Key Summary:
- FDA approves Imaavy for warm autoimmune haemolytic anaemia.
- Imaavy shows a higher haemoglobin response than placebo.
- J&J now testing the drug in several other autoimmune diseases.
Patients with a rare and potentially life-threatening blood disorder now have an FDA-approved treatment for the first time.
The US regulator has cleared Johnson & Johnson’s Imaavy (nipocalimab) for warm autoimmune haemolytic anaemia, or wAIHA, in patients aged 12 and older who are using or have used corticosteroids.
The decision gives J&J its first label expansion for Imaavy, 16 months after the drug was approved for generalised myasthenia gravis.
J&J acquired Imaavy when it bought Momenta in 2020, with nipocalimab as the key asset in a deal worth $6.5bn.
What is wAIHA?
wAIHA occurs when the immune system produces IgG antibodies that attack and destroy red blood cells.
Patients can develop severe anaemia and debilitating fatigue, while the disease can flare repeatedly and send haemoglobin levels back down after treatment.
There has been no FDA-approved therapy specifically for wAIHA, so doctors have instead relied on corticosteroids and other immune-suppressing medicines, including rituximab.
Imaavy works further upstream by blocking the neonatal Fc receptor, or FcRn, which helps recycle IgG antibodies and keep them in the bloodstream.
Blocking FcRn reduces those antibody levels, including the harmful IgG involved in wAIHA.
What the trial showed
The approval was based on the Phase 2/3 ENERGY study, which enrolled 118 patients.
At the approved 30 mg/kg dose, 24% of patients achieved a durable haemoglobin response at week 24, compared with 8% on placebo. The lower 15 mg/kg dose did not show a significant benefit over placebo.
The drug also acted quickly, with J&J reporting a mean haemoglobin increase of 1 g/dL by week one. Patients on the 30 mg/kg dose also reported an improvement in fatigue by week 24.
That combination of a sustained blood response and improved fatigue is important in a disease where symptoms can return as haemoglobin falls.
“Patients with wAIHA have been waiting for a treatment that can address the underlying cause of their disease,” said Dr David Kuter, a lead investigator in the trial.
More to come?
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