Funding: This study was endorsed by the Asthma Research Program of the Spanish Respiratory Society (PII de Asma de SEPAR) supported by a grant from Teva Pharmaceutical Industries.Background: Patients with severe allergic and eosinophilic asthma could qualify for different biologic therapies. Objective: To evaluate the efficacy and safety of weight-based intravenous reslizumab dosing in patients who have previously failed therapy with omalizumab. Methods: We carried out a 24-week prospective, multicenter, open-label, single-group, self-controlled study in patients with severe eosinophilic asthma who had previously failed to respond to omalizumab. The main objective was to determine whether treatment with reslizumab significantly improved asthma symptoms assessed by the Asthma Control Test (ACT) at week 24. Secondary objectives were to evaluate symptoms at weeks 4 and 12, change in FEV at week 24, and the incidence of severe exacerbations over the study period. Results: Twenty-nine patients (62.1% women, median age, 50.8 years) were included in the study. The median ACT score significantly increased from 13.0 (interquartile range, 8.0-18.0) at baseline to 21.0 (interquartile range, 14.0-24.0) at 24 weeks (P =.002). Only 2 of 29 patients developed at least 1 severe exacerbation during follow-up and none of them required hospitalization. Overall, 15 of 25 patients (60%) were considered as being controlled (ACT score of ≥20 and no exacerbations) at week 24. The percentage of patients who were receiving daily systemic corticosteroids significantly decreased from 72.4% to 52.0% (P =.019). Adverse events were mostly moderate and within the range of previously reported side effects with reslizumab. Conclusion: Reslizumab is an effective and safe option for patients with severe eosinophilic asthma and a history of omalizumab failure
