Biomedical subjects

Michael Keating

Publications and source records attributed to Michael Keating.

At least 37 records · Page 2Linked to original sources

PubMed2004

Free circulating soluble CD52 as a tumor marker in chronic lymphocytic leukemia and its implication in therapy with anti-CD52 antibodies.

BACKGROUND: The CD52 antigen is a glycoprotein anchored on the cell membrane of mature B and T lymphocytes, monocytes, and eosinophils. Alemtuzumab (CAMPATH-1H; anti-CD52) is currently approved for the treatment of patients with refractory chronic lymphocytic leukemia (CLL). The authors investigated the possibility that CD52 may be shed from cells and, once soluble, may bind to injected alemtuzumab, forming immune complexes. METHODS: The authors used Western blot analysis, immunoprecipitation, and enzyme-linked immunoadsorbent assay to investigate the presence of soluble CD52 (sCD52) in the plasma specimens of 117 patients with CLL. They also used in vitro mixing experiments to examine the ability of sCD52 to compete with cells and sequester therapeutic alemtuzumab. RESULTS: The authors detected high levels of sCD52 in the plasma specimens of patients with CLL. sCD52 can compete with cells in vitro for binding to alemtuzumab, and can form complexes in patients receiving alemtuzumab. Plasma levels of sCD52 were found to be correlated (r)with Rai stage (P = 0.0001), beta-2-microglobulin (beta-2M) levels (P = 0.00002), soluble CD23 levels (r = 0.42, P < 0.001), and immunoglobulin mutation status (P = 0.003). In the multivariate analysis adjusted for beta-2M level, patients with sCD52 levels > 2336 nM/L had a nearly 4-fold increase in risk of death. Higher levels of plasma alemtuzumab were achieved when levels of sCD52 were lower. CONCLUSIONS: These data not only demonstrated that sCD52 was detectable and useful in the staging and monitoring of patients with CLL, but also showed that sCD52 formed immune complexes with alemtuzumab and may influence the efficacy and toxicity of alemtuzumab therapy.

Adult↗

PubMed2004

Survival advantage with imatinib mesylate therapy in chronic-phase chronic myelogenous ;eukemia (CML-CP) after IFN-alpha failure and in late CML-CP, comparison with historical controls.

PURPOSE: The purpose of this research was to compare the survival of patients with Philadelphia chromosome (Ph) -positive chronic myelogenous leukemia (CML) post-IFN-alpha failure treated with imatinib to historical experiences with standards of care or other therapies. EXPERIMENTAL DESIGN: The outcome of 261 patients with Ph-positive chronic phase CML post-IFN failure treated with imatinib was compared with 204 historical control patients treated for a similar disease status with existing therapies. A subset of 147 patients in late chronic phase CML and 100% Ph-positive status treated with imatinib was compared with 95 patients in a similar disease status treated with IFN. Multivariate analyses were conducted to assess the independent prognostic effect of therapy (imatinib versus other) on survival. RESULTS: In the first analysis involving 261 patients on imatinib plus 204 historical patients, the complete cytogenetic response rates were 62% and 19%, respectively (P < 0.001). A multivariate analysis identified pretreatment peripheral blasts and thrombocytosis to be independent poor prognostic factors for survival. Imatinib therapy (versus others) was a significant independent favorable prognostic factor for survival (hazard ratio, 0.17; P < 0.0001). In the second analysis involving the subset of 147 patients receiving imatinib plus 95 historical patients treated with IFN regimens, the complete cytogenetic response rates were 41% and 7%, respectively (P < 0.001). A multivariate analysis selected pretreatment anemia and peripheral blasts to be significant independent poor prognostic factors for survival. Imatinib therapy (versus IFN) was an independent favorable prognostic factor for survival (hazard ratio, 0.20; P < 0.0001). Three-month and 6-month landmark analyses showed that patients in all cytogenetic response categories (major, minor, and none) after imatinib therapy had survival outcomes better than the historical control population. Within each cytogenetic response category, survival was also better with imatinib than with other therapies. CONCLUSIONS: This analysis provides evidence for a survival advantage with imatinib versus other therapies in chronic-phase CML post-IFN failure, and for a survival advantage with imatinib versus IFN in late chronic-phase CML.

