Nipocalimab + SoC improves MG-ADL scores in adults with myasthenia gravis

Adding nipocalimab to standard-of-care (SoC) treatment significantly improves Myasthenia Gravis-Activities of Daily Living (MG-ADL) scores in patients with generalized MG (gMG), according to the pivotal phase III Vivacity-MG3 study presented at EAN 2024.

Nipocalimab is an investigational monoclonal antibody, designed to bind with high affinity and selectively block antineonatal Fc receptor (FcRn) to reduce levels of circulating immunoglobulin G  antibodies, while preserving immune function without causing broad immunosuppression, according to Dr Carlo Antozzi from the Neuroimmunology and Neuromuscular Diseases Unit at Fondazione IRCCS Istituto Neurologico Carlo Besta in Milan, Italy.

The phase III Vivacity-MG3 study analysed 153 adults (mean age 52.4 years, 60.1 percent female) with AChR*, MuSK**, or LRP4** antibody-positive gMG who had an inadequate response to SoC therapy. Participants were randomized 1:1 to receive nipocalimab⁺ (n=77) or placebo (n=76) in addition to SoC for 24 weeks.

At baseline, mean MG-ADL and Quantitative Myasthenia Gravis (QMG) total scores were 9.2 and 15.4 points, respectively.

Over 24 weeks, MG-ADL score was significantly improved by 4.70 points from baseline among patients treated with nipocalimab plus SoC compared with a 3.25-point improvement in those treated with placebo plus SoC (p=0.002). [EAN 2024, abstract EPR-116]

Additionally, QMG score — which quantifies the severity of MG disease, with higher scores indicating increased severity — improved significantly from baseline to weeks 22–24 in the nipocalimab group vs the placebo group (-4.86 vs -2.05; p<0.001).

Secondary endpoints

At weeks 22–24, the proportion of MG-ADL responders, defined as individuals who had a ≥2-point improvement in MG-ADL, was significantly higher among those treated with nipocalimab plus SoC than those treated with placebo plus SoC (68.8 percent vs 52.6 percent; p=0.021).

More nipocalimab-treated patients also demonstrated a sustained response, defined as a ≥2-point improvement in MG-ADL from weeks 4–24, (55.8 percent vs 26.3 percent) and achieved a ≥50-percent improvement in MG-ADL from weeks 22–24 (46.8 percent vs 25 percent) than placebo-treated patients.

“The sustained response of nipocalimab over 6 months among this broad MG population is an important finding given the chronic, unpredictable exacerbations typically seen with MG,” said Antozzi in a press release. “We are encouraged by the potential of nipocalimab to uniquely help address this gap for people living with MG.”

In terms of safety, the overall incidence of adverse events was comparable between the nipocalimab and placebo arms (81.6 percent and 82.7 percent, respectively).

“Overall, nipocalimab demonstrated statistically significant and clinically meaningful improvements in MG-ADL and QMG, as well as a high responder rate,” Antozzi concluded. “Vivacity is the first registrational study of an FcRn blocker to show sustained efficacy through 6 months of dosing … and nipocalimab was generally well tolerated in gMG patients.”