Characteristics and outcome of patients with therapy-related acute promyelocytic leukemia front-line treated with or without arsenic trioxide

Therapy-related acute promyelocytic leukemia (t-APL) is relatively rare, with limited data on outcome after treatment with arsenic trioxide (ATO) compared to standard intensive chemotherapy (CTX). We evaluated 103 adult t-APL patients undergoing treatment with all-trans retinoic acid (ATRA) alone (n=7) or in combination with ATO (n=24), CTX (n=53), or both (n=19). Complete remissions were achieved after induction therapy in 57% with ATRA, 100% with ATO/ATRA, 78% with CTX/ATRA, and 95% with CTX/ATO/ATRA. Early death rates were 43% for ATRA, 0% for ATO/ATRA, 12% for CTX/ATRA and 5% for CTX/ATO/ATRA. Three patients relapsed, two developed therapy-related acute myeloid leukemia and 13 died in remission including seven patients with recurrence of the prior malignancy. Median follow-up for survival was 3.7 years. None of the patients treated with ATRA alone survived beyond one year. Event-free survival was significantly higher after ATO-based therapy (95%, 95% CI, 82-99%) as compared to CTX/ATRA (78%, 95% CI, 64-87%; P=0.042), if deaths due to recurrence of the prior malignancy were censored. The estimated 2-year overall survival in intensively treated patients was 88% (95% CI, 80-93%) without difference according to treatment (P=0.47). ATO when added to ATRA or CTX/ATRA is feasible and leads to better outcomes as compared to CTX/ATRA in t-APL.

Mitoxantrone, etoposide and cytarabine following epigenetic priming with decitabine in adults with relapsed/refractory acute myeloid leukemia or other high-grade myeloid neoplasms: a phase 1/2 study

DNA methyltransferase inhibitors sensitize leukemia cells to chemotherapeutics. We therefore conducted a phase 1/2 study of mitoxantrone, etoposide, and cytarabine following “priming” with 5-10 days of decitabine (dec/MEC) in 52 adults (median age 55 [range: 19-72] years) with relapsed/refractory acute myeloid leukemia (AML) or other high-grade myeloid neoplasms. During dose escalation in cohorts of 6-12 patients, all dose levels were well-tolerated. As response rates appeared similar with 7 and 10-days of decitabine, a 7-day course was defined as the recommended phase 2 dose (RP2D). Among 46 patients treated at/above the RP2D, 10 (22%) achieved a complete remission (CR), 8 without measurable residual disease; five additional patients achieved CR with incomplete platelet recovery, for an overall response rate of 33%. Seven patients (15%) died within 28 days of treatment initiation. Infection/neutropenic fever, nausea, and mucositis were the most common adverse events. While the CR rate compared favorably to a matched historic control population (observed/expected CR ratio=1.77), CR rate and survival were similar to two contemporary salvage regimens used at our institution (G-CLAC and G-CLAM). Thus, while meeting the pre-specified efficacy goal, we found no evidence that dec/MEC is substantially better than other cytarabine-based regimens currently used for relapsed/refractory AML.

PR1 peptide vaccine induces specific immunity with clinical responses in myeloid malignancies

PR1, an HLA-A2-restricted peptide derived from both proteinase 3 and neutrophil elastase, is recognized on myeloid leukemia cells by cytotoxic T lymphocytes (CTL) that preferentially kill leukemia and contribute to cytogenetic remission. To evaluate safety, immunogenicity and clinical activity of PR1 vaccination, a phase I/II trial was conducted. Sixty-six HLA-A2+ patients with acute myeloid leukemia (AML: 42), chronic myeloid leukemia (CML: 13) or myelodysplastic syndrome (MDS: 11) received three to six PR1 peptide vaccinations, administered subcutaneously every 3 weeks at dose levels of 0.25, 0.5 or 1.0 mg. Patients were randomized to the 3 dose levels after establishing the safety of the highest dose level. Primary endpoints were safety and immune response, assessed by doubling of PR1/HLA-A2 tetramer-specific CTL, and the secondary endpoint was clinical response. Immune responses were noted in 35 of 66 (53%) patients. Of the 53 evaluable patients with active disease, 12 (24%) had objective clinical responses (complete: 8, partial: 1 and hematological improvement: 3). PR1-specific immune response was seen in 9 of 25 clinical responders vs. 3 of 28 clinical non-responders (p=0.03). In conclusion, PR1 peptide vaccine induces specific immunity that correlates with clinical responses, including molecular remission, in AML, CML and MDS patients.

Pre- and post-transplant quantification of measurable ('minimal') residual disease via multiparameter flow cytometry in adult acute myeloid leukemia

Measurable (“minimal”) residual disease (MRD) before or after hematopoietic cell transplantation (HCT) identifies adults with AML at risk of poor outcomes. Here, we studied whether peri-transplant MRD dynamics can refine risk assessment. We analyzed 279 adults receiving myeloablative allogeneic HCT in first or second remission who survived at least 35 days and underwent 10-color multiparametric flow cytometry (MFC) analyses of marrow aspirates before and 28±7 days after transplantation. MFC-detectable MRD before (n=63) or after (n=16) transplantation identified patients with high relapse risk and poor survival. Forty-nine patients cleared MRD with HCT conditioning, whereas 2 patients developed new evidence of disease. The 214 MRD^neg/MRD^neg patients had excellent outcomes, whereas both MRD^neg/MRD^pos patients died within 100 days following transplantation. For patients with pre-HCT MRD, outcomes were poor regardless of post-HCT MRD status, although survival beyond 3 years was observed among the 58 patients with decreasing but not the 7 patients with increasing peri-HCT MRD levels. In multivariable models, pre-HCT but not post-HCT MRD was independently associated with OS and RR. These data indicate that MRD^pos patients before transplantation have a high relapse risk regardless of whether or not they clear MFC-detectable disease with conditioning and should be considered for pre-emptive therapeutic strategies.

Resistance prediction in AML: analysis of 4601 patients from MRC/NCRI, HOVON/SAKK, SWOG and MD Anderson Cancer Center

Therapeutic resistance remains the principal problem in acute myeloid leukemia (AML). We used area under receiver-operating characteristic curves (AUCs) to quantify our ability to predict therapeutic resistance in individual patients, where AUC=1.0 denotes perfect prediction and AUC=0.5 denotes a coin flip, using data from 4601 patients with newly diagnosed AML given induction therapy with 3+7 or more intense standard regimens in UK Medical Research Council/National Cancer Research Institute, Dutch-Belgian Cooperative Trial Group for Hematology/Oncology/Swiss Group for Clinical Cancer Research, US cooperative group SWOG and MD Anderson Cancer Center studies. Age, performance status, white blood cell count, secondary disease, cytogenetic risk and FLT3-ITD/NPM1 mutation status were each independently associated with failure to achieve complete remission despite no early death ('primary refractoriness'). However, the AUC of a bootstrap-corrected multivariable model predicting this outcome was only 0.78, indicating only fair predictive ability. Removal of FLT3-ITD and NPM1 information only slightly decreased the AUC (0.76). Prediction of resistance, defined as primary refractoriness or short relapse-free survival, was even more difficult. Our limited ability to forecast resistance based on routinely available pretreatment covariates provides a rationale for continued randomization between standard and new therapies and supports further examination of genetic and posttreatment data to optimize resistance prediction in AML.

Management of older or unfit patients with acute myeloid leukemia

Acute myeloid leukemia (AML) is primarily a disease of older adults, for whom optimal treatment strategies remain controversial. Because of the concern for therapeutic resistance and, in particular, excessive toxicity or even treatment-related mortality, many older or medically unfit patients do not receive AML-directed therapy. Yet, evidence suggests that outcomes are improved if essentially all of these patients are offered AML therapy, ideally at a specialized cancer center. Medical fitness for tolerating intensive chemotherapy can be estimated relatively accurately with multiparameter assessment tools; this information should serve as basis for the assignment to intensive or non-intensive therapy. Until our accuracy in predicting the success of individual therapies improves, all patients should be considered for participation in a randomized controlled trial. Comparisons between individual trials will be facilitated once standardized, improved response criteria are developed, and standard treatment approaches have been defined against which novel therapies can be tested.

