An experimental therapy called cemdisiran showed promise in a clinical trial assessing its use in generalized myasthenia gravis (MG), according to a press release by its maker, Regeneron Pharmaceuticals.
Cemdisiran is an investigational subcutaneous therapy that works by lowering levels of circulating complement factor 5, which is likely to be beneficial in patients with myasthenia gravis. Cemdisiran can be administered as a monotherapy, meaning as a single drug on its own, or it can be taken together with pozelimab, a C5 antibody.
Regeneron Pharmaceuticals conducted a study in which they assessed the efficacy and safety of cemdisiran as a monotherapy, as well as the combination of cemdisiran and pozelimab. In this study, 64 patients with anti-AChR-positive MG were on cemdisiran, 67 were on both cemdisiran and pozelimab and 59 were given a placebo. Researchers used two questionnaires, the Myasthenia Gravis Activities of Daily Living (MG-ADL) scale and the Quantitative Myasthenia Gravis (QMG) scale, to assess treatment response.
This study (called NIMBLE) showed that at week 24, both patients who took only cemdisiran and those who took the combination therapy had better outcomes compared with patients who were on the placebo. This was apparent in improvements in both the MG-ADL and the QMG scores. However, when cemdisiran monotherapy was compared against cemdisiran and pozelimab combination therapy, cemdisiran monotherapy demonstrated superior efficacy.
Read more about myasthenia gravis testing and diagnosis
Furthermore, researchers announced that no participant experienced a meningococcal infection, which pozelimab increases the risk of. There were no cases of treatment discontinuation from intolerable side effects. Serious treatment-emergent adverse events, which are side effects possibly associated with the initiation of a new therapy, occurred in 3% of patients on cemdisiran and 9% of patients on cemdisiran and pozelimab combination therapy.
During the first 24 weeks, no deaths occurred; however, after 24 weeks, there was one death in the cemdisiran group due to pneumonia and another death in the cemdisiran-pozelimab combination group due to sepsis. Both patients were on immunosuppressants in addition to the study drug.
“The NIMBLE trial results underscore the potential for cemdisiran to offer a best-in-class profile for those suffering with myasthenia gravis, providing for robust efficacy with a convenient quarterly subcutaneous administration,” said George Yancopoulos, president and chief scientific officer at Regeneron Pharmaceuticals.
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