Rystiggo wins regulatory approval in Canada for adults with gMG
Injection therapy OK'd for patients with antibodies against AChR, MuSK
UCB’s injection therapy Rystiggo (rozanolixizumab-noli) has been granted regulatory approval in Canada for adults with generalized myasthenia gravis (gMG) who test positive for antibodies against the acetylcholine receptor (AChR) or muscle-specific tyrosine kinase (MuSK) proteins.
Anti-AChR or anti-MuSK antibodies — self-reactive antibodies that target the body’s own healthy tissues — are the two most common MG-driving antibodies. Rystiggo, given through a subcutaneous, or under-the-skin infusion, speeds the pace at which these harmful antibodies are destroyed, reducing their levels in the bloodstream.
With this approval, it can now be administered once weekly for six weeks, which should help ease gMG symptoms.
“Health Canada’s approval of Rystiggo further supports UCB Canada’s commitment to advancing care for the gMG community,” Rodrigo Reis, general manager of UCB Canada, said in a company press release. Reis added that UCB is determined to continue to “raise the standard of care and make a meaningful difference in the lives of people affected by gMG.”
Muscular Dystrophy Canada says new treatment was ‘long awaited’
In gMG, self-reactive antibodies target proteins involved in nerve-muscle communication, leading to symptoms of muscle weakness and fatigue, which may affect the muscles of the eyes, face, neck, arms, and legs, as well as those required for breathing.
For most patients, gMG is caused by self-reactive antibodies that target AChRs — protein receptors found on muscle cells that respond to nerve signals. Less frequently, other proteins involved in nerve-muscle communication, such as MuSK, are targeted.
Stacey Lintern, CEO of Muscular Dystrophy Canada, notes that gMG “can profoundly impact a person’s physical, emotional, social, and financial well-being” with its “unpredictable and fluctuating symptoms.” These symptoms, Lintern said, “can be debilitating, significantly affecting patients’ day-to-day lives.”
Lintern said Muscular Dystrophy Canada welcomes this approval.
“The gMG community in Canada has long awaited new treatment options that extend beyond symptom management and offer the potential to improve outcomes and reduce burden. The availability of a new treatment option that promises to enhance the quality of life for many Canadians brings new hope and marks a significant step forward in the ongoing need for improved and accessible treatment options for gMG,” Lintern said.
Rystiggo is designed to target a protein known as neonatal Fc receptor, or FcRn. This protein normally prevents the breakdown of antibodies circulating in the bloodstream, including those that drive MG. By binding to FcRn and preventing antibodies from interacting with it, Rystiggo is expected to accelerate the rate at which harmful MG-driving antibodies are broken down, lowering their levels in the blood, and easing MG symptoms.
Regulatory approval in Canada supported by Phase 3 trial data
Health Canada’s decision to approve Rystiggo was supported by data from the Phase 3 MycarinG trial (NCT03971422), which enrolled 200 adults with gMG. Among them, 179 were positive for anti-AChR antibodies, and 21 had anti-MuSK antibodies. The participants were randomly assigned to receive Rystiggo or a placebo, given as weekly subcutaneous infusions for six weeks.
Data showed that Rystiggo treatment led to significant improvements in scores on the MG Activities of Daily Living (MG-ADL) scale, a patient-reported measure of disease severity, relative to the placebo from the study’s start to day 43. Rystiggo also led to significant improvements in scores on the Quantitative MG (QMG) scale, a clinician-rated measure of symptom severity, compared with the placebo, within the same time frame.
[Rystiggo] is a new treatment option, targeting one of the mechanisms of gMG to provide symptom improvement in patient- and physician-reported outcomes.
Vera Bril, the trial’s lead investigator and a professor of neurology at the University of Toronto, noted that gMG patients “often face treatment options that are broad-acting, and that have traditionally only offered symptomatic relief.”
According to Bril, “there is a significant need for new, innovative treatment options to reduce the day-to-day burden of gMG. [Rystiggo] is a new treatment option, targeting one of the mechanisms of gMG to provide symptom improvement in patient- and physician-reported outcomes at day 43.”
Rystiggo is the second therapy from UCB to gain approval in Canada for the treatment of adults with gMG. The first was Zilbrysq (zilucoplan), a once-daily subcutaneous injection therapy that can be self-administered, and which earned approval in the country last year for gMG patients who are positive for antibodies targeting AChRs.
The company stated that it’s working on a timeline to make Rystiggo available to Canadian patients as quickly as possible.
“With two therapeutic solutions now approved in Canada for gMG, our focus now will be to secure reimbursement so that patients can benefit from these treatments,” Reis said.
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