Antineoplastic Agents↗

PubMed2004

Alemtuzumab: validation of a sensitive and simple enzyme-linked immunosorbent assay.

Alemtuzumab (MabCampath) is a humanized rat monoclonal antibody that targets the CD52 antigen. It has been approved for the treatment of patients with resistant chronic lymphocytic leukaemia (CLL). Measuring plasma/serum levels of alemtuzumab is important for optimizing the dosing and scheduling of therapy; however, current assays in serum or plasma, based on the capture of alemtuzumab using CD52, are complicated and difficult to adapt for high throughput testing. We developed a simple sandwich enzyme-linked immunosorbent assay (ELISA) to measure alemtuzumab that takes advantage of the remaining rat sequence in alemtuzumab. Using specific anti-rat immunoglobulin (Ig) antibodies (absorbed against human Ig), alemtuzumab levels were measured in the serum and plasma of patients treated with alemtuzumab. Levels were similar between plasma and serum samples, in fresh samples and samples stored at 4 degrees C for 24 h, but were significantly lower in samples stored at room temperature for 24h. The assay was successfully used to determine serum alemtuzumab pre- and post-treatment. This assay is simple and adaptable for high throughput testing, with a limit of detection of 0.05 microg/ml and a coefficient of variation of +/-12.5%. No false positivity was observed in >200 samples tested. This validated assay should help optimize the dosing and scheduling of alemtuzumab therapy. The underlying principles are also applicable to the measurement of other humanized antibodies using an appropriate anti-Ig.

Alemtuzumab↗

PubMed2004

Management guidelines for use of alemtuzumab in B-cell chronic lymphocytic leukemia.

An expert opinion roundtable held August 8-9, 2002, brought together clinicians with the most extensive experience with the use of alemtuzumab to pool knowledge and develop treatment goals and guidelines for optimal therapy. By sharing our collective experience, we have been able to formulate recommendations for current clinical practice, which are included in this report, and have emphasized results that have implications for future practice. Guidelines for the management of acute "first-dose" events, prophylaxis for infection, detection and treatment of cytomegalovirus reactivation, and hematologic support are presented, with emphasis on allowing patients to proceed smoothly through therapy while maximizing therapeutic benefit. Management of adverse events is facilitated by the predictable timing of their appearance. In general, hematologic adverse events are transient, manageable, and reversible. Clinicians should be cautious of prematurely terminating treatment at 4-6 weeks in patients whose disease responds to treatment. Although resolution of peripheral blood lymphocytosis occurs early in most patients, bone marrow is unlikely to be clear of disease. In particular, grade 4 neutropenia at this time is common and, because it is manageable, it is not an indication to discontinue treatment. The eradication of minimal residual disease from blood and bone marrow observed with alemtuzumab therapy is a major step forward in the treatment of B-cell chronic lymphocytic leukemia. Combination therapies such as alemtuzumab/fludarabine with the potential to maximize eradication at all disease sites should be systematically investigated. Because high response rates and few complications are observed in previously untreated patients, the use of alemtuzumab earlier in therapy may provide optimum benefit to patients.

Aged↗

PubMed2003

Imatinib mesylate therapy improves survival in patients with newly diagnosed Philadelphia chromosome-positive chronic myelogenous leukemia in the chronic phase: comparison with historic data.

