Just 16 months after Johnson & Johnson scored its initial FDA approval for Imaavy, the pharma giant has tacked on a label expansion for the monoclonal antibody and potential blockbuster.
The FDA has signed off on Imaavy to treat warm autoimmune hemolytic anemia (wAIHA), a rare, life-threatening disorder in which pathogenic immunoglobulin G (IgG) autoantibodies destroy red blood cells.
As an immuno-selective neonatal fragment crystallizable receptor (FcRn) blocker, Imaavy brings a new mechanism of action to the indication as it becomes the first approved treatment to target the IgG autoantibodies thought to drive the disease.
The indication covers wAIHA patients ages 12 and older who are using or have used corticosteroids.
“Living with wAIHA often means relentless fatigue and the constant uncertainty of not knowing what tomorrow will bring,” Karen Jones, President and Executive Director of wAIHA Warriors, said in a release. “Patients may cycle through periods where they start to feel like themselves again—and then their hemoglobin drops, the exhaustion returns, and they’re back to square one.”
Backing the approval are results from a phase 2/3 trial which showed a statistically significant durable red blood-cell count response on J&J's drug. The study, which randomized 115 participants to receive two different doses of Imaavy or placebo, demonstrated that three times as many patients who were infused with a 30 mg/kg dose of Imaavy achieved durable hemoglobin (Hgb) levels versus those on placebo after 24 weeks.
“As the first therapy approved for wAIHA, Imaavy has the potential to redefine the management of wAIHA, particularly for those with uncontrolled disease,” David Lee, M.D., Ph.D., J&J’s Global Immunology Therapeutic Area Head, added in a statement. “This milestone reinforces our motivation to continue pursuing advanced therapies for people living with allo- and autoantibody diseases like wAIHA.”
J&J acquired Imaavy in its $6.5 billion buyout of Momenta Pharmaceuticals in 2020. Five years later, the FDA endorsed it for generalized myasthenia gravis (gMG), as it became the third FcRn blocker to make the grade in the indication. The others were argenx’s blockbuster Vyvgart, which gained its approval in 2021, and UCBs Rystiggo, which scored its FDA nod in 2023.
J&J has yet to divulge sales of Imaavy.The company has tabbed the treatment with peak sales potential of $5 billion or more.
This could be the first of several label expansions for Imaavy as the drug undergoes phase 3 testing for Sjogren’s disease, hemolytic disease of the fetus and newborn and fetal neonatal alloimmune thrombocytopenia. Each of the programs has received FDA fast-track designation.
The company also is investigating Imaavy in chronic inflammatory demyelinating polyneuropathy, systemic lupus erythematosus and idiopathic inflammatory myopathy. In 2024, J&J surrendered its attempt to advance Imaavy as a combination agent in rheumatoid arthritis.