REMS (Risk Evaluation and Mitigation Strategy)

A Risk Evaluation and Mitigation Strategy (REMS) is a drug safety program that the U.S. Food and Drug Administration (FDA) can require a drug or biologic manufacturer to implement when a product’s serious risks would otherwise outweigh its benefits without additional controls beyond standard professional labeling. FDA’s authority to require a REMS comes from the Food and Drug Administration Amendments Act of 2007 (FDAAA), which added Section 505-1 to the Federal Food, Drug, and Cosmetic Act (21 U.S.C. 355-1), the same statute the Durham-Humphrey Amendment amended in 1951 to create the prescription-only drug class. A REMS can be required at the time of approval, or imposed on an already-marketed drug if FDA becomes aware of new safety information.

What a REMS Can Require

Not every REMS uses every tool available under the statute. FDA tailors the specific elements to the drug’s risk profile, and a REMS may include any combination of:

• Medication Guide or Patient Package Insert — FDA-approved, patient-directed information dispensed with the prescription, distinct from the professional prescribing label.
• Communication Plan — materials FDA requires the manufacturer to send to prescribers, pharmacists, or other healthcare providers to alert them to the serious risk and any REMS-specific requirements before they prescribe or dispense the drug.
• Elements to Assure Safe Use (ETASU) — the most restrictive tier, reserved for drugs with especially severe risks. ETASU can require prescriber certification/training, pharmacy certification, dispensing only in certain healthcare settings, mandatory patient monitoring or lab testing, or enrollment of patients in a registry.
• Implementation System — required whenever a REMS includes ETASU, this is the operational infrastructure (often a shared, cross-manufacturer platform for products in the same drug class) that monitors and enforces compliance with the ETASU requirements.

Manufacturers must also periodically assess and report to FDA on whether the REMS is achieving its stated goals, and FDA can require modifications if it is not.

Why REMS Exists: Balancing Access and Risk

REMS was created specifically as a middle path between two blunter tools: approving a drug with ordinary labeling alone, or refusing to approve it (or withdrawing it) because of unacceptable risk. By attaching enforceable risk-mitigation conditions to approval, FDA can authorize access to therapies with serious but manageable risks — opioid analgesics with abuse-deterrent programs, isotretinoin (associated historically with the iPLEDGE program) for severe teratogenic risk, or clozapine for a risk of severe neutropenia — that would be difficult to approve, or difficult to keep on the market, under standard labeling alone.

REMS vs. Standard Product Labeling

Every prescription drug has FDA-approved labeling (the package insert) describing risks, warnings, and contraindications. A REMS is not a substitute for labeling and does not replace it — it is an additional, legally enforceable layer of risk control that goes beyond what labeling alone can accomplish, because labeling relies on prescribers and patients reading and following it voluntarily, while REMS elements (particularly ETASU) can be structurally enforced through certification, restricted dispensing, or mandatory monitoring.

Relevance to Clinical Research Administration

REMS requirements are directly relevant to clinical trial operations when an investigational or already-approved REMS drug is used in a study: sites may need prescriber/pharmacy certification under the drug’s REMS program before they can dispense study drug, and research administrators coordinating Investigational New Drug (IND) applications or expanded access / compassionate use requests for a REMS-restricted product need to build REMS enrollment and certification into study startup timelines, since it is a separate compliance track from IRB approval or the IND itself.

Elements to Assure Safe Use (ETASU): what each element means

ETASU is the most restrictive tier FDA can require under a REMS, reserved for drugs whose risks would not be adequately controlled by labeling, a Medication Guide, or a communication plan alone. FDA selects only the specific ETASU elements a given drug’s risk profile actually warrants — a REMS is not required to use every tool available under the statute. The elements FDA can draw on, individually or in combination, include:

• Prescriber certification/training — healthcare providers must complete specific training (and in some programs, pass a knowledge assessment) and enroll with the REMS program before they are authorized to prescribe the drug.
• Pharmacy certification — dispensing pharmacies must enroll and, in many programs, verify prescriber and/or patient enrollment status in the REMS system before they can dispense the product, not just fill a valid prescription.
• Dispensing only in certain healthcare settings — some ETASU-level REMS restrict dispensing to settings with the infrastructure to manage a specific risk, such as hospital pharmacies equipped to monitor a patient immediately after administration.
• Mandatory patient monitoring or laboratory testing — REMS can condition continued dispensing on documented lab results or clinical monitoring, such as periodic blood counts, reviewed before each refill is authorized.
• Patient enrollment in a registry — some ETASU-level programs require patients to enroll and, in certain programs, complete a patient-prescriber agreement acknowledging the risk before dispensing.

Whenever a REMS includes ETASU, FDA also requires an implementation system — the operational infrastructure, often a shared, cross-manufacturer platform for products in the same drug class, that actually enrolls and verifies prescribers, pharmacies, and patients and enforces the ETASU requirements in practice, rather than leaving compliance to each party’s own record-keeping.

How prescriber, pharmacy, and patient enrollment actually works

For an ETASU-level REMS, the enrollment and certification workflow generally runs in this order, though the specific steps and portal a given REMS uses vary by program:

• Prescriber enrollment — the prescriber completes the required REMS training/knowledge assessment and enrolls (often through the REMS’s own online portal), which the implementation system records as an active certification status tied to that prescriber.
• Pharmacy enrollment — the dispensing pharmacy separately enrolls and certifies its staff/processes with the REMS program; a pharmacy that has not enrolled generally cannot dispense the drug even if it holds a valid, correctly written prescription.
• Patient enrollment (where the REMS requires it) — the patient enrolls in the program, which can include acknowledging risk information, agreeing to required monitoring, or enrolling in a registry, before the first dispensing and often before each refill.
• Verification at dispensing — the pharmacy checks the prescriber’s and (where applicable) the patient’s active enrollment/authorization status in the REMS system before dispensing each fill, not only at the first prescription.