BACKGROUND: The International Randomized study of Interferon-alpha plus cytarabine (IFN-alpha plus ara-C) versus STI571 (imatinib mesylate) [IRIS trial] in patients with newly diagnosed Philadelphia chromosome (Ph)-positive, chronic-phase chronic myelogenous leukemia (CML) has not shown (to date) a survival advantage for imatinib. This was most likely because approximately 90% of patients receiving IFN-alpha plus ara-C changed to imatinib therapy after a median of 8 months into therapy. METHODS: The authors analyzed the results with imatinib therapy in patients with newly diagnosed Ph-positive CML in chronic phase and compared their outcome with patients who received IFN-alpha regimens. A total of 187 patients with Ph-positive CML in early chronic phase treated with imatinib were compared with a historic group of 650 similar patients treated with IFN-alpha regimens from 1982 until 1997. RESULTS: Patients who received imatinib were significantly older and had significantly more bone marrow basophilia and less leukocytosis. The complete cytogenetic response (Ph 0%) rates were better with imatinib (81% vs. 32%; P < 0.001), as were the survival rates (30-month estimated survival rates 98% vs. 88%; P = 0.01). A multivariate analysis of the total study group of 837 patients identified imatinib therapy to be a significant independent favorable prognostic factor for survival (P = 0.01). CONCLUSIONS: The current study is the first to indicate the survival advantage of imatinib compared with IFN-alpha, the previous standard of care, in patients with early chronic-phase CML.

Administration, Oral↗

PubMed2003

Relative increase in leukemia-specific DNA in peripheral blood plasma from patients with acute myeloid leukemia and myelodysplasia.

Using loss of heterozygosity (LOH) and X-chromosome inactivation, we compared peripheral blood (PB) plasma with bone marrow (BM) cells in detecting genomic abnormalities in patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). We detected LOH in the PB plasma of all 45 patients who had cytogenetically documented chromosomal abnormalities (5q-, 7-, +8, 17-, or 20-). BM cells from the same patients showed LOH in 89% of patients with MDS and 70% of patients with AML. Posttherapy samples from 16 of these patients demonstrated complete concordance between LOH and cytogenetics in detecting residual disease in 15 samples. Of the 16 samples, 4 showed LOH in plasma with normal BM morphology. Using X-chromosome inactivation, clonality was detectable in 19 (73%) of 26 BM samples, whereas all PB plasma samples showed clonality. These data support the conclusion that PB plasma is enriched by tumor-specific DNA and can replace BM cells for studying genomic abnormalities.

Adult↗

PubMed2003

Clofarabine, a novel nucleoside analog, is active in pediatric patients with advanced leukemia.

Despite progress in leukemia therapy, most children who experience relapse have a dismal prognosis. New, effective approaches are needed. We conducted a phase 1 study of a novel nucleoside analog, clofarabine, in pediatric patients with refractory and relapsed leukemia. Clofarabine was infused intravenously over 1 hour each day for 5 days. Six dose levels, between 11.25 and 70 mg/m(2) per day for 5 days, were studied in 25 patients. A modified 3 + 3 phase 1 design was followed with 30% dose escalation until the dose-limiting toxicity (DLT) was defined. The maximum tolerated dose (MTD) was 52 mg/m(2) per day for 5 days. At the end of infusion at MTD, clofarabine triphosphate levels in leukemia blasts varied between 6 microM and 19 microM, which resulted in complete and sustained inhibition of DNA synthesis. The DLT was reversible hepatotoxicity and skin rash at 70 mg/m(2) per day for 5 days. Twenty-five patients were treated. Five patients achieved complete remission (CR), and 3 achieved partial remission (PR), for an overall response rate of 32%. Clofarabine is well tolerated and shows significant antileukemic activity in heavily pretreated children. Multicenter phase 2 trials in pediatric acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) are ongoing.

Adenine Nucleotides↗

PubMed2003

Effects of the proteasome inhibitor, bortezomib, on apoptosis in isolated lymphocytes obtained from patients with chronic lymphocytic leukemia.

