ADAPT).

BACKGROUND

The ADAPT phase 3 trial (NCT03669588) showed efgartigimod was well tolerated and efficacious in acetylcholine receptor antibody-positive (AChR-Ab +) patients with generalized myasthenia gravis (gMG). This analysis utilized data from the ADAPT trial to investigate the efficacy and safety of efgartigimod in different patient subgroups.

METHODS

ADAPT included a broad population of AChR-Ab + participants who received a stable dose of ≥ 1 (any) treatment for gMG and were randomized 1:1 to efgartigimod (10 mg/kg) or placebo (administered as four once-weekly infusions per cycle) for 26 weeks. Myasthenia Gravis Activities of Daily Living (MG-ADL) and Quantitative Myasthenia Gravis (QMG) responder rates in cycles 1 and 2, and rates of treatment-emergent adverse events (TEAEs) were analyzed in the following patient subgroups: history of nonsteroidal immunosuppressive treatment (NSIST), concomitant use of gMG treatments throughout the study, and baseline patient and disease characteristics, including time since diagnosis, age, baseline MG-ADL score, body mass index (BMI), sex, and prior thymectomy.

RESULTS

In total, 129 AChR-Ab + participants were included (efgartigimod, n = 65; placebo, n = 64). Across all subgroups, higher MG-ADL and QMG responder rates were observed in participants treated with efgartigimod versus placebo during cycles 1 and 2. Rates of TEAEs were similar between participants treated with efgartigimod and placebo, regardless of concomitant gMG treatment type.

CONCLUSION

Similar to outcomes observed in the ADAPT overall population, efgartigimod was well tolerated and efficacious across a broad range of patients, regardless of NSIST treatment history, concomitant use of gMG treatments, or baseline patient and disease characteristics.

TRIAL REGISTRATION: ClinicalTrials.gov: NCT03669588 (registered September 13, 2018).