Background and importance Severe uncontrolled asthma is characterised by poor control despite treatment with inhaled glucocorticoids (IGC) and beta₂ adrenergic agonists (LABA) at high doses, and/or oral glucocorticoids (OGC). This type of asthma comprises a heterogeneous group of phenotypes treated with targeted therapy. Anti-IL-5 monoclonal antibodies (mepolizumab, reslizumab and benralizumab) are indicated in severe eosinophilic asthma (SEA).

Aim and objectives To assess the effectiveness and safety of anti-IL-5 biologic agents in a tertiary level hospital.

Material and methods This retrospective observational study included patients with SEA receiving treatment with anti-IL-5 agents from June 2017 to August 2019. Electronic clinical records were used to obtain sociodemographic variables (age, sex, concomitant medicines and previous biologicals), effectiveness (reduction in eosinophil blood levels, change in levels of exhaled nitric oxide (FeNO), forced expiratory volume in 1 s (FEV₁) and score in the asthma control test (ACT)) and safety (reported adverse effects).

Results Thirty-four patients were included, 67.6% (23) women, and mean age was 56.2 (41–69) years. Twenty patients received mepolizumab with an average duration of 40 weeks, 4 reslizumab for 27.7 weeks and 9 benralizumab for 19.9 weeks. A total of 56% of patients were diagnosed with SEA and 44% had a mixed eosinophilic–allergic phenotype. All patients received IGC+LABA at high doses. Thirteen patients were taking montelukast and two OGC at low doses; 53% (18) had received omalizumab previously.

Regarding effectiveness, mepolizumab decreased eosinophils from 840.6 (400–2012) to 143.75 (0–500) cells/µl, FeNO decreased to 17.14 (0–89) ppb, FEV₁ improved to 0.325 mL (0.12–0.65) and ACT improved to 6 points (2–9). With reslizumab, eosinophils decreased from 420 (100–1000) to 50 (0–100) cells/µl, FeNO decreased to 24.5 (0–35) ppb, FEV₁ improved to 0.4 mL (0.17–0.45) and ACT improved to 4 points (2–6). Benralizumab decreased eosinophils from 622.2 (0–1900) to 66.6 (0–600) cells/µL, FeNO decreased to 22.6 (0–43) ppb, FEV₁ improved to 0.36 mL (0.07–0.84) and ACT improved to 2.4 points (0–6). Two patients (10%) who received mepolizumab developed respiratory infection and one patient (5%) developed back pain. With benralizumab, two patients developed myalgias (22.2%) and one patient (11.1%) had diarrhoea.

Conclusion and relevance In conclusion, anti-IL-5 therapy was effective and safe. Adequate monitoring is needed to optimise treatment.

References and/or acknowledgements No conflict of interest.