Accurate detection of uniparental disomy and microdeletions by SNP array analysis in myelodysplastic syndromes with normal cytogenetics

Progress in the management of patients with myelodysplastic syndromes (MDS) has been hampered by the inability to detect cytogenetic abnormalities in 40-60% of cases. We prospectively analyzed matched pairs of bone marrow and buccal cell (normal) DNA samples from 51 MDS patients by single nucleotide polymorphism (SNP) arrays, and identified somatically acquired clonal genomic abnormalities in 21 patients (41%). Among the 33 patients with normal bone marrow cell karyotypes, five (15%) had clonal, somatically acquired aberrations by SNP array analysis, including four with segmental uniparental disomies (UPD) and one with three separate microdeletions. Each abnormality was detected more readily in CD34+ cells then in unselected bone marrow cells. Paired analysis of bone marrow and buccal cell DNA from each patient was necessary to distinguish true clonal genomic abnormalities from inherited copy number variations and regions with apparent LOH. UPDs affecting chromosome 7q were identified in two patients who had a rapidly deteriorating clinical course despite a low-risk International Prognostic Scoring System score (IPSS). Further studies of larger numbers of patients will be needed to determine whether 7q UPD detected by SNP array analysis will identify higher-risk MDS patients at diagnosis, analogous to those with 7q cytogenetic abnormalities.

PR1 peptide vaccination for patients with myeloid leukemias

7017

Background: PR1 is a nanomeric HLA-A2-restricted peptide derived from the myeloid leukemia-associated antigens proteinase 3 and neutrophil elastase. Methods: Sixty-six HLA-A2+ patients with acute myeloid leukemia (42), chronic myeloid leukemia (13) or myelodysplastic syndrome (11) were treated with PR1 peptide vaccine. The first 54 patient received three vaccinations, and the last 12 patients were given six vaccinations. The vaccine was injected subcutaneously, at 3 week intervals at one of three dose levels: 0.25, 0.5 or 1.0 mg per vaccination. Immune response to the vaccine was defined as a ≥ 2-fold increase in PR1-specific cytotoxic T lymphocytes. Results: Fifty-three patients had measurable disease (MD) and 13 were in complete remission. The vaccine was well tolerated, with toxicity limited to grade I and II injection site reactions. Forty-four of the 53 patients with MD were evaluable for both immune and clinical responses. PR1-specific immune response was observed in 35/44 (57%) of the evaluable patients. Clinical responses were observed in 10 of the 25 immune responders versus 2 of the 19 immune non-responders (p=0.04). PR1 vaccine-induced immune response was associated with a longer event-free survival, 8.7 months vs. 4.1 months in immune non-responders (p = 0.17). Older age and high blast count were associated with short event-free survival (p=0.01 and <0.001). Conclusion: PR1 peptide vaccine-induced immune response is associated with a superior overall clinical response and a trend towards longer event-free survival in patients with persistent myeloid leukemia.

[Table: see text]

Risk factors of myelodysplastic syndromes: a case-control study

Little is known about the etiology of myelodysplastic syndromes (MDS). A hospital-based case-control study of 354 adult de novo MDS cases and 452 controls was conducted to investigate associations between lifestyle characteristics and MDS risk. The distribution by French-American-British (FAB) type was 67 (19%) refractory anemia (RA), 38 (11%) refractory anemia with ringed sideroblasts (RARS), 43 (12%) chronic myelomonocytic leukemia (CMML), 136 (38%) RA with excess blasts (RAEB), and 70 (20%) RAEB in transformation (RAEBT). Multivariate logistic regression analyses were performed among all MDS cases and among each FAB type and gender. For all MDS combined, family history of hematopoietic cancer (odds ratio (OR) = 1.92), smoking (OR = 1.65), and exposure to agricultural chemicals (OR = 4.55) or solvents (OR = 2.05) were associated with MDS risk. Among RA/RARS cases, smoking (OR = 2.23) and agricultural chemical exposure (OR = 5.68) were the only risk factors identified. For RAEB/RAEBT cases, family history of hematopoietic cancer (OR = 2.10), smoking (OR = 1.52), and exposure to agricultural chemicals (OR = 3.79) or solvents (OR = 2.71) were independent risk factors. Drinking wine reduced risk for all FAB types by almost 50% (OR = 0.54). We found a joint effect between smoking and chemical exposure with the highest risk among smokers exposed to solvents/agricultural chemicals (OR = 3.22). Results from this large study suggest that several factors play a role in MDS predisposition with possible joint effects. Risk profiles seem to differ by FAB type and gender.

Having a higher blast percentage in circulation than bone marrow: clinical implications in myelodysplastic syndrome and acute lymphoid and myeloid leukemias

Determining the percentage of peripheral blood (PB) and bone marrow (BM) blasts is important for diagnosing and classifying acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). Although most patients with acute leukemia or MDS have a higher percentage of BM blasts than PB blasts, the relative proportion is reversed in some patients. We explored the clinical relevance of this phenomenon in MDS (n = 446), AML (n = 1314), and acute lymphoblastic leukemia (ALL) (n = 385). Among patients with MDS or ALL, but not AML, having a higher blast percentage in PB than in BM was associated with significantly shorter survival. In multivariate analyses, these associations were independent of other relevant predictors, including cytogenetic status. Our findings suggest that MDS and ALL patients who have a higher percentage of PB blasts than BM blasts have more aggressive disease. These data also suggest that MDS classification schemes should take into account the percentage of blasts in PB differently from the percentage of blasts in BM.

Disease burden may identify patients more likely to benefit from second allogeneic hematopoietic stem cell transplantation to treat relapsed acute myelogenous leukemia

The major cause of failure after allogeneic hematopoietic stem cell transplantation (HSCT) for acute myelogenous leukemia (AML) is disease relapse or progression. We analyzed the outcome of second HSCT for treatment of patients with relapsed, refractory AML/myelodysplastic syndrome (MDS) at our institution. A total of 72 patients were eligible for this analysis. In all, 25 (35%) patients received salvage chemotherapy prior to the second transplant procedure and only two (3%) patients were in complete remission at the time of the second transplant. A total of 20 patients (28%) had low leukemia burden as measured by the absence of peripheral blood blasts and <or=5% blasts in the bone marrow at the time of the second transplant. Although, the overall median survival after the second transplant was 6 months, a subset of patients who had low leukemia burden at the time of the second transplant had a 5-year survival of 25 vs 12% in those with a high leukemia burden. Thus, a second transplant may offer the possibility of long-term disease control in a subset of patients who have a 'low bulk' disease at the time of transplantation.

Antithymocyte globulin (ATG)-based therapy in patients with myelodysplastic syndromes

The purpose of this study was to determine the efficacy of and tolerance to antithymocyte globulin (ATG)-based therapy in patients with myelodysplastic syndrome (MDS). Therapy consisted of ATG 40 mg/kg/day daily intravenously (i.v.) for 4 days; cyclosporine daily orally for 6 months with levels titrated between 200 and 400 mg/dl; and methylprednisone 1 mg/kg i.v. daily before each dose of ATG. Of 32 patients treated, 31 patients were evaluable. The median age was 59 years (range, 28-79 years). A total of 18 patients had refractory anemia (RA) or RA with ringed sideroblasts (RARS), 10 patients had RA with excess blasts (RAEB), two patients had RAEB in transformation, and one patient had chronic myelomonocytic leukemia. ATG, cyclosporine, and methylprednisone induced complete (N=4) or partial (N=1) remission in five patients (16% of total; RA, two patients; RARS, two patients; and RAEB, one patient). Durable complete remissions were observed in three of 18 patients (17%) with RA (N=1) or RARS (N=2) (12, 41+, and 60+ months). The most common adverse events were fever and allergic reactions. Hepatic and renal dysfunction, albeit consistently reversible, occurred in 19 and 13% of the patients, respectively. In conclusion, an ATG-based regimen can produce durable complete remissions in a subset of patients with MDS.

