Institutional Review Board (IRB)

Key facts

FDA regulation

21 CFR Part 56

HHS regulation

45 CFR Part 46 (the Common Rule)

Minimum membership

At least five members, including a nonscientist and an unaffiliated member

Registration

With the HHS Office for Human Research Protections (OHRP)

What is an Institutional Review Board?

An IRB is the ethics gatekeeper for a clinical study. Before a trial can enroll participants, an IRB must review the protocol, the informed consent documents and recruitment materials, and it keeps overseeing the study while it runs.

FDA regulations at 21 CFR Part 56 govern IRBs that review FDA-regulated research, and the HHS regulations at 45 CFR Part 46, known as the Common Rule, govern federally funded research. Outside the United States, the same function is usually performed by an independent ethics committee or research ethics committee.

Some IRBs belong to a hospital or university, while independent IRBs review studies for many sites and sponsors.

How IRB review works

Federal rules set out what an IRB must find before approving research, including:

• Risks to participants are minimized and reasonable in relation to anticipated benefits.
• Selection of participants is equitable.
• Informed consent will be sought and appropriately documented, unless a permitted waiver applies.
• Data are monitored to protect participant safety, and privacy and confidentiality are protected.
• Additional safeguards are in place for vulnerable groups such as children and prisoners.

Single IRB review for multisite studies

Traditionally, each site in a multisite trial used its own local IRB, repeating the same review many times. NIH policy has required a single IRB for most NIH-funded multisite studies since 2018, and the revised Common Rule requires a single IRB for most federally funded cooperative research at U.S. institutions.

FDA proposed a rule in 2022 to require single IRB review for FDA-regulated cooperative research. Check its current status before assuming it applies to an industry-sponsored trial.

Why IRBs matter

IRB approval is often one of the longest steps in activating a trial site, so the IRB model and its turnaround time are central to startup planning. Site feasibility work checks which institutions insist on their own IRB and which accept a central one.

For compliance teams, IRB records are part of the evidence that a study was conducted ethically. FDA inspects IRBs as well as investigators and sponsors, and problems found can put the usability of trial data at risk.