Another trial adds more weight to the early use of rituximab in newly diagnosed generalised myasthenia gravis, finding it reduces the risk of deterioration and the need for rescue therapies.
The small Swedish RINOMAX trial involved 47 adults with new-onset generalised myasthenia gravis (gMG) symptoms with a QMG score of 6 or greater, and MGFA score of II to IV. All but 2 patients had AChR antibodies and patients with suspected thymoma, thymectomy, and prior noncorticosteroid immunosuppressants or high-dose pulsed corticosteroids use for the prior 12 months were excluded.
Patients were randomised to a one-off treatment with 500 mg rituximab (n=25) or placebo (n=22) and were followed for up to 48 weeks.
A total of 71% in the rituximab treated group vs 29% in the placebo group reached the primary end point of minimal manifestations at 16 weeks [defined as a QMG score of 4 or less with prednisolone 10mg daily or less and no rescue treatment between weeks 9 to 16], which correspond to a probability ratio of 2.48.
The treatment group also needed fewer rescue treatments and lower doses of cortisone than the placebo group, the researchers reported in JAMA Neurology [link here].
The number of adverse events was greater in the rituximab group compared with placebo (81 vs 44), with 6 vs 4 severe adverse events in the rituximab and placebo arms, respectively.
“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,” said study lead Prof. Fredrik Piehl of the Department of Clinical Neuroscience, Karolinska Institutet, in a statement.
According to an accompanying editorial [link here] , the current trial provides evidence that low-dose rituximab may be effective in some patients with generalised AChR gMG, especially if started early after diagnosis.
However, they said the results needed to be put into context of the BeatMG trial which did not show rituximab effect at higher doses, although they noted that differences in patients and study endpoints could account for discrepancies between the studies.
“With the emergence of 2 new FDA approved drug classes, we have entered a new MG treatment era. Nevertheless, older and repurposed drugs like rituximab may still have a role in MG treatment,” they concluded.