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PubMed2004

Sustained cytogenetic response after discontinuation of imatinib mesylate in a patient with chronic myeloid leukaemia.

A 58-yr-old woman was diagnosed with Ph(+) chronic myeloid leukaemia in May 2001. She was initially treated with hydroxyurea and subsequently with interferon-alpha (IFN-alpha). Imatinib mesylate was started in April 2002 after failure of IFN-alpha to induce a cytogenetic response. The patient remained on treatment with imatinib mesylate for 3 months during which she suffered daily fever resulting in discontinuation of the treatment. Response evaluation performed shortly after discontinuing imatinib mesylate revealed a complete cytogenetic remission and a substantial molecular response. Fifteen months later, she was still enjoying a major cytogenetic response. This case illustrates that a short course of imatinib mesylate may result in a sustained haematological and cytogenetic response.

Benzamides↗
PubMed2006

Application of oligonucleotide microarrays to assess the biological effects of neoadjuvant imatinib mesylate treatment for localized prostate cancer.

PURPOSE: Neoadjuvant administration of antineoplastic therapies is used to rapidly assess the clinical and biological activity of novel systemic treatments. To assess the feasibility of using microarrays to assess molecular end points following targeted treatment in a heterogeneous tumor, we measured global gene expression in localized prostate cancer before and following neoadjuvant treatment with imatinib mesylate. PATIENTS AND METHODS: Patients with intermediate-risk to high-risk prostate cancer were treated for 6 weeks with 200 to 300 mg of oral imatinib mesylate. Frozen tissue was obtained from pretreatment ultrasound-guided biopsies and posttreatment radical prostatectomy specimens. Oligonucleotide microarray analysis following laser capture microdissection (LCM) and RNA amplification was used to assess gene expression changes associated with imatinib mesylate therapy. Immunohistochemistry was used to measure protein expression of MKP1 and CD31 and to assess cellular apoptosis. RESULTS: Of the 11 patients enrolled, high-quality microarray data was obtained from both biopsies (n = 7) and radical prostatectomy specimens (n = 9). Technically introduced intrasample gene expression variability was found to be significantly less than intertumor biological variability. Large gene expression differences were observed, and the gene with the most consistent differential expression (MKP1) was validated by immunohistochemistry. Gene set enrichment analysis suggests that imatinib mesylate therapy results in apoptosis of microvascular endothelial cells, an observation anecdotally supported by immunohistochemistry. CONCLUSIONS: This study shows that high-quality microarray data can be generated using LCM and RNA amplification to discover potential mechanisms of targeted therapy in cancer.

Adenocarcinoma↗
PubMed2002

BCR-ABL point mutants isolated from patients with imatinib mesylate-resistant chronic myeloid leukemia remain sensitive to inhibitors of the BCR-ABL chaperone heat shock protein 90.

Clinical resistance to imatinib mesylate is commonly observed in patients with advanced Philadelphia chromosome- positive (Ph(+)) leukemias. Acquired resistance is typically associated with reactivation of BCR-ABL due to kinase domain mutations or gene amplification, indicating that BCR-ABL remains a viable target for inhibition in these patients. Strategies for overcoming resistance can be envisioned through exploitation of other molecular features of the BCR-ABL protein, such as its dependence on the molecular chaperone heat shock protein 90 (Hsp90). To determine whether inhibition of Hsp90 could induce degradation of imatinib mesylate-resistant, mutant BCR-ABL proteins, hematopoietic cells expressing 2 mutant BCR-ABL proteins found in imatinib mesylate-resistant patients (T315I and E255K) were examined for sensitivity to geldanamycin and 17-allylaminogeldanamycin (17-AAG). Both compounds induced the degradation of wild-type and mutant BCR-ABL and inhibited cell growth, with a trend indicating more potent activity against mutant BCR-ABL proteins. These data support clinical investigations of 17-AAG in imatinib mesylate-resistant Ph(+) leukemias.

Antineoplastic Agents↗
PubMed2003

Imatinib mesylate inhibits autonomous erythropoiesis in patients with polycythemia vera in vitro.

