Chiang Mai, Thailand—Patients with chronic spontaneous urticaria (CSU), which presents with hives and/or angioedema lasting more than 6 weeks but without any known cause, are usually desperate for help. The unpredictable nature of the condition makes it hard to keep up with work or school, and quality of life often is diminished.

Yet less than half of patients receive adequate treatment with licensed doses of second-generation H1 antihistamines, according to a study in JAMA Dermatology.

That’s why Thai pharmacist researchers from Chiang Mai University set out to gauge the comparative benefits and harms of all available pharmacologic treatments for H1 antihistamine–refractory CSU.

In their network meta-analysis of 23 randomized clinical trials, which included 2,480 participants, the biologic agent ligelizumab 72 or 240 mg had the largest beneficial effect, while another biological agent, omalizumab at 300 or 600 mg, had moderate beneficial effect. Although the beneficial effects were somewhat smaller, researchers also suggest that dapsone, hydroxychloroquine, cyclosporine, and zafirlukast can be used.

For the meta-analysis, searches were conducted of MEDLINE, Embase, PubMed, Cochrane Library, Web of Science, Scopus, and CINAHL from inception to April 19, 2021, with no language restrictions. The study team also added gray literature from Google Scholar, ongoing trial registers, and preprint reports to the searches of electronic databases.

Considered for inclusion were randomized clinical trials using validated measurement tools that investigated the benefits and harms of pharmacologic treatments among adolescent or adult patients with CSU who had an inadequate response to H1 antihistamines. Two investigators screened each study independently and extracted study data according to the predefined list of interests.

Researchers focused on changes in urticaria symptoms from baseline and unacceptability of treatment, based on how many patients dropped out of the trial.

Ultimately, the analysis included 23 randomized clinical trials with 2,480 participants that compared 18 different interventions or dosages and placebo.

Standardized mean differences for change in urticaria symptoms were:
• −1.05 (95% CI, −1.37 to −0.73) for ligelizumab 72 mg
• −1.07 (95% CI, −1.39 to −0.75) for ligelizumab 240 mg
• −0.77 (95% CI, −0.91 to −0.63) for omalizumab 300 mg
• −0.59 (95% CI, −1.10 to −0.08) for omalizuma, 600 mg

“No significant differences in treatment unacceptability were observed,” the authors write. “With respect to benefits and harms, the network estimates illustrated that the most efficacious treatments were achieved with ligelizumab, 72 or 240 mg (large beneficial effect) and omalizumab, 300 or 600 mg (moderate beneficial effect).”

The researchers add, “Head-to-head trials with high methodologic quality and harmonized design and outcome definitions are needed to help inform subsequent international guidelines for the management of CSU.”

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