Researchers Identify ALL Patients At Risk for Low Oral Mercaptopurine Adherence

A study assessed the effect of a daily text message intervention on oral mercaptopurine adherence in adolescents with acute lymphoblastic leukemia (ALL). Although the intervention did not appear to have an effect on adherence, the study did unearth a group at risk for low adherence who should be the target of future intervention strategies—adolescents with low adherence at baseline.

In previous research of children with ALL, “Poor mercaptopurine adherence (mean adherence rates, <90% to 95%) was associated with a 2.5- to 3.9-fold higher relapse risk; up to 59% of ALL relapses were attributable to poor mercaptopurine adherence,” the researchers reported. “The most common reason for missing mercaptopurine was forgetfulness; adherent patients and parents endorsed parental vigilance as a strategy to overcome forgetfulness.”

For the present study, researchers compared mercaptopurine adherence between patients who received daily text message reminders plus education versus education alone.

The randomized clinical trial took place from July 16, 2012, through Aug. 8, 2018, at 59 Children’s Oncology Group institutions across the U.S. ALL patients diagnosed up to age 21 years and on maintenance mercaptopurine were randomized 1:1 to either the intervention or education alone. The text message intervention included a personalized text message every day.  The main outcome was the proportion of patients whose adherence rates were 95% or greater over the intervention duration; comparisons were made for the study group overall, as well as between patients aged younger than 12 years versus 12 years and older.

Final analysis included 444 patients (median age, 8.1 years; 68% were male): 230 intervention patients and 214 education alone patients. Overall, 40.5% of participants were white, 38.3% were Hispanic, 11.5% were Asian or of mixed race/ethnicity, and 9.5% were black. In the intervention and education alone groups, the rate of patients with adherence rates 95% or higher was not significantly different (65% vs. 59%; odds ratio=1.33; 95% confidence interval [CI], 1.0 to 2.0; P=0.08). When analyzing patients aged 12 years and older, intervention patients had a higher mean adherence rate than education alone patients (93.1% vs. 90.0%; difference, 3.1%; 95% CI, 0.1% to 6.0%; P=0.04). Among older patients whose baseline adherence was less than 90%, the difference between intervention versus education alone patients was even more significant (83.4% vs. 74.6%; difference, 8.8%; 95% CI, 2.2% to 15.4%; P=0.008).

The study was published in JAMA Network Open.

The researchers concluded that while the study did not meet its primary endpoints, “the intervention resulted in higher adherence rates in patients aged 12 years and older with baseline adherence less than 90%. These findings inform the next steps to enhance the efficacy of the intervention— that is, refinement in patient selection by including those at risk for poor adherence.”