Long-term follow-up effect of omalizumab in chronic spontaneous urticaria and its association with serum C-reactive protein levels.

This study aims to determine the efficacy of omalizumab, a humanized monoclonal anti-immunoglobulin E antibody, in patients with chronic spontaneous urticaria (CSU) refractory to conventional therapy, together with the evaluation of serum CRP levels. All the patients with a diagnosis of CSU who were continuously treated with omalizumab (300 mg/mo) for at least 3 months between June 2016 and July 2019 were included in this study. Urticaria activity score (UAS-7) was used for assessment of disease activity. Serum CRP levels were also retrospectively analyzed. When UAS-7 scores before the initiation of therapy were compared to the week 4, 12, 24, and 36 scores after the treatment, each were significantly different from the pretreatment results (P < .01). CRP level prior to treatment was found to be strongly correlated with baseline UAS scores of the patients' (P = .00). At the 12th week of treatment, decline of CRP level was positively and strongly correlated with the decline of UAS (P = .037). In this study, mean UAS decreased, mean rescue medication use declined, and overall therapeutic response improved with omalizumab treatment. Additionally, significant correlation between the decline of CRP levels and treatment response was found.