Recruitment plans start with a headcount: this many patients with the condition, in these regions, so the trial is feasible.
The math looks sound. The patients are real.
Then enrollment stalls, and the assumption underneath the plan goes unquestioned: that a patient who exists is a patient the trial can reach.
Those are two different things. And the gap between them is where feasible-on-paper studies quietly fall behind
The access gap is measurable.
In one 2024 lung cancer Medicaid analysis, only 57% of metastatic patients had evidence of any biomarker testing, a prerequisite many modern protocols depend on.
A patient is available if they have the condition.
They are accessible only if they can travel the distance from interested to enrolled.
A patient is accessible only if they can travel the distance from interested to enrolled without hitting a step the protocol assumes they've already taken. That assumption is easy to make, because the barrier rarely shows itself:
For the sponsor, the cost is a slipping timeline.
For the patient, it’s a treatment they couldn't get anywhere else.
They didn’t decline the trial opportunity. They were interested, diagnosis-eligible, and ready to consider the study, but blocked by a prerequisite they assumed they already cleared.
Before a clinical trial site opens, you can test whether interested patients can clear the protocol as written.
The process is simple: put real patients through the same eligibility criteria, outreach, and screening logic the study will depend on later. Then measure where they qualify, where they drop, and which prerequisite blocks them.
It answers the question a headcount can't: of the patients who exist and are interested, how many can actually clear the protocol as written?
That’s what a Market Feasibility Test (MFT) is built to show.
In an Antidote lung cancer Market Feasibility Test (65 respondents, 2025), the interest was unmistakable and the access gap was just as clear:
Availability tells you the patients exist.
Accessibility tells you whether your study can reach them.
Only one of those is on your recruitment plan, and it is usually the wrong one.