6600 Background: Imatinib (IM) is the most commonly used drug in the treatment of chronic myeloid leukemia-chronic phase (CML-CP) patients (pts). This study investigated the treatment patterns and outcomes for veteran CML-CP pts initiated on IM. Methods: Pts (age >18 yrs) with >1 CML diagnosis codes documented (ICD-9 CM: 205.1x) between 1/1/2000 and 12/31/2010 were identified from the VISN 16 data warehouse. Pts were required to have initiated IM as the first-line therapy in CML-CP. Accelerated and blastic phases (A/BP) were identified based on WHO classification using CBC information. IM dose adjustments were assessed as dose increase from <400 mg to >600mg or from 400-600mg to >800 mg daily. Rates of IM discontinuation (no use of IM for >60 days) and switching to other drug therapy (dasatinib/nilotinib (DS/NL), hydroxyurea, and interferon-alpha) were estimated. Time to discontinuation, progression to A/BP, and survival were assessed using Kaplan-Meier analysis (K-M). Overall survival was measured from IM initiation while survival among pts with disease progression was measured from the date of progression. Results: Among the 137 pts selected, average age was 64.8 yrs and follow-up time was 4.0 yrs. 16.8% of pts had dose increase from <400mg to >600mg and 21.7% of these pts switched to other therapy after dose increase. 13.1% of pts had dose increase from 400-600mg to >800 mg with 22.2% of these pts switching to other therapy later. During the study, 83.8% of the 74 pts who discontinued IM did not use other drug therapies; and 16.2% (12 pts) switched, among which 9 pts took DS/NL. K-M showed that 25.6% and 42.4% pts discontinued IM treatment by year 1 and 2 and 8.1% and 16.0% pts experienced disease progression by year 1 and 2, respectively. Among the 28 patients who had disease progression, 32.1% continued IM use after progression and only 7.1% switched to other therapies (50% switching to DS/NL). The mortality rates were 3.0% and 9.5% by year 1 and 2 after IM initiation, and 21.7% and 42.7% by year 1 and 2 after disease progression, respectively. Conclusions: The majority of IM-treated patients, including patients with disease progression, discontinued IM use without switching to other effective therapies.
PCN185 A Multi-Country Retrospective Study of Patient Characteristics and Treatment Patterns in Chronic Myeloid Leukemia