Comparison of idarubicin + ara-C-, fludarabine + ara-C-, and topotecan + ara-C-based regimens in treatment of newly diagnosed acute myeloid leukemia, refractory anemia with excess blasts in transformation, or refractory anemia with excess blasts

It has been unclear whether regimens containing topotecan + ara-C (TA) or fludarabine + ara-C (FA) +/- idarubicin are superior to regimens containing idarubicin + ara-C (IA) without either fludarabine or topotecan for treatment of newly diagnosed acute myeloid leukemia (AML), refractory anemia with excess blasts in transformation (RAEB-t), or RAEB. Of 1279 patients treated here for these diagnoses between 1991 and 1999, 322 received IA regimens, 600 FA regimens, and 357 TA regimens. All regimens used ara-C doses of 1 to 2 gm/m(2)/d, given by continuous infusion in IA, and over 2 to 4 hours in FA and TA. Complete remission (CR) rates were lower with FA (55%) and TA (59%) than with IA (77%). Both event-free survival (EFS) in CR and survival were shorter: median EFS in CR (95% confidence interval) was 63 weeks (range, 55-76 weeks) for IA, 40 (range, 31-46 weeks) for FA, and 36 (range, 27-44 weeks) for TA; median survival was 77 weeks (range, 57-88 weeks) for IA, 30 (range, 27-35 weeks) for FA, and 41 (range, 35-50 weeks) for TA. These trials were not randomized, and patients with worse prognoses were disproportionately given the FA and TA regimens. Nonetheless, after accounting for prognosis the FA and TA regimens remained highly significantly associated with lower CR rates, shorter EFS in CR, and shorter survival. Accounting for possible effects of individual trials within each of the IA, FA, and TA groups did not alter these findings. It is unlikely that, as given here, either FA or TA is, in general, superior to IA, highlighting the need for new treatments.

High-dose chemotherapy in high-risk myelodysplastic syndrome: covariate-adjusted comparison of five regimens

BACKGROUND

Antileukemic chemotherapy has been used for two decades to treat high-risk myelodysplastic syndrome (refractory anemia with excess of blasts [RAEB] and RAEB in transformation into acute leukemia [RAEB-t]) patients. Because the results of standard regimens have been disappointing, high-dose chemotherapeutic regimens were investigated recently. In the absence of randomized trials, the relative merits of various treatment regimens are unknown.

METHODS

The authors analyzed the outcome for 394 newly diagnosed patients treated between 1991 and 1999 with five regimens consisting of intermediate- or high-dose cytosine arabinoside (A) in combination with idarubicin (I), and introduced cyclophosphamide (C) and the new agents fludarabine (F) and topotecan (T) into new combinations with A. In addition to defining the role of high-intensity chemotherapy in the overall outcome for patients with RAEB-t and RAEB, the authors determined the relative merits of the five regimens (IA, FA, FAI, TA, and CAT), accounting for the nonrandom distribution of the prognostic covariates.

RESULTS

The overall complete response (CR) rate of 58% was significantly associated with karyotype, performance status (PS), treatment in the laminar air flow room, duration of antecedent hematologic disorder and age, but not French-American-British or International Prognostic Scoring System risk categories. Multivariate analysis did not identify statistically significant differences in CR rates obtained with each regimen. Induction death rates increased with age with all but the TA regimen; they were lowest with TA (5.4%) and highest with FAI (20.7%), and these differences were significant in patients older than 65 years. The trend for time to death was the same as for time to recurrence in all groups. Multivariate analysis of time to death identified treatment regimen (FA, FAI, and CAT), cytogenetic status (-5/-7), increasing age, and PS greater than 2 as significant independent unfavorable prognostic factors. After prognostic variables were accounted for, survival with IA treatment remained superior to that of FA and FAI but comparable to TA, and CR duration was only marginally shorter with FA. Landmark analysis showed the overall survival of responders to be superior to that of nonresponders, the difference remaining significant after adjustment for prognostic covariates.

CONCLUSIONS

Although the newer regimens did not improve outcome, TA and CAT produced results comparable to those of IA and may be considered treatment alternatives. The TA regimen was particularly effective in RAEB patients and could be delivered safely, with low induction mortality. Our results indicated that although CR seemed associated with survival advantage, innovative post-remission managements represent a challenge because improvement in outcome is not likely to come from intensified therapy.

Therapeutic options for acute myelogenous leukemia

BACKGROUND

General therapeutic options for patients with acute myelogenous leukemia (AML) are reviewed and specific new therapies are described.

METHODS

Data in this review came from the published literature and the M. D. Anderson Cancer Center's acute leukemia database.

RESULTS

Outcome following standard therapy of AML is so variable that is best to speak of a range of outcomes determined by various prognostic factors. Therapy can (and usually does) fail because of treatment-induced mortality or (more usually) resistance to therapy. Performance status and age are the principal predictors of early death, whereas cytogenetics, a history of abnormal blood counts, and MDR1 expression are predictors of resistance. Using this information, physicians can categorize patients into those in whom 1) standard therapy is indicated, 2) either standard or investigational therapy is appropriate, and 3) investigational therapy is indicated. The majority of even newly diagnosed patients belong to Group 3. The availability of allogeneic or autologous transplantation does not alter this conclusion. Investigational therapies have been developed that are directed against the CD33 surface antigen, the multidrug-resistant MDR1 protein, and other targets. Because of the number of new therapies clinical research in AML should emphasize pilot trials rather than traditionally large Phase III studies.

CONCLUSIONS

Most patients with newly diagnosed AML should be offered investigational regimens.

Thiotepa, busulfan, and cyclophosphamide as a preparative regimen for allogeneic transplantation for advanced myelodysplastic syndrome and acute myelogenous leukemia

Sixty-two adults underwent marrow or blood stem cell transplantation from an HLA-matched related donor using high-dose thiotepa, busulfan, and cyclophosphamide (TBC) as the preparative regimen for treatment of advanced myelodysplastic syndrome (MDS) (refractory anemia with excess blasts with or without transformation) or acute myelogenous leukemia (AML) past first remission. All evaluable patients engrafted and had complete donor chimerism. A grade 3-4 regimen-related toxicity occurred in eight (13%) patients, and a diagnosis of MDS was the only independent risk factor for grade 3-4 regimen-related toxicity (hazard ratio 9.25, P = 0.01). Day-100 treatment-related mortality (TRM) was 19%. Poor-prognosis cytogenetics increased the risk of day-100 TRM (hazard ratio 11.4, P = 0.003), and use of tacrolimus for graft-versus-host disease prophylaxis reduced the risk of day-100 TRM (hazard ratio 0.13, P = 0.027). For all patients, the three-year relapse rate was 43% (95% CI, 28%-58%). Refractoriness to conventional induction chemotherapy prior to transplantation was an independent risk factor for relapse (hazard ratio 10.8, P = 0.02). Three-year survival was 26% (95% CI, 14%-37%); survival rates were 29% for those transplanted for AML in second remission, 31% transplanted for AML in relapse, and 17% with MDS, and there were no independent risk factors for survival. TBC is an active preparative regimen for advanced AML. Patients with advanced MDS appeared to have a higher risk of toxicity and early mortality, and alternative preparative regimens should be considered for these patients.

Mylotarg (gemtuzumab ozogamicin) therapy is associated with hepatic venoocclusive disease in patients who have not received stem cell transplantation

BACKGROUND

Mylotarg (Wyeth-Ayerst Laboratories, St. Davids, PA) is the brand name for a calicheamicin-conjugated humanized anti-CD33 monoclonal antibody (gemtuzumab ozogamicin, CMA-676) and has been approved recently for the treatment of a subset of elderly patients who have relapsed acute myeloid leukemia (AML). Mylotarg is associated with an incidence of approximately 20% Grade 3 or 4 hyperbilirubinemia and liver transaminitis in this patient population. Hepatic venoocclusive disease (VOD) has been reported in patients who have undergone stem cell transplantation (SCT) after Mylotarg therapy. Outside of the SCT setting, VOD has been associated very rarely with cytotoxic therapy.

