Adverse Event Profiles of Adalimumab in Children: A Disproportionality Analysis

Adalimumab has been approved by the U.S. Food and Drug Administration (FDA) for the treatment of adult rheumatoid arthritis (RA), and subsequently approved for pediatric treatment of various autoimmune diseases in children of different ages. Due to genetic differences between children and adults in terms of physiology and immunity, there is a need to explore the safety of adalimumab in children in the real world. The aim of this study is to identify potential adverse event (AE) signals associated with the use of adalimumab in pediatric patients (<18 years old) using data from the FDA Adverse Event Reporting System (FAERS).

AEs associated with adalimumab in pediatric patients reported in the FAERS database from the first quarter (Q1) of 2017 to the third quarter (Q3) of 2022 were systematically gathered. Reporting odds ratio (ROR), the proportional reporting ratio (PRR), the information component (IC), and the empirical Bayes geometric mean (EBGM) were used to assess the relationship between adalimumab and AEs in children.

Out of 8,363,304 reports collected from the FAERS database during the study period, 3819 reports on children on adalimumab were identified. Adalimumab-related AEs reports were concentrated on 10 toxicity areas and a total of 202 positive signals were detected, of which injection site papule (ROR = 261.97) and intestinal fistula (ROR = 122.09) had the strongest signals. Unexpected significant AEs, including intestinal obstruction, immunodeficiency, abdominal abscess, and Takayasu's arteritis might also occur. In comparison with patients of all ages in the same time window, the median onset time of children was shorter (99 vs. 149 days). Most of the AE cases occurred in children within the first 1 (1.71%), 2 (8.12%), and 3 months (8.39%) and had early failure types after adalimumab initiation. Methotrexate, folic acid, prednisone, azathioprine, and mesalamine were the top five drugs used concomitantly for adalimumab-associated AEs.

When adalimumab is used in children, especially in the first 3 months of treatment, in addition to the AEs recorded in the drug package insert, close attention should be paid to the new potential AEs off-label to ensure the safety of adalimumab in children.