Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hair depigmentation has been shown to occur with disruption of the interaction between the ligand stem cell factor (SCF) with its class III receptor tyrosine kinase c-kit, also called the stem cell factor receptor. This article reports the case of a patient who experienced depigmentation of her eyelashes, eyebrows, and temporal scalp hair six-to-eight weeks after initiating treatment with dasatinib (BMS-354825 or Sprycel), a novel dual Bcr-Abl/Src family tyrosine kinase inhibitor for chronic myeloid leukemia (CML). This case illustrates a previously unreported side-effect of dasatinib that is most likely due to the drug's inhibition of the c-kit, Src family, and platelet-derived growth factor receptor beta (PDGFRbeta) tyrosine kinases. Further study of hair depigmentation as a side effect of multi-kinase inhibitors can provide useful information on hair and melanocyte physiology.
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PMID:Hair depigmentation during chemotherapy with dasatinib, a dual Bcr-Abl/Src family tyrosine kinase inhibitor. 1936 59

Dasatinib is the most potent BCR-ABL inhibitor, with 325-fold higher potency than imatinib against unmutated BCR-ABL in vitro. Studies have demonstrated the benefits of dasatinib 70 mg twice daily in patients with accelerated-phase chronic myeloid leukemia intolerant or resistant to imatinib. A phase 3 study compared the efficacy and safety of dasatinib 140 mg once daily with the current twice-daily regimen. Here, results from the subgroup with accelerated-phase chronic myeloid leukemia (n = 317) with a median follow-up of 15 months (treatment duration, 0.03-31.15 months) are reported. Among patients randomized to once-daily (n = 158) or twice-daily (n = 159) treatment, rates of major hematologic and cytogenetic responses were comparable (major hematologic response, 66% vs 68%; major cytogenetic response, 39% vs 43%, respectively). Estimated progression-free survival rates at 24 months were 51% and 55%, whereas overall survival rates were 63% versus 72%. Once-daily treatment was associated with an improved safety profile. In particular, significantly fewer patients in the once-daily group experienced a pleural effusion (all grades, 20% vs 39% P < .001). These results demonstrate that dasatinib 140 mg once daily has similar efficacy to dasatinib 70 mg twice daily but with an improved safety profile. This trial is registered at www.clinicaltrials.gov as #CA180-035.
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PMID:Phase 3 study of dasatinib 140 mg once daily versus 70 mg twice daily in patients with chronic myeloid leukemia in accelerated phase resistant or intolerant to imatinib: 15-month median follow-up. 1994 22

Dasatinib is a tyrosine kinase inhibitor (including BCR-ABL and the SRC family) that is effective in patients with chronic myeloid leukemia. Dasatinib has pH-dependent solubility and is bioavailable as an oral formulation. The effect of gastric pH modifiers on dasatinib pharmacokinetics is evaluated in an open-label, randomized, 3-period, 3-treatment crossover study. Twenty-four healthy subjects receive treatment A (2 doses of dasatinib 50 mg separated by 12 hours), treatment B (famotidine 40 mg given 2 hours after dasatinib 50 mg and 10 hours before another dose of dasatinib 50 mg), and treatment C (30 mL of an antacid containing aluminum/magnesium hydroxides given 2 hours before dasatinib 50 mg and concomitantly with dasatinib 50 mg 12 hours after the previous dasatinib dose); a 7-day washout separates each treatment period. When famotidine is administered 2 hours after dasatinib, dasatinib exposure is similar to dasatinib administered alone. However, dasatinib exposure is reduced by approximately 60% when famotidine is administered 10 hours before dasatinib dosing. In contrast, dasatinib exposure is unchanged when antacid (Maalox) is administered 2 hours before dasatinib; but when the antacid is coadministered with dasatinib, dasatinib exposure is reduced by approximately 55% to 58%. This indicates that H(2)-receptor antagonists should not be coadministered with dasatinib. Dasatinib may be administered with acid-neutralizing antacids if the doses are temporally separated by at least 2 hours.
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PMID:Phase I study of the effect of gastric acid pH modulators on the bioavailability of oral dasatinib in healthy subjects. 1939 85

