IMAAVY - Occurrence of Hypersensitivity Reactions in Patients with Warm Autoimmune Hemolytic Anemia

SUMMARY

• The company cannot recommend any practices, procedures, or usage of IMAAVY that deviate from the approved labeling.
• In a 24-week, phase 2/3, randomized, double-blind, placebo (PBO)-controlled trial (ENERGY) in adult patients with warm autoimmune hemolytic anemia (wAIHA), hypersensitivity reactions were reported in 5.3%, 8.1%, and 0% of patients in the IMAAVY 30 mg/kg every 4 weeks (Q4W) group, IMAAVY 15 mg/kg every 2 weeks (Q2W) group, and PBO group, respectively.^1,2

CLINICAL DATA

ENERGY Study 

Fattizzo et al (2026)² evaluated the efficacy and safety of IMAAVY in adults with wAIHA in a phase 2/3 multicenter, randomized, double-blind, PBO-controlled study.

Study Design/Methods

• The study included adults (≥18 years of age) diagnosed with primary or secondary wAIHA for ≥3 months, defined as having all of the following:^2,3   
  • Hemoglobin (Hgb) <10 g/dL
  • Signs of hemolysis (lactic dehydrogenase [LDH] >upper limit of normal [ULN], or indirect bilirubin >ULN, or haptoglobin [Hp] <lower limit of normal [LLN])
  • Direct antiglobulin test (DAT) positive for immunoglobulin G (IgG) +/- complement component 3d (C3d)
• The study consisted of a 2-week screening phase, followed by a 24-week, double-blind, PBO-controlled treatment phase, a 144-week open-label extension (OLE) phase, and safety follow-up at 8 weeks after the last infusion.² 
• Eligible patients were randomized (1:1:1) to receive intravenous (IV) IMAAVY 30 mg/kg Q4W, IMAAVY 15 mg/kg Q2W, or matching PBO Q2W through week 24. 
• The safety analysis population included all randomized patients who received any dose of study treatment. This included 3 patients who received IMAAVY 30 mg/kg Q2W; however, this regimen was subsequently discontinued.

Results

Double-Blind Phase

• A total of 117 patients (IMAAVY, n=78; PBO, n=39) were included in the safety analysis dataset.² 
• Hypersensitivity reactions were reported in 5.3% (2/38) of patients in the IMAAVY 30 mg/kg Q4W group, 8.1% (3/37) of patients in the IMAAVY 15 mg/kg Q2W group, and no patients in the PBO group (see Table: Incidence of Hypersensitivity Reactions).¹
• No Grade 3 hypersensitivity reactions were observed and none led to discontinuation of study drug.¹ 

Literature Search

A literature search of MEDLINE^®, EMBASE^®, BIOSIS Previews^®, and DERWENT^® (and/or other resources, including internal/external databases) was conducted on 31 August 2026.