PURPOSE: Bortezomib is a peptide boronic acid inhibitor of the proteasome developed for cancer therapy. The compound is being evaluated currently in Phase II and III clinical trials. Here we characterized the effects and mechanisms of action of bortezomib in cells obtained from patients with chronic lymphocytic leukemia (CLL). EXPERIMENTAL DESIGN: We exposed isolated CLL lymphocytes from >100 patients to various concentrations of bortezomib or other proapoptotic stimuli, and measured DNA fragmentation by propidium iodide staining and flow cytometry. We characterized the effects of bortezomib on release of apoptosis-associated mitochondrial factors and measured downstream effects on caspase activation using a fluorogenic substrate cleavage assay. We assessed potential effects of the drug on inhibitor of apoptosis protein family apoptosis inhibitors by immunoblotting. Finally, we quantified the effects of bortezomib on apoptosis in 5 patients on a Phase II clinical trial. RESULTS: Bortezomib stimulated apoptosis more rapidly than positive controls (glucocorticoid and fludarabine), although substantial heterogeneity was noted with respect to the concentration of drug required to induce cell death. Bortezomib-induced apoptosis was associated with release of SMAC, apoptosis-inducing factor, and cytochrome c from mitochondria, but the drug did not affect levels of inhibitor of apoptosis protein family cell death inhibitors. Levels of apoptosis were marginally elevated in CLL cells obtained from 2 of 5 fludarabine-refractory patients treated with bortezomib in vivo. CONCLUSION: Our data confirm that bortezomib, like other proteasome inhibitors, has proapoptotic activity in CLL cells.

Antineoplastic Agents↗

PubMed2003

Results of decitabine (5-aza-2'deoxycytidine) therapy in 130 patients with chronic myelogenous leukemia.

BACKGROUND: General and site-specific DNA methylation is associated with tumor progression and resistance in several cancers, including chronic myelogenous leukemia (CML). Decitabine is a hypomethylating agent that has shown encouraging preliminary anti-CML activity. This study evaluated the activity and toxicity of decitabine in different phases of CML. METHODS: One hundred and thirty patients with CML were treated: 123 with Philadelphia chromosome (Ph)-positive CML (64 blastic, 51 accelerated, 8 chronic) and 7 with Ph-negative CML. Decitabine was given at 100 mg/m(2) over 6 hours every 12 hours x 5 days (1000 mg/m(2) per course) in the first 13 patients, 75 mg/m(2) in the subsequent 33 patients, and 50 mg/m(2) in the remaining 84 patients. RESULTS: A total of 552 courses were given to the 130 patients. Only four patients (3%) died during the first course from myelosuppressive complications (three patients) or progressive disease (one patient). Of 64 patients in the CML blastic phase, 18 patients (28%) achieved objective responses. Of these 18 patients, 6 achieved complete hematologic responses (CHR), 2 achieved partial hematologic responses (PHR), 7 achieved hematologic improvements (HI), and 3 returned to the second chronic phase (second CP). Five patients (8%) had cytogenetic responses. Among 51 patients in the accelerated phase, 28 patients (55%) achieved objective responses (12 CHR, 10 PHR, 3 HI, and 3 second CP). Seven patients (14%) had cytogenetic responses. Among eight patients treated in the chronic phase, five (63%) had objective responses. Of seven patients treated for Ph-negative CML, four (57%) had objective responses. There was no evidence of a dose-response effect. The estimated 3-year survival rate was less than 5% in the blastic phase and 27% in the accelerated phase. The only significant toxicity reported was severe myelosuppression, which was delayed, prolonged, and dose dependent. With decitabine 50-75 mg/m(2), the median time to granulocyte recovery above 0.5 x 10(9)/L was about 4 weeks. Myelosuppression-associated complications included febrile episodes in 37% and documented infections in 34%. CONCLUSIONS: Decitabine appears to have significant anti-CML activity. Future studies should evaluate lower-dose, longer-exposure decitabine schedules alone in imatinib-resistant CML, as well as combinations of decitabine and imatinib in different CML phases.

