The Clinical Trial Site You Picked Based on Relationships Will Blow Your Timeline

You got the IND cleared. You have a protocol. You have a PI who sat on your SAB dinner two years ago, published in your space, and told you over conference cocktails that his site "does this kind of thing all the time."

Photo by Polina Tankilevitch on Pexels.

So you signed the site agreement and started the clock.

Nine months later, you have enrolled three patients against a target of forty. Your Series B is contingent on interim data. Your lead investor is asking questions you don't want to answer. And the PI, who genuinely likes you and wants this to work, is buried under seven other studies, two grant submissions, and a departmental review that nobody saw coming.

This is not a horror story. This is Tuesday.

Why Relationships Are the Wrong Selection Criterion

Founding teams pick clinical sites the same way they pick scientific advisors: based on trust, proximity, and enthusiasm. Those things matter, but they do not predict enrollment velocity, regulatory compliance, or operational bandwidth.

A site's ability to execute on your study depends on factors your PI contact has almost no control over: coordinator capacity, IRB turnaround times, patient population density in the specific indication you're targeting, competing protocols recruiting from the same pool, and the institutional appetite for the kind of device or therapeutic you're running.

None of those factors come up over cocktails. None of them appear in a CV.

The PI you trust may be the right scientific lead and the wrong operational bet. Those are separate questions, and conflating them is how you lose a year.

What Feasibility Assessment Actually Means

Every CRO will tell you to do a feasibility assessment. Most early-stage companies do a version of it that amounts to asking the PI: "Do you think you can enroll patients?" The PI says yes. You move on.

Real feasibility looks different. Pull the site's enrollment history on clinicaltrials.gov for studies with comparable indication and patient profile. Ask specifically how many coordinators are currently assigned to the site and how many active protocols they're managing. Get the last three IRB submission-to-approval timelines in writing, not anecdotally. Ask who handles monitoring visits and whether they have an internal QA function or outsource it.

Then ask the question that makes PIs uncomfortable: what happens to enrollment when you're at a conference or on sabbatical?

If the site lives and dies by one person's bandwidth, it will die on your timeline.

The Enrollment Math Nobody Does Upfront

Here is a simple way to gut-check whether a site can actually carry your study:

graph TD
    A[Target Enrollment] --> B(Monthly Enrollment Rate Needed)
    B --> C{Site Screen Rate}
    C --> D[Eligible Patient Pool at Site]
    D --> E(Screen Failure Rate)
    E --> F{Realistic Monthly Accrual}
    F --> G[Does It Close on Time?]

Work backward from your trial close date. Divide total enrollment by available months. That is your required monthly accrual rate per site. Now ask each candidate site what their screen-to-enroll ratio looks like for similar studies. Most sites have a historical screen failure rate of 40 to 70 percent in chronic disease indications. Run the math.

If the site needs to screen six patients a month to enroll two, and their patient volume in your indication is eight per month total, you have a problem before you sign anything.

Multi-Site Is Not Just for Large Studies

Founders treat multi-site trials as complexity to be avoided. One site feels manageable. Two feels like overhead.

Flip that. A single-site trial puts your entire data package on the operational reliability of one institution. If that site stumbles, your timeline slips with no backup. Two or three sites with moderate enrollment targets each gives you redundancy and, often, better data on generalizability that acquirers and regulators both value.

Yes, multi-site adds coordination costs. So does missing your enrollment window by eight months while your bridge loan burns.

The Conversation to Have Before You Sign

Before you execute the site agreement, ask the PI directly: what are the two most likely reasons this study slips at your site? Listen carefully. A PI who has run trials before will give you a real answer. A PI who hasn't will give you reassurance.

Reassurance is not data. Build your timeline around the real answer.

Your relationship with the investigator is an asset. Just stop using it as a substitute for operational due diligence. The two can coexist, and your runway will thank you.