Omalizumab for treatment of idiopathic angioedema

Background: Omalizumab has been found to improve outcomes in patients with chronic spontaneous urticaria (CSU). Idiopathic angioedema (IAE) is increasingly being recognized as a condition with similar underlying mechanisms as CSU and a form of CSU. We hypothesized that add-on therapy with omalizumab would benefit patients with uncontrolled IAE.

Objective: To study the safety and efficacy of omalizumab for the treatment of IAE in adults.

Methods: We conducted a randomized, placebo-controlled trial to study the efficacy of omalizumab in adults with 2 or more episodes of angioedema (AE) in the past 6 months for which no clinical or laboratory cause of AE could be found. A total of 10 patients were randomized on a 1:1 basis to receive omalizumab 300 mg subcutaneously or placebo every 4 weeks for 24 weeks with a 12-week follow-up period. The primary endpoint was the change in the Angioedema Activity Score. Secondary endpoints included the Angioedema Quality of Life Questionnaire, the Visual Analogue Scale, and the number of angioedema episodes per month.

Results: We observed improvement in the Angioedema Activity Score (-2.93 ln odds; 95% confidence interval [CI], -4.84 to -1.02; P = .003), Visual Analogue Scale (-3.49 ln odds; 95% CI, -6.58 to -0.40; P = .03), Angioedema Quality of Life Questionnaire (-9.43 score; 95% CI, -17.63 to -1.24; P = .03), and number of angioedema episodes per month (-1.93 ln count; 95% CI, -3.23 to -0.63; P = .005) in patients who received omalizumab vs placebo.

Conclusion: This study provides preliminary prospective evidence that omalizumab improves outcomes in patients with IAE.

Trial registration: ClinicalTrials.gov Identifier: NCT02966314.

Clinicaltrials: gov URL:https://clinicaltrials.gov/ct2/show/NCT02966314?term=omalizumab&cond=Angioedema&draw=2&rank=1.