Lower efficacy of omalizumab in older adults with chronic spontaneous urticaria

Omalizumab is known to be effective in treating chronic spontaneous urticaria (CSU) with an inadequate response to H₁ -antihistamine. Although many reports have described pre-treatment biomarkers to predict the efficacy of omalizumab in CSU, there are few reports that examined the relationship between age and the therapeutic effectiveness of omalizumab. Thus, we aimed to investigate the relationship between response to omalizumab and age. This retrospective study comprised 52 CSU patients receiving three consecutive omalizumab courses during the period from April 2017 to March 2021. Participants were categorized as responders or non/partial responders using the urticaria control test to evaluate clinical variables on week 12. The female rate tended to be higher, and the mean age and the median disease duration tended to be lower with no significance in responders compared with in non/partial responders. In addition, they exhibited no significant differences regarding serum immunoglobulin E levels, basophil counts, eosinophil counts, d-dimer, and autologous serum skin test results reported as predictor in the past between two groups. Interestingly, when patients were categorized as age <65 years or ≥65 years, those in the ≥65 years group had a significantly lower response to omalizumab than those aged <65 years. These findings suggest that physicians should keep in mind that the age of their CSU patients may be a predictor of the therapeutic efficacy of omalizumab.