Omalizumab is a high-cost therapy recommended for the treatment of severe allergic asthma. This study aimed to find clinical parameters that are related to the sustained response to omalizumab. This retrospective, real-life, 4-year follow-up was provided in Poland between March 2013 and May 2019. The success of omalizumab was assessed based on composed subjective and objective criteria. Simple (multiple) regression analyses were performed to search for predictors of the response to omalizumab.

In total, 989 severe allergic asthma patients were referred for omalizumab therapy, of whom 854 patients were considered eligible for treatment. At weeks 16 and 52, omalizumab was successful in 84% and 91% of patients, respectively. Treatment effectiveness was maintained up to the 4-year follow-up. Four predictors of the response to omalizumab were found at week 16 and two at week 52. The results at week 16 may be used as predictors of success at week 52 based on the model, including baseline FEV1% and change in ACQ-7 and miniAQLQ score at week 16: the area under the ROC curve equals 0.746.

Omalizumab therapy is effective, with this efficacy sustained after four years of treatment. The therapy’s success can be predicted from the baseline FEV1% and clinical improvement (based on ACQ-7 and miniAQLQ scores) at week 16.