Clinical Trial Enrollment Timelines: Hidden Causes Behind Big Delays

by Dan McDonald
Clinical trial enrollment timelines

This is the second in my three-part series revealing hidden causes behind delays in clinical studies. The first part is here. This installment explores strategies to meet clinical trial enrollment goals.

Tell me when your first patient was enrolled, and I will tell you the chances your study will be a success. It’s not a magic trick, it’s just statistics.

First Patient In (FPI) is a key indicator of the overall success of a study. If that first patient is enrolled on time or within 30 days of the FPI goal, your study will begin on sound footing. The further you miss that goal, the more success will elude you. Here are the statistics:

clinical trial enrollment

Getting that first patient into the study on time is critical. If that goal isn’t met, it takes longer to gain traction and raises the likelihood that you will not hit your clinical trial enrollment targets. Your study will not meet its timelines.

This makes strategic patient recruitment an important tool in meeting FPI and LPFV (Last Patient/First Visit) goals.

In the past, about 70 percent of our business consisted of rescue programs for low-enrolling studies. We have seen considerable progress in this area: more than 70 percent of the studies we support today have proactive recruitment programs.

Sponsors have grown more sophisticated with recruitment, and many have even created internal departments tasked with accelerating enrollment. Merck’s Global Trial Optimization team is a noteworthy example.

Nevertheless, there is still room for improvement. A survey conducted by Imperial a few years ago revealed that 45 percent of line managers at sponsor companies had no proactive recruitment plans but also lacked the authority to put plans in place. Unfortunately, they are setting themselves up for delays.

Bring in the sites as a clinical trial enrollment strategy

Sites are the front lines of research and enrollment. Maximizing communication with sites early and often will help boost their performance.

Sites have tremendous insights and expertise that can be tapped. Here are tips on maximizing site performance:

  • Capture site buy-in early and often
  • Site support is a must-have topic at investigator meetings and training
  • Involve clinical research coordinators in the planning and execution
  • Arm sites with tools (75 percent of sites utilize patient recruitment materials)
  • Show sites that you care and you are investing in their success and want their input
  • Minimize the lag time between site feasibility, investigator meeting, and study initiation

Communicate on a fixed schedule

We find sites are vocal – and helpful — when asked for their perspective and input. We recommend forming site steering committees. These committees are made up of coordinators from top-performing sites and also mid and low-performing sites. Meet monthly or every six weeks to share recruitment and retention best practices as well as challenges.

And always remember that you are often competing with other sponsors’ studies for the site’s efforts and attention. Spending time with site staff and applying the tips I’ve mentioned to demonstrate your commitment can differentiate you from other sponsors and go a long way in motivating them to be enthusiastic about your study and clinical study enrollment goals.

Getting clinical trial enrollment right and getting it wrong

Studies that routinely meet FPI and LPFV timelines employ these planning strategies:

  • Recruitment planning starts with protocol design
  • Budgets are realistic
  • Plans are revisited often
  • Country startup planning ensures that the slowest locations are not activated last
  • Outside voices (partner/recruitment vendor) are often utilized
  • A multifaceted strategy is employed to meet study goals, including such tools as:
    • Physician referral programs
    • Community outreach
    • Advocacy groups

By contrast, here are common practices that will seal the fate of any study (yes, this really does happen):

  • Not being competitive (lowballing contracts and grants)
  • Paying sites late
  • Falling into the key opinion leader trap (placing too much faith in “experts” or using the wrong experts)
  • Failing to plan for backup sites to be activated if necessary
  • Fixating on the latest single silver bullet, shiny ball approach
  • Waiting too long to ask for help


Effective recruitment strategies, utilizing site expertise, and keeping a sharp focus on proactive planning are the heart of meeting clinical trial enrollment timelines and reaching study success.

Imperial is here to help. Optimize your clinical trial recruitment and retention plans with our evidence-based patient recommendations. Imperial’s diverse therapeutic knowledge and 25+ years of research patient engagement experience position us to collaborate with you on any indication and patient population. Our subject matter experts are here to help — contact us!

In my next post in this series, I will write about hidden delays in patient retention and compliance.





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