Eculizumab May Allow Patients With MG to Reduce Immunosuppressive Therapy

Eculizumab (Soliris), a particularly high-cost biologic that treats rare and ultra-rare diseases, has recently seen its first biosimilar launch in Russia. While US and European competition from biosimilars will likely take several years more, multiple biosimilar developers, including Amgen and Samsung Bioepis, are developing their own biosimilars referencing Soliris.

During the coming week’s 2019 annual meeting of the American Academy of Neurology, held May 4-10 in Philadelphia, Pennsylvania, researchers will report new data on eculizumab in one of the drug’s more recently approved indications: generalized myasthenia gravis (MG).

The research team will present an interim analysis of the changes in concomitant immunosuppressive therapy used by patients with generalized, refractory, and anti-acetylcholine receptor antibody—positive MG during a phase 3, open-label extension of a study of eculizumab. The data cut-off for this analysis was December 31, 2017.

The extension enrolled 117 patients who had completed the REGAIN study, a 6-month, randomized, double-blind, placebo-controlled study of the biologic therapy. While during the REGAIN study patients were not allowed to receive concomitant therapy, during the extension, participants could, at the investigator’s discretion, have their concomitant therapy added to their 1200 mg of eculizumab that was given every 2 weeks.

Median eculizumab treatment from the open-label extension baseline was 22.7 months (range, 1 day to 37.3 months). At baseline of the extension, 98.3% of the patients were receiving at least 1 immunosuppressive therapy.

During the extension, 67.5% stopped or reduced the dose of their immunosuppressive therapy on 439 occasions in total, mostly because their MG symptoms had improved (46.2% of patients on 256 occasions). On 63 occasions, 53.8% of the patients started or increased their dose of immunosuppressive agents; in 32.5% (and on 89 occasions), this start or increase was due to worsening of MG symptoms.

The authors concluded that a numerically larger proportion of patients stopped or reduced their doses of immunosuppressive therapies than started or increased, and that symptom improvement or worsening were the main reasons for changes to concomitant therapy.

Reference

Nowak RJ, Muppidi S, Beydoun SR, O’Brien F, Yountz M, Howard JF. Changes in concomitant immunosuppressive therapy use during a phase 3 open-label study of eculizumab in adults with generalized myasthenia gravis: an interim analysis. Presented at: 2019 American Academy of Neurology Annual Meeting; May 4-10, 2019; Philadelphia, PA. Abstract P5.2-080.