There are 39,000 active clinical trials in the United States.
Clinical trials in the US are tracked by a number of private services
that link the trials to prospective participants. One of the most
well-known of these sites is Centerwatch, which operates a service
they call the Clinical Trials Listing Service.
On the Centerwatch homepage at:
you'll find the following information:
Welcome to the Centerwatch Clinical Trials Listing Service!
You can use this site to find a wealth of information about clinical
research, including listings of more than 41,000 active industry and
government-sponsored clinical trials, as well as new drug therapies in
research and those recently approved by the FDA.
Elsewhere on the site they provide a bit more detail:
Clinical Trials Listing Service - Searchable Database...listing over
41,000 current phase I - IV clinical trials listings (approx. 8,000
private industry and 31,000 gov't sponsored).
A pamphlet titled "Volunteering for a clinical trial" can be found here:
and includes the following information:
"Our web site...provides an extensive list of clinical trials
conducted throughout North America; many of these trials may be
appropriate for your participation. The CenterWatch Clinical Trials
Listing Service lists 41,000 clinical trials actively seeking study
So...if their database contains 41,000 active clinical trials, why did
I provide you an answer of only 39,000?
The reason is that the Centerwatch database, though heavily
concentrated on clinical trials in the United States, also includes a
number of international listings as well, which are described more
Welcome to CenterWatch World.
In CenterWatch World, you'll find international listings of ongoing
clinical trials and profiles of research centers and other clinical
trials service providers. These international listings are not
exhaustive. We are working hard to make this new section more
comprehensive and more valuable to our visitors every day.
By adding up the numbers of clinical trials shown in each category at
the CenterWatch World site (for instance, Immunology/Infectious
Diseases -- 184 clinical trials) it is clear that there are almost
2,000 listings for clinical trials in countries other than the United
So, by simple subtraction, there are approximately 41,000 - 2,000 =
39,000 clinical trials in the United States, the bulk of which (about
31,000) are government sponsored, while the remainder are sponsored by
I hope this information addresses your question in a comprehensive fashion.
But before rating this answer, please let me know if you have any
questions or need more information. Just post a Request for
Clarification, and I'll be happy to assist you further.
search strategy: used bookmarked sites for clinical trial data.
Clarification of Answer by
15 May 2004 09:55 PDT
Perhaps I should have been more explicit about the process here at
Google Answers, since you are a first time user of the service.
If anything about an answer requires elaboration -- or if you need
more information -- in the future you can simply let the researcher
know by posting a Request for Clarification. We are always happy to
continue to assist our clients as best we can.
However, once a question has been rated by a customer, it is generally
considered closed, so it is best to ask for clarification prior to
posting a rating.
I took a second look at clinicaltrials.gov, as it seems to be what you
need in terms of a "referencable" source.
At their "About" page:
they note the following statistics:
ClinicalTrials.gov currently contains approximately 10,200 clinical
studies sponsored by the National Institutes of Health, other federal
agencies, and private industry. Studies listed in the database are
conducted primarily in all 50 States and in over 90 countries.
By playing around with their search system at:
I was able to determine that 8418 of these studies are based in the
United States, of which 3825 are actively recruiting patients.
Hope these data meet your needs. And hope we'll see you back here at
Google Answers one of these days.