US Risk Evaluation and Mitigation Strategies with Elements to Assure Safe Use: A Longitudinal Analysis of REMS Modifications (2008-2022).

introductionRisk evaluation and mitigation strategies (REMS) are risk management healthcare interventions required by the US Food and Drug Administration (FDA) for certain prescription medicines with serious safety concerns to protect public health and ensure that the benefits outweigh its risks. REMS are expected to evolve over a drug's lifecycle on the basis of new pharmacovigilance evidence and changing healthcare delivery context.

objectiveThe aim of this study is to characterize the frequency and types of REMS modifications over time to inform health policy and pharmacovigilance practice.

methodsA retrospective longitudinal case series study was conducted using publicly available data on program characteristics and change history from the FDA's public website (REMS@FDA). All REMS programs with elements to assure safe use (ETASU; N = 100) approved by the FDA between 1 January 2008 and 31 December 2022 were linked longitudinally into "REMS Classes" based on common drug class and/or moiety (N = 67). Median follow-up per program was 7.4 (interquartile range [IQR] 2.3-11.6) years after the index REMS approval. Type of REMS modification was coded and categorized as major or minor using the FDA's guidance to the industry. Frequency and type of modification and time to first major modification were assessed.

resultsThe median number of new REMS Classes approved per year was four. In the last 5 years of observation (2017-2022), REMS were being exclusively introduced concurrently with product approval. The median number of modifications per year per REMS class was 1.2 (IQR 0.7-1.6), representing 671 modifications and 364 unique dates. The median time to first modification was 15.4 (IQR 6.9-25.8) months and did not vary by when the index REMS was approved. Of the REMS classes, 96% (n = 64) had at least one modification by end of observation. As the cumulative number of REMS classes increased over time, modifications to approved REMS classes outpaced the approval of new REMS classes 17:1. The most common types of modifications were changes to REMS goals and/or design (n = 221) and changes to REMS materials (n = 167). However, no clear patterns were observed to suggest a specific type of early modification was more common than another. Among the 32 REMS classes approved in the first 5 years following the FDA Amendments Act of 2007 (FDAAA; 2008-2012), approximately one half (n = 14) had evolved to a shared system REMS by end of observation and one third (n = 10) had been released (median time to release 7.0 years, IQR 4.7-7.2 years).

conclusionsREMS modifications were common and demonstrated responsiveness to new evidence about the drug and adaptation to changing patterns of healthcare delivery within a learning health system.