No benefit from adding GM-CSF to induction chemotherapy in transforming myelodysplastic syndromes: better outcome in patients with less proliferative disease

Mutations in histone modulators are associated with prolonged survival during azacitidine therapy

Early therapeutic decision-making is crucial in patients with higher-risk MDS. We evaluated the impact of clinical parameters and mutational profiles in 134 consecutive patients treated with azacitidine using a combined cohort from Karolinska University Hospital (n=89) and from King's College Hospital, London (n=45). While neither clinical parameters nor mutations had a significant impact on response rate, both karyotype and mutational profile were strongly associated with survival from the start of treatment. IPSS high-risk cytogenetics negatively impacted overall survival (median 20 vs 10 months; p<0.001), whereas mutations in histone modulators (ASXL1, EZH2) were associated with prolonged survival (22 vs 12 months, p=0.01). This positive association was present in both cohorts and remained highly significant in the multivariate cox model. Importantly, patients with mutations in histone modulators lacking high-risk cytogenetics showed a survival of 29 months compared to only 10 months in patients with the opposite pattern. While TP53 was negatively associated with survival, neither RUNX1-mutations nor the number of mutations appeared to influence survival in this cohort. We propose a model combining histone modulator mutational screening with cytogenetics in the clinical decision-making process for higher-risk MDS patients eligible for treatment with azacitidine.

Restoration of MYC-repressed targets mediates the negative effects of GM-CSF on RUNX1-ETO leukemogenicity

GM-CSF signaling regulates hematopoiesis and immune responses. CSF2RA, the gene encoding the α subunit for GM-CSF, is significantly downregulated in t(8;21) (RUNX1-ETO or RE) leukemia patients, suggesting that it may serve as a tumor suppressor. We previously reported that GM-CSF signaling is inhibitory to RE leukemogenesis. Here we conducted gene expression profiling of primary RE hematopoietic stem/progenitor cells (HSPCs) treated with GM-CSF to elucidate the mechanisms mediating the negative effects of GM on RE leukemogenicity. We observed that GM treatment of RE HSPCs resulted in a unique gene expression profile that resembles primary human cells undergoing myelopoiesis, which was not observed in control HSPCs. Additionally we discovered that GM-CSF signaling attenuates MYC-associated gene signatures in RE HSPCs. In agreement with this, a functional screen of a subset of GM-CSF-responsive genes demonstrated that a MYC inhibitor, MXI1, reduced the leukemic potential of RE HSPCs and t(8;21) AML cells. Furthermore, MYC knockdown and treatment with the BET inhibitor JQ1 reduced the leukemic potential of t(8;21) cell lines. Altogether, we discovered a novel molecular mechanism mediating the GM-CSF-induced reduction in leukemic potential of RE cells, and our findings support MYC inhibition as an effective strategy for reducing the leukemogenicity of t(8;21) AML.

Granulocyte and granulocyte-macrophage colony stimulating factors for newly diagnosed patients with myelodysplastic syndromes

BACKGROUND

Myelodysplastic syndromes (MDS) are a heterogeneous group of haematological diseases which are characterised by a uni- or multilineage dysplasia of haematological stem cells. Standard treatment is supportive care of the arising symptoms including red blood cell transfusions or the administration of erythropoiesis-stimulating agents (ESAs) in the case of anaemia or the treatment with granulocyte (G-CSF) and granulocyte-macrophage colony stimulating factors (GM-CSF) in cases of neutropenia.

OBJECTIVES

The objective of this review is to assess the evidence for the treatment of patients with MDS with G-CSF and GM-CSF in addition to standard therapy in comparison to the same standard therapy or the same standard therapy and placebo.

SEARCH METHODS

We searched MEDLINE (from 1950 to 3 December 2015) and CENTRAL (Cochrane Central Register of Controlled Trials until 3 December 2015), as well as conference proceedings (American Society of Hematology, American Society of Clinical Oncology, European Hematology Association, European Society of Medical Oncology) for randomised controlled trials (RCTs). Two review authors independently screened search results.

SELECTION CRITERIA

We included RCTs examining G-CSF or GM-CSF in addition to standard therapy in patients with newly diagnosed MDS.

