Johnson & Johnson Launches First Head-to-Head FcRn Blocker Study in Myasthenia Gravis
Key Insights
Johnson & Johnson announced the EPIC Phase 3b study, the first head-to-head comparison of FcRn (search) blockers IMAAVY and efgartigimod in generalized myasthenia gravis (search) patients.
New pediatric data from the Vibrance-MG study showed IMAAVY achieved sustained 73% reduction in IgG levels and maintained disease control through 72 weeks in patients aged 12 and older.
IMAAVY is currently the only FcRn (search) blocker approved for both adult and pediatric gMG patients with anti-AChR or anti-MuSK antibodies, offering sustained disease control across key antibody subtypes.
Johnson & Johnson announced plans to initiate the first head-to-head study comparing FcRn (search) blockers for patients with generalized myasthenia gravis (search) (gMG), positioning IMAAVY™ (nipocalimab-aahu (search)) as the FcRn blocker of choice for appropriate gMG patients. The announcement was made at the 2025 Myasthenia Gravis (search) Foundation of America Scientific Session and the American Association of Neuromuscular and Electrodiagnostic Medicine Annual Meeting.
EPIC Study Design Targets Treatment Optimization
The EPIC Phase 3b study represents a randomized, open-label trial designed to compare FcRn (search) blockers in adults with gMG. The study will evaluate whether treatment with IMAAVY provides superior disease control versus efgartigimod in adults with gMG who have never received an FcRn blocker. Additionally, it includes a treatment-switch arm to assess efficacy and safety of IMAAVY in participants switching from efgartigimod to IMAAVY.
The study's key primary and secondary endpoints are change from baseline in total immunoglobulin G (IgG) levels and sustained disease control measured by MG-ADL and QMG scores 8-12 weeks post-initiation of treatment, respectively.
"The EPIC study marks an important step forward in advancing care for people living with gMG," said Leonard L. Dragone, M.D., Ph.D., Disease Area Leader, Autoantibody and Rheumatology, Johnson & Johnson Innovative Medicine. "By directly comparing IMAAVY to another FcRn (search) blocker and incorporating a treatment-switch arm, EPIC will provide critical insights into how physicians can best start and transition gMG patients within this class."
Sustained Pediatric Efficacy Demonstrated
Accompanying the EPIC study announcement, Johnson & Johnson presented new positive data from the Vibrance-MG Phase 2/3 long-term extension study. These data show treatment with IMAAVY plus standard of care in pediatric patients aged 12 and older with gMG demonstrated sustained reductions in IgG through 72 weeks, disease control, functional improvements and long-term safety.
The Vibrance-MG analysis revealed that treatment with IMAAVY led to a rapid and sustained reduction in IgG levels, with a median reduction of approximately 73% by Week 24. Improvements in both daily function and muscle strength were also observed through 72 weeks, indicating sustained disease control over time. The treatment was generally well tolerated and no new safety concerns emerged during extended follow-up.
"Pediatric patients with gMG have long been an underserved population in neuromuscular disease research," said Jonathan Strober, M.D., Director of the Pediatric Neuromuscular Program and Professor of Pediatrics and Neurology at the University of California at San Francisco. "These new Vibrance-MG LTE pediatric data are especially encouraging, showing treatment with IMAAVY achieved sustained meaningful improvements in daily function and muscle strength, echoing the results seen in the Vivacity-MG3 OLE study in adults."
Differentiated Treatment Profile Across Patient Populations
The findings are consistent with positive results from the pivotal Vivacity-MG3 study and ongoing open-label extension in adult patients with gMG. Together, the data highlight the differentiated treatment profile of IMAAVY across key antibody subtypes (anti-acetylcholine receptor (search) positive [AChR+], anti-muscle-specific tyrosine kinase (search) positive [MuSK+]) and the potential to provide long-term sustained disease control for the broadest population of people living with gMG.
IMAAVY is currently approved by the U.S. Food and Drug Administration for adult and pediatric patients (12 years of age and older) with anti-AChR or anti-MuSK antibody positive gMG. The drug has also received approval in Brazil by ANVISA for anti-AChR, anti-MuSK or anti-LRP4 antibody positive adults and pediatric patients aged 12 and older, and in Japan by the Pharmaceuticals and Medical Devices Agency for treatment of all patients living with gMG.
Clinical Trial Details and Patient Population
The Phase 2/3 Vibrance-MG study enrolled seven participants aged 12-17 years with a diagnosis of gMG as reflected by a Myasthenia Gravis (search) Foundation of America Class of II through IV at screening, and an insufficient clinical response to ongoing, stable standard of care therapy. Participants must have a positive blood test for either anti-AChR or anti-MuSK autoantibodies.
The pivotal Phase 3 Vivacity-MG3 study enrolled 199 patients, 153 of whom were antibody positive, in a 24-week double-blind placebo-controlled trial. Randomization was 1:1, with 77 patients receiving nipocalimab plus current standard of care (30 mg/kg IV loading dose followed by 15 mg/kg every two weeks) and 76 patients receiving placebo plus current standard of care.
Disease Burden and Unmet Medical Need
Myasthenia gravis (search) is an autoantibody disease in which the immune system mistakenly makes antibodies that target proteins at the neuromuscular junction and can block or disrupt normal signaling from nerves to muscles, thus impairing or preventing muscle contraction. The disease impacts an estimated 700,000 people worldwide.
Approximately 85% of MG patients experience advancement to generalized myasthenia gravis (search), characterized by severe muscle weakness and difficulties in speech and swallowing. Approximately 100,000 individuals in the U.S. are living with gMG. Vulnerable gMG populations, such as pediatric patients, have more limited therapeutic options.
Among juvenile MG patients, girls are affected more often than boys with over 65% of pediatric MG cases in the U.S. diagnosed in girls. Approximately 10 to 15% of new cases of MG are diagnosed in pediatric patients 12-17 years of age.