Characteristics of successful recruitment in prospective pediatric pharmacogenetic studies

There is a need to explore feasible means of accruing an appropriate study cohort to help fill the knowledge gap between pharmacogenetic contributions to drug response and clinical application in the pediatric population.

The aim of this study was to identify factors affecting recruitment of eligible subjects in pharmacogenetic studies at a large Midwestern pediatric academic medical center. The objectives were to evaluate recruitment success of ongoing trials and ascertain contributors to differential recruitment rates. We hypothesized that studies with good recruitment of eligible subjects would share characteristics not present in studies with lower than anticipated recruitment. The goal was to better understand barriers to good recruitment in pharmacogenetic studies to help inform future trial and infrastructure design.

Investigators designed a survey with proposed elements of success, which was then completed by lead and/or site investigators of all pharmacogenetics studies at the institution. Results were evaluated using an investigator-developed likelihood of success scoring system.

Two studies recruited >95% of the approached eligible patients; 4 studies were consistent with investigator-anticipated recruitment (>50%), and 1 study did not meet expected recruitment. A study's total score on the investigator-devised scoring tool correlated well with the proportion of approached patients recruited (Pearson's correlation, r = 0.82; P < 0.001). Multiple factors impacted successful recruitment into these pharmacogenetic studies. Features of studies with successful recruitment included standardized clinical care, an ongoing team-patient relationship, severe and/or life-threatening outcome measures, study coordinator with experience in clinical research, a study medication with few or no alternative treatment options, and active involvement of the research team in clinical care.

A scoring system for study characteristics may be useful to calculate the risk of failure for successful recruitment, allow discrimination among characteristics contributing to the risk, and permit study design alterations to improve likelihood of successful recruitment in pediatric pharmacogenetic studies.