Mercaptopurine Ingestion Habits and Risk of Relapse in Children With Acute Lymphoblastic Leukemia


Key Points

  • In children with acute lymphoblastic leukemia, mercaptopurine ingestion habits associated with an increased likelihood of nonadherence included taking medication with dairy and at varying times.
  • After adjustment for adherence and other prognostic factors, there was no significant association between ingestion habits and relapse risk.

In a report from the Children’s Oncology Group Study AALL03N1 published in the Journal of Clinical Oncology, Landier et al found no association between oral mercaptopurine ingestion habits in children with acute lymphoblastic leukemia and risk of relapse after adjustment for medication adherence. Patients usually are instructed to take mercaptopurine in the evening and without food or dairy products.

Study Details

The study included 441 children from 81 participating institutions receiving mercaptopurine maintenance. Adherence was monitored over 48,086 patient-days using the Medication Event Monitoring System. Nonadherence was defined as an adherence rate < 95%. Patients had a median age of 6 years.

Ingestion Habits and Relapse Risk

Overall, 43.8% of patients were nonadherent to the mercaptopurine regimen. Ingestion habits e associated with an increased likelihood of nonadherence included taking medication with dairy (odds ratio [OR] = 1.9, P = .003) and taking medication at varying times vs in the evening/night (OR = 3.4, P = .0001). In an analysis adjusting for adherence and other prognostic factors, there was no association between relapse risk and taking mercaptopurine with food (hazard ratio [HR] = 0.7, P = .5), with dairy (HR = 0.3, P = .2), in the evening/night (HR = 1.1, P = .9), or at varying times (HR = 0.3, P = .3).

Analysis among only adherent patients showed no association between average dose–adjusted red cell thioguanine nucleotide levels (in pmol/8 × 108 erythrocytes) and taking mercaptopurine with vs without food (206.1 vs 220.6, P = .5), with vs without dairy (220.1 vs 216.3, P =.7), or in the evening/night vs morning/midday vs varying times (218.8 vs 195.5 vs 174.8, P = .6 overall).

The investigators concluded: “Commonly practiced restrictions surrounding [mercaptopurine] ingestion might not influence outcome but may hinder adherence. Future recommendations regarding [mercaptopurine] intake during maintenance therapy for childhood [acute lymphoblastic leukemia] should aim to simplify administration.”

The study was supported by the National Cancer Institute, the National Institute of General Medical Sciences, the Children’s Oncology Group, St. Baldrick’s Foundation, and the American Lebanese Syrian Associated Charities.

Smita Bhatia, MD, MPH, of the Institute for Cancer Outcomes and Survivorship, University of Alabama at Birmingham, is the corresponding author of the Journal of Clinical Oncology article.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.