IntroductionThe most commonly reported adverse event, based on frequency of Medical Dictionary for Regulatory Activities (MedDRA) preferred terms (PTs), in the US FDA Adverse Event Reporting System (FAERS) database is “drug ineffective” (DI). This study aimed to describe the DI reports and provide data to support recommendations on how to best evaluate these reports.MethodsWe characterized all FAERS reports coded with the MedDRA PT “drug ineffective” received between 1 September 2012 and 31 August 2016 using all other FAERS reports as a comparator. Additionally, we conducted a manual evaluation to identify informative data elements in the report narratives.ResultsDuring the study period, 247,513 (6.4% of all FAERS reports) DI reports were entered in FAERS. Compared with non-DI reports, DI reports were more likely to be reported by consumers (69.8 vs. 48.1%) and less likely to report a serious outcome (26.2 vs. 56.3%). Most DI reports (88%) were from the USA. Manual evaluation of 552 sample US reports identified 43 reports (7.8%) deemed “useful”; a higher proportion of “useful” reports provided a batch or lot number (39.5 vs. 17.2%) and were coded with additional PTs beyond “drug ineffective” (83.7 vs. 59.2%), the most frequent of which were “product quality issue” (23.3%) and “product substitution issue” (18.6%).ConclusionsDI was the most frequently reported adverse event in the FAERS database; however, the yield from these reports in terms of usefulness from a pharmacovigilance perspective was low. Efficient strategies are needed to identify which DI reports are more likely to contain useful information.

Most safety issues led to prompt regulatory actions predominantly based on spontaneous reports. Some safety issues that were not easily detected by the spontaneous reporting system were identified years after approval. In addition, several safety issues required assessments of multiple drug products, which prolonged the decision-making process.