The overproduction of red blood cells in patients with polycythemia vera (PV) is reflected in vitro by the formation of erythroid burst-forming units (BFU-Es) in the absence of exogenous erythropoietin. In contrast to other myeloproliferative disorders, the molecular mechanism of PV is unknown and no specific chromosomal abnormality has been described. We speculated that imatinib mesylate may reverse the pathological overproduction of red cells by inhibition of autonomous erythropoiesis. In the present study, imatinib mesylate was found to either block or strongly inhibit autonomous BFU-E formation in vitro in all patients tested. Moreover, autonomous BFU-E growth was also markedly reduced by exposure of PV cells to imatinib mesylate prior to cultivation in semisolid medium. The profound effect of imatinib mesylate on autonomous erythropoiesis suggests the involvement of an as yet unidentified kinase in the pathogenesis of PV and should provide the rationale for a forthcoming clinical trial.

Antineoplastic Agents↗
PubMed2003

Results of a prospective phase 2 study combining imatinib mesylate and cytarabine for the treatment of Philadelphia-positive patients with chronic myelogenous leukemia in chronic phase.

In chronic myelogenous leukemia (CML) imatinib mesylate has been shown to selectively inhibit the tyrosine kinase domain of the oncogenic bcr-abl fusion protein. Using this agent alone high rates of cytogenetic responses were recorded. However, several mechanisms of resistance have been described. In vitro studies examining the effects of imatinib mesylate plus cytarabine have shown synergistic antiproliferative effects of this combination. Thus, the CML French Group decided to perform a phase 2 trial testing a combination of imatinib mesylate and low-dose cytarabine in 30 previously untreated patients in chronic phase. Treatment was administered on 28-day cycles. Patients were treated continuously with imatinib mesylate orally at a dose of 400 mg daily. Cytarabine was given on days 15 to 28 of each cycle at an initial dose of 20 mg/m2/d via subcutaneous injection. Adverse events were frequently observed with grade 3 or 4 hematologic toxicities and nonhematologic toxicities in 53% (n = 16) and 23% (n = 7) of patients, respectively. The cumulative incidence of complete cytogenetic response (CCR) at 12 months was 83% and at 6 months 100% of the patients achieved complete hematologic response (CHR). We concluded that the combination was safe and promising given the rates of response.

Adult↗
PubMed2004

Imatinib mesylate therapy may overcome the poor prognostic significance of deletions of derivative chromosome 9 in patients with chronic myelogenous leukemia.

Deletions of derivative chromosome 9 [der(9)] can be identified by fluorescence in situ hybridization (FISH) in 10% to 15% of patients with chronic myeloid leukemia (CML). Patients with der(9) deletions have been reported to have an adverse outcome when treated with chemotherapy, interferon, and possibly imatinib mesylate. We investigated the frequency and prognostic significance of der(9) deletions among 352 patients with CML treated with imatinib mesylate at our institution, in whom a deletion status of der(9) was determined. Thirty-three patients (9%; 95% CI 0.07, 0.13) (30 in chronic phase, 3 in accelerated phase) had der(9) deletions. The rates of major (82% vs 79%, P = 0.82) and complete cytogenetic response (76% vs 66%, P = .33) with imatinib mesylate therapy were similar in patients with and without der(9) deletions, respectively. After a median follow-up of 28 months, there was no difference in overall survival (P = .30) or response duration (P = .49) in patients with and without deletions. In a multivariate analysis, der(9) deletions had no significant impact on response, survival, or response duration. We conclude that treatment with imatinib mesylate overcomes the adverse prognostic significance of der(9) deletions in patients with CML.

Adolescent↗
PubMed2005

Coordination of intrinsic, extrinsic, and endoplasmic reticulum-mediated apoptosis by imatinib mesylate combined with arsenic trioxide in chronic myeloid leukemia.

