Omalizumab Linked to Greatest Rate of Hypersensitivity Reactions in Atopic Diseases

A retrospective cohort study, presented at the 2025 American Academy of Allergy, Asthma, & Immunology (AAAAI) annual meeting in San Diego from February 28 – March 3, reported the severity and the prevalence of hypersensitivity reactions to specific biologics for atopic diseases.1

Biologics have transformed the treatment of allergic conditions, yet they carry a risk of hypersensitivity reactions. Investigators aimed to report the types and outcomes of hypersensitivity reactions to biologics for atopic diseases at a tertiary care center. The team used descriptive and comparative analyses to identify patterns and risk factors.

In their retrospective review of Mayo Clinic Health System records from January 2009 to August 2024, investigators, led by Valerie Jaroenpuntaruk, MD, from the Mayo Clinic, identified 65 patients using the term “anaphylaxis” in the “allergies/contraindications” section related to biologics. As a result, all patients had hypersensitivity reactions to biologics—and 2 patients (3%) reacted to multiple biologics. The biologics examined included benralizumab, dupilumab, mepolizumab, omalizumab, reslizumab, and tezepelumab.

Other than biologic administration, investigators collected data on patient demographics, reaction types, severity, and outcomes. The sample, including 60 females, had a mean age of 45.2 years. Most patients (74%) had ≥ 1 atopic condition, and patients had a mean of 16.7 documented allergies each, such as regarding drugs, foods, and aeroallergens.

Patients were prescribed biologics to manage symptoms of asthma, chronic urticaria, atopic dermatitis, idiopathic anaphylaxis, chronic rhinosinusitis with nasal polyps, eosinophilic esophagitis, and mast cell disorders. Omalizumab was associated with the most frequent reactions (n = 44), followed by dupilumab (N = 15), benralizumab (n = 6), mepolizumab (n = 3), and tezepelumab (n = 1). Ironically, last February the US Food and Drug Administration approved omalizumab to reduce allergic reactions in patients with ≥ 1 food allergy.2

The hypersensitivity reactions were classified as allergic (n = 54) or non-allergic reactions (n = 15). Allergic reactions either occurred immediately (n = 33), were possible anaphylaxis (n = 11), delayed (n = 11), or unknown (n = 10).1

The study found hypersensitive reactions led to many biologic discontinuations. However, 6 patients tried and tolerated other biologics.

“Hypersensitivity reactions to biologics for atopic diseases vary in type and severity,” investigators concluded. “Understanding these reactions helps manage and prevent adverse events. Further research is needed to enhance patient safety.”

References

1. Jaroenpuntaruk, V, Sitek, A, Pongdee, T, et al. Hypersensitivity Reactions to Biologics for Atopic Diseases: A Retrospective Cohort Study. Poster presented the AAAAI 2025 annual meeting in San Diego from February 28 – March 3.

2. Fitch, J. FDA approves omalizumab to reduce allergic reactions in patients with 1 or more food allergies. Contemporary Pediatrics. February 16, 2024. https://www.contemporarypediatrics.com/view/fda-approves-omalizumab-reduce-allergic-reactions-patients-1-more-food-allergies. Accessed February 20, 2025.