Predictability of serious adverse reaction alerts for monoclonal antibodies

Objective: We analyzed the predictability of the United States Food and Drug Administration's Medwatch safety alerts on monoclonal antibodies with the aim of assessing the adequacy of their pre-approval safety evaluation. Methods: An alert was considered observed when increased frequency, severity, or other new properties were reported for previously identified suspected adverse reactions. Results: Up until January 2010, 36 safety alerts to mAbs were issued containing 61 alert terms. Just above a half (32) of the alert terms were assessed as observed. Discussion: In addition to the observed reactions, a large proportion of unobserved reactions could have been predicted based on the mechanism of action and antibody target. Although retrospective assessment necessarily implies an element of subjectivity, there appears to be room for improvement in predicting adverse reactions to mAbs. Conclusions: Adverse reaction risk management and pharmaceutical care must focus on the observed reactions, but all effort should be made to extrapolate from the observed reactions to predict further safety issues. This should be taken into account by marketing authorization holders, prescribers, clinical trial sponsors, investigators and regulators.