Johnson & Johnson (NYSE: JNJ) presented 12 abstracts at the European Academy of Neurology 2026 Congress on June 26, offering new post-hoc analyses from the Phase 3 Vivacity-MG3 study of IMAAVY (nipocalimab-aahu) in adults with generalized myasthenia gravis (gMG).

Among the key findings, patients diagnosed within five years who received IMAAVY plus standard of care (SOC) showed greater reductions in MG-ADL scores at Week 24 compared with placebo plus SOC (-4.9 vs. -2.7). Patients with lower baseline symptom burden also showed greater MG-ADL score reductions with IMAAVY plus SOC versus placebo plus SOC (-4.5 vs. -2.3) at Week 24. A separate analysis found that patients in the IMAAVY arm maintained symptom improvements within two weeks after contracting common infections, compared with increases in symptom scores in the placebo group.

Safety data were consistent with prior nipocalimab studies. The overall incidence of adverse events was 84% in both the IMAAVY and placebo arms, while serious adverse events occurred in 9% of the IMAAVY group compared with 14% in the placebo group.

Johnson & Johnson also presented the design of the PETUNIA study, a post-marketing requirement from the U.S. Food and Drug Administration intended to collect real-world safety data on pregnancy, maternal, and infant outcomes following IMAAVY exposure during pregnancy.

IMAAVY is approved by the FDA and the European Medicines Agency for adults and pediatric patients aged 12 and older with antibody-positive gMG. The drug works by blocking the neonatal Fc receptor, which reduces circulating immunoglobulin G antibodies associated with the disease. The most common side effects include respiratory tract infection, peripheral edema, and muscle spasms.

The analyses presented at EAN 2026 are post-hoc in nature and were drawn from a 24-week double-blind, placebo-controlled trial enrolling 199 patients, 153 of whom were antibody positive.