Treatment with imatinib has demonstrated high response rates and improved prognosis in chronic myelogenous leukemia. However, while the short-term response to imatinib is high, there are some concerns that the long-term response is substantially lower. Durable response with imatinib is difficult to achieve in patients with resistant disease. The use of higher doses has also been associated with increased toxicity and intolerance. Dasatinib is a new SRC-ABL-kinase inhibitor that has been developed for treating chronic myelogenous leukemia patients, across all phases of disease, who are resistant or intolerant to imatinib. This article details the existing evidence on the clinical efficacy, safety and value for money of dasatinib in the treatment of imatinib-resistant and -intolerant patients with chronic myelogenous leukemia. Dasatinib is associated with higher levels of response compared with high-dose imatinib. In addition, higher levels of response are associated with improved health outcomes in terms of both quality- and quantity-of-life years.
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PMID:Pharmacoeconomic benefits of dasatinib in the treatment of imatinib-resistant patients with chronic myelogenous leukemia. 1940 98

Dasatinib is associated with increased risk of bleeding among patients with chronic myeloid leukemia, even in the absence of thrombocytopenia, suggesting the presence of a hemostatic defect. We tested platelet aggregation in 91 patients with chronic myeloid leukemia in chronic phase either off-therapy (n = 4) or receiving dasatinib (n = 27), bosutinib (n = 32), imatinib (n = 19), or nilotinib (n = 9). All but 3 patients simultaneously receiving imatinib and warfarin had normal coagulation studies. All 4 patients off therapy had normal platelet aggregation. Impaired platelet aggregation on stimulation with arachidonic acid, epinephrine, or both was observed in 70%, 85%, and 59% of patients on dasatinib, respectively. Eighty-five percent of patients on bosutinib, 100% on nilotinib, and 33% on imatinib had normal platelet aggregation. Dasatinib 400 nM induced rapid and marked prolongation of closure time to collagen/epinephrine in normal whole blood on the PFA-100 system. In conclusion, dasatinib and, to some extent, imatinib produce abnormalities in platelet aggregometry testing.
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PMID:Tyrosine kinase inhibitor-induced platelet dysfunction in patients with chronic myeloid leukemia. 1941 63

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.
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PMID:Clinical profile of dasatinib in Asian and non-Asian patients with chronic myeloid leukemia. 1945 91

PURPOSE Patients with chronic myelogenous leukemia in accelerated phase (CML-AP) that is resistant or intolerant to imatinib have limited therapeutic options. Dasatinib, a potent inhibitor of BCR-ABL and SRC-family kinases, has efficacy in patients with CML-AP who have experienced treatment failure with imatinib. We now report follow-up data from the full patient cohort of 174 patients enrolled onto a phase II trial to provide a more complete assessment of the efficacy and safety of dasatinib in this population. PATIENTS AND METHODS Patients with imatinib-resistant (n = 161) or -intolerant (n = 13) CML-AP received dasatinib 70 mg orally twice daily. Results At a median follow-up of 14.1 months (treatment duration, 0.1 to 21.7 months), major and complete hematologic responses were attained by 64% and 45% of patients, respectively, and major and complete cytogenetic responses were achieved in 39% and 32% of patients, respectively. Responses were achieved irrespective of imatinib status (resistant or intolerant), prior stem-cell transplantation, or the presence of prior BCR-ABL mutation. The 12-month progression-free survival and overall survival rates were 66% and 82%, respectively. Dasatinib was generally well tolerated; the most frequent nonhematologic severe treatment-related adverse event was diarrhea (52%; grade 3 to 4, 8%). Cytopenias were common, including grade 3 to 4 neutropenia (76%) and thrombocytopenia (82%). Pleural effusion occurred in 27% of patients (grade 3 to 4, 5%). CONCLUSION Dasatinib is effective in patients with CML-AP after imatinib treatment failure.
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PMID:Dasatinib in the treatment of chronic myeloid leukemia in accelerated phase after imatinib failure: the START a trial. 1948 85

