Teens With Generalized Myasthenia Gravis Maintain Gains Over Two Years on Imaavy

Adolescents with generalized myasthenia gravis (gMG) who were treated with Imaavy (nipocalimab-aahu) maintained improvements in daily function and muscle strength for two years, according to new data presented at the 2026 Myasthenia Gravis Foundation of America Scientific Session and the American Association of Neuromuscular & Electrodiagnostic Medicine Annual Meeting.

Johnson & Johnson announced the results in 15 new abstracts on the therapy.

Myasthenia Gravis in Teens

Myasthenia gravis (MG) is an autoimmune condition in which the immune system makes antibodies that disrupt communication between nerves and muscles. The result is muscle weakness that can come and go. Symptoms often start in the eyes, such as drooping eyelids or double vision. About 85% of people go on to develop generalized MG, which can affect speech, swallowing and other muscles throughout the body.

Although MG is often thought of as an adult disease, about 10% to 15% of new cases are diagnosed in teens ages 12 to 17. Among young people, girls are affected more often than boys. Treatment options for younger patients have historically been limited.

“For adolescents living with generalized myasthenia gravis, unpredictable muscle weakness and symptoms such as eyelid droop and double vision can affect more than physical health; they can disrupt school, friendships and their growing independence,” said Jonathan Strober, M.D., director of the Pediatric Neuromuscular Program and Neuromuscular Clinic at UCSF Benioff Children’s Hospital, sponsored by the Muscular Dystrophy Association. Strober has provided consulting, advisory and speaking services to Johnson & Johnson.

How Imaavy Works

Imaavy is an FcRn blocker. It lowers levels of immunoglobulin G, the type of antibody that drives gMG, while preserving other parts of the immune system. It is approved for adults and children 12 and older with gMG who test positive for anti-acetylcholine receptor (AChR) or anti-muscle-specific tyrosine kinase (MuSK) antibodies. It is the only FcRn blocker currently approved for patients as young as 12.

Improvements Held Steady Through Two Years

The ongoing Phase 2/3 Vibrance-MG study (NCT05265273) enrolled seven adolescents ages 12 to 17 with antibody-positive gMG whose symptoms weren’t well controlled on standard treatment. Participants received Imaavy by IV infusion every two weeks, followed by a long-term extension phase.

The new data focus on teens with anti-AChR antibodies. At Week 108, roughly two years into treatment, participants with available data showed the following:

• An average improvement of 2.88 points on the MG Activities of Daily Living scale, which measures how symptoms affect everyday tasks
• An average improvement of 8.25 points on the Quantitative Myasthenia Gravis scale, a clinician-performed test of muscle strength

These improvements were consistent with those seen as early as Week 4 and at every check-in through two years. The results also mirror long-term findings in adults.

Some Teens Reduced or Stopped Steroids

Corticosteroids are commonly used to manage MG, but long-term use can cause side effects. Of the six adolescents taking corticosteroids when the study began, three lowered their dose and one stopped taking them after two years on Imaavy.

No new safety concerns were identified, and the safety profile in teens was similar to that seen in adults.

It is important to note that the adolescent study is very small, with only seven participants, and it is open-label without a comparison group.

Growing Options for Long-Term Control

For teens with gMG, these two-year results add to a growing body of evidence that steady, lasting symptom control is within reach. That includes the possibility of relying less on steroids over time. With Imaavy now approved for patients as young as 12, families have more options to discuss as they plan for the years ahead.