TOPLINE:

The presence of a positive chronic urticaria index, low blood histamine content, or both low immunoglobulin (Ig) E content and low blood histamine content in patients with chronic spontaneous urticaria (CSU) was associated with an increased likelihood of nonresponse to omalizumab at 12 weeks. Among patients with all three negative biopredictors, 69% had poor symptom control.

METHODOLOGY:

• Researchers conducted a retrospective analysis of three randomized phase 3 trials (ASTERIA I, ASTERIA II, AND GLACIAL) to assess how baseline biopredictors such as the chronic urticaria index, IgE content, and blood histamine content affected response to omalizumab in patients with CSU who did not respond to antihistamines.
• They analyzed 363 patients (mean age, 43 years; 75% female) who received 300 mg of omalizumab subcutaneously every 4 weeks for 12 weeks.
• Participants were evaluated using the Urticaria Activity Score over 7 days (UAS7), and treatment responses were categorized on the basis of symptom control: complete (UAS7 = 0), well controlled (UAS7 ≤ 6), or poorly controlled (UAS7 > 6).

TAKEAWAY:

• A positive chronic urticaria index was associated with higher odds of nonresponse at 12 weeks (adjusted odds ratio, 2.54; P = .0002).
• A blood histamine content value ≤ 6.4 ng/mL was associated with nonresponse (area under the curve, 0.59; P < .012).
• In patients with low baseline IgE content, low blood histamine content was a predictor of nonresponse to omalizumab (P = .04).
• At 12 weeks, 69% of patients with all three negative biopredictors had UAS7 > 6, whereas 70% of patients without those biopredictors achieved UAS7 ≤ 6 (P = .0001).

IN PRACTICE:

“Although some patients with negative biomarkers may still respond, these biomarkers provide useful context for guiding shared therapeutic decision-making with patients, particularly as new therapeutic options continue to emerge,” the authors of the study wrote.

SOURCE:

Sarbjit S. Saini, MD, Johns Hopkins University School of Medicine, Baltimore, was the corresponding author of the study, which was published online on November 28 in the Journal of Allergy and Clinical Immunology.

LIMITATIONS:

The study was limited by variation in background antihistamine therapy across trials, which may have confounded associations; the lack of data on omalizumab updosing, which prevented the assessment of higher‑dose efficacy or predictors of response to updosing; and the use of UAS7 ≤ 6 (rather than UAS7 = 0) combined with overlapping baseline biopredictors, which may have overstated clinical control and hindered the determination of the independent predictive value.

DISCLOSURES:

The authors declared having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.