Comparison of long term efficacy and cost-effectiveness of omalizumab in 150 mg and 300 mg doses in patients with chronic spontaneous urticaria.

Background: Chronic spontaneous urticaria (CSU) is a clinical condition that affects patients quality of life. Omalizumab is preferred in antihistamines resistant CSU cases. Urticaria activity score-7 (UAS-7) is a scale that shows the severity of the disease.

Objectives: The authors aimed to compare the long-term (60 months) efficacy and side effects of 150 mg and 300 mg doses of omalizumab in patients with CSU.

Methods: 108 patients followed up at the clinic with the diagnosis of CSU were included. Omalizumab was started in patients who were resistant to conventional CSU treatment. Two groups were formed to receive 150 mg and 300 mg doses of omalizumab. Urticaria activity score (UAS-7), antihistamine usage, time to achieve disease-free stage, relapse after treatment, and side effects of omalizumab treatment were compared in the two groups.

Results: There were no statistically significant differences between the groups regarding basal characteristics and laboratory findings. Average follow-up time was sixty months. UAS-7 scores were similar in the follow-up. There were no adverse events in both groups.

Study limitations: Retroactive design and single-center nature to reach a more significant number of patients. Lack of patients receiving the lowest dose 75 mg and the highest dose 600 mg of omalizumab. Absence of total body mass indexes of all patients. Besides, the use of distinct drugs may contribute to non confident results and is another limitation of this study.

Conclusion: Since there is no significant difference between 150-300 mg omalizumab doses regarding long-term treatment efficacy and side effects in CSU patients, starting treatment with a 150 mg dose may be suitable. In patients who do not respond to 150 mg, the omalizumab dose can be increased to 300 mg. It will prevent unpredictable dose and time-dependent complications and will be a cost-effective approach even in strong economies.