Patient recruitment and retention rates struggle

A new study has found that while nine out of 10 clinical trials worldwide meet enrollment goals, reaching those goals could mean doubling original timelines.

The research from the Tufts Center for the Study of Drug Development (CSDD) looked at 150 clinical trials from more than 16,000 trial sites worldwide.

“Patient recruitment and retention are among the greatest challenges that the clinical research enterprise faces today, and they are a major cause of drug development delays,” says Ken Getz, director of sponsored research at Tufts CSDD. “The results of our recent study paint a complex picture of global practices and their effectiveness and characterize a very high level of investigative site performance risk.” (More information on the study can be found at

The study also found that most drug sponsors and contract research sites rely on a limited number of traditional recruitment strategies, such as physician referrals and media such as television, print, and radio ads, and have not yet embraced social media and other new or non-traditional methods.

Other study findings include:

  • 89% of all clinical trials meet enrollment goals, with site activation rates reflecting success with study startup and speed to recruit the first patients.
  • The highest site activation rates are in Western Europe (93%), Eastern Europe (92%), and Asia/Pacific (91%).
  • Enrollment achievement rates vary by region, ranging from 75% to 98% of targeted levels, with Asia/Pacific and Latin America achieving the highest rates.
  • Eleven percent of sites in a given trial typically fail to enroll a single patient, 37% under-enroll, 39% meet their enrollment targets, and 13% exceed their targets.