The FDA has approved omalizumab (Xolair) for treatment of chronic idiopathic urticaria, drugmaker Genentech announced Friday.
The indication granted in this type of hives, which last more than 6 weeks, was for people 12 and older whose symptoms don't clear up with H1-antihistamine therapy.
Omalizumab, an anti-immunoglobulin E antibody, is the first biologic approved in chronic idiopathic urticaria.
Approval was based on the pivotal phase III trials ASTERIA I and II, which randomized patients to 75, 150, or 300 mg of omalizumab or placebo for 24 and 12 weeks, respectively, atop their established H1-antihistamine regimen.
For the primary endpoints in ASTERIA I, average Itch Severity Scores at week 12 fell by a mean 6.7 points on the intermediate dose and by 9.4 on the highest dose compared with a 3.6 point reduction with placebo (47%, 66%, and 25% reductions, respectively, both P<0.0001).
Substantially more patients on omalizumab had complete resolution of hives and itch at week 12 as with placebo (36% at 300 mg and 15% at 150 mg versus 9%).
Similar results emerged in the ASTERIA II study.
The lowest dose was significantly better than placebo in one trial but not the other and wasn't approved by the FDA.
A third phase III had also been done with similar effects sustained to week 24.
Although the trials dosed the drug once every 4 weeks for 12 or 24 weeks, "the appropriate duration has not been established," Genentech spokesperson Allison Neves told MedPage Today.
"Doctors are being advised to periodically reassess the need for continued therapy," she said.
The most common side effects of the drug across studies were nausea, headaches, swelling of the inside of the nose, throat, or sinuses, cough, joint pain, and upper respiratory tract infection.
The company also warned about a risk of anaphylaxis, which can occur upon injection or days later and with the first dose or after many doses.
Genentech is jointly developing and marketing omalizumab with Novartis.