Rituximab, a drug used to treat rheumatoid arthritis, can reduce the risk of deterioration in myasthenia gravis, an autoimmune disease that causes loss of muscle control.
Details of the study, which was led by researchers at Karolinska Institutet in Sweden, have been published in Jama Neurology.
“Patients with new onset myasthenia who received rituximab as a complement to standard care showed greater improvement compared with patients who were given a placebo,” said Fredrik Piehl, professor at the Department of Clinical Neuroscience, Karolinska Institutet, and the study’s principal investigator.
“They also needed fewer adjuvant treatments and lower doses of cortisone than the placebo group. These are encouraging results that give hope for a more effective strategy for controlling new onset myasthenia more quickly, even if larger studies will be needed to assess the long-term effects of the treatment.”
What is Myasthenia?
Myasthenia causes the immune system to attack receptors between nerves and muscles, which can lead to muscle weakness and fatigue. Myasthenia usually starts around the eye and can quickly spread to other muscles in the body. There is no curative treatment for the condition, so intervention is primarily aimed at dampening the immune system and treating symptoms. The disease mostly affects women and around 25 people per 100,000 people in Sweden live with the condition.
Currently, there is only one approved treatment for myasthenia, Soliris. This treatment is expensive and very few patients have been able to benefit from it. Many patients are treated with cortisone instead, which can cause negative side effects.
Karolinska Institutet’s study included 47 adult patients diagnosed with myasthenia in the past year. Of these, 25 were given a one-off treatment of 500mg of rituximab, a proven drug used to treat rheumatoid arthritis. The other 22 participants were given a placebo. The study took place over seven weeks and the patients were followed up for up to 48 weeks.
After four months, 71% of the participants who received rituximab had attained good control of their disease according to a 13-item rating scale. Only 29% of the placebo group reported similar positive results. Follow-up reports at six, nine, and twelve months reported similar results.
Rituximab can have negative side-effects
The group that was treated with rituximab also received lower doses of cortisone and needed fewer adjuvant treatments. However, this group reported more adverse reactions, most of which were mild.
The researchers acknowledge that the study had limitations. The research was completed with a relatively small number of participants, with an imbalance in some of the baseline characteristics between the two groups.
“The use of rituximab for myasthenia in Sweden increased even before the study results were finalised. It is also a treatment that neurologists in Sweden are very familiar with, thanks to the widespread and somewhat debated off-label prescribing for multiple sclerosis (MS). We will now, in a way similar to that with MS, analyse the long-term benefit-risk balance of the treatment with the help of national data collected via the Swedish myasthenia registry and national health registries. We also need to find markers that can predict the course of the disease at an early stage,” concluded Piehl.
