Repeated cycles of Rystiggo don’t increase safety problem risk
Researchers analyzed 188 patients who received at least one cycle
Repeated cycles of Rystiggo (rozanolixizumab-noli) do not increase the risk of safety problems in people with generalized myasthenia gravis (gMG), according to a new analysis of clinical trial data.
“These results showed that treatment with [Rystiggo] in patients with gMG was well tolerated and that the incidence of side effects did not increase with repeated cycles of treatment,” the researchers wrote.
Findings from the analysis were detailed in the study, “Long-term safety of cyclical rozanolixizumab in patients with generalized myasthenia gravis: Results from the Phase 3 MycarinG study and an open-label extension,” published in the Journal of Neuromuscular Diseases. The work was funded by UCB, which markets Rystiggo.
MG is an autoimmune disease caused by self-reactive antibodies that interfere with the communication between nerve and muscle cells, leading to symptoms of muscle weakness and fatigue.
Rystiggo is an antibody-based therapy that’s designed to reduce the antibodies’ levels. It’s approved in the U.S. and Europe to treat gMG in patients with self-reactive antibodies that target acetylcholine receptor (AChR) or muscle-specific tyrosine kinase (MuSK), the most common types of MG-causing antibodies.
The therapy is given by an infusion under the skin, or subcutaneously, once a week in six-week cycles. If patients continue to have continual or worsening symptoms after one six-week cycle, additional treatment cycles may be given. Its approvals were based mainly on data from a Phase 3 clinical trial called MycarinG (NCT03971422), which tested the therapy against a placebo in people with gMG who were positive for antibodies against AChR or MuSK. Those who completed the placebo-controlled trial were able to join MG0007 (NCT04650854), an open-label extension study where they were treated with Rystiggo and monitored for long-term outcomes.
Safety with repeated Rystiggo treatment
In an effort to understand the safety profile of repeated treatment cycles, the researchers analyzed data from 188 patients who received at least one cycle of Rystiggo in MycarinG and MG0007. On average, each patient received more than three cycles of treatment.
Nearly all of them (89.9%) had at least one adverse event. The most common safety issues reported in Rystiggo-treated patients were headache, diarrhea, and fever, all being established side effects. The rates of these side effects didn’t increase with more than one cycle of treatment.
About a third of the patients (26.6%) had severe adverse events, most commonly related to MG worsening or myasthenic crisis. Serious safety issues, including MG worsening, myasthenic crisis, and COVID-19, were reported in 22.3%. The rates of serious or severe safety issues also didn’t increase with repeated treatment cycles and no deaths related to Rystiggo were documented.
Safety issues leading to discontinuing the study occurred in 15.4% of patients and included MG worsening and myasthenic crisis. Discontinuation rates tended to remain low over repeated treatment cycles.
Some side effects, particularly headache, were more common in females and younger patients, differences that mirror trends in the general population.
The results from this analysis “build on the positive results of the Phase 3 MycarinG study and demonstrate an acceptable safety profile of long-term [Rystiggo] treatment in patients with gMG that is consistent across repeated treatment cycles,” the researchers wrote.
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