RESUMEN
Dasatinib is a BCR-ABL inhibitor with 325-fold higher potency than imatinib against unmutated BCR-ABL in vitro. Imatinib failure is commonly caused by BCR-ABL mutations. Here, dasatinib efficacy was analyzed in patients recruited to phase 2/3 trials with chronic-phase chronic myeloid leukemia with or without BCR-ABL mutations after prior imatinib. Among 1043 patients, 39% had a preexisting BCR-ABL mutation, including 48% of 805 patients with imatinib resistance or suboptimal response. Sixty-threedifferent BCR-ABL mutations affecting 49 amino acids were detected at baseline, with G250, M351, M244, and F359 most frequently affected. After 2 years of follow-up, dasatinib treatment of imatinib-resistant patients with or without a mutation resulted in notable response rates (complete cytogenetic response: 43% vs 47%) and durable progression-free survival (70% vs 80%). High response rates were achieved with different mutations except T315I, including highly imatinib-resistant mutations in the P-loop region. Impaired responses were observed with some mutations with a dasatinib median inhibitory concentration (IC(50)) greater than 3nM; among patients with mutations with lower or unknown IC(50), efficacy was comparable with those with no mutation. Overall, dasatinib has durable efficacy in patients with or without BCR-ABL mutations. All trials were registered at http://www.clinicaltrials.gov as NCT00123474, NCT00101660, and NCT00103844.
Asunto(s)
Proteínas de Fusión bcr-abl/genética , Leucemia Mielógena Crónica BCR-ABL Positiva/tratamiento farmacológico , Leucemia Mielógena Crónica BCR-ABL Positiva/genética , Inhibidores de Proteínas Quinasas/uso terapéutico , Pirimidinas/uso terapéutico , Tiazoles/uso terapéutico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Ensayos Clínicos Fase II como Asunto , Ensayos Clínicos Fase III como Asunto , Análisis Mutacional de ADN , Dasatinib , Femenino , Humanos , Estimación de Kaplan-Meier , Leucemia Mielógena Crónica BCR-ABL Positiva/mortalidad , Masculino , Persona de Mediana Edad , Mutación , Ensayos Clínicos Controlados Aleatorios como Asunto , Resultado del Tratamiento , Adulto JovenRESUMEN
Resistance and intolerance to imatinib are of particular clinical relevance to Asian patients because of their lower body surface area. Dasatinib is 325-fold more potent than imatinib in inhibiting BCR-ABL in vitro and is indicated for the treatment of chronic myeloid leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia resistant or intolerant to imatinib. Data from a series of phase I/II research trials were analyzed to compare the efficacy, safety and pharmacokinetic profile of dasatinib 70 mg twice daily in Asian and non-Asian patients. Results from 55 Asian and 615 non-Asian patients demonstrated that the efficacy and safety of dasatinib was comparable. Dasatinib was well tolerated, with no observed toxicities exclusive to Asian patients. A higher incidence of adverse events and lower rate of response observed among Asian patients with myeloid blast phase CML reflected the aggressive nature of the disease. Analyses of noncompartmental pharmacokinetics (5 Asian and 49 non-Asian patients) and population pharmacokinetics (17 Asian and 382 non-Asian patients) were also comparable. The efficacy, safety and pharmacokinetic profile of dasatinib 70 mg twice daily is similar in Asian and non-Asian patients with CML. Dasatinib is therefore an important therapeutic option for this patient population.