Safety of Biological Therapies for Severe Asthma: An Analysis of Suspected Adverse Reactions Reported in the WHO Pharmacovigilance Database

Background: The management of uncontrolled severe asthma has greatly improved since the advent of novel biologic therapies. Up to August 2022, five biologics have been approved for the type 2 asthma phenotype: anti-IgE (omalizumab), anti-IL5 (mepolizumab, reslizumab, benralizumab), and anti-IL4 (dupilumab) monoclonal antibodies. These drugs are usually well tolerated, although long-term safety information is limited, and some adverse events have not yet been fully characterized. Spontaneous reporting systems represent the cornerstone for the detection of potential signals and evaluation of the real-world safety of all marketed drugs. Objective: The aim of this study was to provide an overview of safety data of biologics for severe asthma using VigiBase, the World Health Organization global pharmacovigilance database. Methods: We selected all de-duplicated individual case safety reports (ICSRs) attributed to five approved biologics for severe asthma in VigiBase, up to 31st August 2022 (omalizumab, mepolizumab, reslizumab, benralizumab and dupilumab). Descriptive frequency analyses of ICSRs were carried out both as a whole class and as individual products. Reporting odds ratios (ROR) with 95% confidence intervals (CIs) were used as the measure of disproportionality for suspected adverse drug reactions (ADRs) associated with the study drugs compared with either all other suspected drugs (Reference Group 1, RG1) or inhaled corticosteroids plus long-acting β-agonists (ICSs/LABAs) (Reference Group 2, RG2) or with oral corticosteroids (OCSs) (Reference Group 3, RG3). Results: Overall, 31,724,381 ICSRs were identified in VigiBase and 167,282 (0.5%) were related to study drugs; the remaining reports were considered as RG1. Stratifying all biologic-related ICSRs by therapeutic indication, around 29.4% (n = 48,440) concerned asthma use; omalizumab was mainly indicated as the suspected drug (n = 20,501), followed by dupilumab, mepolizumab, benralizumab and reslizumab. Most asthma ICSRs concerned adults (57%) and women (64.1%). Asthma biologics showed a higher frequency of serious suspected ADR reporting than RG1 (41.3% vs 32.3%). The most reported suspected ADRs included asthma, dyspnea, product use issue, drug ineffective, cough, headache, fatigue and wheezing. Asthma biologics were disproportionally associated with several unknown or less documented adverse events, such as malignancies, pulmonary embolism and deep vein thrombosis with omalizumab; alopecia and lichen planus with dupilumab; alopecia and herpes infections with mepolizumab; alopecia, herpes zoster and eosinophilic granulomatosis with polyangiitis related to benralizumab; and alopecia with reslizumab. Conclusions: The most frequently reported suspected ADRs of asthma biologics in VigiBase confirmed the presence of well-known adverse effects such as general disorders, injection-site reactions, nasopharyngitis, headache and hypersensitivity, while some others (e.g. asthma reactivation or therapeutic failure) could be ascribed to the indication of use. Moreover, the analysis of signals of disproportionate reporting suggests the presence of malignancies, effects on the cardiovascular system, alopecia and autoimmune conditions, requiring further assessment and investigation.