A treatment strategy that combines arsenic trioxide (ATO) with the tyrosine kinase inhibitor imatinib mesylate (STI571, Gleevec) appears to induce markedly more cell apoptosis than imatinib mesylate alone in chronic myeloid leukemia (CML). To understand the mechanisms underlying the synergistic/additive action of these agents, we applied cDNA microarrays, component plane presentation integrated self-organizing map (CPP-SOM), and methods of protein biochemistry to study cell apoptosis induced by imatinib mesylate, ATO, and the combination of the 2 agents in the CML cell line K562. Numerous features with temporospatial relationships were revealed, indicating the coordinated regulation of molecular networks from various aspects of proapoptotic and apoptotic activities in CML. Imatinib mesylate appears to induce mainly the intrinsic pathway of cell apoptosis, whereas ATO induces the endoplasmic reticulum (ER) stress-mediated pathway of cell apoptosis, and the combination of the 2 agents seems to more effectively induce the intrinsic, extrinsic, and ER stress-mediated pathways of cell apoptosis, which results in a more effective and efficient induction of programmed cell death in K562 cells. This finding appears to be supported also by data derived from bone marrow cells of 2 patients with CML, one in chronic phase and the other in blast-crisis phase of the disease.

Antineoplastic Agents↗
PubMed2003

Imatinib mesylate in the treatment of chronic myeloid leukaemia.

Imatinib mesylate (Gleevec, Glivec), formerly STI571; Novartis Pharmaceuticals) is an inhibitor of the Bcr-abl tyrosine kinase that is central to the pathogenesis of chronic myeloid leukaemia (CML). The remarkable results of imatinib mesylate in clinical trials have rapidly and profoundly changed the management of patients with CML. This article will review the development of this molecularly targeted agent. The clinical trials with imatinib mesylate will be summarised along with the pharmacology of this agent. Despite the impressive responses seen in chronic-phase patients, numerous questions remain. For example, how durable will responses to imatinib mesylate be and is it necessary or possible to improve upon these results? Ongoing efforts to address these issues will be discussed.

Antineoplastic Agents↗
PubMed2005

Extramedullary blast crisis derived from 2 different clones in the central nervous system and neck during complete cytogenetic remission of chronic myelogenous leukemia treated with imatinib mesylate.

We describe a patient with Philadelphia chromosome (Ph)-positive chronic myelogenous leukemia (CML) who developed an extramedullary blast crisis in the central nervous system (CNS) and then a subcutaneous tumor of the neck during treatment with imatinib mesylate. Administered 400 mg of imatinib mesylate after the diagnosis of chronic-phase CML, the patient achieved a complete cytogenetic remission 4 months later. However, he developed a mixed myeloid/B-cell blast crisis with additional karyotype abnormalities only in the CNS during a complete cytogenetic remission in the bone marrow. Several doses of intrathecal chemotherapy and whole-brain irradiation were effective in treating the blast crisis in the CNS. After 7 months of complete cytogenetic remission, the patient experienced a subcutaneous tumor in the right neck. A biopsy of the tumor revealed a mixed myeloid/T-cell blast crisis. The cytogenetic analysis showed that the blast crisis clone in the neck tumor was different from that of the CNS. An increased dose of imatinib mesylate was ineffective in treating the neck tumor. Irradiation to the right neck was therefore undertaken. This case suggests that the development of a clone resistant to imatinib mesylate is not always detected in the bone marrow and that multiple Ph-positive clones have the potential to become transformed into a blast crisis.

Adolescent↗
PubMed2003

Current results on the use of imatinib mesylate in patients with relapsed Philadelphia chromosome positive leukemia after allogeneic or syngeneic hematopoietic stem cell transplantation.

Here, we describe a patient diagnosed with chronic myelogenous leukemia who relapsed after matched unrelated donor SCT. The patient was treated with imatinib mesylate and donor lymphocyte infusions, and achieved a complete molecular remission. Additionally, safety and efficacy of imatinib mesylate in a total of 134 patients from 8 centers who underwent allogeneic or syngeneic stem cell transplantation (SCT) and had a relapse of Philadelphia chromosome positive leukemia was reviewed. Data was compiled from abstracts accepted as oral or poster presentations at the ASH (American Society of Hematology) 2001 and EBMT (European Group for Blood and Marrow Transplantation) 2001 & 2002 meetings and additionally literature published on this patient group. Efficacy of imatinib therapy was assessed by morphology, cytogenetic analysis, and determination of donor chimerism. In the evaluable population, hematologic and cytogenetic responses were observed in 66% and 60% of the patients, respectively. Fifty-one of 114 (45%) patients achieved a complete cytogenetic response. No response or progress of disease was noted in 22 out of evaluable 91 patients. The observation period was limited to a maximum of 28 months. A significant improvement in donor chimerism was frequently observed. Only five cases of significant GVHD were reported. Preliminary results show that imatinib mesylate has the potential to positively influence the ratio of donor and recipient cells without inducing a high incidence of severe GVHD. The data suggest that earlier start of imatinib mesylate prior to hematologic relapse in minimum residual disease (MRD) positive patients is a promising treatment concept.

