The total number of trials, worldwide, can't be quantified precisely.
The Thomson Corporation maintains the aforementioned, very
comprehensive site, "Center Watch":
Center Watch estimates that over 41,000 medical trials (which include
medical devices, drug efficacy, quality of life, and other types of
trials) are currently underway; that is, *known* trials: trials that
are registered with regulatory agencies and/or medical organizations.
The best estimate I can give you on IRBs is 4,000-6,000, discussed in
the section on IRBs, below.
That estimate on trials, 41,000+, appears to be the best estimate,
based on my research. (I can call Thomson on Monday to verify that
that number is for *global* trials; that is how I'm interpreting it )
Some trials aren't registered with any agency in any country, so it's
impossible to be certain just what the exact total is. For instance,
some drug companies don't make their clinical trials known until the
trial has ended. (And, they may not report the trial at all, if the
results were disappointing.)
As noted in this July 23, 2003 report published in the JAMA (Journal
of the American Medical Association), "Registering Clinical Trials,"
written by Kay Dickersin, PhD, MA, and Drummond Rennie, MD:
"That it is not possible to find information about all initiated
clinical trials is of international concern. This is a particular
worry because scientists tend to publish their positive findings more
often than their negative findings (publication bias). A comprehensive
register of initiated clinical trials, with each trial assigned a
unique identifier, would inform reviewers, physicians, and others (eg,
consumers) about which trials had been started and directly address
the problem of publication bias. . . ."
This concern has prompted several high profile organizations to demand
that all trials be made public: This past June the International
Committee of Medical Journal Editors urged pharmaceutical companies to
release more information regarding their clinical trials, while the
American Medical Association (AMA) called for a "public registry" of
all clinical trials.
See: the Jun 15 2004 edition of Health Day:
(Scroll down to header "Drugmakers May Have to Publicly Register Clinical Trials.")
And on April 2, 2004, the World Health Organization (WHO) announced
that WHO "and Current Controlled Trials (CCT) have announced that,
from today, all randomized controlled trials approved by the WHO
ethics review board will be assigned an International Standard
Randomised Controlled Trial Number (ISRCTN).1 As a result, the
scientific community should now find it easier to keep up-to-date with
current research" from 192 countries. See the press release "WHO leads
drive for international coordination of clinical research":
Check out "Current Controlled-Trials" at
At right center on that page go to "CT metaRegister of Controlled
Trials (mRCT) International database combining registers of ongoing
randomised controlled trials in all areas of healthcare" and click on
"Click To Enter,"
to bring up:
At left, see mRCT's FAQ:
See "Is the mRCT a complete record of trials around the world?"
"The mRCT is not a comprehensive record of all randomised trials
worldwide. It is therefore wise to search other sites (for example
those in 'Links' section) to complement the information in the mRCT."
You'll see a directory listing trials by category and, as you scroll
down that page, you'll see links to various agencies, institutes,
universities, and drug companies currently conducting trials all over
But counting those links won't give you a true total, as many of those
organizations have more than one trial in-progress, and some links to
lead to databases of every known trial underway for a specific
So, the best we can do for now is to rely on the best estimates made
by organizations that track trials. As noted, Center Watch estimates
41,000 plus worldwide. For a *very rough* sampling of how that all
The article "Active Clinical Trials Worldwide (Phase I-III)," from the
Products In Development journal (published by Barnett), notes that
"More than 3,000 clinical trials (Phase I, II, or III) are taking
place worldwide, according to a March 2003 analysis of data reported
by the three major pharmaceutical pipeline databases--Adis R&D Insight
(Adis International Limited), IMS R&D Focus (IMSworld Publications
Ltd), and Pharmaprojects (PJB Publications) (as searchable on The
. . . ."
But note that that total of 3,000 refers only to pharmaceutical trials.
(Btw, the Dialog Corporation, noted above, is owned by Thomson
Corporation. That reference is to Dialog's Adis Clinical Trials
Drug Development Pipeline:
Fletcher Allen Health Care (Fletcher Allen is an "academic medical
center" affiliated with the University of Vermont College of
Medicine,) reports that 1,800 cancer studies are currently in-progress
at the National Cancer Institute (NCI):
You can also check out "Clinical Trials" site, which is maintained by the NIH:
"ClinicalTrials.gov currently contains approximately 11,000 clinical
studies [though presumably, some of them are closed]sponsored by the
National Institutes of Health, other federal agencies, and private
industry." (You can check the database at that site, which includes
trials from "all 50 States and in over 90 countries.")
