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A Hochhaus

Publications and source records attributed to A Hochhaus.

At least 37 records · Page 2Linked to original sources
PubMed2005

Induction of centrosome and chromosome aberrations by imatinib in vitro.

Imatinib (STI571, Gleevec/Glivec) is a potent selective tyrosine kinase inhibitor and is used successfully in the treatment of chronic myeloid leukemia (CML). While karyotype alterations, in addition to the Philadelphia chromosome, are a common phenomenon of progressing CML, the observation of BCR-ABL-negative leukemic clones with distinct aberrant karyotypes under an imatinib regimen is not yet understood. Here we test the hypothesis that such tumor clones may be induced de novo from normal cells by imatinib. In vitro experiments with varying drug concentrations (5-20 microM) were performed on normal human dermal fibroblasts (NHDF), Chinese hamster embryonal and Indian muntjak fibroblasts. After 3 weeks of treatment, analysis of cell cultures by centrosome immunostaining and conventional cytogenetics revealed that imatinib induced centrosome and chromosome aberrations in all cultures in a significant dose-dependent and species-independent manner. Moreover, the results of NHDF long-term culture experiments demonstrated that aberrant phenotypes, emerging under imatinib treatment for 12 weeks, were not reversible after prolonged propagation omitting the drug. These observations suggest a causative role of imatinib in the origin of centrosome and karyotype aberrations (genetic instability) and thus may explain the emergence of clonal chromosomal abnormalities in BCR-ABL-negative progenitor cells under imatinib therapy.

Animals↗
PubMed2005

Compensatory PI3-kinase/Akt/mTor activation regulates imatinib resistance development.

BCR/ABL-kinase mutations frequently mediate clinical resistance to the selective tyrosine kinase inhibitor Imatinib mesylate (IM, Gleevec). However, mechanisms that promote survival of BCR/ABL-positive cells before clinically overt IM resistance occurs have poorly been defined so far. Here, we demonstrate that IM-treatment activated the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTor)-pathway in BCR/ABL-positive LAMA-cells and primary leukemia cells in vitro, as well as in a chronic phase CML patient in vivo. In fact, PI3K/Akt-activation critically mediated survival during the early phase of IM resistance development before manifestation of BCR/ABL-dependent strong IM resistance such as through a kinase mutation. Accordingly, inhibition of IM-induced Akt activation using mTor inhibitors and Akt-specific siRNA effectively antagonized development of incipient IM-resistance in vitro. In contrast, IM-resistant chronic myeloid leukemia (CML) patients with BCR/ABL kinase mutations (n=15), and IM-refractory BCR/ABL-positive acute lymphatic leukemia patients (n=2) displayed inconsistent and kinase mutation-independent autonomous patterns of Akt-pathway activation, and mTor-inhibition overcame IM resistance only if Akt was strongly activated. Together, an IM-induced compensatory Akt/mTor activation may represent a novel mechanism for the persistence of BCR/ABL-positive cells in IM-treated patients. Treatment with mTor inhibitors may thus be particularly effective in IM-sensitive patients, whereas Akt-pathway activation variably contributes to clinically overt IM resistance.

Antineoplastic Agents↗
PubMed2004

[Therapy of chronic myelogenous leukemia in 2004].

Chronic myelogenous leukemia constitutes a clinical model for other neoplastic diseases. The cytogenetic hallmark of CML, the Ph chromosome with the molecular juxtaposition of BCR and ABL genes and the multistep pathogenesis with the stable chronic phase, the accelerated phase and the terminal blast crisis provide the background for the translation of molecular-cytogenetic findings into clinical practice. The systematic development of the selective BCR-ABL inhibitor imatinib was based on the discovery of the molecular pathogenesis of CML. Promising preclinical data were confirmed in phase I-III trials. Concerning hematologic and cytogenetic response and adverse effects imatinib is superior to interferon alpha. Open questions are treatment duration in patients with good response, long term side effects, persistence of minimal residual disease in almost all patients, development of resistance after long term therapy, and the efficacy of combination treatments. Prospective clinical trials, e. g. CML study IV of the German CML Study Group, should answer these questions. The impact of the various treatment modalities (imatinib, interferon alpha, ara-C, allogeneic stem cell transplantation) will be elucidated. The recruitment of newly diagnosed CML patients into CML-study IV is recommended.