The novel tyrosine kinase inhibitor dasatinib (Sprycel; BMS-354825) is approved for use in imatinib (Gleevec; STI 571)-resistant or -intolerant chronic myelogenous leukemia and may be useful for other tumors in the central nervous system (CNS). The objective of this study was to investigate the role of P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) in modulating the CNS penetration of dasatinib. Results from the in vitro studies indicate that cellular delivery of dasatinib is significantly limited by active efflux due to both P-gp and BCRP. Permeability studies indicated greater permeability in the basolateral-to-apical direction than in the apical-to-basolateral direction due to active efflux by P-gp or BCRP. Selective inhibitors of P-gp and BCRP, such as (R)-4-((1aR,6R,10bS)-1,2-difluoro-1,1a,6,10b-tetrahydrodibenzo-(a,e)cyclopropa(c) cycloheptan-6-yl)-alpha-((5-quinoloyloxy)methyl)-1-piperazineethanol, trihydrochloride (zosuquidar; LY335979) and 3-(6-isobutyl-9-methoxy-1,4-dioxo-1,2,3,4,6,7,12,12alpha-octahydropyrazino1',2': 1,6pryrido3,4-bindol-3-yl)-propionic acid tert-butyl ester (Ko143), were able to restore the intracellular accumulation and abolish the directionality in net flux of dasatinib. In vivo brain distribution studies showed that the CNS distribution of dasatinib is limited, with the brain-to-plasma concentration ratios less than 0.12 in wild-type mice, which increased approximately 8-fold in Mdr1a/b(-/-) Bcrp1(-/-) mice. Dasatinib brain distribution was significantly increased in Mdr1a/b(-/-) mice and when wild-type mice were pretreated with LY335979. Simultaneous inhibition of P-gp and BCRP by elacridar [N-(4-[2-(1,2,3,4-tetrahydro-6,7-dimethoxy-2-isoquinolinyl)ethyl]-phenyl)-9,10-dihydro-5-methoxy-9-oxo-4-acridine carboxamide] (GF120918) resulted in a 5-fold increase in brain concentration. These in vitro and in vivo studies demonstrate that dasatinib is a substrate for the important efflux transporters p-glycoprotein and BCRP. These transport systems play a significant role in limiting the CNS delivery of dasatinib and may have direct implications in the treatment of primary and metastatic brain tumors.
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PMID:P-glycoprotein and breast cancer resistance protein influence brain distribution of dasatinib. 1949 23

Dasatinib is an oral potent adenosine triphosphate (ATP)-competitive inhibitor of BCR-ABL, cKIT, platelet-derived growth factor receptor, and SRC family kinases (SFKs), which has demonstrated high efficiency in patients with imatinib-resistant chronic myelogenous leukemia. Here, we show that dasatinib weakly affects platelet activation by thrombin or adenosine diphosphate but is a potent inhibitor of platelet signaling and functions initiated by collagen or FcgammaRIIA cross-linking, which require immunoreceptor tyrosine-based activation motif phosphorylation by SFKs. Accordingly, dasatinib treatment rapidly decreases the volume of thrombi formed under arterial flow conditions in whole blood from patients or mice perfused over a matrix of collagen. Moreover, treatment of mice with dasatinib increases the tail bleeding time in a dose-dependent manner. Interestingly, these effects are rapidly reversible after interruption of the treatment. Our data clearly demonstrate that, in contrast to imatinib, dasatinib affects platelet functions in vitro and in vivo, which has important implications in clinic and could explain increased risks of bleeding observed in patients. Moreover, dasatinib efficiently prevents platelet activation mediated by FcgammaRIIA cross-linking and by sera from patients with heparin-induced thrombocytopenia, suggesting that reversible antiplatelet agents acting as ATP-competitive inhibitors of SFKs may be of therapeutic interest in the treatment of this pathology.
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PMID:The new tyrosine-kinase inhibitor and anticancer drug dasatinib reversibly affects platelet activation in vitro and in vivo. 1971 76

The BCR-ABL inhibitor imatinib is standard first-line therapy for patients with chronic myeloid leukemia (CML) and has revolutionized treatment of the disease. However, resistance and intolerance to the agent have emerged as major clinical complications. Dasatinib is the first and only dual BCR-ABL/SRC family kinase inhibitor approved by the U.S. Food and Drug Administration for the treatment of patients with CML in any phase or Philadelphia chromosome-positive acute lymphoblastic leukemia who are resistant to or intolerant of imatinib. The agent is well tolerated and has shown clinical activity in such patients. As with other oral tyrosine kinase inhibitors, nonadherence to the prescribed dasatinib treatment regimen could obstruct a successful outcome. A new recommended dose of 100 mg once daily has been approved for patients with chronic phase CML. That dosing regimen, combined with appropriate management of dasatinib-related adverse events, may help patients adhere to their prescribed treatment and achieve maximum therapeutic benefit. This article highlights recent changes to the dasatinib label, including results with the 100 mg once-daily starting dose for patients with chronic phase CML, and discusses nursing strategies for the successful management of adverse events in patients receiving dasatinib.
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PMID:A once-daily dasatinib dosing strategy for chronic myeloid leukemia. 1950 90


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