DATA COLLECTION AND ANALYSIS

We used hazard ratios (HR) as effect measure for overall survival (OS), progression-free survival (PFS) and time to progression, and risk ratios for response rates, adverse events, antibiotic use and hospitalisation. Two independent review authors extracted data and assessed risk of bias. Investigators of two trials were contacted for subgroup information, however, no further data were provided. G-CSF and GM-CSF were analysed separately.

MAIN RESULTS

We screened a total of 566 records. Seven RCTs involving 486 patients were identified, but we could only meta-analyse the two evaluating GM-CSF. We judged the potential risk of bias of these trials as unclear, mostly due to missing information. All trials were randomised and open-label studies. However, three trials were published as abstracts only, therefore we were not able to assess the potential risk of bias for these trials in detail. Overall, data were not reported in a comparable way and patient-related outcomes like survival, time to progression to acute myeloid leukaemia (AML) or the incidence of infections was reported in two trials only.Five RCTs (N = 337) assessed the efficacy of G-CSF in combination with standard therapy (supportive care, chemotherapy or erythropoietin). We were not able to perform meta-analyses for any of the pre-planned outcomes due to inconsistent and insufficient reporting of data. There is no evidence for a difference for overall survival (hazard ratio (HR) 0.80, 95% confidence interval (CI) 0.44 to 1.47), progression-free survival (only P value provided), progression to AML, incidence of infections and number of red blood transfusions (average number of 12 red blood cell transfusions in each arm). We judged the quality of evidence for all these outcomes as very low, due to very high imprecision and potential publication bias, as three trials were published as abstracts only. Data about quality of life and serious adverse events were not reported in any of the included trials.Two RCTs (N = 149) evaluated GM-CSF in addition to standard therapy (chemotherapy). For mortality (two RCTs; HR 0.88, 95% CI 0.62 to 1.26), we found no evidence for a difference (low-quality evidence). Data for progression-free survival and serious adverse events were not comparable across both studies, without evidence for a difference between both arms (low-quality evidence). For infections, red blood cell and platelet transfusions, we found no evidence for a difference, however, these outcomes were reported by one trial only (low-quality evidence). Time to progression to AML and quality of life were not reported at all.Moreover, we identified two cross-over trials, including 244 patients and evaluating GM-CSF versus placebo, without publishing results for each arm before crossing over. In addition, we identified two ongoing studies, one of which was discontinued due to withdrawal of pharmaceutical support, the other was terminated early, both without publishing results.

AUTHORS' CONCLUSIONS

Although we identified seven trials with a total number of 486 patients, and two unpublished, prematurely finished studies, this systematic review mainly shows that there is a substantial lack of data, which might inform the use of G-CSF and GM-CSF for the prevention of infections, prolonging of survival and improvement of quality of life. The impact on progression to AML remains unclear.

Idarubicin and cytarabine in combination with gemtuzumab ozogamicin (IAGO) for untreated patients with high-risk MDS or AML evolved from MDS: a phase II study from the EORTC and GIMEMA Leukemia Groups (protocol 06013)

The primary objective of this trial was to assess the feasibility, toxicity profile, and antitumor activity of gemtuzumab ozogamicin (GO) combined with a chemotherapy remission-induction regimen in adults with untreated high-risk myelodysplastic syndrome (HR-MDS) or secondary acute myeloid leukemia (sAML). In this phase II trial, 30 patients with median age of 58 years received 1 day of GO as a 1-h infusion at the dose level of 5 mg/m² on day 7 of the remission-induction course further consisting of a continuous infusion of cytarabine 100 mg/m²/day for 10 days and idarubicin 12 mg/m²/day on days 1, 3, and 5. A consolidation course, consisting of intermediate-dose cytarabine (A) and idarubicin (I) followed by hematopoietic stem cell transplantation (HSCT) was planned for patients in complete remission (CR). The primary endpoints were response rate (CR/CRi) and severe toxicity rate. The secondary endpoint(s) were survival and progression-free survival (PFS) from start of treatment. Thirteen patients (43 %) achieved CR (eight patients) or CR with incomplete hematopoietic recovery (CRi) (five patients). In patients who achieved CR or CRi, the median time to recovery of neutrophils to 0.5 × 10⁹/l and of platelets to >50 × 10⁹/l was 29 and 30 days, respectively. Grade 3 to 4 severe toxicities occurred in nine patients. The most prominent was liver toxicity, as shown by elevated bilirubin levels in 16 patients and one case of nonfatal veno-occlusive disease (VOD). All 13 patients with CR/CRi received consolidation therapy, which was followed by allogeneic HSCT in five patients and autologous HSCT in three patients. According to the statistical design of the study, the idarubicin and cytarabine in combination with gemtuzumab ozogamicin (IAGO) regimen did not show sufficient activity to warrant further exploration of this regimen in adult patients with HR-MDS or sAML.