Adolescent↗

PubMed2003

Transient down-modulation of CD20 by rituximab in patients with chronic lymphocytic leukemia.

Lymphoid cells in most patients with chronic lymphocytic leukemia (CLL), when treated with rituximab, become CD20-. This is thought to be due to masking of CD20 by rituximab. We used specific antimouse immunoglobulin antibodies to detect rituximab on the surface of CLL lymphocytes and we demonstrate that rituximab is rarely detectable after therapy. Only 3 of 65 patients with CLL had rituximab detectable on their lymphocytes after rituximab therapy despite the fact that most had no detectable CD20 expression. In vitro mixing of CLL or Raji cells with rituximab demonstrated that rituximab was detectable on the surface of cells due to its binding to CD20. However, the addition of plasma led to the down-modulation of CD20 expression, and the rituximab became undetectable. This down-modulation of CD20 protein expression was associated with a down-modulation of CD20 mRNA. CLL cells that lost their CD20 expression regained CD20 expression after 24 hours in culture. These data suggest that rituximab therapy leads to a substantial but transient down-modulation of CD20 expression and that negativity for CD20 in cells from patients treated with rituximab is not necessarily due to CD20 masking. The importance of this down-modulation in the efficacy of current therapy with rituximab needs further investigation.

Antibodies, Monoclonal↗

PubMed2003

Sudden onset of the blastic phase of chronic myelogenous leukemia: patterns and implications.

BACKGROUND: Therapeutic options in Philadelphia chromosome-positive chronic myelogenous leukemia (Ph-positive CML) in chronic phase include allogeneic stem cell transplantation (SCT) and treatments other than allogeneic SCT. The choice of therapy often depends on the mortality risk of allogeneic SCT. Delaying SCT until the disease demonstrates resistance to other strategies (e.g., imatinib mesylate or interferon-alpha) entails the risk of the development of a sudden blastic phase, which may not permit enough time to perform a SCT. METHODS: The current study was performed to define the incidence and patterns of sudden-onset blastic-phase CML in relation to the risk inherent in delaying allogeneic SCT. Of a study group of 1286 patients who were referred in early chronic-phase CML between 1981-2001 and who received therapies other than allogeneic SCT, 1093 patients had regular follow-up at the study institution. A sudden onset of blastic phase was defined as having its onset within 3 months from a previously documented complete hematologic response. RESULTS: Among the 1093 patients, 183 patients developed blastic-phase disease, which was of sudden onset in 46 patients (25%; 4% of the total). The incidence of sudden blastic phase was 0.4% in the first year, 1.8% in the second year, and 2.6% in the third year. Patients with sudden blastic-phase disease were found to have more often low-risk features at the time of presentation, including low incidences of blasts and thrombocytosis. Sudden blastic-phase CML was found to be associated with a higher incidence of lymphoid blastic morphology (67% vs. 22%; P < 0.0001), which resulted in a higher response rate to blastic-phase therapy (70% vs. 29%; P < 0.0001) and significantly longer survival from the onset of blastic-phase disease (median of 12 months vs. 6 months; P < 0.01). Twenty-four of the 42 patients with sudden blastic-phase disease who were treated at the M. D. Anderson Cancer Center were able to undergo allogeneic SCT in second chronic phrase (n = 13) or transformed phase (n = 11); at the time of last follow-up, 6 patients were alive without evidence of disease at a median of 18 months. CONCLUSIONS: The low rates of sudden blastic transformation in the first 3 years of the course of disease for CML and the salvage rate of these patients with allogeneic SCT should be considered in relation to the transplantation mortality in patients with early chronic-phase disease and the early promising results with imatinib mesylate therapy.

Adult↗

PubMed2003

Phase 2 clinical and pharmacologic study of clofarabine in patients with refractory or relapsed acute leukemia.