Adult↗
PubMed2002

Imatinib mesylate for Philadelphia chromosome-positive, chronic-phase myeloid leukemia after failure of interferon-alpha: follow-up results.

We treated 261 patients with Philadelphia chromosome (Ph)-positive chronic myeloid leukemia (CML) in chronic phase after failure of IFN-alpha with the Bcr-Abl tyrosine kinase inhibitor imatinib mesylate (400 mg/day given p.o.) and analyzed hematological and cytogenetic responses, long-term prognosis, factors associated with achievement of major cytogenetic response and survival, and comparative survival in similar patients treated with other regimens. Median patient age was 55 years; 34% were 60 years or older, and median chronic-phase duration was 33 months. Overall, 94% achieved a complete hematological response, and 71% had a cytogenetic response [major (Ph+ cells <35%) in 62% and complete in 45%]. At a median follow-up of 17 months, 241 patients (92%) were still taking imatinib mesylate; estimated 18-month freedom from progression and survival rates were 93 and 96%. Multivariate analysis of factors associated with major cytogenetic response identified long chronic phase, marrow basophilia, high percentage of Ph+ cells before therapy, and prior hematological resistance to IFN-alpha as being adverse factors. This model was used to generate good-, intermediate- and poor-risk subgroups who had estimated major cytogenetic response rates of 93, 53, and 34%, respectively. Univariate analysis in terms of survival identified leukocytosis, high percentages of peripheral and marrow blasts, marrow basophilia, and the presence of cytogenetic clonal evolution as being adverse factors. Achieving a cytogenetic response at 3 or 6 months of therapy was associated with prolonged survival. In a subset analysis, survival rates among 161 patients with Ph-positive CML after hematological or cytogenetic failure after IFN-alpha who had been treated with imatinib mesylate were better than those for similar patients treated previously with other regimens. In summary, imatinib mesylate is highly effective in chronic-phase CML after IFN-alpha failure. We identified pretreatment and treatment-associated factors that were associated with higher major cytogenetic response rates and with improved survival.

Benzamides↗
PubMed2002

Imatinib mesylate therapy for relapse after allogeneic stem cell transplantation for chronic myelogenous leukemia.

Twenty-eight adults with chronic myelogenous leukemia (CML) that had relapsed after allogeneic stem cell transplantation (SCT) received imatinib mesylate (400-1000 mg/d). Disease was in chronic phase in 5 patients, accelerated in 15, and blastic in 8 (7 medullary, 1 extramedullary); median time from transplantation to relapse was 9 months (range, 1-137 months). Thirteen patients had undergone salvage donor lymphocyte infusion (DLI) (median time from DLI to imatinib mesylate therapy, 4 months [range, 2-39 months]). The overall response rate was 79% (22 of 28 patients); the complete hematologic response (CHR) rate was 74% (17 of 23 patients), and the cytogenetic response rate was 58% (15 of 26 patients; complete response in 9 [35%] patients). CHR rates were 100% for chronic phase, 83% for accelerated phase, and 43% for blastic phase. The patient with extramedullary blastic disease achieved complete response. Cytogenetic response rates were 63% (12 of 19 patients) for chronic or accelerated phases (complete cytogenetic response in 8) and 43% for blastic phase (3 of 7 patients). At median follow-up of 15 months, 19 patients were alive, 9 with no evidence of disease. The 1-year estimated survival rate was 74%. Five patients had recurrence of grade 3 (3 patients) or grades 1 to 2 (2 patients) graft-versus-host disease (GVHD). Severe granulocytopenia developed in 43% of patients and thrombocytopenia in 27%; both conditions reversed with dose adjustments of imatinib mesylate. We conclude that imatinib mesylate effectively controlled CML that recurred after allogeneic SCT, but it was associated with side effects including myelosuppression and recurrence of severe GVHD.

