The FDA will decide whether to require a Risk Mitigation and Evaluation Strategy after weighing known and potential adverse events, the seriousness of the condition, and the drug’s expected benefits, according to draft guidance to industry.

The agency also will consider whether a drug is a new molecular entity, the overall duration of treatment, and the estimated size of the population likely to use the drug. No single factor will determine whether a REMS will be required, the FDA said. The agency is required to consider these factors by the FDA Amendments Act of 2007.

These six factors also influence what types of elements might be necessary to assure safe use, such as requirements that prescribers have specific training, or that the drug be administered in a certain setting. Other strategies may include medication guides, patient package inserts, and communication plans with health care providers.