Nipocalimab Does Well in Top-line Results of Phase 2 Vivacity-MG Trial

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by Steve Bryson, PhD |

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Nipocalimab (M281) led to a rapid and sustained response at all four dosing regimens, while causing significant reductions in disease severity among people with generalized myasthenia gravis (gMG), top-line results of the Phase 2 Vivacity-MG clinical trial show.

The investigational therapy, developed by Momenta Pharmaceuticals, also showed a strong relationship between reduced levels of immunoglobulin G (IgG) autoantibodies — which drive MG development — and clinical benefit, and was well-tolerated. 

Based on these findings, Momenta plans to hold meetings with regulatory agencies before the end of the year to discuss the Phase 2 findings. Presentation of final efficacy data, as well as findings from secondary goals,  also is expected this year.

“We are thrilled with the success of nipocalimab’s proof of concept trial in MG,” Craig Wheeler, president and CEO of Momenta, said in a press release. “We met our primary endpoint [goal] in this trial, demonstrating rapid and durable responses in all four dosing arms and a significant correlation between IgG reduction and efficacy.” 

“The data we are sharing [now] continues to build the evidence that nipocalimab has the potential to be a best-in-class agent in terms of efficacy, safety, and dosing,” he said.

In people with MG, IgG autoantibodies wrongly attack components of the neuromuscular junction, the site where nerves communicate with muscle cells. 

Nipocalimab is an antibody designed to target a receptor known as FcRn, which plays a central role in prolonging the duration of IgG autoantibodies in the bloodstream. As such, nipocalimab is intended to lower the levels of disease-causing autoantibodies and ease symptoms of gMG.

Vivacity-MG (NCT03772587) is a multi-center study designed to evaluate the safety and effectiveness of nipocalimab, administered by intravenous infusion (into the bloodstream), in 68 adults with moderate-to-severe gMG. 

Treatment with one of four regimens of nipocalimab — 5 or 30 mg/kg (milligrams per kilograms of the patient’s weight) every four weeks, 60 mg/kg every two weeks, or 60 mg/kg as a single dose — was compared to a placebo

The primary outcome was a statistically significant change from baseline in the patient-reported MG Activities of Daily Living (MG-ADL) score — a validated measure of MG severity. 

Results showed that 52% of patients who received nipocalimab had a significant and durable reduction in MG-ADL scores for at least four consecutive weeks across all four dosing regimens, compared to 15% of participants on a placebo. Clinically meaningful changes were rapid, occurring within two weeks.

People taking nipocalimab also showed a statistically significant relationship between IgG autoantibody reduction and clinical benefit. 

Nipocalimab was well-tolerated. No severe or serious treatment-related adverse events (side effects) were reported, and most were mild. Also, no reported adverse events led to treatment discontinuation. 

The trial is set to wrap up later this year. Participants in VIVACITY-MG may have the opportunity to enroll in a long-term extension study, in which they all will receive nipocalimab for a longer time.

“Thank you to the patients, families, and researchers who made this study possible,” said Wheeler. “We look forward to sharing the full data set later this year at a medical conference and discussing our phase 3 plans as we work to bring forward what we hope will be the best in class FcRn agent.”

While most current treatments show some effectiveness, many patients do not respond or experience significant side effects. 

“For patients with myasthenia gravis, current treatment options include medications such as acetylcholinesterase inhibitors, corticosteroids, and immunosuppressants which may provide improvement in muscle strength; however, many patients fail to respond, have substantial side effects or have uncontrolled disease symptoms that limit their daily function and quality of life,” said Jeffrey Guptill, MD, study lead. “The promise of nipocalimab to reduce pathogenic [disease-causing] autoantibodies in a dose dependent manner brings me great hope in providing these patients with a new treatment option.  

“The correlation between IgG reduction and symptom control across all doses in the nipocalimab trial may provide physicians the ability to optimally adjust patient dosing,” he added.

A replay of a recent webcast discussing the trial’s results is available here.

Besides gMG, the therapy was granted fast track and orphan drug designations by the U.S. Food and Drug Administration for the treatment of warm autoimmune hemolytic anemia. A Phase 2/3 clinical trial in this indication is expected to begin enrollment late this year.