Suggestions from the data
The post hoc subgroup analysis should be interpreted with caution, and the study does not provide firm conclusions, Dr. Nowak noted. In addition, the trial population does not reflect all patients with myasthenia gravis. Dr. Nowak routinely uses rituximab in patients with muscle-specific kinase antibody-positive disease, he said. For acetylcholine receptor antibody-positive generalized myasthenia gravis, which has approved therapies available, Dr. Nowak presents rituximab as an option for some patients. Further research may clarify where B-cell depletion therapy may fit into the treatment paradigm.
Nonetheless, BeatMG and the subgroup analysis may help physicians better understand the disease and the role of various therapies. Investigators successfully lowered prednisone dose “at a pretty high rate in the placebo arm,” he said. “It suggests that many of our patients potentially may be on higher than required prednisone doses.”
Finally, the BeatMG findings emphasize the need for placebo-controlled trials to understand potential therapies. “We need to pause when we see a lot of retrospective and uncontrolled studies that are very promising,” Dr. Nowak said.
The study was supported by the National Institute of Neurological Disorders and Stroke. Genentech provided the study drug and placebo through an investigator-sponsored study agreement. Dr. Nowak has received research support from Alexion Pharmaceuticals, Genentech, Grifols, and Ra Pharmaceuticals. He has served as a paid consultant for Alexion, Momenta, Ra, Roivant, Shire, Grifols, and CSL Behring.
SOURCE: Nowak R et al. AANEM 2019. Unnumbered Abstract: Rituximab in patients with moderate to severe myasthenia gravis: a subgroup analysis of the BeatMG study