Frequency of treatment changes observed in chronic myeloid leukemia (CML) patients using imatinib mesylate (IM)

Abstract

16003 Background: Although the response rates in CML associated with IM treatment is well-documented, little research exists on actual practice patterns with IM. The objective of this study is to document treatment changes in a large CML patient population using IM. Methods: Patients ≥ 18 years of age diagnosed with CML (ICD9 = 205.1) between 2000 and 2004 and treated with IM were selected from the Medstat MarketScan Commercial, Medicaid and Medicare Research Databases. Disease phase was defined using a CML specific disease staging algorithm and was assigned at the time of imatinib initiation. A treatment change is defined as evidence of any of the following: any dose increase ≥50 mg, CML treatment added to IM, or IM discontinuation. Summary statistics reported are medians and interquartile ranges (IQR). Results: Four hundred adult IM-treated CML patients (mean age, 56 years; 50% male) were included. 81% and 18% were in chronic phase (CP) and accelerated phase (AP), respectively; with 1% in remission. IM 400 mg was most frequently used regardless of CML phase or year of treatment. The daily starting dose was 400 mg in 305 (78%) patients, 600–799 mg in 34 (9%) patients, ≥ 800 mg in 17 (4%), and the remaining 39 (9%) started at doses < 400 mg. Median follow-up of treatment duration was 9 (IQR: 4.6, 18.9) months. 158 (40%) patients on IM had at least one treatment change, with rates higher in AP patients than in CP (52% vs. 37%). Dose increases were reported in 108 (27%) patients, 3 (<1%) had additional CML treatment, and 64 (16%) discontinued IM altogether. Conclusions: 40% of patients treated with IM had at least one treatment change. The frequency of treatment change increased with longer duration of IM treatment. [Table: see text] [Table: see text]