Side effects of cytokines approved for therapy

Cytokines, currently known to be more than 130 in number, are small MW (<30 kDa) key signaling proteins that modulate cellular activities in immunity, infection, inflammation and malignancy. Key to understanding their function is recognition of their pleiotropism and often overlapping and functional redundancies. Classified here into 9 main families, most of the 20 approved cytokine preparations (18 different cytokines; 3 pegylated), all in recombinant human (rh) form, are grouped in the hematopoietic growth factor, interferon, platelet-derived growth factor (PDGF) and transforming growth factor β (TGFβ) families. In the hematopoietin family, approved cytokines are aldesleukin (rhIL-2), oprelvekin (rhIL-11), filgrastim and tbo-filgrastim (rhG-CSF), sargramostim (rhGM-CSF), metreleptin (rh-leptin) and the rh-erythropoietins, epoetin and darbepoietin alfa. Anakinra, a recombinant receptor antagonist for IL-1, is in the IL-1 family; recombinant interferons alfa-1, alfa-2, beta-1 and gamma-1 make up the interferon family; palifermin (rhKGF) and becaplermin (rhPDGF) are in the PDGF family; and rhBMP-2 and rhBMP-7 represent the TGFβ family. The main physicochemical features, FDA-approved indications, modes of action and side effects of these approved cytokines are presented. Underlying each adverse events profile is their pleiotropism, potency and capacity to release other cytokines producing cytokine 'cocktails'. Side effects, some serious, occur despite cytokines being endogenous proteins, and this therefore demands caution in attempts to introduce individual members into the clinic. This caution is reflected in the relatively small number of cytokines currently approved by regulatory agencies and by the fact that 14 of the FDA-approved preparations carry warnings, with 10 being black box warnings.

Survival improvement of poor-prognosis AML/MDS patients by maintenance treatment with low-dose chemotherapy and differentiating agents

We evaluated a maintenance, post-remission treatment with low-dose chemotherapy plus differentiating agents on poor-prognosis acute myeloid leukemia (AML)/myelodysplastic syndrome (MDS) patients ineligible to allografting. Patients had either age over 60 and/or secondary AML, therapy-related AML, previous relapse, high-risk MDS. Forty-five patients received the maintenance therapy based on two alternated schedules: (a) 6-thioguanine + 13-cis retinoic acid + dihydroxylated vitamin D3 and (b) low-dose cytarabine + 6-mercaptopurine + all-trans retinoic acid + dihydroxylated vitamin D3. We compared their outcome, at a median follow-up of 52 months, to that of a matched population of 49 patients who stopped treatments after consolidation. Maintenance group had a lower relapse incidence (70.3 vs. 86.4 % at 5 years p = 0.007) and a longer disease-free survival (median 21.2 vs. 8.7 months, p = 0.017). The relapse reduction improved overall survival: median 40.4 months (35.9 % at 5 years) for maintenance group vs. 15.8 (14.2 % at 5 years) for controls (p = 0.005). At multivariate Cox analysis, both cytogenetic and maintenance therapies resulted independent outcome predictors for overall survival. Maintenance treatment also reduced minimal residual disease (detected by WT1 and CBFβ-MYH11) in five of eight evaluable patients. The present results suggest that our strategy of maintenance therapy might improve the outcome of poor-risk AML/MDS patients.

