Trial data show long-term promise for gMG treatment Imaavy
1 in 3 patients note few to no symptoms after 2 years in Phase 3 study
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Nearly one in three people with generalized myasthenia gravis (gMG) experienced prolonged periods of few or no symptoms while on treatment with Imaavy (nipocalimab-aahu), according to more than two years of data from a global clinical trial.
These and other data from the Phase 3 Vivacity-MG3 (NCT04951622) trial were presented at this year’s annual meeting of the American Academy of Neurology (AAN), held April 18-22 in Chicago and online.
“These data reinforce our confidence in Imaavy and our commitment to delivering treatments that can help more people living with gMG achieve meaningful, lasting disease control,” Chris Gasink, MD, vice president of medical affairs at Johnson & Johnson, the therapy’s developer, said in a company press release.
In gMG, self-targeting antibodies interfere with communication between nerve and muscle cells, leading to MG symptoms such as muscle weakness and fatigue. The most common types of MG-causing antibodies target the acetylcholine receptor (AChR) or muscle-specific kinase (MuSK) proteins.
Imaavy works to reduce disease-driving antibody levels by blocking the activity of the neonatal Fc receptor (FcRn), a protein that normally helps prevent antibodies from being broken down.
New data focus on sustained benefits
The therapy, which is given by infusion into the bloodstream every two weeks, is approved in the U.S. and Europe for people with gMG, 12 and older, who are positive for antibodies against AChR or MuSK.
Imaavy’s approvals were based primarily on data from Vivacity-MG3, which enrolled nearly 200 people with gMG, most of whom were positive for anti-AChR or anti-MuSK antibodies. For the first six months of the study, participants were randomly assigned to receive Imaavy or a placebo, in addition to standard-of-care treatment.
The trial met its main goal, which was to show that Imaavy was better than the placebo at reducing scores on the MG Activities of Daily Living (MG-ADL), a standardized assessment of the disease’s impact on daily life in which higher scores indicate greater impairment.
Newly announced data focused mainly on the proportion of patients who experienced sustained minimal symptom expression (MSE), or MG-ADL scores of 0 or 1 (little to no disease impact), for at least eight weeks (about two months).
Patients given Imaavy were about four times more likely to achieve sustained MSE than those on the placebo, according to Johnson & Johnson. Those experiencing sustained MSE at six months showed significantly greater improvements in quality of life than those with non-sustained MSE or those who did not attain MSE.
Participants completing the trial’s placebo-controlled portion had the option to continue into an open-label extension, in which all are being treated with Imaavy and monitored for long-term outcomes.
Long-term data, covering 96 weeks (nearly two years) in the extension portion alone and a total of 120 weeks (little over two years), showed that half of the participants experienced MSE at some point, and 32% achieved sustained MSE.
MG-ADL score reductions with Imaavy were also sustained over time. At the latest available follow-up, mean MG-ADL scores had dropped significantly by 6.47, indicating a deeper response than the 4.7-point reduction reported for Imaavy-treated patients in the six-month placebo-controlled portion.
Scores on the Quantitative MG (QMG) scale — which assesses muscle weakness, with higher scores indicating greater weakness — also showed a significant reduction, of 5.97 points. Again, this reflected a slightly greater drop relative to that seen with Imaavy in the placebo-controlled part (4.86 points).
“For people living with gMG, consistent and durable symptom control is the central goal of treatment,” said Constantine Farmakidis, MD, a professor at the University of Kansas Medical Center. “These long-term results, now extending to beyond two years, provide further evidence that disease control, as initially observed in the [placebo-controlled portion], can be sustained, and add to the body of evidence that may help guide clinical decision-making.”
Long-term data showed that more than half of participants (57%) reduced their corticosteroid doses to 5-10 mg per day. Corticosteroids are a standard gMG treatment, but their long-term use or high doses are associated with serious side effects.
No unexpected adverse events were reported with longer Imaavy treatment.
“Evidence demonstrating sustained disease control alongside sustained improvements in quality of life underscores our progress toward more effective treatment options,” Mark Graham, PhD, therapeutic area head, immunology, for Johnson & Johnson’s Europe, Middle East and Africa region, said in a company press release. “We remain committed to advancing innovative approaches that address persistent unmet needs and improve long-term outcomes for patients.”
The company recently launched a Phase 3 trial, EPIC (NCT07217587), to directly compare Imaavy against Vyvgart (efgartigimod alfa-fcab), another FcRn-targeting therapy sold by Argenx. Recruitment of adults with AChR-related gMG who have not previously received FcRn-targeting treatments is ongoing at sites in the U.S. and Israel.
Participants will receive either Imaavy or Vyvgart for about three months, with the main goal of evaluating changes in antibody levels. Secondary goals include changes in MG-ADL and QMG scores.
Eligible participants treated with Vyvgart for three months and newly enrolled patients already taking Vyvgart or its under-the-skin injection formulation, Vyvgart Hytrulo, will be switched to Imaavy for three months.
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