(248) Surveillance of outcomes identified with use of biologics indicated for asthma: a comparison of events observed with pediatric utilization

Background: Atopic conditions such as asthma and atopic dermatitis affect many children worldwide. The introduction of several new biologic medications offer an effective alternative particularly for those with moderate to severe conditions or those with concurrent atopic conditions. Early detection of potential adverse events in pediatric patients is important to define the safety profile of these agents in younger populations.

Objectives: To describe the pattern of adverse events associated with new initiation of biologic therapies with an indication for an atopic condition in patients <18 years old.

Methods: This study was conducted using Merative MarketScan claims data from October 1, 2016 to June 30, 2023. Patients were included if they were 2 to <18 years old with ≥1 dispensing or administration of the following biologics: omalizumab, dupilumab, or mepolizumab, reslizumab, benralizumab (anti-IL5) identified by National Drug Codes (NDC) on pharmacy dispensing claims or Healthcare Common Procedure Coding System (HCPCS) codes in medical claims. Patients were required to be (1) new users (defined as no prior exposure to a biologic) in the 6 months before first dispensing or administration, with (2) up to 183 days continuous healthcare enrollment after index date. Using a hierarchical tree of ICD-10-CM diagnosis codes, we measured thousands of possible outcomes observed in all healthcare settings in 3 time periods ranging from 1 to 28, 56 and183 days after cohort entry. Outcome codes were required to be the first in 400 days without a similar outcome occurring, defined as sharing the first 3 digits of the ICD tree. Outcomes associated with conditions related to pregnancy and the perinatal period, external causes of morbidity, factors indicating health status or contact with a healthcare service, and age-related comorbidities were excluded.

Results: There were 4271,1175, and 185 patients with new use of dupilumab, omalizumab and anti-IL-5 biologics respectively. Mean (±SD) age of users for each group was 12.9 (±3.9) years for dupilumab, 13.7(±3.1) for omalizumab, and 13.8 (±2.9) for anti-IL5. There were 2.1 outcomes/user for dupilumab (9173/4271) , 3.4 outcomes/user observed for omalizumab (3972/1175) and 3.8 outcomes/user (709/185) for anti-IL5. Time to event of an outcome in users were similar across the 3 groups (median=93 to 96, IQR=45-139). Short-term outcomes (day 1-30 after index date) for omalizumab users include acute pharyngitis (1.8%), idiopathic urticaria (1.6%) and fever (1.5%). Among dupilumab users, dermatitis (1.4%), acute pharyngitis (1.4%), acute upper respiratory infection (1.1%) were the most frequently observed. In users of anti-IL5, allergic rhinitis (2.8%), pulmonary eosinophilia (2.8%) and non-infective gastroenteritis (2.8%) were the most common outcomes observed.

Conclusion: We observed slight differences in the type and onset of outcomes in pediatric patients using a biologic for atopic conditions with half of these outcomes occurring 3 months after initiation. Next, we will supplement our results with data from publicly insured patients and execute tree-based scan statistics.