Imatinib-treated Patients Research Articles

Pharmacokinetics and cellular uptake of imatinib and its main metabolite CGP74588.

Despite the remarkable clinical response rates to imatinib in the treatment of bcr-abl leukemic patients, pharmacokinetic data on this relatively novel substance are needed to improve our understanding of the emergence of resistance, the interindividual variations of clinical response and the clinical and biologic relevance of its main metabolite N-desmethyl-imatinib. We present here pharmacokinetic data obtained with a newly designed HPLC approach in 97 patients with chronic myeloid leukemia or acute lymphatic leukemia (ALL) under treatment with imatinib that allowed us to calculate the AUC (39.5 microg.h/ml for an oral dose of 400 mg daily), the t(1/2) (18.2 h) and the peak concentration (1.92 micro/ml for an oral dose of 400 mg daily) of imatinib in plasma. In a subgroup of patients, the same parameters were analyzed for N-desmethyl-imatinib. We also provide data on the imatinib concentration in the cerebrospinal fluid (CSF) of ALL patients and demonstrate that oral administration of imatinib resulted only in a marginal flux across the blood-brain barrier. Finally, in an in vitro setting, we determined cellular concentrations of imatinib in HL-60 cells and showed an over-proportional uptake both in RPMI medium and in human plasma. Using an arithmetical approach combining all parameters obtained in imatinib-treated patients, we finally provide a conclusive approximation of basic pharmacokinetic data for both imatinib and its main metabolite N-desmethyl-imatinib.

How to Monitor Patients with Chronic Myelogenous Leukemia

The introduction of imatinib has radically altered the treatment options and, perhaps, prognosis for patients with newly diagnosed chronic myelogenous leukemia (CML). However, although the majority of patients appear to benefit from this agent, it is important to recognize as early as possible the patients who experience a suboptimal response and those who may be at risk of disease progression. This article reviews current available methods of monitoring and provides recommendations for appropriate follow up of imatinib-treated patients.

Imatinib in patients with newly diagnosed chronic-phase chronic myeloid leukemia

The International Randomized Study of Interferon and STI571 (IRIS) study prospectively compared imatinib with interferon-alpha/low-dose cytarabine (IFN/LDAC) in 1,106 newly diagnosed patients with Philadelphia chromosome-positive chronic myeloid leukemia (CML). Patients not responding to or intolerant of their assigned treatment were allowed to cross over. At 18 months, the projected probability of achieving a complete cytogenetic response was 76.2% for imatinib and 14.5% for IFN/LDAC, respectively (P < .01). Freedom from progression to accelerated phase or blast crisis was 96.7% for imatinib versus 91.5% for IFN/LDAC (P < .01). At the time of the analysis, 85.7% of imatinib-treated patients continued on first-line therapy, but only 10.8% of patients continued with IFN/LDAC. Most cross-overs to imatinib were due to interferon-intolerance. Overall survival was not different in the two groups at 19 months, reflecting efficient rescue of IFN/LDAC failures with imatinib. Imatinib should now be considered the standard therapy for newly diagnosed patients with CML. Semin Hematol 40(suppl 2):26-30. © 2003 Elsevier Inc. All rights reserved.

Imatinib in patients with newly diagnosed chronic-phase chronic myeloid leukemia

The International Randomized Study of Interferon and STI571 (IRIS) study prospectively compared imatinib with interferon-alpha/low-dose cytarabine (IFN/LDAC) in 1,106 newly diagnosed patients with Philadelphia chromosome-positive chronic myeloid leukemia (CML). Patients not responding to or intolerant of their assigned treatment were allowed to cross over. At 18 months, the projected probability of achieving a complete cytogenetic response was 76.2% for imatinib and 14.5% for IFN/LDAC, respectively (P < .01). Freedom from progression to accelerated phase or blast crisis was 96.7% for imatinib versus 91.5% for IFN/LDAC (P < .01). At the time of the analysis, 85.7% of imatinib-treated patients continued on first-line therapy, but only 10.8% of patients continued with IFN/LDAC. Most cross-overs to imatinib were due to interferon-intolerance. Overall survival was not different in the two groups at 19 months, reflecting efficient rescue of IFN/LDAC failures with imatinib. Imatinib should now be considered the standard therapy for newly diagnosed patients with CML. Semin Hematol 40(suppl 2):26-30. © 2003 Elsevier Inc. All rights reserved.

Demonstration of Philadelphia chromosome negative abnormal clones in patients with chronic myelogenous leukemia during major cytogenetic responses induced by imatinib mesylate.

Imatinib mesylate, an Abl-specific kinase inhibitor, produces sustained complete hematologic responses (CHR) and major cytogenetic responses (MCR) in chronic myeloid leukemia (CML) patients, but long-term outcomes in these patients are not yet known. This article reports the identification of clonal abnormalities in cells lacking detectable Philadelphia (Ph) chromosome/BCR-ABL rearrangements from seven patients with chronic- or accelerated-phase CML, who were treated with imatinib. All seven patients were refractory or intolerant to interferon therapy. Six of seven patients demonstrated MCR and one patient, who had a cryptic translocation, achieved low-level positivity (2.5%) for BCR-ABL by fluorescence in situ hybridization. The median duration of imatinib treatment before the identification of cytogenetic abnormalities in BCR-ABL-negative cells was 13 months. The most common cytogenetic abnormality was trisomy 8, documented in three patients. All patients had varying degrees of dysplastic morphologic abnormalities. One patient exhibited increased numbers of marrow blasts, yet consistently demonstrated no Ph-positive metaphases and the absence of morphologic features of CML. The presence of clonal abnormalities in Ph-negative cells of imatinib-treated CML patients with MCR and CHR highlights the importance of routine metaphase cytogenetic testing and long-term follow-up of all imatinib-treated patients.