Revisiting use of growth factors in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) represent a heterogeneous group of clonal hematologic neoplasms characterized by morphologic dysplasia, aberrant hematopoiesis and peripheral blood refractory cytopenias. MDS is recognized to be associated with an increased risk of symptomatic anemia, infectious complications and bleeding diathesis, as well as a risk of progression to acute myeloid leukemia, particularly in patients with a high IPSS score. The advent of use of hematopoietic growth factors such as granulocyte colony-stimulating factor (G-CSF) and recombinant erythropoietin (EPO) has improved symptoms in MDS patients in addition to some data that suggest there might be an improvement in survival. G-CSF is an effective therapeutic option in MDS patients, and it should be considered for the management of refractory symptomatic cytopenias. G-CSF and EPO in combination can improve outcomes in appropriate MDS patients such as those with lower-risk MDS and refractory anemia with ring sideroblasts (RARS) . This article reviews use of growth factors for lower-risk MDS patients, and examines the data for G-CSF, EPO and thrombopietic growth factors (TPO) that are available or being developed as therapeutic modalities for this challenging disease.

Colony-stimulating factors for prevention and treatment of infectious complications in patients with acute myelogenous leukemia

BACKGROUND

Acute myelogenous leukemia (AML) is a fatal bone marrow cancer. Colony-stimulating factors (CSFs) are frequently administered during and after chemotherapy to reduce complications. However, their safety with regard to disease-related outcomes and survival in AML is unclear. Therefore, we performed a systematic review and meta-analysis to evaluate the impact of CSFs on patient outcomes, including survival.

OBJECTIVES

To assess the safety/efficacy of CSFs with regard to disease-related outcomes and survival in patients with AML.

SEARCH METHODS

We conducted a comprehensive search strategy. We identified relevant randomized clinical trials by searching the Cochrane Central Register of Controlled Trials (The Cochrane Library 2010, Issue 7), MEDLINE (January 1966 to July 2010), LILACS (up to December 2009), databases of ongoing trials and relevant conference proceedings.

SELECTION CRITERIA

Randomized controlled trials that compared the addition of CSFs during and following chemotherapy to chemotherapy alone in patients with AML. We excluded trials evaluating the role of CSFs administered for the purpose of stem cell collection and/or priming (e.g. before and/or only for the duration of chemotherapy).

DATA COLLECTION AND ANALYSIS

Two review authors appraised the quality of trials and extracted data. For each trial, we expressed results as relative risk (RR) with 95% confidence intervals (CI) for dichotomous data. We analyzed time-to-event outcomes as hazard ratios (HRs).

MAIN RESULTS

The search yielded 19 trials including 5256 patients. The addition of CSFs to chemotherapy yielded no difference in all-cause mortality at 30 days and at the end of follow up (RR 0.97; 95% CI 0.80 to 1.18 and RR 1.01; 95% CI 0.98 to 1.05, respectively) or in overall survival (HR 1.00; 95% 0.93 to 1.08). There was no difference in complete remission rates (RR 1.03; 95% CI 0.99 to 1.07), relapse rates (RR 0.97; 95% CI 0.89 to 1.05) and disease-free survival (HR 1.00; 95% CI 0.90 to 1.13). CSFs did not decrease the occurrence of bacteremias (RR 0.96; 95% CI 0.82 to 1.12), nor the occurrence of invasive fungal infections (RR 1.40; 95% CI 0.90 to 2.19). CSFs marginally increased adverse events requiring discontinuation of CSFs as compared to the control arm (RR 1.33; 95% CI 1.00 to 1.56).

AUTHORS' CONCLUSIONS

In summary, colony-stimulating factors should not be given routinely to acute myelogenous leukemia patients post-chemotherapy since they do not affect overall survival or infectious parameters including the rate of bacteremias and invasive fungal infections.

Colony-stimulating factors for prevention and treatment of infectious complications in patients with acute myelogenous leukemia

BACKGROUND

Acute myelogenous leukemia (AML) is a fatal bone marrow cancer. Colony-stimulating factors (CSFs) are frequently administered during and after chemotherapy to reduce complications. However, their safety with regard to disease-related outcomes and survival in AML is unclear. Therefore, we performed a systematic review and meta-analysis to evaluate the impact of CSFs on patient outcomes, including survival.

