Delays in Clinical Trials: What We See Most & How To Avoid Them

Clinical trial delays happen for all kinds of reasons. The causes vary. The results, almost always, do not: frustration and a budget that keeps climbing.

The numbers tell the story plainly. Delays cost sponsors between $40,000 per day in direct operational expenses and anywhere from $500,000 to $800,000 per day in lost future prescription drug sales.

At Remington-Davis, we've partnered with sponsors and CROs across a range of therapeutic areas and trial complexities. Certain delay patterns show up again and again. Here's what we see most often and what can be done about it.

1. Contract Bottlenecks Extend Trial Timelines

A trial can't start until the paperwork is signed. That's obvious. What's less obvious is how often a slow contract turnaround is the first domino in a cascade of downstream delays.

Contract negotiations between sponsors, CROs, and sites can stretch for weeks or even months. Legal teams review, revisions go back and forth, and the site sits waiting. In the meantime, the window for enrolling the right patients narrows, staff momentum stalls, and the projected start date quietly slips further into the calendar.

Contract turnaround time is worth asking about directly when evaluating sites. It's a leading indicator of how a site manages its commitments across the board.

How to avoid it:

• Prioritize sites with a proven track record of fast contract execution. At Remington-Davis, we turn contracts around in two business days, without sacrificing accuracy or thoroughness.
• Assign clear internal ownership of the contract review process on both sides to eliminate the back-and-forth that can consume weeks.
• Set explicit turnaround expectations in your site selection criteria.

2. Supply Chain Issues Tie Up Resources

Even when contracts are signed and a site is ready to go, a trial can stall before it starts if the necessary supplies aren't there. Investigational products, specialty lab kits, cold chain materials — any one of these arriving late can push back a start date by weeks.

Supply chain disruptions driven by manufacturing delays, shipping bottlenecks, or global shortages are an increasingly common source of trial delays. Sponsors and CROs carry most of the mitigation responsibility here, but the research sites you choose impact how early problems get surfaced.

Sites experienced in complex or logistically demanding trials have seen these situations before. They raise flags earlier, build buffer time into their planning, and communicate proactively rather than waiting until a gap becomes a delay.

How to avoid it:

• Map your supply chain dependencies at the protocol stage. Know which materials have long lead times and build contingency timelines around them.
• Establish clear communication protocols with your sites so supply concerns surface before they become timeline-altering problems.
• Select sites with experience in logistically complex trials. They've navigated supply gaps before, know what to watch for, and will escalate proactively rather than wait for something to go wrong.

3. Patient Enrollment Challenges Stall Progress

Patient enrollment is, by a wide margin, the most common source of clinical trial delays. Estimates suggest that up to 80% of trials fail to meet their original enrollment timelines.

Several dynamics make enrollment harder than it looks on paper. Sites are often provided draft protocols, and by the time the final version clears IRB, eligibility criteria may have shifted in ways that shrink the qualifying patient pool.

Beyond eligibility, keeping enrolled patients engaged throughout a trial is its own challenge. Socioeconomic factors — transportation, time off work, childcare, language barriers — are real obstacles that often get underweighted in planning.

How to avoid it:

• Use protocol clarification letters to align sites on final eligibility definitions before enrollment opens.
• Look at the socioeconomic data for a site's geography when planning enrollment. Build in support structures — transportation reimbursement, flexible scheduling, multilingual staff — that reduce the burden on patients.
• Prioritize sites with strong local healthcare provider relationships that enable targeted outreach to specific and diverse patient populations, as well as individualized support that keeps participants engaged.

The Site You Choose Matters in Minimizing Clinical Trial Delays

Avoiding delays starts well before a trial opens. It starts with selecting sites that have the infrastructure, the relationships, and the operational discipline to perform.

Independent sites like Remington-Davis offer something that's hard to replicate at scale: small teams with low turnover, fewer administrative layers, and an investment in every trial we take on. That agility shows up in how quickly we execute contracts, how proactively we communicate, and how much we put into the patient experience.

If you want to go deeper into what separates high-performing sites from those that sink trials, our own Jennifer Botte recently shared her perspective in a video on site performance traps — what they are, how they develop, and what sponsors can do to avoid them. It's worth a watch before your next site selection conversation.

Frequently Asked Questions About Delays in Clinical Trials

How do patient outcomes contribute to the need to reduce trial delays?

Every day a trial runs behind schedule is a day a potential treatment stays out of reach for patients who need it. Yes, delays affect budget, but they also push back the timeline for approvals that could meaningfully change patients’ health and outcomes.

How do clinical trial delays affect the broader drug development pipeline?

Pharma companies typically run multiple programs simultaneously. When one trial slips, it creates ripple effects across the pipeline: resource reallocation, revised timelines, and in some cases, strategic decisions about whether to continue development at all. Reducing delays in any one trial protects the integrity of the broader portfolio.

What can pharma companies do earlier in drug development to set trials up for success?

Delay risk is typically baked in before a trial ever opens. Sponsors who invest in site feasibility assessments, realistic enrollment modeling, and protocol design reviews early in drug development tend to see better performance once trials are underway.

What's the most underestimated factor in patient recruitment?

Patient burden. Researchers often focus on finding eligible patients but underestimate what it takes to keep them engaged. Transportation, scheduling conflicts, and financial strain are among the major reasons patients drop out, and they're addressable with the right site support structures in place.

How should pharma companies evaluate sites to reduce delays before a trial starts?

Look beyond patient volume. Ask about contract turnaround times, staff turnover rates, experience with similar protocols, and how sites handle unexpected issues mid-trial. The sites best positioned to reduce delays treat operational performance as seriously as clinical performance.