METHODS

The authors assessed the incidence of VOD in 119 patients who were receiving Mylotarg-containing non-SCT regimens. VOD was diagnosed through the use of standard Seattle and Baltimore criteria.

RESULTS

A cohort of 119 (61 previously untreated, 58 with relapsed disease) patients with AML (92 patients), advanced myelodysplastic syndrome (25 patients), or chronic myeloid leukemia in blast phase (2 patients), received Mylotarg-based regimens. Fourteen (12%) developed VOD. The diagnosis of VOD was supported by histology in 2 patients and radiologic studies in a further 10 patients. Five (36%) of 14 patients with VOD had received no prior antileukemic cytotoxic therapy, including 2 patients who received single-agent Mylotarg therapy.

CONCLUSIONS

Mylotarg was shown to be associated with the development of potentially fatal VOD in patients with leukemia who had not received SCT. VOD occurred when Mylotarg was used either as a single agent or when it was given with other cytotoxic agents. VOD occurred in Mylotarg-treated patients who had received no prior cytotoxic therapy. The current study concluded that risk factors for VOD should be assessed when considering Mylotarg therapy, and that attempts to avoid and treat VOD are warranted in patients who receive Mylotarg therapy.

Growth factors in acute myeloid leukaemia

Clinical trials of colony-stimulating factors (CSFs) have been conducted for over 10 years. Initially, these agents, generally either granulocyte-macrophage (GM)- or granulocyte (G)-CSF, were hypothesized to reduce rates of major infection and/or death in the initial weeks after administration of chemotherapy. Although trials have consistently shown that both cytokines accelerate neutrophil recovery, only 1 out of 5-10 large randomized trials has reported that a decrease in major infection occurs as a result. While some of these trials have found that the use of cytokines lowers days in hospital, on antibiotics, or with fever, it is unclear whether the magnitude of these effects outweighs the expense currently entailed in CSF administration; indeed it appears that estimates of cost are themselves quite variable. The second major use of cytokines has been in priming acute myeloid leukaemia (AML) blasts to the cytotoxic actions of chemotherapy. Here again, the results of several randomized trials do not justify application of this strategy. It remains possible that there are subsets of AML patients who would benefit from priming. However, the identification of such patients might require years of accrual into clinical trials from which the majority of patients would not benefit. Future years may see trials of cytokines (e.g. pegylated recombinant human megakaryocytic growth and development factor +G- or GM-CSF) in patients in remission and as a means to increase the number of normal granulocytes that can be given to patients with infections. Further therapies may target cytokine receptors on AML blasts, to improve anti-leukaemia therapy.

11q23 abnormalities in patients with acute myelogenous leukemia and myelodysplastic syndrome as detected by molecular and cytogenetic analyses

11q23 chromosomal abnormalities and rearrangement of the mixed lineage leukemia (MLL) gene are important prognostic factors in acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS). However, the presence of 11q23 abnormalities does not always correlate with that of MLL gene rearrangement. We retrospectively compared the occurrence of 11q23 abnormalities (measured by karyotyping) and MLL gene rearrangement (measured by Southern blotting) in bone marrow from 311 consecutive adult patients with AML or MDS. 11q23 abnormalities were found in 18 patients (5.8%), of whom 7 (39%) did not have the MLL gene rearrangement. MLL gene rearrangement was detected in 35 patients (11.2%). Of these 35 patients, only 11 (31%) had cytogenetic evidence of 11q23 abnormalities. None of the 21 patients with chronic myelomonocytic leukemia had 11q23 abnormalities or MLL gene rearrangement. 11q23 abnormalities were associated with shorter survival than was a diploid karyotype. Both cytogenetic and molecular studies should be performed to detect 11q23 abnormalities in patients with AML or MDS.

A new statistical method for dose-finding based on efficacy and toxicity in early phase clinical trials

Most statistical methods for dose-finding in phase I clinical trials determine a maximum tolerable dose based on toxicity while ignoring efficacy. Most phase II designs assume that an acceptable dose has been determined and aim to estimate treatment efficacy, possibly with early stopping rules for safety monitoring. The purpose of this paper is to describe a new statistical strategy for dose-finding in single-arm clinical trials where patient outcome is characterized in terms of both response and toxicity. The strategy, which may be considered a phase I/II hybrid, was first proposed by Thall and Russell [1] and subsequently modified by Thall [2]. The underlying mathematical model expresses the probabilities of response and toxicity as interdependent functions of dose. The method is based on fixed standards for the minimum probability of response and the maximum probability of toxicity appropriate for the particular trial. The best acceptable dose is chosen for each successive patient cohort adaptively, based on the fixed standards and the dose-outcome data from patients treated previously in the trial. The scientific goals are to select one best acceptable dose for future patients and to estimate the response and toxicity probabilities at that dose, or to stop the trial early if it becomes sufficiently unlikely that any dose is both safe and efficacious. An application of the method to a trial of donor lymphocyte infusion as salvage therapy for chemo-refractory AML/MDS patients is described. To illustrate the method's flexibility and potential breadth of application, two additional examples are provided, including a hypothetical trial in which a 5% response rate is of interest.

Identification of a group of AML/MDS patients with a relatively favorable prognosis who have chromosome 5 and/or 7 abnormalities

BACKGROUND AND OBJECTIVE

Patients with AML, RAEB-t, or RAEB and abnormalities involving chromosomes 5 and/or 7 (-5, -7) generally, but not always, have poorer prognoses than patients with a normal karyotype. Our objective was to see whether the occasional relatively favorable outcome in -5/-7 patients is a random event or, rather, reflects true heterogeneity in -5/-7.

DESIGN AND METHODS

We examined 3 factors known to be prognostic in AML for their prognostic significance in 400 -5/-7 patients treated at the M.D. Anderson Cancer Center from 1980-1998 for AML or MDS. The outcome of comparative interest was survival as assessed by log-rank test.

RESULTS

There was evidence that outcome was better in -5/-7 patients with a simple (rather than complex) karyotype, with > 1 normal metaphase (rather than only metaphases containing -5/-7), and without an antecedent hematologic disorder. More importantly, the 10% of the patients with a simple karyotype, > 1 normal metaphase, and no antecedent hematologic disorder not only had a better outcome than the other -5/-7 patients but had essentially identical outcomes to the 669 AML/MDS patients with a normal karyotype treated at M.D. Anderson during the same period.

INTERPRETATION AND CONCLUSIONS

The results indicate that the -5/-7 group should not a priori be regarded as having an unfavorable prognosis, and more generally suggest the need to refine prognosis within each of the cytogenetic subsets of AML.

Treatment of relapsed and refractory acute myelogenous leukemia

Evidence suggests that the salvage therapy utilized for relapsed and refractory acute myelogenous leukemia (AML) should differ based on the duration of a patient's complete remission (CR), the principal predictor of outcome. While standard regimens have produced higher CR rates than investigational regimens, these rates have not translated into improved survival in patients with initial remission durations of <1 year. Accordingly, there is no need to give standard regimens to these patients who rather should receive investigational therapy once relapse is discovered. In contrast, in patients with initial remission durations of 1-2 years, standard regimens do increase survival compared to investigational regimens. A somewhat artificial distinction has been placed between phase I and phase II studies. The agents to be studied in phase II trials are many, but the patients are limited, so we need to be more innovative in our trial designs. One such proposal, utilizing a Bayesian selection design which calls for randomizing a small number of patients among several investigational treatments, will be discussed.

