Leukemia
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Multicenter Study Comparative Study Clinical Trial
Early reduction of BCR-ABL mRNA transcript levels predicts cytogenetic response in chronic phase CML patients treated with imatinib after failure of interferon alpha.
The degree of tumor load reduction as measured by cytogenetic response is an important prognostic factor for chronic myelogenous leukemia (CML) patients on therapy. We sought to determine whether BCR-ABL transcript levels can predict chromosomal response. Residual disease was evaluated in 120 CML patients in chronic phase (CP) treated with the selective tyrosine kinase inhibitor imatinib after resistance or intolerance to interferon alpha (IFN). ⋯ BCR-ABL/ABL ratios after 1 month were not predictive, but results after 2 months correlated with the consecutive cytogenetic response (P = 0.0008). The probability for a major cytogenetic response was significantly higher in patients with a BCR-ABL/ABL ratio <20% after 2 months of imatinib therapy. We conclude that: (1) quantitative determination of residual disease with real time RT-PCR is a reliable and sensitive method to monitor CML patients on imatinib therapy; (2) BCR-ABL/ABL ratios correlate well with cytogenetic response; (3) in IFN-pretreated patients all complete responders to imatinib have evidence of residual disease with the limited follow-up available; and (4) cytogenetic response at 6 months of therapy in CP patients is predictable with real time RT-PCR at 2 months.
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Multiparameter immunophenotypic analysis of neoplastic cells has proven to be of great help for the investigation of minimal residual disease in acute leukemias; however, its utility has not been systematically explored in B cell chronic lymphoproliferative disorders. The aim of the present study was to investigate the incidence of phenotypic aberrations in a series of 467 consecutive leukemic B cell chronic lymphoproliferative disorders through the comparison of the phenotypic characteristics of tumor vs normal peripheral blood (n = 10) and bone marrow (n = 10) B cells, in order to explore the applicability of this strategy for minimal residual disease monitoring. An additional goal of our study was to evaluate the sensitivity of multiparameter flow cytometry for the detection of minimal residual disease in leukemic B cell chronic lymphoproliferative disorders through dilutional experiments (n = 19). ⋯ These include CD22/CD23/CD19/CD5 and sIg(kappa)/sIg(lambda)/CD19/CD5 for lymphocytic leukemia/small lymphocytic lymphoma and prolymphocytic leukemia, CD103/CD25 or CD22/CD19/CD11c for hairy cell leukemia, FMC7/CD22/CD19/CD103 and sIg(kappa)/sIg(lambda)/CD22/CD19 for splenic marginal zone lymphomas, CD22/CD23/CD19/CD10 for follicular lymphomas and CD10/CD22/CD19/CD5 for mantle cell lymphomas. Serial dilutional experiments showed that the sensitivity level of immunophenotyping ranges between 10(-4) and 10(-5). In summary, the present study shows that immunophenotypic analysis allows the identification of aberrant phenotypes in 98% of leukemic B cell chronic lymphoproliferative disorders and these phenotypes can be used for minimal residual disease monitoring with a sensitivity limit of 10(-4)-10(-5).
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Multicenter Study Clinical Trial
Safety and efficacy of STI-571 (imatinib mesylate) in patients with bcr/abl-positive chronic myelogenous leukemia (CML) after autologous peripheral blood stem cell transplantation (PBSCT).
We examined safety and efficacy of STI-571 in 24 bcr/abl-positive patients with CML post PBSCT. At start of STI-571 therapy, nine patients presented in blast crisis (BC) or in accelerated phase (AP), and 15 in chronic phase (CP). Patients were evaluated for hematologic, cytogenetic and molecular response, survival and toxicity. ⋯ This report indicates that STI-571 is a safe and effective drug in heavily pretreated patients. No apparent additional side-effects were noted in this patient cohort. The high rate of complete hematologic and complete cytogenetic responses in CP patients is remarkable, as intensive treatment approaches plus IFN-alpha failed to be efficient in achieving long-term stabilization of CML in this patient cohort.
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As the drug discovery and developmental arm of the National Cancer Institute (NCI), the Developmental Therapeutics Program (DTP) plans, conducts and facilitates development of therapeutic agents for cancer and AIDS. DTP's goal is to turn 'molecules into medicine for the public health'. Areas of support by DTP are discovery, development and pathways to development for the intramural and the extramural community. ⋯ It has changed the NCI emphasis from a compound-oriented drug discovery effort to a disease-panel oriented exercise, emphasized human tumor cells derived from solid tumors, developed a high volume screening method that can adapt to processing of numerous chemical agents or natural source-derived extracts, that has minimized the use of animals, and saved on the amount of material required for the initial screening. The hollow fiber assay created at the DTP has demonstrated the ability to provide quantitative initial indices of in vivo drug efficacy, with minimum expenditures of time and materials and is currently being utilized as the initial in vivo experience for agents found to have reproducible activity in the in vitroanticancer drug screen. Drugs showing activity with unique mechanisms of actions are being further developed for treatment of hematopoietic neoplasms, prominent examples being flavopiridol, UCN-01 and depsipeptide among others.