Johnson & Johnson is presenting the first comprehensive results from the phase 2/3 ‘energy’ study showing that Imaavy (nipocalimab-aahu) produced a statistically significant durable haemoglobin (Hgb) response with rapid onset of effect in patients with warm autoimmune haemolytic anaemia (wAIHA) in the 30 mg/kg treatment group, compared with those who received placebo.
The randomised, placebo-controlled trial demonstrated approximately three times as many patients achieved durable Hgb levels versus placebo by 24 weeks. Overall, patients treated with this dose of Imaavy showed a mean Hgb improvement of at least 1g/dL as early as week 1.
To be presented at the European Hematology Association (EHA) 2026 Congress, these results mark an important step forward for people living with wAIHA, a rare, life-threatening condition for which patients currently have no US Food and Drug Administration (FDA)-approved treatment options.
Key findings from the phase 2/3 study
The study compared Imaavy to placebo in achieving the primary endpoint of durable Hgb improvement, which was defined as achieving the following stringent criteria:
- An increase from baseline in Hgb ≥2 g/dL
- Hgb concentration ≥10 g/dL
- For at least three visits (≥28 days, where criteria was met, starting by week 16)
- Without the need for rescue therapy or changes to background medications for wAIHA.
In the 30 mg/kg treatment group, a mean increase of 1 g/dL in Hgb was observed at week 1, compared to no change in the placebo group. In wAIHA, treatment also aims to maintain Hgb ≥10 g/dL and achieve a ≥2 g/dL increase from baseline and nearly two-thirds of patients achieved both of these targets by week 24.
Imaavy was also associated with improvements in fatigued and reduction in steroid use, two key secondary endpoints. Changes in patient-reported fatigue were observed as early as week 2 and sustained throughout the 24-week treatment period.
In the study, Imaavy demonstrated a safety profile consistent with the established safety profile of Imaavy in the approved indication of generalised myasthenia gravis. The most common adverse reactions (≥10%) in patients with wAIHA treated with Imaavy were peripheral oedema, diarrhoea and fever.
By targeting the pathogenic IgG autoantibodies that lead to red blood cell destruction in wAIHA, Imaavy is designed to utilise a differentiated, immunoselective approach, preserving underlying key humoral immune functions in a condition where many patients currently can only rely on unapproved therapies, including corticosteroids and broad immunosuppressants.