In a phase 2 study, 62 patients with relapsed and refractory acute myeloid leukemia (AML; n = 31), myelodysplastic syndrome (MDS; n = 8), chronic myeloid leukemia in blastic phase (CMLBP; n = 11), and acute lymphocytic leukemia (ALL; n = 12) received 40 mg/m2 clofarabine intravenously over 1 hour daily for 5 days, every 3 to 6 weeks. Twenty patients (32%) achieved complete response (CR), 1 had a partial response (PR), and 9 (15%) achieved CR but without platelet recovery (CRp), for an overall response rate of 48%. In AML, responses were noted in 2 (18%) of 11 patients in first salvage with short first CR (</= 12 months), in 7 (87%) of 8 patients with longer first CR, and in 8 (67%) of 12 patients in second or subsequent salvage. Responses were observed in 4 of 8 patients with high-risk MDS (50%), in 7 (64%) of 11 with CML-BP, and in 2 (17%) of 12 with ALL. Severe reversible liver dysfunction was noted in 15% to 25%. After the first clofarabine infusion, responders accumulated more clofarabine triphosphate in blasts compared with nonresponders (median 18 vs 10 microM; P =.03). This increased only in responders (median, 1.8-fold; P =.008) after the second clofarabine infusion. In summary, clofarabine is active in acute leukemias and MDS; cellular pharmacokinetics may have prognostic significance.

Adenine Nucleotides↗

PubMed2003

Telomerase activity is prognostic in pediatric patients with acute myeloid leukemia: comparison with adult acute myeloid leukemia.

BACKGROUND: Significantly elevated telomerase activity (TA) has been found in samples from patients with almost all malignant hematologic diseases. The impact of elevated TA on the course of pediatric patients with acute myeloid leukemia (P-AML) is unknown. METHODS: Using a modified polymerase chain reaction-based, telomeric repeat-amplification protocol assay, the authors measured TA in bone marrow samples from 40 patients with P-AML and, for comparison, in 65 adult patients with AML (A-AML), excluding patients with French-American-British M3 disease. The results were correlated with patient characteristics and survival. RESULTS: TA in patients with P-AML was significantly lower compared with TA in patients with A-AML (P = 0.005). Patients who had P-AML with low TA had a projected 5-year survival rate of 88%, whereas patients who had P-AML with high TA had a projected 5-year survival rate of 43% (P = 0.009). Conversely, patients who had A-AML with very high TA (upper quartile) had significantly longer survival compared with patients who had A-AML with lower TA (P = 0.03). There was no correlation between complete remission rate or disease free survival and TA in P-AML or A-AML. In the A-AML group, when patients were separated by cytogenetic findings (poor prognosis vs. others), it was found that TA was significantly lower in patients with a poor prognosis, but the prognostic value of TA was not independent of cytogenetic status. CONCLUSIONS: The current results suggest, that for patients with P-AML, bone marrow TA is a highly significant prognostic factor.

Acute Disease↗

PubMed2003

Clinical relevance of the expression of the CD31 ligand for CD38 in patients with B-cell chronic lymphocytic leukemia.

BACKGROUND: CD31 (platelet endothelial cell adhesion molecule-1 [PECAM-1]) is the ligand for CD38, a transmembrane glycoprotein that is expressed on the surface of leukemic cells in many patients with B-cell chronic lymphocytic leukemia (B-CLL). In a previous study, the authors showed that CD38 expression was correlated with a poor prognosis in patients with B-CLL. In the current study, blood samples from patients with B-CLL were examined to identify CD31 surface marker expression, and CD31 expression was correlated with several other known prognostic variables, including CD38. METHODS: Using flow cytometry, peripheral blood samples from 120 patients with B-CLL were analyzed for CD31 and CD38 expression on CD19 positive leukemic B cells. RESULTS: Thirteen of 120 patients (11%) had CD31 expression on < 20% of their B cells, and the remaining patients had various levels of CD31 expression. The median expression of CD31 was 76% of leukemic, CD19 positive cells. Levels of CD31 expression were not correlated with survival outcomes or with any of the known prognostic parameters when all patients were considered. Patients who had high CD38 expression (>or= 20%), as expected, had significantly shorter survival (P = 0.001) compared with patients who had low CD38 expression (< 20%). However, in patients with low CD38 expression, a subgroup with low CD31 expression (< 76%) had significantly longer survival compared with the survival for the entire group (P = 0.0001). Moreover, the survival pattern of patients with low CD38 expression and high CD31 expression was not significantly different from the survival pattern seen in patients with high CD38 expression. CONCLUSIONS: CD31 expression further defined a subgroup of patients with B-CLL who had a different survival outcome. Defining the interaction between CD31 expression and CD38 expression in patients with CLL will require further exploration.

