Reasons for participation in optional pharmacokinetic studies in children with cancer: a Children's Oncology Group phase 1 consortium study.

Purpose: Pharmacokinetic (PK) studies provide critical information about the disposition of anticancer drugs in children. In the Children's Oncology Group (COG) Phase 1 Consortium, pharmacokinetic studies are usually optional. We surveyed the attitudes towards PK studies among subjects in phase 1 trials at COG institutions.

Methods: Subjects were eligible if they participated in a phase 1 anticancer drug study with optional PK studies within the 4 weeks, regardless of whether they agreed to participate in the PK studies. Staff provided demographics; subjects/parents completed a questionnaire.

Results: Fifty eligible subjects enrolled. Thirty-six (72%) of the 50 eligible subjects consented to participate in PK studies; 14 (25%) declined. The most common reasons for participating were "the results might help researchers learn more about the drug" and "results from the pharmacokinetic studies might help other children." The most common reasons for not participating were "having the samples drawn would mean spending extra time in the hospital," and "my child might have needed a separate IV catheter in order to participate."

Conclusions: The majority of subjects identified altruistic motives for participation in PK studies. Subjects who did not participate in PK studies identified extra time and need for an extra IV as important concerns. Simple interventions like sending staff to the subjects' home to draw PK samples or drawing samples from existing catheters could increase the number of subjects who are willing to participate in PK studies.