Effect of time to complete remission on subsequent survival and disease-free survival time in AML, RAEB-t, and RAEB

The authors examined the relationship between the time required to enter complete remission (CR) after a first course of chemotherapy for newly diagnosed acute myeloid leukemia (AML), refractory anemia with excess blasts in transformation (RAEB-t), or refractory anemia with excess blasts (RAEB). They also examined subsequent survival time and disease-free survival time after accounting for cytogenetic status, age, and treatment. The data set consisted of 1101 patients with these diagnoses treated at the M. D. Anderson Cancer Center between 1980 and 1996 for whom outcomes were established after first-course therapy. Of the 1101 patients, 740 (67%) were in CR after this time; 508 of these 740 (69%) have died (80% had disease recurrence before death). The authors used the parametric model of Shen and Thall to estimate, in particular, T(C) (time to CR), T(C,D) (time from CR to death = residual survival after CR), and T(C,R) (residual disease-free survival [DFS] after CR) as functions of the covariates noted above and to estimate the dependence of T(C,D) and T(C,R) on T(C). There was a strong inverse association between T(C) and both T(C,D) and T(C,R) (P <.001 for both) that was independent of cytogenetic status, age, or treatment. The residual survival time of patients who required >50 days to enter CR was closer to the residual survival time of resistant patients than to that of patients known to be in CR within approximately 30 days of the start of treatment. Time to CR is an independent predictor of residual survival and disease-free survival in patients with newly diagnosed AML who achieve CR after 1 course of chemotherapy. (Blood. 2000;95:72-77)

Secondary acute myeloid leukemia with inv(16): report of two cases following paclitaxel-containing chemotherapy and review of the role of intensified ara-C therapy

Acute myeloid leukemia developing secondary to prior cytotoxic chemotherapy (s-AML) encompasses a range of distinct entities. We report two cases of s-AML with inv(16)(p13q22) who had prior exposure to paclitaxel. Additionally, two previously reported cases of s-AML with inv(16) had prior paclitaxel exposure raising the possibility that the taxanes may predispose to this specific syndrome of s-AML. One of our patients received escalated-dose ara-C chemotherapy, achieving a complete remission (12+ months). We therefore examined the prognosis of previously reported cases of s-AML with inv(16) and analyzed the influence of escalated-dose ara-C (>/=400 mg/m2/day). A total of 25 evaluable cases were identified, with 96% attaining CR independent of ara-C dose. The estimated median remission duration was 40 months and the median survival has not been reached (actuarial 5-year survival 52 +/- 18%). Although not achieving statistical significance, patients treated with escalated dose ara-C (n = 15) had longer remission duration and overall survival than those treated with standard dose ara-C (n = 10) (P = 0.063 and 0.20, respectively). In univariate analysis, younger age, male gender, and the presence of additional cytogenetic abnormalities were associated with a tendency towards adverse outcomes (P< 0.1). Age and gender were equally distributed between ara-C dose cohorts, but more patients treated with standard-dose ara-C had additional cytogenetic abnormalities (P = 0.048). Within the limitations of this retrospective study, this analysis suggests that, similar to de novo AML with inv(16), secondary cases may also potentially benefit from treatment with escalated-dose ara-C. This is consistent with the premise that the underlying molecular defect, rather than the presence of prior cytotoxic drug exposure, may be the most important determinant of disease behavior and chemotherapy responsiveness in AML.

Expression of Bcl-2-related genes in normal and AML progenitors: changes induced by chemotherapy and retinoic acid

The expression of Bcl-2 family members was examined in normal and leukemic hematopoietic cells. Immature hematopoietic progenitor cells (CD34+/33-/13-) did not express Bcl-2 but Bcl-XL, the majority of CD34 cells expressed Bcl-2, Bcl-XL and BAD, and normal promyelocytes (CD34-/33+) lacked expression of both Bcl-2 and Bcl-XL, while leukemic CD34+progenitors and promyelocytes expressed these anti-apoptotic proteins. In AML, Bcl-2 expression was higher on CD34+ than on all AML cells, however, expression of Bcl-2 or Bcl-XL did not predict achievement of complete remission. Surprisingly, low Bcl-2 content was associated with poor survival in a group of patients with poor prognosis cytogenetics. The anti-apoptotic BAD protein was found to be expressed in AML, but was phosphorylated in 41/42 samples. Phosphorylation was found at both sites, Ser 112 and Ser 136. During induction chemotherapy, Bcl-2 levels of CD34 cells increased significantly. In the context of evidence for small numbers of leukemic CD34+ cells expressing very high levels of Bcl-2 prior to therapy, this finding is interpreted as a survival advantage of Bcl-2 overexpressing progenitors and rapid elimination of cells with low Bcl-2. Bcl-2 and Bcl-XL were both expressed in minimal residual disease cells. Downregulation of Bcl-2 mRNA and protein was observed by ATRA and the combination of Ara-C, followed by ATRA, resulted in markedly increased cytotoxicity in HL-60 cells, as compared to Ara-C alone or ATRA followed by Ara-C. Implications of these findings for the development of new therapeutic strategies for AML are discussed.

Phenylarsine oxide blocks interleukin-1beta-induced activation of the nuclear transcription factor NF-kappaB, inhibits proliferation, and induces apoptosis of acute myelogenous leukemia cells

Arsenic compounds have recently been shown to induce high rates of complete remission in patients with acute promyelocytic leukemia (APL). One of these compounds, As(2)O(3), induces apoptosis in APL cells via a mechanism independent of the retinoic acid pathway. To test the hypothesis that arsenic compounds may be effective against other forms of acute myelogenous leukemia (AML), we studied the membrane-permeable arsenic compound phenylarsine oxide (PAO). Because interleukin-1beta (IL-1beta) plays a key role in AML cell proliferation, we first tested the effect of PAO on OCIM2 and OCI/AML3 AML cell lines, both of which produce IL-1beta and proliferate in response to it. We found that PAO inhibited the proliferation of both OCIM2 and OCI/AML3 cells in a dose-dependent fashion (0.01 to 0.1 micromol/L) and that IL-1beta partially reversed this inhibitory effect. We then measured IL-1beta levels in these cells by using an enzyme-linked immunosorbent assay and Western immunoblotting and found that PAO almost completely abolished the production of IL-1beta in these AML cells, whereas it did not affect the production of IL-1 receptor antagonist. Because PAO inhibits activation of the transcription factor NF-kappaB and because NF-kappaB modulates an array of signals controlling cellular survival, proliferation, and cytokine production, we also studied the effect of PAO on NF-kappaB activation in AML cells and found that PAO suppressed the IL-1beta-induced activation of NF-kappaB. Because inhibition of NF-kappaB may result in cellular apoptosis, we also tested whether PAO may induce apoptotic cell death in AML cells. We found that PAO induced apoptosis in OCIM2 cells through activation of the cystein protease caspase 3 and subsequent cleavage of its substrate, the DNA repair enzyme poly (ADP-ribose) polymerase. The PAO-induced apoptosis was caspase dependent, because it was completely blocked by the caspase inhibitor Z-DEVD-FMK. Finally, we tested the effect of PAO on fresh AML marrow cells from 7 patients with newly diagnosed AML and found that PAO suppressed AML colony-forming cell proliferation in a dose-dependent fashion. Taken together, our data showing that PAO is an effective in vitro inhibitor of AML cells suggest that this compound may have a role in future therapies for AML.

