TOPLINE:

Intracellular histamine content of basophils did not distinguish among rapid, delayed, and late or no responses to omalizumab in patients with chronic spontaneous urticaria (CSU), nor did it predict the treatment duration.

METHODOLOGY:

• Researchers assessed whether the intracellular histamine content of basophils could serve as a biomarker to predict and monitor response to omalizumab treatment in patients with CSU.
• A total of 164 adults with CSU (median age, 32 years, 67.7% female) who had total cellular blood histamine levels measured were included; 106 patients initiated omalizumab treatment, of whom 101 were omalizumab-naive at baseline and were analyzed for treatment response patterns.
• The investigators classified treatment responses as fast (within 1 month), delayed (within 3 months), or late (after 3 months).

TAKEAWAY:

• Intracellular histamine content per basophil did not differ among patients with fast (n = 44), delayed (n = 36), and late or no (n = 17) response to omalizumab treatment.
• Histamine content did not significantly differ between patients with a good overall response to treatment (n = 62), a partial response (n = 28), or a poor or no response (n = 7).
• No statistically significant link was observed between treatment duration and intracellular histamine content per basophil.

IN PRACTICE:

“While our study confirms that intracellular histamine content per basophil is associated with features of type IIb CSU, it also demonstrates that this biomarker is not suitable for predicting omalizumab treatment response, long-term dosing requirements, or drug survival,” the authors of the study wrote.

SOURCE:

Ditte Georgina Zhang, MD, PhD, Bispebjerg Hospital, Copenhagen, Denmark, was the corresponding author of the research letter, which was published online on April 26 in Clinical & Experimental Allergy.

LIMITATIONS:

Some of the estimates were based on relatively small subgroups, which may limit their statistical power and precision.

DISCLOSURES:

One author reported being the founder and scientific advisor of RefLab ApS, and another author reported employment with the laboratory. Several authors reported serving as speakers or consultants for pharmaceutical companies and receiving research support from them.

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