Rituximab reduced risk for disease worsening in generalized myasthenia gravis

A single, 500 mg dose of rituximab was associated with greater probability of minimal myasthenia gravis manifestations and reduced the need for rescue medications compared with placebo, researchers reported in JAMA Neurology.

Although severity of myasthenia gravis varies, it is well-known that in patients with general symptoms, many experience substantial morbidity and life-threatening events, Fredrik Piehl, MD, PhD, professor of neurology at Karolinska Institute in Sweden, and colleagues wrote.

Seeking to assess the efficacy and safety of rituximab compared with placebo as an add-on to standard of care for myasthenia gravis, researchers conducted a randomized, double-blind, placebo-controlled study over the course of 48 weeks at seven regional clinics in Sweden.

Eligible participants were aged 18 years and older with onset of generalized symptoms within 12 months of inclusion and a Quantitative Myasthenia Gravis (QMG) score of at least 6. The primary study outcome was the proportion of patients with minimal disease manifestations (QMG 4), prednisolone at 10 mg/day or less and no rescue treatment.

Of 47 randomized patients, 25 received 500 mg IV infusion of rituximab (mean age, 67.4 years; 28% women), and 22 received placebo (mean age, 58 years; 32% women). A greater proportion of the rituximab group (71%) met the primary endpoint, compared with those in the placebo group (29%; probability ratio = 2.48; 95% CI, 1.2-5.11).

Further, rescue treatments were more frequently reported in the placebo group (36%) compared with the rituximab group (4%).

“We here observed that a single infusion of 500 mg of rituximab increased probabilities to attain minimal disease manifestations,” the authors wrote. “Further studies are needed to shed light on long-term benefit-risk balance with rituximab in generalized [myasthenia gravis] as well as to define predictive markers for disease severity early in the disease course.”