Clinical trial implementation and recruitment: lessons learned from the early closure of a randomized clinical trial

The NHLBI-sponsored Sickle Cell Disease Clinical Research Network (SCDCRN) conducted a multi-center, acute intervention randomized clinical trial of two methods of Patient Controlled Analgesia for acute pain. This trial was terminated early due to low enrollment. We analyzed the perceived barriers and recruitment difficulties as reported by the coordinators and principal investigators.

Participating sites completed a missed eligibility log of subjects admitted in pain crisis throughout the study and a survey at the end of the trial. The survey covered site-specific factors, policies, and procedures in study implementation, recruitment strategies, and eligibility factors. The New England Research Institutes (NERI) collected de-identified surveys from 31 respondents at 29 of 31 participating sites.

From December 2009 to June 2010, 1116 patient encounters for SCD and pain occurred at participating institutions: 38 subjects were enrolled (14 pediatric and 24 adults) and 34 completed the trial, below the projected 278 subjects. Fourteen sites enrolled subjects and seventeen did not. Recruitment barriers included insufficient staff, subject ineligibility or in too much pain to consent, competing protocols, and concerns regarding pain control. Recruitment methods were referrals from urgent care, SCD clinics and in house databases. No use of media or outside physicians was reported.

We identified multiple barriers to patient accrual including short duration of enrollment period, protocol design, complex dosing schedule, requirement for staff availability during week-end and after hours, multiple departments' involvement, protocol acceptance, eligibility criteria, competing protocols, and limited staff. Each of these areas should be targeted for intervention in order to plan and conduct successful future clinical trials.