Adverse Event Profiles of Monoclonal Antibodies: A Descriptive Analysis of FAERS Data.

Introduction: Monoclonal antibodies (mAbs) are bioengineered molecules designed to replicate the immune system's precise targeting of pathogens and abnormal cells. While monoclonal antibodies (mAbs) are targeted therapies, they carry risks like immunogenic reactions and drug interactions. Objective: The current study utilizes FAERS to describe the distribution of reported adverse events, patient demographics, and reporting patterns associated with selected monoclonal antibody therapies. Methods: The analysis included all monoclonal antibody adverse event reports in FAERS through March 31, 2025, with subsequent reports and non-monoclonal antibody drugs excluded, and utilized descriptive statistics to present results as numbers and percentages. Results: FAERS data through March 31, 2025, for 18 monoclonal antibodies showed distinct adverse event (AE) patterns. Most AEs occurred in adults aged 18-64, with females reporting more events except for cancer-related mAbs such as cetuximab (67.09% males) and ipilimumab (64.15% males). Healthcare professionals were the primary reporters, though some drugs-like adalimumab (72.13%)-had mainly consumer reports. Common AEs included injection-site pain (7.44%), rash, in addition to reports categorized as "drug ineffective," a MedDRA preferred term used in FAERS to reflect reporter perception of treatment failure (e.g., 17.96% for secukinumab; 28.14% for tocilizumab). Conclusion: The most frequently reported events included treatment-ineffectiveness perceptions and administration issues, which warrant further investigation in controlled studies. Some reports included product use issues such as dose omission or incorrect administration. However, due to the spontaneous reporting nature of FAERS, the relationship between adherence-related issues and clinical outcomes cannot be definitively established. The findings of the study describe reporting patterns in FAERS and may serve as a basis for future pharmacovigilance or epidemiologic research.