Antineoplastic Agents↗
PubMed2004

Capecitabine in combination with mitomycin C in patients with gastrointestinal cancer: results of an extended multicentre phase-I trial.

The aim of this study was to determine the dose-limiting toxicity (DLT) and establish the recommended dose for mitomycin C added every 3 weeks to the standard combination dose of capecitabine. Cohorts of at least three patients with pretreated gastrointestinal carcinoma received capecitabine 1000 mg m(-2) orally twice daily on days 1-14 plus i.v. bolus mitomycin C on day 1 at doses of 4, 6, 8 or 10 mg m(-2) (corresponding to dose levels I-IV). Cycles were repeated every 3 weeks. Two treatment cycles were considered for the evaluation of DLTs. Of the 53 patients enrolled, the majority had colorectal (n=27) or gastric (n=14) cancers. Patients had received a median of two lines of prior chemotherapy (34% with >/=3 lines and 87% with prior 5-FU-based therapy). At the recommended dose level (IV, n=30), grade 3 adverse events during cycles 1 and 2 were: anaemia (10%); leukopenia (3%); thrombocytopenia (3%); stomatitis/mucositis (3%); hand-foot syndrome (3%). Two patients experienced DLTs (mucositis, n=1; neutropenic fever, n=1), but there were no grade 4 events. The median dose intensity for capecitabine and mitomycin C was 100% during cycles 1 and 2 and only four patients required postponement of therapy. Of the 43 patients evaluable for efficacy, seven achieved partial and minor remissions (16%; 95% CI, 5-28%), and 12 patients (28%) had stable disease. The favourable safety profile and promising activity of the capecitabine/mitomycin C combination, even in heavily pretreated patients, warrant further evaluation in patients with advanced colorectal and gastric cancers.

Adult↗
PubMed2004

Pegylated liposomal doxorubicin in combination with mitomycin C, infusional 5-fluorouracil and sodium folinic acid. A phase-I-study in patients with upper gastrointestinal cancer.

Mitomycin C (MMC) in combination with infusional 5-fluorouracil (FU) plus folinic acid (FA) is an effective treatment for metastatic gastrointestinal cancer. Anthracyclines are commonly used in the treatment of upper gastrointestinal cancer. The aim of this study was to determine the maximum tolerated dose of liposomal, pegylated doxorubicin (Caelyx) in combination with infusional 5-FU/sodium FA and MMC. Escalating doses of Caelyx (15-25-30-35 mg m(-2) corresponding to dose levels I-IV) were applied on days 1 and 29, given to fixed doses of 24-h 5-FU (2000 mg m(-2)) and sodium FA (500 mg m(-2), mixed with 5-FU in one pump) weekly for 6 weeks, and MMC 7 mg m(-2) on days 8 and 36. At least three patients were treated at each dose level. A total of 25 patients are evaluable. No dose-limiting toxicity (DLT) was observed on level I (n=3). On level II, DLT occurred in three out of five patients (mucositis and leucopenia). Owing to the early DLTs at this dose, we added a 20 mg m(-2) Caelyx dose level (Ia). In total, 17 patients were treated at this dose level. Among these, only two patients experienced DLT in cycle one and 37 complete cycles have been administered in association with a low toxicity profile. The median dose intensity was 100% for each drug during the first course and no treatment delay exceeding 7 days was required. The recommended dose of 4-weekly Caelyx in combination with weekly 24-h 5-FU/sodium FA and 4-weekly MMC is 20 mg m(-2). Preliminary antitumour activity has been observed in patients with pretreated pancreatic cancer and in untreated gastric cancer.

Adenocarcinoma↗
PubMed2004

Modern diagnostics in chronic myeloproliferative diseases (CMPDs).

