This week, the U.S. Food and Drug Administration (FDA) issued new guidance on how pharmaceutical companies can change their Risk Evaluation and Mitigation Strategies (REMS)—plans that manage the known or potential serious risk associated with a particular drug or biologic. In 2012, the FDA announced it would review changes to approved REMS within 60 days. The new guidance aims to categorize changes to REMS “by the degree of their potential effect on the risk message and/or other REMS requirements.” Two new categories of REMS changes have been announced: revisions and modifications. As defined by the FDA, revisions are editorial in nature, having no bearing on the efficacy and safety of a drug product. Modifications are more substantial than revisions and include both major and minor changes to a REMS. The FDA’s guidance document contains various examples of both changes. You can find the guidance here.