The use of a single low-dose rituximab infusion may help improve symptoms in patients with refractory myasthenia gravis (MG), according to a study published in the Journal of Neurological Sciences.
In the small study cohort, 13 out of the 17 patients responded to the rituximab treatment, with 6 even achieving asymptomatic status. The patients who improved showed durable efficacy and stable MG symptoms for a median of 12 months after infusion.
The patients also had an average 75% reduction in prednisone dose after 6 months compared to baseline doses they were receiving at the time of their rituximab infusions.
The study cohort was made up of 5 patients positive for anti-muscle-specific kinase antibodies (MuSK+), 10 positive for anti-acetylcholine receptor antibodies (AChR+), and 2 patients who were double seronegative. All 5 of the MuSK+ patients, 7 of the 10 AChR+ patients, and 1 of the double seronegative patients responded to treatment. Asymptomatic status was achieved in 3 MuSK+ and 3 AChR+ patients.
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“These results suggest that a single low-dose rituximab infusion is worth trying in refractory MG, including AChR+MG patients, as some patients showed good and durable responses. These results are particularly relevant to resource-limited settings,” the study’s authors said.
Prednisone treatment was discontinued in 80% of MuSK+ patients and 20% of AChR+ patients. In the AChR+ group overall, the prednisone doses were significantly reduced (≥30%; P =.008).
All 5 MuSK+ patients improved their MG Foundation of America (MGFA) clinical class by greater than 1 class and 60% of AChR+ patients improved by at least 1 MGFA class. The MG composite (MGC) score also significantly improved in the AChR+ patients (P =.0156). When considering just the AChR+ responders, the median MGC scores improved from 24 to 6, which was maintained for a median of 12 months.
A total of 17 patients with refractory MG were recruited for the study between February 2016 and October 2021. All but 1 of the patients were female. The median time from symptom onset to rituximab infusion was 6 years and the median follow-up duration after treatment was 18 months. No significant differences in age at infusion or disease duration prior to rituximab infusion were observed between responders and nonresponders.
Heckmann JM. A single low-dose rituximab infusion in severe chronic refractory myasthenia gravis in resource-limited settings. J Neurol Sci. 2022;442(120394):120394. doi:10.1016/j.jns.2022.120394