ClinicalTrials.gov lists studies by institute, such as NIH, the
National Eye Institute (NEI), National Institute of Mental Health,
(NIMH), the Veterans Administration, and the National Cancer Institute
Also see Yahoo's Directory of Clinical Trials:
And, the Society for Clinical Trials:
Back at Center Watch:
You can check for specific studies according to specialty: cardiac,
gastroenterology, obstetrics/gynecology, oncology, etc., as this page:
That same page has links to studies being conducted by the National
Cancer Institute and by National Institute for Health (NIH).
At the "Additional Resources for Patients" page:
Scoll down to see a long list of international organizations currently
Thomson's Centerwatch also lists trials taking place worldwide:
(I count about 1,560 clinical trials currently underway outside the U.S.)
At that page see links to global research centers, and to
international "providers" who assist in conducting clinical trials,
including adherence to regulatory/ethical (IRB) guidelines:
For one example, check out Origin Pharmaceutical Services, which is
based in Oxford, England:
IRB (Institutional Review Board) & Other Regulatory:
Per my RFC, I'm assuming you wanted to know about the role of IRBs? If
you want to know how many IRBs there are, well, that, too, is up for
The best estimate -- in fact, the only estimate -- I could find is
4,000-6,000 in the U.S. That's the number mentioned in this Sept. 12,
2002 transcript from a meeting of the President's Council on
" 'Again, it seems to me it is hard to know whether the system is
better, worse, going in the right direction, going in the wrong
direction, if you don't systematically, regularly, routinely even know
how many people are on research trials. We don't even know how much we
spend on it. I might say we don't even know exactly how many IRBs
there are. I am sure General Motors knows exactly to the number how
many dealerships it has. We know that there's somewhere between 4,000
and 6,000 IRBs in this country.' "
That statement was made by Ezekiel J. Emanuel, M.D., Ph.D. Chief,
Center for Clinical Bioethics, National Institutes of Health.
You can also check the U.S. Deparment of Health & Human Services" page on IRBs:
To search by location or institution name, but I couldn't find totals.
As to the role of IRBs: these are independent consulting companies
that review clinical trials to ensure the welfare of study
For instance, to oversee medical devices:
See "Guidance for Institutional Review Boards and Clinical Investigators
From the FDA's IRB FAQ:
"1. What is an Institutional Review Board (IRB)?
Under FDA regulations, an IRB is an appropriately constituted group
that has been formally designated to review and monitor biomedical
research involving human subjects. In accordance with FDA regulations,
an IRB has the authority to approve, require modifications in (to
secure approval), or disapprove research. This group review serves an
important role in the protection of the rights and welfare of human
research subjects. . . .
"2. Do IRBs have to be formally called by that name?
No, 'IRB' is a generic term used by FDA (and HHS) to refer to a group
whose function is to review research to assure the protection of the
rights and welfare of the human subjects. Each institution may use
whatever name it chooses. Regardless of the name chosen, the IRB is
subject to the Agency's IRB regulations when studies of FDA regulated
products are reviewed and approved."
Examples of IRB consulting groups:
Schulman Associates' Institutional Review Board:
"Schulman Associates Institutional Review Board, Inc. ('SAIRB' or the
'Board') is an independent IRB that has more than 20 years of
experience in reviewing research protocols and consent forms to
evaluate compliance with all relevant regulations. As an independent
IRB, SAIRB is not part of an institution such as an academic medical
center or research hospital. Working with a network of regional
consultants, the Board can provide IRB services for national
multi-site studies . . . ."
Independent Review Consulting, Inc. (IRC):
In addition, universities and hospitals that conduct clinical trials
have their own IRBs. For example Georgetown University:
Changes Re: Clinical Trials in the EU:
As of May 2004, clinical trials are regulated in the EU, under the "EU
Clinical Trial Directive":
"Directive 2001/20/EC of the European Parliament and of the Council
on the approximation of the laws, regulations and administrative
provisions of the Member States relating to the implementation of good
clinical practice in clinical trials":
Trials will be registered here:
So, keep checking back at that site.
This May 2001 paper, "Review of the European Union Clinical Trial
Directive," by Biologics Consulting, discusses IRB/ethics issues in
Scroll down to "Article 3: Protection of Clinical Trial Subjects."
estimate number clinical trials worldwide
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"total number" AND "clinical trials"
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FDA clinical trials
"World Health Organization" AND "clinical trials"
Europe AND regulate AND "clinical trials"
EU clinical trials
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I hope my research is of help to you. If you require clarification, or
need help navigating any of the above links, please post a "Request
For Clarification," PRIOR to rating my answer.
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