OBJECTIVES

To assess the safety/efficacy of CSFs with regard to disease-related outcomes and survival in patients with AML.

SEARCH STRATEGY

We conducted a comprehensive search strategy. We identified relevant randomized clinical trials by searching the Cochrane Central Register of Controlled Trials (The Cochrane Library 2010, Issue 7), MEDLINE (January 1966 to July 2010), LILACS (up to December 2009), databases of ongoing trials and relevant conference proceedings.

SELECTION CRITERIA

Randomized controlled trials that compared the addition of CSFs during and following chemotherapy to chemotherapy alone in patients with AML. We excluded trials evaluating the role of CSFs administered for the purpose of stem cell collection and/or priming (e.g. before and/or only for the duration of chemotherapy).

DATA COLLECTION AND ANALYSIS

Two review authors appraised the quality of trials and extracted data. For each trial, we expressed results as relative risk (RR) with 95% confidence intervals (CI) for dichotomous data. We analyzed time-to-event outcomes as hazard ratios (HRs).

MAIN RESULTS

The search yielded 19 trials including 5256 patients. The addition of CSFs to chemotherapy yielded no difference in all-cause mortality at 30 days and at the end of follow up (RR 0.97; 95% CI 0.80 to 1.18 and RR 1.01; 95% CI 0.98 to 1.05, respectively) or in overall survival(HR 1.00; 95% 0.93 to 1.08). There was no difference in complete remission rates(RR 1.03; 95% CI 0.99 to 1.07), relapse rates(RR 0.97; 95% CI 0.89 to 1.05) and disease-free survival(HR 1.00; 95% CI 0.90 to 1.13). CSFs did not decrease the occurrence of bacteremias(RR 0.96; 95% CI 0.82 to 1.12), nor the occurrence of invasive fungal infections(RR 1.40; 95% CI 0.90 to 2.19). CSFs marginally increased adverse events requiring discontinuation of CSFs as compared to the control arm(RR 1.33; 95% CI 1.00 to 1.56).

AUTHORS' CONCLUSIONS

The addition of CSFs to chemotherapy does not adversely influence all-cause mortality, complete remission or relapse rates in patients with AML. Although the benefit of CSFs is limited to reduction of neutropenic and febrile days, they can be administered safely when necessary.

Maintenance treatment with azacytidine for patients with high-risk myelodysplastic syndromes (MDS) or acute myeloid leukaemia following MDS in complete remission after induction chemotherapy

This prospective Phase II study is the first to assess the feasibility and efficacy of maintenance 5-azacytidine for older patients with high-risk myelodysplastic syndrome (MDS), chronic myelomonocytic leukaemia and MDS-acute myeloid leukaemia syndromes in complete remission (CR) after induction chemotherapy. Sixty patients were enrolled and treated by standard induction chemotherapy. Patients that reached CR started maintenance therapy with subcutaneous azacytidine, 5/28 d until relapse. Promoter-methylation status of CDKN2B (P15 ink4b), CDH1 and HIC1 was examined pre-induction, in CR and 6, 12 and 24 months post CR. Twenty-four (40%) patients achieved CR after induction chemotherapy and 23 started maintenance treatment with azacytidine. Median CR duration was 13.5 months, >24 months in 17% of the patients, and 18-30.5 months in the four patients with trisomy 8. CR duration was not associated with CDKN2B methylation status or karyotype. Median overall survival was 20 months. Hypermethylation of CDH1 was significantly associated with low CR rate, early relapse, and short overall survival (P = 0.003). 5-azacytidine treatment, at a dose of 60 mg/m(2) was well tolerated. Grade III-IV thrombocytopenia and neutropenia occurred after 9.5 and 30% of the cycles, respectively, while haemoglobin levels increased during treatment. 5-azacytidine treatment is safe, feasible and may be of benefit in a subset of patients.

