A Phase 3, Randomized, Double-blind, Placebo-controlled, Parallel, Multicenter Study to Evaluate the Safety and Efficacy of ALXN1720 in Adults with Generalized Myasthenia Gravis

This COM presentation summarizes a Phase 3, randomized, double-blind, placebo-controlled, parallel, multicenter study (ALXN1720-MG-301; ClinicalTrials.gov NCT05556096) sponsored by Alexion Pharmaceuticals, Inc. The protocol evaluates the safety and efficacy of ALXN1720 in adults with generalized myasthenia gravis (gMG) who are seropositive for autoantibodies against the acetylcholine receptor (AChR). The study began in November 2022 and is scheduled through May 2025. Recruitment for the trial is complete. The central objective is to determine whether ALXN1720 provides a favorable risk-benefit profile for treating generalized MG in AChR-positive adults who meet clinical criteria corresponding to Myasthenia Gravis Foundation of America (MGFA) Class II, III or IV.

Eligibility requirements ensure enrollment of adult males and females aged 18 years and older with a confirmed diagnosis of generalized MG and a positive serological test for AChR autoantibodies. Key exclusion criteria include a history of thymectomy or other thymic surgery within 12 months prior to screening, untreated thymic malignancy (including thymoma or carcinoma), a history of Neisseria meningitidis infection, and pregnancy, breastfeeding, or intention to conceive during the study period. These criteria are intended to create a well-defined adult gMG population for assessing therapeutic impact while minimizing potential confounding safety risks associated with thymic disease or infectious history.

The trial is being conducted across multiple research sites in the United States, demonstrating geographic distribution to capture diverse clinical settings. Listed locations include research sites in Orange, California; Fort Collins, Colorado; Washington, D.C.; Bradenton, Florida; Maitland, Florida; and Tampa, Florida. The multicenter design and parallel-group, randomized, double-blind, placebo-controlled structure are aligned with rigorous standards to assess both efficacy and safety endpoints objectively and to support potential regulatory review.

The protocol summary emphasizes evaluating safety and efficacy outcomes in adults with generalized MG who have autoantibodies against AChR. As a Phase 3 study, ALXN1720-MG-301 is positioned to confirm clinical benefit, characterize the adverse event profile, and provide definitive data on ALXN1720's therapeutic value in the target population. The study's design elements, randomization, blinding, placebo control, and parallel groups, support internal validity and aim to reduce bias in outcome assessment.