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The Struggles of Clinical Trial Enrollment - How to Address Site Specific Issues

The general public may not give much thought to clinical trials until after receiving a diagnosis for heart disease, cancer or another debilitating disease. When faced with a disability or even death, the idea of hope and a cure make signing up for a trial an easy decision. But for other conditions, it’s not this easy.

Struggling with clinical trial enrollment stems from three main issues. This article explores these complex hurdles and offers solutions you can use with your CRO and clinical research sites.

Site Specific Issues

site specific issues, barriers to clinical trials

Finding Study Participants

Have you ever been prepping for a new study and notice lots of potential candidates, only to see that once enrollment opens those candidates are no longer around? It happens to study staff everywhere. And, even if you find candidates, they may not fit the inclusion criteria. Here are a few hurdles common to potential enrollees:

  • Medical Barriers - Some patients are trying to cope with their new diagnosis and are not able to psychologically handle the idea of “experimenting” with a new drug or treatment.
  • Visit Barriers - Study participants may find it difficult to attend study visits due to transportation issues or missing multiple days of school or work. 
  • Study Protocol Barriers - If a study requires invasive testing or monitoring, it may scare away potential candidates who don’t think they can handle the requirements of the study.

Struggles with Enrollment Deadlines

deadlines, struggles for clinical sites

Clinical trials are notoriously fraught with complexity. If it's a trial for a rare disease, the patient population may be quite small and hard to reach. Patients may be located all over the country and are therefore not amenable to a site-specific model.

Slow patient enrollment can create struggles with enrollment completion and preliminary data-point deadlines. Impending deadlines can create a stressful work environment. When faced with deadline barriers, there are better solutions than putting unnecessary pressure on colleagues, your CRO or other clinical partner.

Competing Trials

If it's a trial for a large patient population, your primary investigators may be involved in multiple competing trials sponsored by various companies. When trials are close to ending, the site has to make sure there’s another study coming to keep the research site running strong.

Multiple studies for the same disease or diagnosis can create clinical trial barriers. They can slow down enrollment due to a limited patient population or small numbers of study staff since the site isn’t always focused solely on one project.

Two Solutions for Clinical Sites

Looking for solutions to these everyday clinical site struggles? Here are are a couple we like.

Solution #1 - Meet Face to Face

solution meet face to face

Working in partnership with your investigator teams is critical to solving the enrollment issues at your site. This partnership can be done in two ways:

  • As a group at an investigator meeting
  • Via individual clinical site visits, where nuances about a specific hospital system or region can be further explored.

Meeting with your primary investigators, sub-investigators, and study coordinators will answer a lot of questions to the "why" of the problem.

They will know if patients find the protocol too difficult to follow or if the testing is inconvenient. It’s important to listen to your study team to help brainstorm solutions. In cases like these, it may be best to see if any modifications to the protocol are possible. Are there more convenient ways to get the same measurements and test results? Perhaps the sponsoring company or CRO can create some educational materials that make it easier for the patients to understand why things must be done in a particular manner.

Partner with your investigators and clinical sites to understand the root of the problem and devise solutions. Be creative and host a “breakout group” discussion at an investigator meeting or advisory board. Ask questions like:

  • “How can we get more enrollees?”
  • “Do we need a more creative approach?”
  • “Can we put the protocol outline in straightforward language for patients?”

Study staff will also know if patients have challenges with getting to the trial and/or missing work. Solutions include:

  • Transportation Services - Many clinical trials now offer transportation to the site via Lyft or Uber, to make it easier for patients to participate. Clinical trial company Science 37 conducts trials based on a siteless model, where patients may be monitored at home via traveling nurses and an online system called NORA.
  • Missing Work - Some enrollees may not be able to take time off of work to go to the site for testing. In those cases, some sponsoring companies may reimburse those patients for the corresponding lost wages.

Solution #2 - Increase Awareness

patient support groups

Another approach can be working directly with patients to increase awareness of the trial.


Three ideas include:

  • Patient Support Groups - Sponsors can work with patient support groups on a national or regional level. Following appropriate regulatory guidance, the support groups can inform patients about the trial. 
  • Advertising Firms - There are also many advertising firms, such as Subjectwell, that can work to promote the trial to potential study patients in unique and authentic ways.
  • Work with Referring Physicians - Connecting with primary physicians as a study referral source is another approach to consider. 

Some physicians who aren't investigators may be reluctant to refer a patient to a trial. They may fear losing the regular ongoing business of the patient. In these cases, educate the physician that the relationship with the patient is strictly related to the trial. Consider contracts that can be put in place to protect the physician’s relationships with their patients. Host a local networking evening for referring physicians, which offers an excellent opportunity to educate them about the trial while building new relationships.

Clinical trial enrollment and maintenance is a large and complex process. Engaging with your investigator teams through investigator meetings or clinical site visits, connecting with referring physicians via newsletters or networking evenings, and reaching out to patients via support and advocacy groups are all vital steps in the process. By using these solutions, you will improve the likelihood of meeting timelines and enrollment goals, so that you are closer to a potential cure or treatment.