Abstract
OBJECTIVE: To assess rates of adherence to oral chemotherapy during maintenance chemotherapy in children with acute lymphoblastic leukemia (ALL).
BACKGROUND: 25-30% of children with ALL eventually relapse. Relapse can be explained by high risk biological features in a minority of ALL patients, but why the majority of children relapses, has not been determined. An important part of treatment for leukemia consists of a prolonged period of maintenance oral chemotherapy. Prolonged low dose medication is thought to kill newly dividing leukemic cells. Discontinuing medication early might therefore increase the risk of relapse.
METHODS: Children with ALL diagnosed at Riley Hospital were identified. Pharmaceutical claims data from Indiana Medicaid for 1/1992 – 12/ 2004 were analyzed to investigate chemotherapy use patterns for Methotrexate and 6-Mercaptupurine during maintenance chemotherapy and then were compared to prescription orders from written medical records. Multigraph timeline visualizations were used to analyze prescription data, medication fill data and laboratory data on each patient.
RESULTS: A total of 56 patients who took 6-Mercaptopurine and Methotrexate were identified in the Medicaid database. Two measures were used for medication adherence: the continuous measure of medication availability during maintenance therapy and the continuous measure of medication gaps. Two-thirds of the children were prescribed at least 75% of the recommended protocol dosage for 6-Mercaptopurine and Methotrexate. However, only 32% of the children filled between 75-100% of the prescribed medication while 21% filled 50-75%, 14% filled 25-50%, and 12% filled less than 25% of the prescribed medication. 21% over filled. Only 46% of the children had medication available for 75-100 % of the days during maintenance chemotherapy whereas 11% had medication available less 25% of the time.
CONCLUSIONS: Reducing the amount of maintenance therapy in clinical trials has been shown to reduce the event free survival for ALL. However adherence to medication is not studied or monitored in any of the national clinical trials. Pharmacy refill data allows analysis of large numbers of patients over prolonged periods of time and can help determine the upper limit of possible medication adherence. Our study shows that only 46% of the children filled enough of their medication to be able to take it more than 75% of the time. Multigraph timeline visualization of the prescription data, refill data and laboratory data gives a more complete picture of actual medication adherence than currently exists and can allow real-time monitoring of patients during their maintenance chemotherapy.
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Ragg, S., Paine, J., Lee, N. et al. 25 Profile of Noncompliance with Oral Chemotherapy in Children with Acute Lymphoblastic Leukemia.. Pediatr Res 60, 494 (2006). https://doi.org/10.1203/00006450-200610000-00047
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DOI: https://doi.org/10.1203/00006450-200610000-00047