Enrollment is a community problem before it is a marketing problem.

Ask patients how they decided to join a clinical trial and you'll hear some version of the same answer: my doctor thought it was a good idea. Now look at the other side of that conversation. When the Tufts Center for the Study of Drug Development surveyed 755 physicians and 1,255 nurses, physicians reported referring a median of five patients a year into industry-funded trials, less than 0.2 percent of the patients they see. Nurses referred even fewer.

It isn't a lack of goodwill. In the same Tufts study, nine in ten physicians said they were comfortable discussing trials with patients, and only 9 percent said fear of losing the patient held them back. What they named instead was not having the information and not having the time. Those are problems a research site can solve.

What the numbers say

The cost of that gap shows up in site performance. In a Tufts study of nearly 16,000 sites across 151 Phase II and III trials, 11 percent of sites enrolled no one at all, 37 percent under-enrolled, 39 percent met their target, and 13 percent beat it. More than half of the trials had to extend their enrollment timelines, and one in six took more than twice as long as planned, as Ken Getz reported.

The funnel is unforgiving, too. In the average trial in that study, 928 patients were screened, 622 enrolled, and 516 completed. A site that wants completers needs a steady flow of qualified candidates, not a burst of ad responses.

Why ads alone stall

Advertising can fill an inbox with inquiries. It can't make those people eligible, and it can't answer the question most of them ask before they sign a consent form: what does my doctor think? When the doctor has never heard of the site, the answer defaults to caution.

Getz made the same point years ago: lasting enrollment depends on engaging healthcare providers and other trusted sources of health information, not only on reaching patients who are already searching.

Build the referral layer

Start with the practices whose patients match your protocols: endocrinology for a diabetes study, dermatology for psoriasis, primary care for almost everything. Then remove the two barriers physicians named themselves. Give each practice a one-page summary of the study and who qualifies, so information isn't the problem. Give them one contact who answers the same day, so time isn't the problem.

Close the loop every time. Tell the referring doctor what happened, and send the patient back to their care when the study ends. Practices keep referring to sites that treat their patients well and keep them informed. And show up in the community, at health fairs, churches, and patient advocacy groups, where trust gets built long before a study opens.

Track referrals to randomization

Tag every candidate with a source: the practice that referred them, the campaign that reached them, the event where they heard about the study. Then follow each source all the way through, from referred to pre-screened, screened, consented, and randomized.

Two sources can send the same number of people and produce very different results. A practice that sends five patients who all qualify is worth more than a campaign that sends fifty who don't. Review those numbers monthly as a team, share results with referring practices without patient details, and spend your time where randomizations actually come from.

Where marketing fits

Marketing earns its budget when it amplifies relationships that already exist: campaigns that point patients toward trusted local partners, measured by randomizations rather than clicks. When it tries to replace those relationships, it rarely does.