According to the new WHO classification a group of chronic myeloproliferative diseases (CMPDs) were defined: chronic myeloid leukemia (CML), chronic neutrophilic leukemia (CNL), chronic eosinophilic leukemia and hypereosinophilic syndrome (CEL/HES), polycythemia vera (PV), chronic idiopathic myelofibrosis (with extramedullary hematopoiesis, CIMF), essential thrombocythemia (ET), and so called CMPD/unclassifiable. As clinical features and laboratory findings differ widely between these diseases several diagnostic approaches are mandatory at diagnosis for classification and are needed also for follow up studies, especially for the measurement of minimal residual disease (MRD). We here outline the laboratory set up at diagnosis and during follow up in CMPDs with specific focus on the respective therapeutical consequences. Only by using a comprehensive diagnostic panel including cytomorphology, cytogenetics, and molecular genetic methods establishing the correct diagnosis, optimizing treatment as well as evaluating treatment response is possible in CMPDs today.

Blood Cell Count↗
PubMed2004

Imatinib therapy in chronic myelogenous leukemia: strategies to avoid and overcome resistance.

Imatinib is a molecularly targeted therapy that inhibits the oncogenic fusion protein BCR-ABL, the tyrosine kinase involved in the pathogenesis of chronic myelogenous leukemia (CML). Selective inhibition of BCR-ABL activity by imatinib has demonstrated efficacy in the treatment of CML, particularly in chronic phase. Some patients, however, primarily those with advanced disease, are either refractory to imatinib or eventually relapse. Relapse with imatinib frequently depends not only on re-emergence of BCR-ABL kinase activity but may also indicate BCR-ABL-independent disease progression not amenable to imatinib inhibition. Results from phase 2/3 trials suggest that rates of resistance and relapse correlate with the stage of disease and with the monitoring parameters--hematologic, cytogenetic and molecular response. These observations and more recent trials with imatinib, combined with insights provided by an increased understanding of the molecular mechanisms of resistance, have established the rationale for strategies to avoid and overcome imatinib resistance in the management of CML patients. To prevent resistance, early diagnosis and prompt treatment with appropriate initial dosing is essential. Management of resistance may include therapeutic strategies such as dose escalation to achieve individual optimal levels, combination therapy, as well as treatment interruption.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2004

Impact of chemoradiotherapy-induced anemia on survival in uniformly staged patients with locally advanced squamous cell carcinoma of the esophagus.

AIM: Objective of this study was to evaluate the hemoglobin level (Hb) as potential prognostic factor in uniformly staged patients (pts) undergoing primary chemoradiotherapy (ChRT) for locally advanced squamous cell carcinoma (SCC) of the esophagus. PATIENTS AND METHODS: Pts with histologically proven SCC of the esophagus (uT3/4 Nx or uTx N+) were included in the analysis. Staging procedures comprised endoscopic ultrasound, barium swallow and computed tomography. All pts received radiotherapy (> or =40 Gy) and > or =2 courses of fluorouracil/folinic acid, and cisplatin (5 days/month). In selected pts surgical resection after neoadjuvant ChRT was carried out. Clinical parameters, especially Hb were retrospectively evaluated for their impact on survival. RESULTS: 46 pts were treated between 1996 and 2001. Median survival was 16 months. Survival for pts treated with definitive ChRT (n = 28) was 14 months, whereas pts treated surgically after neoadjuvant ChRT (n = 18) survived 19 months (p = 0.79). Pts with low Hb levels at baseline did not show a worse outcome in comparison with pts with normal Hb levels (16 months), whereas a significant decrease in Hb level within the time period of ChRT was associated with a significantly inferior outcome (11 vs. 31 months; p = 0.046). Pts requiring blood transfusion tended to have inferior survival (11 vs. 24 months; p = 0.07). CONCLUSION: In this retrospective analysis a significant decrease of Hb level during ChRT was identified as prognostic factor for pts undergoing ChRT of SCC of the esophagus.

Aged↗
PubMed2003

Dose-dependent severe cutaneous reactions to imatinib.

The protein kinase inhibitor imatinib has been approved as an efficient anticancer drug with common but mild cutaneous toxicities. We here report on two out of four melanoma patients treated with high-dose imatinib presenting with severe and strongly dose-dependent skin eruptions, suggesting a cutaneous reactivity pattern different from allergic hypersensitivity.

Adult↗
PubMed2003

Preexistence and evolution of imatinib mesylate-resistant clones in chronic myelogenous leukemia detected by a PNA-based PCR clamping technique.