Molecular remissions induced by liposomal-encapsulated all-trans retinoic acid in newly diagnosed acute promyelocytic leukemia

All-trans retinoic acid administered orally (oral ATRA) may not regularly lead to either molecular complete remissions (CRs) or prolonged hematologic CRs (HCR) unless combined with chemotherapy. Because serum tretinoin concentrations are higher, and maintained longer, after use of liposomal-encapsulated ATRA (lipoATRA) rather than oral ATRA, we investigated lipoATRA monotherapy in newly diagnosed acute promyelocytic leukemia (APL). Patients received lipoATRA 90 mg/m(2) every other day for remission induction. The same dose was given 3 times a week until 9 months had elapsed from HCR date. Treatment then stopped. Chemotherapy (idarubicin 12 mg/m(2) daily days 1-2 for 2 courses) was to be added only if 2 polymerase chain reaction (PCR) tests, performed 2 weeks apart, were positive at 3, 6, or 9 months from HCR date. The sensitivity level of the PCR was 10(-4). We treated 18 patients (median age, 54 years; median white blood cell [WBC] count 4,500/microL). The HCR rate was 12/18 (67%, 95% confidence interval [CI], 41% to 87%). This rate was similar to that we observed in a previous study using oral ATRA + idarubicin. Nine of 10 patients studied at HCR date were PCR-positive. Subsequently, however, overall (+/- idarubicin) rates of PCR positivity were 0/12 at 3 months, 1/10 at 6 months, 1/7 at 9 and 12 months, and 0/4 at 15 to 17 months. Idarubicin has been added in 3 patients, with this addition occurring at 6 months in 2 patients and at 9 months in 1 patient. Among patients who had not received idarubicin when the PCR was evaluated, 0 of 12 were PCR-positive at 3 months, 1 of 10 was positive at 6 months, 1 of 6 was positive at 9 months, 0 of 4 were positive at 12 months, and 0 of 3 were positive at 15 to 17 months. Morphologic APL has recurred in 1 patient, with a median follow-up time of 13 months in the 11 patients remaining in first CR. The median follow-up time is 91/2 months (range, 3 to 17) in the 9 patients who have received only lipoATRA and who remain PCR-negative and in first CR. Our data suggest that lipoATRA is an effective means of producing molecular CR in newly diagnosed APL.

Use of peripheral blood blasts vs bone marrow blasts for diagnosis of acute leukemia

Acute leukemia can be diagnosed when blasts constitute 30% or more of the nucleated cells in a patient's peripheral blood (PB) sample. To determine whether in such cases bone marrow (BM) aspirates are still necessary, we compared the results of diagnostic studies performed on PB samples with blast counts of 30% or more with those performed on the same patients' BM samples. We found no differences in morphologic features, cytochemistry, or immunophenotype between the blasts in PB and BM samples in any of 30 cases studied. However, in 10 (23%) of 44 cases in which cytogenetic analysis was performed, PB but not BM samples were insufficient for analysis. The converse never occurred. Five of the 10 cases had acute lymphoblastic leukemia and 5 had acute myeloid leukemia (41% of the patients with acute lymphoblastic leukemia and 17% of the patients with acute myeloid leukemia). In cases with adequate metaphases, there was strong correlation between the cytogenetic results for PB and BM samples. Some PB samples with blast counts of 30% or more are adequate for diagnosis of acute leukemia, especially when therapy can be delayed until it is known that an adequate number of analyzable metaphases are recovered from the PB samples.

Treatment of newly diagnosed AML, RAEB-t or RAEB with lisofylline or placebo in addition to chemotherapy

To determine whether the addition of lisofylline (LSF) to idarubicin (12 mg/m2 daily x 3) + ara-C (1.5 g/m2 daily x 4) affects the rates of infection, serious infection, CR or mortality during remission induction of newly diagnosed AML, RAEB-t or RAEB, we randomized 70 patients to 3 mg/kg lisofylline or placebo every 6 h i.v., to begin 6 h before the first dose of idarubicin and to continue until recovery of neutrophil and platelet counts or for 28 days, whichever came first. Eligibility required that patients be below age 71 years, have no history of abnormal counts, or chemotherapy for a prior malignancy, and have a creatinine <1.6 mg/dl and bilirubin <3.0 mg/dl. The study was double-blinded and infections were tabulated separately and independently at MD Anderson and by a three-member outside panel of experts. Logistic regression was used to assess the relative effects of treatment arm (LSF or placebo), age, performance status, treatment site (laminar air flow room or not), and cytogenetics on rates of infection and serious infection following the first course of chemotherapy, and on CR rate. There were 84% and 87% concordance between the expert panel and MD Anderson enumerations of infection and serious infections, respectively. Both analyses found no significant (P < 0.05) differences between the rates of infection, or serious infection, in the placebo and LSF groups. CR, 60-day, and overall mortality rates were similar in the two groups, as were time to neutrophil and blood count recovery and outcome once in CR. Logistic regression analyses supported the above conclusions. Severe nausea/vomiting and mucositis were more frequent in the LSF group. Our results suggest that larger studies of LSF in newly diagnosed AML, RAEB-t, or RAEB are not warranted.

Comparison of touch imprints with aspirate smears for evaluating bone marrow specimens

We compared the differential counts of normal and abnormal bone marrow from touch imprints with those from aspirate smears to determine whether the touch imprint was reliable for independent routine use in the examination of bone marrow and the classification of hematologic abnormalities. Normocellular bone marrow specimens were obtained from 87 patients without hematologic abnormality. Abnormal bone marrow specimens were obtained from 173 patients with treated or untreated neoplastic hematologic disease, including acute myeloid leukemia, myelodysplastic syndrome, chronic lymphocytic leukemia, non-Hodgkin lymphoma, hairy cell leukemia, myeloma, and acute lymphoblastic leukemia. We found no diagnostic difference in the differential counts from touch imprints and aspirate smears of normocellular bone marrow, and although we found some difference between the differential counts in certain cases of diseased bone marrow, the touch imprint proved to be a reliable diagnostic tool for determining the cellular composition of normal bone marrow and more reliable for the diagnosis of bone marrow involved by a neoplastic hematologic disease. Our findings suggest that evaluating touch imprints should be considered a standard practice in examining bone marrow.

Accrual strategies for phase I trials with delayed patient outcome

Phase I dose-finding trials typically are conducted using adaptive rules that select dose levels for successive patient cohorts based on the outcomes of patients treated previously in the trial. When patient outcome cannot be observed immediately after treatment, the problem arises of how to deal with new patients while waiting to observe the current patient cohort's outcomes. We consider two alternative approaches to this problem in the context of a phase I trial conducted using the continual reassessment method. With the first approach, a patient requiring treatment before the next cohort opens is treated off protocol with standard therapy, and otherwise waits until the next cohort opens. The second approach treats each patient immediately upon arrival at the dose recommended based on currently available data. We compare these two approaches by simulation under varying dose--toxicity curves, accrual rates, cohort sizes and early stopping rules. We evaluate patient waiting time, trial duration, number of patients treated off protocol and the probabilities of toxicity and of selecting the correct dose. We also study three strategies for assigning patients to trials when two or more phase I trials may be ongoing simultaneously. Based on our results, we provide practical guidelines for deciding among these approaches and strategies in a given clinical setting.

Randomized phase II study of fludarabine + cytosine arabinoside + idarubicin +/- all-trans retinoic acid +/- granulocyte colony-stimulating factor in poor prognosis newly diagnosed acute myeloid leukemia and myelodysplastic syndrome

