To analyze the eligibility of acetylcholine receptor antibody-positive generalized myasthenia gravis (AChR+ gMG) patients treated in routine care for phase III clinical trials.

Recently, the FDA approved many complement and FCRN inhibitor therapies for AChR+ve gMG. All clinical trials leading to the approval have had similar, restrictive inclusion and exclusion criteria, including moderate symptom burden and restrictions on concomitant therapies.

This cohort study included AChR+ve gMG patients with documented myasthenia gravis activities of daily living (MG-ADL) scores seen in the clinic for the first time between January 2021 and December 2021. Longitudinal clinical information including MG history, concomitant treatment(s), and MG-ADL score was analyzed at each clinic visit to determine the clinical trial eligibility of patients until June 2023.

A total of 84 patients had a total of 437 visits between January 2021 and June 2023. At 420 out of 437 (96.1%) visits, the patients did not meet the eligibility criteria for the clinical trials. Seventy-five out of 84 (89.2%) patients never met the eligibility criteria. Nine out of 84 (10.8%) patients at 17 out of 52 (32.7%) visits met the eligibility criteria for the clinical trials. MG-ADL >5 was the single most frequent criterion not fulfilled, followed by IVIG use within the last 4 weeks of clinic visit. At 99 out of 437 (22.65%) clinic visits where the MG-ADL score was >5, prior use of complement inhibitor medication and IVIG use within the last 4 weeks of clinic visit were the reasons for not meeting the eligibility criteria.

The majority of AChR+ gMG patients seen for routine clinical care would not have met clinical trial criteria for recently completed phase III complement inhibitor and FCRN inhibitor trials. Broader inclusion criteria would increase patient eligibility and contribute to better generalizability of the results in clinical trials.