Adherence to Treatment In Patients with Chronic Myelogenous Leukemia During a 10-Year Time Period: A Medical Record Review.

Over the past 10 years, oral treatment options for chronic myelogenous leukemia (CML) have provided patients autonomy over treatment administration. Low adherence to long-term maintenance therapy is a known challenge in a number of chronic diseases. The correlation between poor adherence and poor clinical outcomes has been previously demonstrated among CML patients in a clinical study setting. Few studies have evaluated adherence to CML treatments in a real-world setting and none have assessed treatment and adherence trends over time in a contemporary cohort of patients. Further, no studies have used medical record review to obtain comprehensive CML diagnosis and treatment information.

Medical and pharmacy claims from HealthCore Integrated Research Database™ (8.5 million covered US lives during study time period) were used to identify patients with CML (2001 – 2005). Review of medical records validated diagnosis and treatment exposure. Currently, additional data are being collected on this cohort to extend follow-up through 2010, and expand the number of CML patients to include data on the newer CML treatments. To measure adherence we used medication possession ratio (MPR) (number of days' supply of prescription divided by 365) and treatment interruptions (TI) (failure to refill prescription within 30 days of end of supply from previous prescription or clinician-directed discontinuation). For the current analysis, adherence to imatinib treatment was assessed for one year following treatment initiation.

In the initial study time frame (2001-2005), during which imatinib was indicated as first-line treatment, 216 CML patients treated with imatinib were identified. Mean age at imatinib initiation was 51 years and 42.6% were female. Fifty-one percent of patients had a MPR <85% for the one year period after imatinib initiation and 57% of patients experienced at least one TI during the follow up.

Our preliminary findings indicate that adherence to imatinib treatment is low in CML patients for the time period studied. This is the first study to use medical record review to validate exposure and adherence by obtaining comprehensive imatinib treatment information on CML patients in a real-world setting and indicates that adherence may be even lower than previously reported. Adherence data from ongoing analyses which includes longer patient follow-up (up to 10 years) and second-generation tyrosine-kinase inhibitors will be presented.

Hirji:Bristol-Myers Squibb: Employment. Davis:Bristol-Myers Squibb: Employment.