Preclinical data suggest that retinoids, eg, all-trans retinoic acid (ATRA), lower concentrations of antiapoptotic proteins such as bcl-2, possibly thereby improving the outcome of anti-acute myeloid leukemia (AML) chemotherapy. Granulocyte colony-stimulating factor (G-CSF) has been considered to be potentially synergistic with ATRA in this regard. Accordingly, we randomized 215 patients with newly diagnosed AML (153 patients) or high-risk myelodysplastic syndrome (MDS) (refractory anemia with excess blasts [RAEB] or RAEB-t, 62 patients) to receive fludarabine + ara-C + idarubicin (FAI) alone, FAI + ATRA, FAI + G-CSF, or FAI + ATRA + G-CSF. Eligibility required one of the following: age over 71 years, a history of abnormal blood counts before M.D. Anderson (MDA) presentation, secondary AML/MDS, failure to respond to one prior course of chemotherapy given outside MDA, or abnormal renal or hepatic function. For the two treatment arms containing ATRA, ATRA was given 2 days (day-2) before beginning and continued for 3 days after completion of FAI. For the two treatment arms including G-CSF, G-CSF began on day-1 and continued until neutrophil recovery. Patients with white blood cell (WBC) counts >50,000/microL began ATRA on day 1 and G-CSF on day 2. Events (death, failure to achieve complete remission [CR], or relapse from CR) have occurred in 77% of the 215 patients. Reflecting the poor prognosis of the patients entered, the CR rate was only 51%, median event-free survival (EFS) time once in CR was 36 weeks, and median survival time was 28 weeks. A Cox regression analysis indicated that, after accounting for patient prognostic variables, none of the three adjuvant treatment combinations (FAI + ATRA, FAI + G, FAI + ATRA + G) affected survival, EFS, or EFS once in CR compared with FAI. Similarly, there were no significant effects of either ATRA ignoring G-CSF, or of G-CSF ignoring ATRA. As previously found, a diagnosis of RAEB or RAEB-t rather than AML was insignificant. There were no indications that the effect of ATRA differed according to cytogenetic group, diagnosis (AML or MDS), or treatment schedule. Logistic regression analysis indicated that, after accounting for prognosis, addition of G-CSF +/- ATRA to FAI improved CR rate versus either FAI or FAI + ATRA, but G-CSF had no effect on the other outcomes. We conclude that addition of ATRA +/- G-CSF to FAI had no effect on CR rate, survival, EFS, or EFS in CR in poor prognosis, newly diagnosed AML or high-risk MDS.

A pilot study of interleukin-2 for adult patients with acute myelogenous leukemia in first complete remission

BACKGROUND

Interleukin-2 (IL-2) has immunomodulatory effects, including stimulating the activity of cytotoxic T cells and natural killer cells, and inducing the generation of lymphokine-activated killer cells. The authors investigated whether IL-2 may improve the duration of complete remission (CR) and survival in acute myelogenous leukemia (AML) patients in first CR.

METHODS

Eighteen patients were included after achieving a CR and receiving at least two courses of consolidation chemotherapy. Therapy was comprised of IL-2 4.5 x 10(5) U/m2 daily by continuous infusion (CI) for 12 weeks, plus boluses of 1 x 10(6) U/m2 on Day 8 and weekly thereafter while continuing the CI. No further chemotherapy was given after the administration of IL-2 was started.

RESULTS

The median age of the patients was 50 years (range, 18-73 years), and 7 patients (39%) had an antecedent hematologic disorder (AHD). The median CR duration was 12 months, with 6 patients still alive in CR at a median follow-up of 64 months (range, 50-82 months). Long term CR by cytogenetics occurred in 2 of 5 patients with a normal karyotype (CR duration of 68+ months and 72+ months, respectively), 1 of 3 patients with t(8;21) (CR duration of 82+ months), 1 patient with inv(16) (CR duration of 67+ months), none of 2 patients with -5/-7 (1 patient died in CR after 10 months), 1 of 2 patients with abnormalities in chromosome 11 (CR duration of 60+ months), and 1 of 4 patients with miscellaneous abnormalities (CR duration of 74+ months). The median survival was 47 months. To assess the significance of these results, the authors selected two historic controls receiving long term postremission chemotherapy per each IL-2 case. The controls had remained in CR for at least as long as the cases when the latter underwent treatment initiation with IL-2 and were matched for the number of induction courses required to achieve CR, AHD, cytogenetic abnormalities, and age. Six of 18 IL-2 patients (33%) were alive in CR at 3 years compared with 7 of 36 controls (19%) (P = 0.31). Nine IL-2 patients (50%) were alive at 3 years compared with 10 controls (28%) (P = 0.13).

CONCLUSIONS

These results suggest that IL-2 is tolerable in AML patients in first CR and should be studied further in future studies as a therapeutic strategy to prolong remission duration.

Expression and function of leptin receptor isoforms in myeloid leukemia and myelodysplastic syndromes: proliferative and anti-apoptotic activities

The receptor for the gene product of the obesity gene, leptin, was recently reported to be expressed on murine and human hematopoietic progenitor cells. Therefore, we studied the expression of the leptin receptor, OB-R, in normal myeloid precursors, human leukemia cell lines, and primary leukemic cells using reverse-transcriptase polymerase chain reaction. In normal hematopoiesis, OB-R was expressed in CD34(+) cells. Normal promyelocytes (CD34(-)33(+) and CD34(-)13(+)) expressed only very low levels of the short, presumably nonsignaling isoform. Both the long and short isoforms of OB-R were expressed in 10 of 22 samples from patients with newly diagnosed primary or secondary acute myeloid leukemia (AML), with a higher incidence of the long isoform in primary AML (87.6% v 28.6%; P =.01). The incidence of OB-R expression was higher in recurrent than in newly diagnosed AML (P <.001), and samples from four patients with refractory AML showed strong expression of both isoforms. Both OB-R isoforms were also expressed in newly diagnosed and recurrent acute promyelocytic leukemia cells but were essentially absent in samples of chronic or acute lymphocytic leukemia. In vitro growth of myeloid leukemic cell lines and of blasts from 14 primary AMLs demonstrated that recombinant human leptin alone induced low level proliferation, significantly (P <.05) increased proliferation induced by recombinant human granulocyte colony-stimulating factor, interleukin 3, and stem cell factor in a subset of AML and increased colony formation (P <.005). Also, leptin reduced apoptosis induced by cytokine withdrawal in MO7E and TF-1 cells. Serum leptin levels correlated only with body mass index (P <. 001) and gender (P =.03). Results confirm the reported expression of leptin receptor in normal CD34(+) cells and demonstrate the frequent expression of leptin receptors in AML blasts. While normal promyelocytes lack receptor expression, leukemic promyelocytes express both isoforms. We also demonstrate proliferative effects of leptin alone and in combination with other physiologic cytokines, and anti-apoptotic properties of leptin. These findings could have implications for the pathophysiology of AML.

Incorporating new modalities into guidelines. Topotecan for myelodysplastic syndromes

The National Comprehensive Cancer Network (NCCN) guidelines for patients with myelodysplastic syndromes (MDS) list myelosuppressive chemotherapy as an option for patients who have MDS with International Prognostic Scoring System (IPSS) scores of "intermediate" or "high." Myelodysplastic syndromes with these IPSS scores have an unfavorable natural history. Topotecan is a myelosuppressive drug that interacts with topoisomerase I and that has been used in the treatment of refractory AML. Its use in MDS has recently received considerable publicity. This paper reviews M. D. Anderson's results with topotecan and topotecan + ara-C in patients with MDS, focusing on comparisons of the results with ara-C and ara-C + fludarabine +/- idarubicin. While it is clear that the drug can produce complete responses, it is less clear that it differs from these other regimens. On average, complete response and survival rates are similar following administration of topotecan + ara-C or the other regimens. On the other hand, among patients with abnormalities of chromosomes 5 and/or 7, complete response rates are higher following topotecan + ara-C than for ara-C alone, or other ara-C combinations. The improvement in complete response rate among patients with abnormalities of chromosomes 5 and/or 7 has not resulted in an improvement in their survival (actuarial median about 6 months), largely reflecting a poor outcome following complete response. Indeed, the frequency of relapse in these patients suggests that any inherent increase in antileukemia activity in patients with abnormalities of chromosomes 5 and/or 7 is minimal. Given the overall results, topotecan +/- ara-C should not be regarded as standard therapy for MDS. The drug is nonetheless interesting and attempts to add to its efficacy are in progress.

