- Subjects who consented within the 4 weeks prior to enrollment on this questionnaire study to a Phase 1 study that included optional PK sampling. (If the subject was a minor and a parent or legally authorized representative provided consent, subject for this questionnaire study refers to the parent). The PK questionnaire should be completed within 4 weeks of when the subject consented to the study that included optional PK sampling. (Note: The Phase 1 study need not have been a COG study).