ADP-ribosyl Cyclase↗

PubMed2003

Gemtuzumab, fludarabine, cytarabine, and cyclosporine in patients with newly diagnosed acute myelogenous leukemia or high-risk myelodysplastic syndromes.

BACKGROUND: Gemtuzumab is used to treat patients with previously untreated or recurrent acute myelogenous leukemia (AML). The fludarabine and cytarabine (ara-C) regimen is active in these patients. Resistance to gemtuzumab is associated with blast multidrug resistance (MDR). The objectives of this study were to evaluate the efficacy and toxicity of a combination regimen of gemtuzumab, fludarabine, ara-C, and the MDR modifier (cyclosporine [CyA]) in patients with previously untreated AML, refractory anemia with excess blasts (RAEB), or RAEB in transformation (RAEBT). METHODS: The MFAC regimen was comprised of gemtuzumab (Mylotarg trade mark ) (6 mg/m(2) intravenously [i.v.] on Day 1); fludarabine and ara-C (15 mg/m(2) and 0.5 g/m(2), respectively, twice daily on Days 2-6); and CSA (6 mg/kg loading dose before gemtuzumab, followed by 16 mg/kg continuous i.v. infusion on Days 1 and 2). RESULTS: Fifty-nine evaluable patients were treated: 39 patients (66%) had AML and 20 patients (34%) had RAEB/RAEBT. Their median age was 57 years (range, 27-76 years). The MFAC regimen induced complete remission (CR) in 27 patients (46%) and CR with incomplete platelet recovery (CRp) in 1 patient (2%). The median survival period is 8 months. At 12 months, the survival rate is 38% and the event-free survival rate in patients with CR/CRp is 27%. Infections complicated 38% of the courses of chemotherapy. Grade 3/4 toxicity included hyperbilirubinemia in 31% and transaminitis in 7% of the patients. Four patients (7%) developed hepatic venoocclusive disease (VOD). CONCLUSIONS: The MFAC regimen may merit further study in patients with AML if measures to avoid and/or treat VOD can be incorporated into the regimen.

Adult↗

PubMed2003

Phase I clinical and pharmacology study of clofarabine in patients with solid and hematologic cancers.

PURPOSE: To define the maximum-tolerated doses (MTDs) and dose-limiting toxicities (DLTs) of clofarabine, given as a 1-hour infusion daily for 5 days, in patients with solid tumors and with acute leukemia. PATIENTS AND METHODS: The initial part of the study defined the MTD and DLT in solid tumors. The second part of the study defined the MTD and DLT in acute leukemia. RESULTS: The starting dose of clofarabine (15 mg/m(2)) was myelosuppressive, requiring several dose de-escalations to 2 mg/m(2), the dose suggested for phase II studies in solid tumors. Dose escalation in acute leukemia started at 7.5 mg/m(2), with several escalations to 55 mg/m(2). The DLT was reversible hepatotoxicity at 55 mg/m(2). The recommended dose for acute leukemia phase II studies was 40 mg/m(2). Among 32 treated patients with acute leukemia, two achieved a complete response and three had a marrow complete response without platelet recovery (hematologic improvement), for an overall response rate of 16%. At 40 mg/m(2), the median plasma clofarabine level was 1.5 micro mol/L (range, 0.42 to 3.2 micro mol/L; n = 7). Cellular and plasma pharmacokinetic studies suggested dose proportionality but showed a wide variation in intracellular concentrations of clofarabine triphosphate. CONCLUSION: This phase I study defined the following two MTDs for clofarabine given as a 1-hour infusion daily for 5 days: 2 mg/m(2) for solid tumors, the DLT being myelosuppression; and 40 mg/m(2) for acute leukemia, the DLT being hepatotoxicity. Encouraging activity was observed in acute leukemia.