Because these checks sit outside the normal pharmacy workflow, a REMS-restricted drug can be dispensed correctly on the underlying prescription and still be blocked at the pharmacy counter if any party’s REMS enrollment has lapsed or was never completed.

REMS in a clinical trial: coordinating with site pharmacy operations

When a study drug is already marketed under a REMS — for example, in a trial comparing a REMS-restricted drug against a new investigational agent, or in an expanded-access/compassionate-use request for a REMS-restricted product — REMS compliance runs as a separate, parallel track alongside IRB approval and any Investigational New Drug (IND) application, not a step folded into either. In practice this means:

• The investigator (as prescriber) and the site’s dispensing pharmacy each need active REMS enrollment/certification before the site can dispense the REMS-restricted drug to a trial participant — this has to be built into site activation and study start-up timelines, since REMS certification can take longer than a single site-initiation visit to complete.
• Any patient-facing REMS requirements (registry enrollment, monitoring, patient-prescriber agreements) apply to trial participants receiving the REMS-restricted product the same way they would to any patient receiving it outside a trial, on top of the trial’s own informed consent and monitoring plan.
• Site pharmacy standard operating procedures for a REMS drug need to account for REMS-system dispensing verification at each fill, in addition to the trial’s own drug accountability and reconciliation logs.
• Study teams coordinating a compassionate use / expanded access request for a REMS-restricted product should confirm REMS enrollment requirements with the manufacturer/REMS program administrator early, since expanded-access timelines are often urgent and REMS certification is not something FDA or the IRB can waive on the sponsor’s behalf.

REMS assessment and modification

Manufacturers must submit REMS assessments to FDA on a schedule set by statute: by default, at 18 months and at 3 years after the REMS is initially approved, and again in the 7th year, unless FDA specifies a different frequency for a particular REMS or removes the assessment requirement (which the statute allows FDA to do after 3 years if it determines the drug’s risks have been adequately identified, assessed, and are being managed). Each assessment reports on whether the REMS is meeting the specific goals set when it was approved — FDA can require the sponsor to modify the REMS’s elements, or add/remove elements entirely, if the assessment data shows it is not.

Shared System REMS

When a reference listed drug is subject to a REMS that includes ETASU, Section 505-1(i)(1) of the FD&C Act generally requires that a generic (ANDA) or 505(b)(2) applicant for the same drug use a single, shared system REMS with the original NDA holder, rather than build a separate, standalone program — unless FDA waives that requirement or the applicant develops REMS elements with comparable ETASU under the framework the Further Consolidated Appropriations Act, 2020 expanded. A shared system REMS lets multiple manufacturers of essentially the same drug (or drug class) pool the operational cost of the implementation system, share adverse-event and safety data, and coordinate REMS modifications and assessments across every product enrolled in the shared platform, instead of each generic entrant standing up a duplicate certification/enrollment system that prescribers and pharmacies would otherwise have to navigate separately for chemically-identical products.

Frequently Asked Questions

Is a REMS the same as a black box warning?

No. A boxed warning is part of the drug’s professional labeling, calling attention to a serious risk in the prescribing information itself. A REMS is a separate, additional program with its own enforceable requirements (which can include a Medication Guide, communication plan, or ETASU) layered on top of labeling. A drug can have a boxed warning without a REMS, and vice versa, though high-risk drugs often carry both.

Who has to comply with a REMS?

Depending on the specific REMS, obligations can fall on the manufacturer (implementing and reporting on the program), prescribers (completing required training or certification), pharmacies (verifying certification status before dispensing), and in some ETASU-level programs, patients themselves (enrolling in a registry or completing required monitoring).

How long does a REMS stay in place?

A REMS remains in effect until FDA determines it is no longer necessary — for example, because post-market data show the risk is adequately managed through routine labeling, or because the drug’s risk-benefit profile has otherwise changed. FDA periodically reviews REMS programs against their stated goals and can modify, or eliminate, elements it finds no longer justified.

What is ETASU under a REMS?

Elements to Assure Safe Use (ETASU) is the most restrictive tier of REMS requirement, reserved for drugs whose serious risks require more than labeling or a communication plan alone. ETASU can include prescriber certification/training, pharmacy certification, dispensing restricted to certain healthcare settings, mandatory patient monitoring or lab testing, and patient registry enrollment — FDA selects only the specific elements a given drug’s risk profile warrants.

What is a Shared System REMS?

A Shared System REMS is a single REMS implementation system used across multiple manufacturers of the same or comparable drug — most commonly a brand and its generic (ANDA) or 505(b)(2) competitors. Section 505-1(i)(1) of the FD&C Act generally requires ANDA/505(b)(2) applicants to join the reference drug’s existing shared system when its REMS includes ETASU, rather than build a separate program, so prescribers and pharmacies work with one enrollment/certification system per drug class rather than one per manufacturer.

How does a REMS get modified?

FDA can require a REMS to be modified based on the sponsor’s periodic REMS assessments (due by default at 18 months and 3 years after approval, and again in year 7), new safety information, or a determination that the current elements are placing an unnecessary burden on patients or the healthcare delivery system without a corresponding safety benefit. Modifications can add, remove, or change specific elements, including ETASU requirements.