FDA Approves Expanded Indication of Eculizumab for Pediatric Generalized Myasthenia Gravis

The FDA has approved an expanded indication of eculizumab (Soliris; Alexion, AstraZeneca) to include pediatric patients 6 years and older with generalized myasthenia gravis (gMG) who are anti-acetylcholine receptor (AChR) antibody positive, making eculizumab the first and only treatment for pediatric patients with gMG, according to a news release from the Muscular Dystrophy Association (MDA).¹

Eculizumab is a humanized monoclonal antibody that attaches to the C5 protein. | Image Credit: © luchschenF - stock.adobe.com

Eculizumab is a humanized monoclonal antibody that links to the human C5 protein, inhibiting the cleavage of C5 into C5a and C5b, according to study investigators. It was first approved for in gMG for adults with AChR-positive disease. In patients who are AChR-positive, postsynaptic damage occurs through activation of the complement system. Eculizumab is designed to halt the formation of inflammatory proteins and the membrane attack complex in the complement system that result in tissue damage and cause the debilitating effects of gMG.^1,5

Researchers demonstrated that eculizumab had consistent adverse reactions with pediatric patients compared with adults in a 26-week, single-arm trial of 11 patients aged 12 to 17 years. The therapy is administered intravenously over a 35-minute period for adults and for 1 to 4 hours in pediatric patients, according to the MDA and eculizumab’s prescribing information.^1,2

Importantly, the therapy remains contraindicated for patients with unresolved serious Neisseria meningitidis (N meningitidis) infection. This requires that patients set to receive therapy be vaccinated against meningococcal disease at least 2 weeks before beginning treatment, unless the risks of delaying administration outweigh the risk of developing a potentially serious infection, according to eculizumab’s prescribing information. Even after vaccination, patients can be at higher risk of invasive N meningitidis, necessitating thorough monitoring. Because of these contraindications, eculizumab is only available through a restricted Risk Evaluation Management Strategy (REMS) program.^2,3

“This approval represents a major advancement in the treatment of pediatric myasthenia gravis and provides hope to families navigating this complex disease,” Sharon Hesterlee, PhD, chief research officer of the MDA, said in the news release. “The availability of [eculizumab] for children underscores the importance of continued research and innovation in neuromuscular disease treatments.”¹

First approved by the FDA in 2007 through an accelerated pathway for the treatment of patients with paroxysmal nocturnal hemoglobinuria (PNH) to reduce hemolysis, eculizumab has since received indications in patients with adult gMG with AChR antibodies, hemolytic uremic syndrome (HUS), and neuromyelitis optica spectrum disorder. More recently, the FDA approved eculizumab-aagh (Samsung Bioepis; Epysqli) as a biosimilar to eculizumab for its PNS and HUS indications, further expanding treatment options for patients with these rare neuromuscular diseases.^1,2,4

The effectiveness of eculizumab in adult patients was demonstrated in the phase 3 REGAIN clinical trial (NCT01997229). The randomized, double-blind, placebo-controlled trial enrolled 125 patients across 76 institutions in 17 countries who had all scored 6 or more on the MG-Activities of Daily Living score and were vaccinated against N meningitidis. Sensitivity analyses confirmed that eculizumab effectively improved MG symptoms, had the ability to alleviate disease progression, and was well-tolerated in patients with gMG compared with placebo.⁵

Now that the FDA has expanded the indication of eculizumab, which has already been approved and available for over a decade, pharmacists and other treatment providers must be proactive in educating patients on whether they may qualify for treatment with eculizumab. Pediatric patients with gMG face an increased disease burden due to a lack of treatment options; pharmacists stand to play a large role in counseling and monitoring once a patient begins treatment with eculizumab.

REFERENCES

1. Muscular Dystrophy Association. FDA approves expanded use of eculizumab (Soliris) for pediatric myasthenia gravis, bringing new treatment options for children. News Release. Released March 10, 2025. Accessed March 12, 2025. https://www.mda.org/press-releases/2025/fda-approves-expanded-use-of-eculizumab-soliris-for-pediatric-myasthenia-gravis-bringing-new-treatment-options-for-children

2. Alexion. Highlights of Prescribing Information – SOLIRIS. https://alexion.us/-/media/alexion_global/documents/regulatory/north-america/usa/2024/english/soliris_uspi.pdf

3. Dmytrijuk A, Robie-Suh K, Cohen MH, Rieves D, Weiss K, Pazdur R. FDA report: Eculziumab (Soliris) for the treatment of patients with paroxysmal nocturnal hemoglobinuria. Oncologist. 2008;13(9):993-1000. doi:10.1634/theoncologist.2008.0086

4. Halpern L. Eculizumab-aagh receives FDA approval as biosimilar to Soliris. Pharmacy Times. Published July 22, 2024. Accessed March 12, 2025. https://www.pharmacytimes.com/view/eculizumab-aagh-receives-fda-approval-as-biosimilar-to-soliris

5. Zhou A, Ho S, Vickers A. Eculizumab in myasthenia gravis: A review. Saudi J Ophthalmol. 2024;38(1):34-40. doi:10.4103/sjopt.sjopt_74_23