Adenine Nucleotides↗

PubMed2003

A randomized trial of liposomal daunorubicin and cytarabine versus liposomal daunorubicin and topotecan with or without thalidomide as initial therapy for patients with poor prognosis acute myelogenous leukemia or myelodysplastic syndrome.

BACKGROUND: Because angiogenesis may play a role in the pathogenesis of acute myeloid leukemia (AML) and high-risk myelodysplastic syndrome (MDS), and thalidomide (Th) has shown significant anti-angiogenic activity, this study was designed to investigate the potential role of Th in the treatment of patients with AML and MDS and the possible role of a non-ara-C-containing regimen. METHODS: Adults with AML or high-risk MDS and cytogenetic abnormalities other than inv (16), t(8;21), -Y or -X were randomized to receive liposomal daunorubicin (DNX) and ara-C (DA) or DNX and topotecan (DT). Within each arm, patients were randomized to receive chemotherapy alone (DA or DT) or with thalidomide (DATh or DTTh). Vascular endothelial growth factor (VEGF) plasma levels and microvascular density was measured before and after therapy. Eighty-four patients (median age, 65 years; range, 27-84 years) were treated. RESULTS: None of 11 patients treated with DT or DTTh responded and these arms were closed. Seventeen of 37 patients treated with DA and 15 of 36 treated with DATh achieved an early complete remission. Median complete response duration was 38 and 34 weeks (P = 0.57) and median survival 35 and 28 weeks (P = 0.15), respectively. Patients with high pretreatment VEGF levels had an inferior survival. There was no significant difference in the changes in VEGF levels or microvascular density after treatment in patients who did versus those who did not receive thalidomide. CONCLUSIONS: The authors concluded that thalidomide in combination with chemotherapy does not result in clinical benefit in patients with AML or high-risk MDS.

Adult↗

PubMed2003

Increased telomerase activity is associated with shorter survival in patients with chronic phase chronic myeloid leukemia.

BACKGROUND: Significantly elevated telomerase activity (TA) has been found in samples from patients with many malignant hematologic diseases. However, the impact of elevated TA on the course of patients with chronic phase chronic myeloid leukemia (CP-CML) is unknown. METHODS: Using a modified polymerase chain reaction-based telomeric repeat amplification protocol assay, the authors measured TA in bone marrow samples from 93 patients with CP-CML and correlated it with patient characteristics and survival. TA also was measured in bone marrow samples from 29 patients with accelerated/blastic phase CML. RESULTS: Patients with accelerated/blastic phase CML were found to have somewhat higher levels of TA compared with patients with CP-CML (P = 0.07). Among patients with CP-CML, those with high TA progressed to advanced stages of disease sooner (P = 0.05) and had a significantly shorter survival (P = 0.04) than patients with low TA. No correlation was found between TA and patient age, hemoglobin, platelet and leukocyte counts, percentage of peripheral or bone marrow blasts or basophils, or bone marrow cellularity. On multivariate analysis, high TA retained its significance as a factor associated with shorter patient survival (P = 0.02). CONCLUSIONS: The current study data suggest that TA plays a role in the propagation of CP-CML and that the potential of telomerase inhibitors in patients with CML should be explored, even in those with early phase disease.

Aged↗