Administration, Oral↗
PubMed2002

[Chronic myeloid leukemia associated with sustained severe pancytopenia after imatinib mesylate therapy].

A 73-year-old woman with chronic myeloid leukemia was treated with interferon-alpha, hydroxyurea, and busulfan before imatinib mesylate treatment. The leukocyte count was 8,400/; hemoglobin concentration, 12.0 g/; and platelet count, 19.7 x 10(4)/. She received 400 mg of imatinib mesylate for 17 days before the agent was discontinued because of pancytopenia. A bone marrow biopsy on the 87th day after the last imatinib mesylate administration demonstrated severe hypocellularity. She needed many RBC and Plt transfusions and filgrastim administration. Grade 4 neutropenia continued for 35 days and Grade 3 thrombocytopenia continued for over 122 days. Imatinib mesylate, an agent targeting BCR-ABL, is expected to be useful as an effective therapeutic agent for chronic myeloid leukemia. However the present case suggests that its appropriate dose is individually variable and we should carefully consider the former treatment, and the clinical stage of the disease before initiating imatinib treatment.

Aged↗
PubMed2003

The effect of imatinib mesylate on patients with Philadelphia chromosome-positive chronic myeloid leukemia with secondary chromosomal aberrations.

PURPOSE AND EXPERIMENTAL DESIGN: The acquisition of secondary chromosomal aberrations in chronic myeloid leukemia (CML) patients with Philadelphia chromosome-positive (Ph+) karyotype signifies clonal evolution associated with disease progression to accelerated/blastic phase. Therefore, these aberrations are of clinical and biological importance. We identified 58 cases with secondary abnormalities in addition to t(9;22)(q34;q11.2) or its variants in a review of 137 CML patients treated with imatinib mesylate (STI571). Clinically 13 patients were in chronic phase, 24 in accelerated phase, and 21 in blastic phase. RESULTS: More than 50% of cases showed the major routes of CML clonal evolution [+8, i(17q), +Ph, and/or +19]. The remainder exhibited minor routes of secondary abnormalities with -17/17p-, 11p-/rearr(11p), and -7/rearr(7) as the most frequent abnormalities. Of particular interest, one case developed an inv(16)(p13q22) as a secondary anomaly during blastic transformation. The bone marrow was consistent with myelomonocytic morphology with eosinophilia. Cytogenetic responses to imatinib mesylate occurred in 15 of 58 (26%) patients; 12 achieved complete cytogenetic remission, 2 had a major response, and 1 had a minor response, with most responses noted within 3-6 months. Seven patients remain in remission >17-30 months, 2 patients relapsed between 12 and 19 months on therapy, and 1 patient was treated by bone marrow transplantation. CONCLUSIONS: Although some Ph+ CML patients with clonal evolution can have a complete cytogenetic response to imatinib mesylate, responses tend to be brief, and such patients may benefit from subsequent stem cell transplantation. Therefore, CML patients with clonal evolution may require therapy additional to imatinib mesylate for maximal eradication of the Ph+ leukemic cells.

Adult↗
PubMed2003

Hypopigmentation in an African patient treated with imatinib mesylate: a case report.

Imatinib mesylate (STI 571, Gleevec) is a potent bcr-abl tyrosine kinase inhibitor. It also inhibits c-kit tyrosine kinase. Imatinib mesylate is active in the treatment of cronic myeloid leukemia (CML) and gastrointestinal stromal tumors (GIST). It is considered by some authorities to be the standard of care in newly diagnosed CML as well as patients in chronic phase who do not have a related match. C-kit and its ligand stem-cell factor regulate melanocyte development and survival. Hypopigmentation in patients receiving imatinib mesylate for CML has been reported recently. In this article, we report a black Nigerian male with GIST, who developed hypopigmentation of distal parts of digits, as well as generalized lightening of skin on the body three months after receiving imatinib mesylate. We believe that this is the first case of hypopigmentation reported in a black patient with GIST.

Aged↗
PubMed2003

Advanced gastrointestinal stromal tumors successfully treated with imatinib mesylate: a report of two cases.

