Culturally Informed Motivational Interviewing to Improve Oral Chemotherapy Adherence for Pediatric Acute Lymphoblastic Leukemia Patients and Their Caregivers: A Feasibility, Acceptability, and Preliminary Efficacy Trial

BACKGROUND: Curative therapy for childhood acute lymphoblastic leukemia (ALL) mandates a two-to-three-year maintenance chemotherapy phase wherein patients must take daily oral 6-mercaptopurine (6-MP). 6-MP regimen adherence is challenging and failure to take medication has been associated with an increase in relapse risk. Accordingly, interventions that enhance 6-MP adherence during ALL maintenance chemotherapy may result in decreased morbidity and mortality for pediatric ALL patients. This study investigated the feasibility and acceptability of brief, English- and Spanish-delivered, culturally informed MI sessions during routine outpatient ALL maintenance therapy appointments. Additionally, this study preliminarily explored MI efficacy, compared to an education-only control, for improving caregiver-reported 6-MP adherence, patients' TGN blood serum levels, and caregiver-perceived 6-MP adherence barriers. METHOD: Participants included 121 caregivers (Age M(SD) = 36.66(8.02), 80.7% mothers, 47.1% Hispanic, 23.1% Spanish-speaking) of pediatric ALL patients (Age M(SD) = 7.55(4.80), range = .9-24; 66.1% male; Medicaid = 54.2%; B- and T-ALL risk category: Standard = 50.9%, High/Very High = 49.1%) in maintenance ALL treatment. Eighty caregivers (66.12%) were randomized to receive MI and the remaining 42 caregivers (33.8%) were randomized to the education-only control group. For the purpose of analyses, participants were categorized based on their ethnicity and primary language as a proxy for potential cultural similarities. Cultural categories included: (1) Non-Hispanic, English-speaking caregivers (N=63, 52.07%); (2) Hispanic, English-speaking caregivers (N=30, 24.79%); and (3) Hispanic, Spanish-speaking caregivers (N=28, 23.14%). Participants completed self-report measures assessing demographics, 6-MP adherence, 6-MP knowledge, perceived medication adherence barriers, and intervention acceptability. We obtained biological data (i.e., TGN concentrations) via chart review. MI sessions were audio recorded and rated using the MITI 4.2.1. coding manual to ensure intervention fidelity. Primary analyses included Analysis of Covariance (ANCOVA). We also conducted exploratory post-hoc analyses. RESULTS: Findings confirmed primary MI feasibility and acceptability hypotheses, supporting the possibility of delivering adherence-enhancing MI as part of routine oncological care. Additionally, although methodological limitations hindered adequate assessment of MI efficacy for improving caregiver-reported 6-MP adherence and patients' TGN concentration, post-hoc analyses suggested MI was effective for reducing caregiver-perceived 6-MP adherence barriers. CONCLUSIONS: MI may represent a deliverable, cost-effective, "no-risk" approach to improving adherence and represent an easily incorporated, low cost avenue for enhancing cure. Overall, study findings have the potential to inform a larger, future MI efficacy RCT by establishing the feasibility and acceptability of MI delivery during outpatient oncology clinic visits.