Background Omalizumab is a recombinant humanised monoclonal antibody that suppresses allergen-mediated skin reactions through its block of the IgE receptor in basophils and mast cells. It is used in patients with chronic idiopathic urticaria who remain symptomatic despite antihistamine treatment.
Purpose To assess the effectiveness and safety of omalizumab in chronic idiopathic urticaria in clinical practice.
Material and methods A descriptive retrospective study was conducted. Patients treated with omalizumab for more than 6 months between 1 January 2014 and 31 March 2018 were included. Electronic clinical history and the prescription program Farmatools® were used to record the following: sex, age, previous treatment, dosage, number of doses received, duration of treatment and time until relapse. Effectiveness was measured by urticaria activity score during a 7 day period (UAS7). UAS7 ≤6 after 6 months of treatment was considered effective. Relapse was defined as loss of effectiveness. Safety was evaluated according to the adverse effects (AE) profile.
Results During the study period, 32 patients were included, eight were male (25%)and 24 were female (75%). Mean age was 45 (18–79) years. Previous treatment consisted of antihistamines in 10 (31%) patients, antihistamines+corticoids in nine (28%), and antihistamines+corticoids+ antileukotrienes in 11 (34%). The initial UAS7 was >15 in all patients, and in 11 (34%) cases it was >25. Effectiveness was not evaluated in two patients due to lack of information. Initially all patients received 300 mg of omalizumab once a month for 6 months, and after this time 26 (81%) patients achieved a UAS7 ≤6. Nineteen (59%) patients relapsed after a mean time of 4 (1–14) months, and received a 6 month retreatment. After retreatment 12 (38%) patients reached UAS7 ≤6. Subsequent maintenance was required in 14 (44%) patients, with a dose of 300 mg in six (19%) patients and 150 mg in eight (25%). After 6 months of maintenance treatment UAS7 was ≤6 in 10 (31%) patients. In four (12%) cases UAS7 was never ≤6, and no AE were reported during the treatment.
Conclusion Omalizumab was effective in most cases after a 6 month treatment, but more than a half of the patients required retreatment. Maintenance with lower doses was used in a considerable percentage of patients. Tolerance was excellent, without AE being found.
References and/or acknowledgements No conflict of interest.