PATIENTS and METHODS
Study Context: The DFCI ALL Consortium conducts Phase 3 clinical trials for ALL at 8 U.S. and Canadian centers. DFCI Protocol 11-001 enrolled children from 2012 to 2015, and treatment as per DFCI 11-001 became the standard of care for patients at participating Consortium sites following trial closure after accrual. DFCI 11-001 included a two-year treatment course with a 70-week Continuation (maintenance) phase. Each 3-week cycle included day 1 vincristine (IV), days 1 – 5 dexamethasone (oral), days 1, 8, 15 methotrexate (IV), and days 1-14 6MP (oral). Parents were instructed to administer 6MP at bedtime, on an empty stomach, at least two hours before, and one hour after food or milk.
Patients: Eligible participants were English or Spanish speaking caregivers of children ages 1-18 years receiving Continuation therapy on or as per DFCI 11-001 between February 2015 and March 2017 at one of four participating Consortium sites (Montefiore Medical Center, Bronx, NY, Columbia University Irving Medical Center, New York, NY, DFCI, Boston, MA, and Hasbro Children’s Hospital of Rhode Island, Providence, RI). Informed consent/assent was obtained for all subjects and the study was approved by the Institutional Review Board at participating sites.
Surveys: Parent/guardians completed a single time-point, paper-pencil survey during a regularly scheduled clinic visit on Day 1 of a 3-week Continuation cycle. The survey included sociodemographic variables (patient/parent age, race, ethnicity, country of origin, family structure, education for each parent/guardian, household income, food insecurity, and marital status)4 as well as 33 dichotomous and multiple-choice questions related to 6MP comprehension, administration, and adherence adapted with permission from Bhatia et al.4 Low parental education was defined as having completed some high-school or less vs. high school graduate or more.5 Adherence survey questions inquired about medication-taking routines, daily administration challenges, and perceived risks associated with missing 6MP. Free-text questions asked whether more resources or reminders would be helpful to improve adherence.
Non-adherence: Patients were defined as 6MP non-adherent using two survey metrics of missed doses. These included: (1) a response of <14 days to the question “During the past 3 weeks, how many days did your child take 6MP? ” and (2) endorsement of missed doses during a prior cycle, or other changes to prescribed chemotherapy without instruction from a medical provider.