For most multisite industry trials in the United States, a central IRB is the faster and more consistent choice: one review of the protocol and informed consent, one place to submit amendments, and one set of approval timelines. Local IRB review still matters at many academic medical centers, which may require their own review or a formal reliance agreement, and institutional ancillary reviews continue either way. Your IRB strategy deserves a decision before the CRO is selected, because it shapes site activation more than most sponsors expect.
What is the difference between central and local IRB review?
A local IRB is the institutional review board of the site itself, typically at a hospital or university. A central IRB, often an independent commercial board, reviews the study once on behalf of many sites. Under a central model, each participating site either accepts the central review directly or signs a reliance agreement that defers review to the central board while keeping certain local responsibilities.
Why do most industry sponsors start with a central IRB?
Speed and consistency. A central board reviews the protocol and the master informed consent form once, which avoids negotiating the same consent language with 20 or 30 committees. Amendments are reviewed once as well, so a protocol change does not travel through separate approval cycles at every site. Independent boards also tend to publish their meeting schedules and turnaround times, which makes startup planning more predictable.
When does local review still happen?
Many academic medical centers require their own IRB review for some or all industry studies, or they accept a central IRB only through a reliance agreement that takes time to execute. Even when the central IRB is the board of record, institutions commonly run their own ancillary reviews, such as conflict of interest, radiation safety, pharmacy, and, for studies involving recombinant or synthetic nucleic acid molecules, an institutional biosafety committee. Those local steps often determine the activation date more than the IRB approval itself.
What is changing with single IRB requirements?
Federally funded multisite research in the United States has used single IRB review for several years under NIH policy and the revised Common Rule. FDA proposed a rule in September 2022 that would require single IRB review for most FDA-regulated cooperative research conducted in the United States, and the federal regulatory agenda published in July 2026 lists a final rule with a target of December 2026. Whatever the final timing, the direction is clear, and sponsors designing studies now benefit from building their startup plans around a single board of record.
How does IRB strategy affect study startup?
It determines whether submissions run in parallel or in sequence, how many versions of the consent form you maintain, and how long reliance agreements and ancillary reviews take at each institution. A study with 25 sites using one central IRB and five academic sites requiring local review effectively has two startup tracks. Planning for both, with realistic timelines for the slower track, prevents the academic sites from becoming the last ones activated.
What should you ask CROs about IRB strategy?
During selection, ask each CRO:
Which central IRBs it works with most often, and the typical turnaround it sees for initial review and amendments
How it manages reliance agreements with academic institutions
How it tracks ancillary reviews site by site
Whether its startup timeline assumes a central IRB for every site
How it harmonizes local consent language requirements with the master consent form
How quickly it can submit amendments across all sites once approved
What about sites outside the United States?
Ethics review follows national rules in each country. In the European Union, the Clinical Trials Regulation coordinates the scientific and ethical assessment through a single application in each member state concerned, and national ethics committees participate according to each country's arrangements. Elsewhere, timelines and requirements vary widely, which is one more reason to confirm country-specific ethics assumptions in every CRO proposal.
Keep reading: Why Site Activation Stalls at the Contract and Budget
