Dasatanib (D) in patients (pts) with chronic myelogenous leukemia (CML) in lymphoid blast crisis (LB-CML) or Philadelphia-chromosome positive acute lymphoblastic leukemia (Ph+ALL) who are imatinib (IM)-resistant (IM-R) or intolerant (IM-I): The CA180015 ‘START-L’ study

Abstract

6528 Background: Dasatinib (D) (BMS-354825) is a multi-targeted kinase inhibitor of BCR-ABL and SRC. Preliminary data from a phase I study suggest high efficacy of D in IM pretreated pts. Methods: START L is an open label phase II study of D in IM-R or IM-I pts with LB-CML and Ph+ALL conducted at 42 centers worldwide. D was given orally, 70 mg twice a day (bid), with escalation to 100 mg bid for poor response or reductions to 50 mg and 40 mg bid for toxicity. Pts had weekly blood counts and monthly bone marrow exams, including cytogenetics. The primary endpoint was confirmed (sustained for at least 4 weeks) major hematologic response (MaHR) rates. Results: From January to June 2005, 101 pts were accrued. Data are available on the first 78 treated pts (42 LB-CML, 36 Ph+ALL). Of the 42 LB-CML pts, 37 were IM-R, 52% were male with median (med) age of 47 years. Prior therapy included IM >600 mg/day in 52% and stem-cell transplant (SCT) in 33% of pts. Med baseline platelet (plt) count was 32.5/nl, med BM blasts were 82%, Bcr-Abl mutations were seen in 48%, and extramedullary disease (EMD) was seen in 29% of pts. The D dose was reduced in 14%, temporarily interrupted in 33%, and escalated in 26% of pts. At 6-months, the MaHR rate was 31% including 26% complete hematologic response (CHR), the MCyR rate was 50%, and 17% of pts remained on study. Of the 36 Ph+ALL pts, 34 were IM-R, 64% were male with med age 46 years. Prior therapy included IM> 600 mg/day in 47% and SCT in 42% of pts. Baseline plt count was 53.5/nl, med BM blasts were 69%, Bcr-Abl mutations were seen in 47% and EMD was seen in 31% of pts. The D dose was reduced in 28%, temporarily interrupted in 39%, and escalated in 47% of the pts. At 6-months, the MaHR rate was 42% including 31% CHR, the MCyR rate was 58%, and 33% pts remained on study. Among all 78 pts, grade 3–4 thrombocytopenia and neutropenia was seen in 82% and 76% of pts, respectively. The most frequent D-related non-hematologic toxicities were diarrhea (30%), nausea (23%), fatigue (19%), rash (17%) and pleural effusion (13%). Conclusions: D is active in IM pretreated LB-CML and Ph+ALL pts. Data on all 101 pts will be presented at the meeting. [Table: see text]

Defining and Managing Imatinib Resistance

“…Phase II studies for dasatinib [32][33][34][35] in all phases of CML and Ph + ALL have been reported and supported rapid ap- proval of the compound (named Sprycel) on 6/29/06 for both indications; the recommended dose is 70 mg BID. In the "Start-C" trial of dasatinib in CP CML, 32 60% of patients required dose reductions over time for toxicity and the median dose was closer to 100 mg per day; ongoing trials continue to explore dosing options for dasatinib, including varying total dose and QD versus BID dosing.…”

Evaluación económica del dasatinib en el tratamiento de la leucemia mieloide crónica en pacientes resistentes al imatinib en Chile

“…En modelos de línea celular, el dasatinib inhibió la mayoría de las mutaciones BCR-ABL referidas a la resistencia al imatinib, lo que puede explicar en parte la mayor eficacia reportada con el dasatinib in vitro. (26)(27)(28)(29) Una respuesta durable, tanto hematológica como citogenética y molecular ha sido demostrada con el dasatinib en estudios clínicos fase II y III, en pacientes con leucemia mieloide crónica (30)(31)(32).…”