20,000 Open Trials, and Why Half of Sites Still Miss Enrollment
Greg Van Horn
Trial Data
6
min read
There is no shortage of clinical trials. There is a shortage of patients in them. The numbers tell the story, and they point to an opportunity for independent specialty practices.
How many trials are open right now?
As of September 23, 2026, ClinicalTrials.gov lists 20,683 interventional trials that are recruiting or not yet recruiting at sites in the United States. Of those, 4,631 are sponsored by industry, meaning a drug, device, or biologic company is funding the study.
These counts change daily, and a single trial may be open at dozens of sites. But the scale is clear: at any given time, thousands of industry studies are looking for places to enroll patients.
Why half of sites still miss enrollment
Here is the paradox. With so many trials open, you might expect sites to be busy. Yet research from the Tufts Center for the Study of Drug Development found that about 11% of sites enroll no patients at all, and another 37% enroll fewer patients than planned. That means close to half of sites fall short.
Missed enrollment is expensive for everyone. Sponsors pay to activate sites that never produce patients. Timelines slip. And sites that under-enroll are less likely to be chosen again.
What drives the gap
Sites without patients: many research centers don't treat the condition being studied. They rely on advertising to find patients, which is slow and unpredictable.
Optimistic feasibility: sites often overestimate how many eligible patients they can find, especially for protocols with strict criteria.
Staffing limits: a coordinator juggling several studies may not have time to pre-screen charts or return inquiries quickly.
Complex protocols: specialized procedures or imaging requirements narrow the pool of sites that can actually run the study.
Slow follow-up: interested patients who don't hear back quickly often lose interest.
Where the patients actually are
Many of the patients these trials need are already under the care of a specialist. People with chronic low back pain see pain and spine physicians. People with type 2 diabetes see endocrinologists. People with knee osteoarthritis see rheumatologists and orthopedists. People with migraine see neurologists.
Independent specialty practices see these patients every day. What they usually lack is the research infrastructure to offer them a trial. That is the gap an integrated research organization is built to close.
What this means for practices
If your practice treats a condition with active research, there is a good chance sponsors need sites like yours. The question is not whether trials exist. It is whether your practice has the team and systems to run one well. Read how independent practices add clinical research with no new staff.
What this means for sponsors
Choosing sites that already treat the target population, and that have a real recruitment plan, is one of the most direct ways to reduce the risk of under-enrollment. See why specialist sites enroll faster than standalone research centers.
About the data
Trial counts come from the ClinicalTrials.gov public API, filtered to interventional studies with a status of recruiting or not yet recruiting and at least one U.S. location, pulled September 23, 2026. The industry count adds a filter for studies whose lead sponsor is classified as industry. Enrollment benchmarks are from the Tufts Center for the Study of Drug Development. We refresh these numbers regularly.
Want to know which open trials match your practice? Ask for a free assessment.
There is no shortage of clinical trials. There is a shortage of patients in them. The numbers tell the story, and they point to an opportunity for independent specialty practices.
How many trials are open right now?
As of September 23, 2026, ClinicalTrials.gov lists 20,683 interventional trials that are recruiting or not yet recruiting at sites in the United States. Of those, 4,631 are sponsored by industry, meaning a drug, device, or biologic company is funding the study.
These counts change daily, and a single trial may be open at dozens of sites. But the scale is clear: at any given time, thousands of industry studies are looking for places to enroll patients.
Why half of sites still miss enrollment
Here is the paradox. With so many trials open, you might expect sites to be busy. Yet research from the Tufts Center for the Study of Drug Development found that about 11% of sites enroll no patients at all, and another 37% enroll fewer patients than planned. That means close to half of sites fall short.
Missed enrollment is expensive for everyone. Sponsors pay to activate sites that never produce patients. Timelines slip. And sites that under-enroll are less likely to be chosen again.
What drives the gap
Sites without patients: many research centers don't treat the condition being studied. They rely on advertising to find patients, which is slow and unpredictable.
Optimistic feasibility: sites often overestimate how many eligible patients they can find, especially for protocols with strict criteria.
Staffing limits: a coordinator juggling several studies may not have time to pre-screen charts or return inquiries quickly.
Complex protocols: specialized procedures or imaging requirements narrow the pool of sites that can actually run the study.
Slow follow-up: interested patients who don't hear back quickly often lose interest.
Where the patients actually are
Many of the patients these trials need are already under the care of a specialist. People with chronic low back pain see pain and spine physicians. People with type 2 diabetes see endocrinologists. People with knee osteoarthritis see rheumatologists and orthopedists. People with migraine see neurologists.
Independent specialty practices see these patients every day. What they usually lack is the research infrastructure to offer them a trial. That is the gap an integrated research organization is built to close.
What this means for practices
If your practice treats a condition with active research, there is a good chance sponsors need sites like yours. The question is not whether trials exist. It is whether your practice has the team and systems to run one well. Read how independent practices add clinical research with no new staff.
What this means for sponsors
Choosing sites that already treat the target population, and that have a real recruitment plan, is one of the most direct ways to reduce the risk of under-enrollment. See why specialist sites enroll faster than standalone research centers.
About the data
Trial counts come from the ClinicalTrials.gov public API, filtered to interventional studies with a status of recruiting or not yet recruiting and at least one U.S. location, pulled September 23, 2026. The industry count adds a filter for studies whose lead sponsor is classified as industry. Enrollment benchmarks are from the Tufts Center for the Study of Drug Development. We refresh these numbers regularly.
Want to know which open trials match your practice? Ask for a free assessment.
