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Omalizumab therapy reduced symptoms of chronic idiopathic urticaria

Patients with chronic idiopathic urticaria who remained symptomatic despite using approved doses of antihistamines had diminished symptoms after treatment with omalizumab, according to recent study results.

In a phase 3, multicenter, double blind study, researchers evaluated 323 patients (mean age, 42.5 years; 76% women) with moderate-to-severe chronic idiopathic urticaria who maintained symptoms after undergoing H₁-antihistamine therapy. Patients were randomly assigned to receive three subcutaneous injections of omalizumab at 75 mg (n=82), 150 mg (n=83) or 300 mg (n= 79) or placebo (n=79) at 4-week intervals. A 16-week observation period followed. Change from baseline in a weekly itch-severity score (ranging from 0 to 21, with larger scores indicating greater itching) was the primary efficacy outcome.

Each group recorded a baseline weekly itch-severity score between 14.2 and 13.7. Changes from baseline in weekly itch-severity scores at week 12 showed improvement in the 150-mg (–8.1 ± 6.4; P=.001) and 300-mg omalizumab groups (–9.8 ± 6.0; P<.001), but not among 75-mg omalizumab patients (–5. 9 ± 6.5; P=.46) when compared with placebo (–5.1 ± 5.6).

Similar dose-dependent effects were shown for most secondary outcomes. All patients experienced similar frequency of adverse events. While the serious adverse event frequency was low, patients assigned 300 mg omalizumab had a higher rate (6%) than the placebo (3%), 75-mg and 150-mg omalizumab groups (1% each).

“During the initial 12 weeks, omalizumab at doses of 150 mg and 300 mg significantly improved outcomes as reported by patients with chronic idiopathic urticaria who remained symptomatic despite the use of approved doses of H₁-antihistamines,” the researchers concluded. “The number of patients who were treated was too small to draw any definitive safety conclusions, but serious adverse events were more common in the group treated with the highest doses of omalizumab.

“Further work is needed before the exact role of omalizumab in the treatment of chronic idiopathic or spontaneous urticaria can be defined.”

Disclosure: See the study for a full list of relevant disclosures.