Caspase 2 and caspase 3 protein levels as predictors of survival in acute myelogenous leukemia

Because caspase activation is an essential step in programmed cell death (apoptosis) and cytotoxic drug-induced apoptosis is mediated by caspase 2 and caspase 3, we hypothesized that caspase 2 and 3 levels predict clinical outcome in acute myelogenous leukemia (AML). Using quantitative Western blot analysis, we studied the levels of nonactivated (uncleaved) caspase 2 and 3 in peripheral blood low-density cells from 185 patients with newly diagnosed AML. We also measured the level of activated (cleaved) caspase 3 in 41 randomly selected samples from the 185 patients. Finally, we analyzed the effect of caspase 2 and 3 levels and other prognostic variables on patient survival using a multivariate Cox model. We found that median levels of nonactivated caspase 2 and 3 were higher in AML than in normal peripheral blood cells (P < .001 and P <.02, respectively). There was no association between caspase level and either the percentage of peripheral blasts or any specific type of leukemia cell cytogenetic abnormalities. When the effect of each uncleaved caspase was considered individually, a high level of uncleaved caspase 3 (P = .04), but not of caspase 2 (P = .16), was associated with decreased survival. Conversely, a high level of cleaved caspase 3 denoted improved survival and correlated with the inactivation of the DNA-repair enzyme poly(ADP-ribose) polymerase. Thus, cleaved caspase 3 could stimulate the apoptotic cascade further, and lack of its activation likely caused an accumulation of the uncleaved caspase. Although uncleaved caspase 2 level per se had no prognostic significance, the interactive effect of high levels of both uncleaved caspase 2 and 3 denoted very poor survival (P < .001) and had the largest effect of all prognostic variables (P < .001; estimated relative risk, 2.49; 95% confidence interval, 1.59 to 3. 90). Taken together, caspase 2 and caspase 3 protein levels obtained at diagnosis may constitute a reliable prognostic factor in AML.

New agents for the treatment of acute myelogenous leukemia: focus on topotecan and retinoids

Topotecan and retinoids are among the most promising agents being evaluated for the treatment of acute myelogenous leukemia (AML), refractory anemia with excess blasts (RAEB), and refractory anemia with excess blasts in transformation (RAEB-t). Single-agent topotecan is similar to single-agent ara-C, but may be superior in patients with poor-prognosis chromosome abnormalities (ie, -5,-7). Topotecan plus ara-C is equivalent to topotecan alone in chronic myelomonocytic leukemia (CMML), but significantly more effective in RAEB and RAEB-t. Compared with single-agent ara-C, the complete remission (CR) rate with topotecan plus ara-C is comparable, although it offers special advantages in patients with the -5,-7 karyotype. In patients with poor-prognosis cytogenetics, the combination of cyclophosphamide, ara-C, and topotecan, plus all-trans retinoic acid (ATRA) and granulocyte colony-stimulating factor (G-CSF) appears favorable. In a recent study of triple-agent chemotherapy using fludarabine, ara-C, and idarubicin, with or without ATRA and G-CSF, median survival among poor-prognosis patients was 6-7 months, but those who received ATRA did better than those who did not, primarily because it improved survival in those who did not achieve CR. G-CSF produced higher CR rates but had no effect on survival or disease-free survival.

Thrombopoietin stimulates myelodysplastic syndrome granulocyte-macrophage and erythroid progenitor proliferation

Thrombopoietin (TPO) has been successfully used to stimulate megakaryocyte progenitor proliferation and platelet production both in vitro and in vivo. We and other investigators have found that TPO also stimulates normal marrow colony-forming unit granulocyte-macrophage (CFU-GM) and burst-forming unit-erythroid (BFU-E) growth. In contrast to its effect on normal marrow precursors, TPO stimulates acute myelogenous leukemia (AML) progenitor proliferation in only 25% of the cases. Because the hematopoietic cells in Myelodysplastic syndrome (MDS) originate from both the normal and leukemic clones, we hypothesized that TPO may be a useful therapeutic agent for MDS. To test this hypothesis, we used fresh marrow samples taken from 14 MDS patients. We found that in the presence of fetal calf serum (FCS) and erythropoietin (EPO) TPO (5 to 40 ng/ml) MDS CFU-GM and BFU-E colony-forming cell proliferation were stimulated in a dose-dependent fashion by up to 103% and 93% respectively. This effect was similar to the stimulation obtained with optimal concentrations of granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage CSF (GM-CSF), or interleukin-3 (IL-3). Furthermore, TPO increased the colony-stimulatory effects of G-CSF, GM-CSF, IL-3, and stem cell factor (SCF) on MDS marrow cells. However, depletion of either T lymphocytes or adherent cells abrogated the effect of TPO, suggesting that the effect is not a direct one but is mediated through interaction with cytokines produced by accessory cells. Taken together, our data suggest that the therapeutic role of TPO in the management of MDS warrants further investigation.

Prognosis and therapy of secondary myelodysplastic syndromes

This is an invited review of a condition that is likely to become increasingly frequent in coming years. The objective is to define the varying prognoses of the condition and to discuss treatment options for patients with better and worse prognoses. The source of the data is the literature. Of particular note are the paper by Greenberg et al. describing the International Prognostic Scoring System for MDS and that by Estey et al. describing the similar response of AML, RAEB-t, and RAEB to AML-type chemotherapy. The state of the art is that no satisfactory therapeutic options exist; consequently, the majority of patients with secondary MDS should participate in clinical trials.

1,25-Dihydroxyvitamin D3 and its analogues inhibit acute myelogenous leukemia progenitor proliferation by suppressing interleukin-1beta production

We hypothesized that 1,25-dihydroxyvitamin D3 (1,25D3) and its analogues may inhibit acute myelogenous leukemia (AML) proliferation by interrupting IL-1beta-mediated growth-stimulatory signals. The incubation of the IL-1beta- responsive AML cell line OCIM2 with 10 nM 1,25D3 reduced growth 80% in liquid culture, and a 100-1000-fold lower concentration of 20-epi analogues (MC1288 and MC1301) was sufficient to achieve similar growth inhibition. The growth inhibition was associated with a rapid but transient downregulation of IL-1beta and IL-1beta-converting enzyme (ICE) mRNAs in 1,25D3- and 20-epi analogue- treated cells, and the 20-epi analogue was more effective than 1,25D3 in repressing ICE expression. An examination of long-term changes in the levels of mature IL-1beta and its precursor revealed that 24-h incubation of OCIM2 with either 1,25D3 or its 20-epi analogues abolished the production of mature IL-1beta. The effect of 1,25D3 and its analogues on growth of fresh bone marrow cells from seven AML patients was tested by a clonogenic assay. Growth inhibition of 60% was reached in only one of seven 1,25D3-treated samples, but all seven samples were inhibited 60-90% by the 20-epi analogue MC1301. Growth inhibition by 1,25D3 and the analogue was reversible by addition of IL-1beta. These results suggest that 1,25D3 and its 20-epi analogues interrupt IL-1beta autocrine growth regulation by inhibiting IL-1beta production and processing but not the response to IL-1beta.

Pneumonia during remission induction chemotherapy in patients with AML or MDS

We analyzed the 67 of 278 patients with newly-diagnosed AML or 'high-risk' MDS, treated in 1994 and 1995, who developed pneumonia during course 1 of their induction therapy. Pneumonia responded to treatment in 66%, but outcome depended on when pneumonia was diagnosed. Patients with pneumonia diagnosed during week 1 or 2 (group 2 patients) had the lowest response rate (43%). Patients who developed pneumonia in the 3rd week after treatment initiation had the best outcome with all 16 patients recovering. Patients presenting with pneumonia had an intermediate response rate (75%). The different patient groups were comparable with regard to age, underlying disease, prophylactic therapy, and G-CSF application. Although a lower CR rate was not entirely responsible for the lower response rate in group 2, failure to achieve CR predicted unsuccessful treatment of pneumonia in all groups. Fungal pathogens appeared more common in group 2 patients. However, in these patients, administration of amphotericin B was associated with a significantly higher failure rate (15/21 failures vs 2/9 who received no amphotericin B). We conclude that patients who develop pneumonia during week 1 or 2 are a high-risk group, and that use of amphotericin B indicates a particularly poor prognosis, although we present data suggesting that earlier use of amphotericin might be beneficial. Furthermore, since achievement of CR was an important prognostic factor in all groups, WBC transfusions particularly from donors given G-CSF should be considered as a therapeutic option. Finally, since time to failure of induction therapy and time to CR were similar in high-risk patients, new chemotherapy regimens could potentially improve both the CR rate and the outcome of pneumonia.