Recently, various mutations within the Abl sequence have been described that negatively affect imatinib binding to Bcr/Abl resulting in cellular resistance of chronic myeloid leukemia (CML) cells. So far, little is known as to whether these mutations are preexisting or develop under imatinib therapy as current mutation analyses are limited by a low sensitivity of approximately 1:2 (50%) to 1:5 (20%). By combining peptide nucleic acid (PNA)-based DNA clamping with a fluorescence hybridization probe assay, we developed a new and highly sensitive technique for the detection of known mutations within the Bcr/Abl kinase domain. With this approach we investigated 19 cases of CML refractory to imatinib treatment before and during therapy. By clamping of wild-type Abl through PNA we could effectively enhance the detection sensitivity for the Bcr/Abl mutations Thr315Ile, Glu255Lys, and Tyr253His such that 1 mutant cDNA molecule could be detected in 500 negatives (0.2%). We observed in one case that a Gly255Lys mutation was detectable before treatment. By DNA analysis of buccal swaps, a genetic polymorphism could be excluded. In two cases clonal evolution of known mutations developed gradually under treatment. In another case an initially detectable Tyr253His mutation disappeared after therapy onset but was again observed after 6 weeks of imatinib treatment. Preexisting and evolving Bcr/Abl mutations associated with an unfavorable prognosis could be safely detected by the presented technique. This may facilitate risk stratification in CML and may serve as a model for individualized molecular monitoring and therapeutic strategies in other malignant diseases.

Adult↗
PubMed2003

Cytogenetic and molecular characterization of simultaneous chronic and acute myelocytic leukemia.

We describe a patient initially diagnosed with a chronic myeloproliferative disorder in the accelerated phase. Cytogenetic analysis showed the presence of two independent clones. One clone contained a typical Philadelphia (Ph) chromosome due to t(9;22)(q34;q11), as the sole abnormality which was proven molecularly to result in the b2a2-BCR/ABL fusion. The other clone displayed a complex karyotype with several structural and numerical aberrations including trisomy 11 and 22 but lacking a t(9;22) or any other structural abnormalities involving chromosomes 9 and 22. Fluorescence in situ hybridization demonstrated that the t(9;22) was present only in cells with two copies of chromosomes 11 and 22. In contrast, cells with trisomies 11 and 22 lacked evidence for a BCR/ABL fusion. Based on the genetic findings, simultaneous chronic and acute myelocytic leukemias were diagnosed rather than a blastic phase of a chronic myelocytic leukemia.

Aged↗
PubMed2003

[Chronic myeloproliferative diseases. Diagnosis and therapy].

Chronic myeloproliferative disorders (CMPD) are neoplastic disorders of the hematopoietic stem cell. Four different entities are defined: chronic myeloid leukemia (CML), polycythemia vers, essential thrombocythaemia, and idiopathic myelofibrosis. In addition, overlapping entities within the CMPDs and between CMPDs and myelodysplastic syndrome have been described. Diagnostic measures are performed to classify the subtype exactly and to assess risk factors and prognosis. Cytogenetic and molecular analyses are mandatory for the characterization of the malignant clone. Hydroxyurea and interferon-alpha have proven effective in all CMPE. In CML, specific inhibition of the elevated ABL tyrosine kinase activity with imatinib is associated with high response rates. Allogeneic stem cell transplantation is the only curative treatment option for all entities. In CML, the decision-making analysis should be based on established scores. In BCR-ABL negative CMPDs an allogeneic stem cell transplantation should only be performed in patients with unfavorable prognosis.

Antineoplastic Agents↗
PubMed2003

Stable molecular remission induced by imatinib mesylate (STI571) in a patient with CML lymphoid blast crisis relapsing after allogeneic stem cell transplantation.

We report the response to the ABL kinase inhibitor imatinib mesylate (STI571) in a patient with chronic myeloid leukemia (CML) who relapsed twice after dose-reduced allogeneic stem cell transplantation (alloSCT) for B lymphoid blast crisis (BC) and failed to develop an antileukemic response despite grade 3 graft-versus-host disease (GvHD). Complete hematologic, cytogenetic and molecular responses were achieved within 9 weeks of therapy and are maintained after 27 months. Extensive chronic skin GvHD necessitating immunosuppressive therapy developed after 14 months. This case illustrates the ability of imatinib to induce sustained hematologic and molecular remissions in some patients relapsing with advanced stage CML after alloSCT.

Adult↗