Activation of kit-receptor tyrosine kinase occurs in all cases of gastrointestinal stromal tumors, regardless of the mutation status of kit. Imatinib mesylate (STI 571,Gleevec) is a selective inhibitor of certain protein tyrosine kinases. It has been shown in preclinical models and clinical studies to have activity against such tumors. The aim of the present study was to report the efficacy of imatinib mesylate in the treatment of advanced gastrointestinal stromal tumors. Two adults with histologically confirmed, unresectable, and metastatic gastrointestinal stromal tumors that expressed CD117 (a marker of kit-receptor tyrosine kinase) were identified at our institution during 2000-2002. As the diseases were advanced and not amenable to surgery, chemotherapy, or radiation therapy, imatinib mesylate was used, because this targeted inhibitor has been shown to be active against advanced gastrointestinal stromal tumors and has a mild toxicity profile. Imatinib mesylate induced a sustained response in both patients with advanced unresectable or metastatic gastrointestinal stromal tumors. Inhibition of the KIT signal-transduction pathway is a promising treatment for advanced gastrointestinal stromal tumors, which resist conventional chemotherapy.

Aged↗
PubMed2004

[Imatinib mesylate alone for refractory advanced gastrointestinal stromal tumor].

OBJECTIVE: To evaluate the efficacy and safety of imatinib mesylate in the treatment of patients as preoperative supplement, or used alone for unresectable and(or) metastatic gastrointestinal stromal tumor (GIST). METHODS: A total of 30 cases with advanced GIST were proved pathologically. Among them, CD117 was detected positive in 29 patients; 2 patients received imatinib mesylate before operation and 28 patients with unresectable and(or) metastatic GIST received oral imatinib mesylate daily at dose of 200-600 mg. Three patients were lost in follow-up and the objective effect was evaluated in 25 patients. RESULTS: Fifteen of 25 patients (60.0%) achieved partial response (PR); 5 (20.0%) had stable disease (SD) and 5 (20.0%) had progression disease (PD). Median time to progression (mTTP) was more than 13 months during which most experienced benefit. Twenty-two patients had been followed-up more then 1 year. The 1-year survival rate was 86.4%. The overall median survival has not been obtained to date. Twenty-seven patients were valuable for the toxicity assessment according to the WHO standard. The main toxicity included grade I-II edema of periorbital area and lower limb in 85.2% (23/27) patients, leukopenia was present in 40.7% (11/27) and intratumoral bleeding in 7.4% (2/27). Other toxicities included mild fatigue (29.6%), abdominal pain (14.8%), efflorescence (11.1%), nausea and vomiting (18.5%). CONCLUSION: As an inhibitor of tyrosine kinase, imatinib mesylate is generally well tolerated and has been proved to be effective and safe during prolonged treatment of patients with advanced gastrointestinal stromal tumors.

Adult↗
PubMed2005

[Treatment of patients with gastrointestinal stromal tumour with imatinib mesylate].

BACKGROUND: Gastrointestinal stromal tumour (GIST) is the most frequent mesenchymal tumour type of the digestive tract. Between 30 and 40% of patients have high-risk, malignant GIST with poor prognosis after surgery. Imatinib mesylate is a recently introduced KIT tyrosine kinase inhibitor with effect on metastatic GIST. We report our experience with imatinib mesylate in the treatment of GIST. MATERIAL AND METHODS: Nine patients diagnosed with GIST have received imatinib mesylate since August 2001. Eight patients had metastatic disease, one patient received adjuvant treatment. The patients were evaluated according to standard protocols for clinical performance, effect of treatment, and adverse effects. Tumour tissue was analysed for mutational status in KIT and PDGFRA. RESULTS: All patients with metastatic disease had palliative benefit; three had partial response and the remaining stable disease. The single patient receiving adjuvant treatment had no sign of recurrence. Side effects were mainly mild diarrhoea, nausea and vomiting. Seven patients had mutations in KIT exon 11, one in KIT exon 9, and one in PDGFRA exon 12. INTERPRETATION: The results demonstrate that imatinib mesylate is an effective drug that can stabilise and reduce disease in patients with advanced GIST.

Adult↗