Expression patterns of CD33 and CD15 predict outcome in patients with acute myeloid leukemia

Expression patterns of CD33 and CD15 in normal/reactive bone marrow (n = 13) and in leukemic blasts from patients with acute myeloid leukemia (n = 129) were determined using multiparameter flow cytometry and a standard panel of triple antibody combinations. Five patterns, corresponding to the consecutive stages of myeloid differentiation, were identified [I: CD33-/CD15- (n = 18), II: CD33+/CD15- (n = 43), III: CD33+/CD15 heterogeneous (n = 10), IV: CD33+/CD15+ (n = 50), V: CD33-/CD15+ (n = 8)]. Patients with pattern II had the highest relapse rate and shortest median overall survival (OS, 8 months), but they were also the oldest (median age 72 years) and had the highest frequency of unfavorable cytogenetic aberrations. Pattern V patients had a short OS (median 14 months) even though they were the youngest (median age 50 years), had high remission rate and did not have unfavorable cytogenetics. In multivariate analysis, age, cytogenetics, CD15 expression and the presented immunophenotypic classification were significant for OS (age p = 0.004, cytogenetics p = 0.011, immunophenotype pattern p = 0.024, CD15 p = 0.031). Age (p = 0.001) and immunophenotypic classifications (p = 0.015) were significant for disease-free survival in patients who achieved complete remission.

Negative effect of DNA hypermethylation on the outcome of intensive chemotherapy in older patients with high-risk myelodysplastic syndromes and acute myeloid leukemia following myelodysplastic syndrome

PURPOSE

Promoter hypermethylation of, for example, tumor-suppressor genes, is considered to be an important step in cancerogenesis and a negative risk factor for survival in patients with myelodysplastic syndromes (MDS); however, its role for response to therapy has not been determined. This study was designed to assess the effect of methylation status on the outcome of conventional induction chemotherapy.

EXPERIMENTAL DESIGN

Sixty patients with high-risk MDS or acute myeloid leukemia following MDS were treated with standard doses of daunorubicin and 1-beta-d-arabinofuranosylcytosine. Standard prognostic variables and methylation status of the P15(ink4b) (P15), E-cadherin (CDH), and hypermethylated in cancer 1 (HIC) genes were analyzed before treatment.

RESULTS

Forty percent of the patients achieved complete remission (CR). CR rate was lower in patients with high WBC counts (P = 0.03) and high CD34 expression on bone marrow cells (P = 0.02). Whereas P15 status alone was not significantly associated with CR rate (P = 0.25), no patient with hypermethylation of all three genes achieved CR (P = 0.03). Moreover, patients with CDH methylation showed a significantly lower CR rate (P = 0.008), and CDH methylation retained its prognostic value also in the multivariate analysis. Hypermethylation was associated with increased CD34 expression, but not with other known predictive factors for response, such as cytogenetic profile.

CONCLUSIONS

We show for the first time a significant effect of methylation status on the outcome of conventional chemotherapy in high-risk MDS and acute myelogenous leukemia following MDS. Provided confirmed in an independent study, our results should be used as a basis for therapeutic decision-making in this patient group.

Current status of growth factors in the treatment of acute myeloid and lymphoblastic leukemia

The safety of granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) in patients with acute leukemia has been well established in numerous clinical trials. The primary aim of these studies was to determine whether CSFs, when used as adjuncts to intensive chemotherapy, reduced the duration of neutropenia, prevented febrile neutropenia, infections, and hospitalization rates, and improved response and overall outcome in patients with acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL). Despite considerable efforts in divers clinical settings, the potential advantages of hematopoietic growth factors in the management of these leukemias remain inconclusive. In general, individual published trials have shown declines in the incidence and/or duration of neutropenia but have not consistently demonstrated a reduction in the overall frequency of infectious complications or the duration of hospitalization. Most protocols also have failed to show a benefit in terms of disease-free or overall survival. Nevertheless, improvements in "soft" clinical end points, such as incidence of severe infections, may be clinically important and contribute, even if only incrementally, to the patient's quality of life. Selection of those patients likely to benefit from growth factors in a specific clinical setting is a worthwhile endeavour.

Heat-inducible amplifier vector for high-level expression of granulocyte-macrophage colony-stimulating factor

PURPOSE

In cytokine immunotherapy of cancer it is critical to deliver sufficiently high local cytokine concentrations in order to reach the therapeutic threshold needed for clinical efficacy. Simultaneously, for optimal clinical safety adverse effects caused by high systemic cytokine levels must be minimized. One of the most promising anti-cancer therapeutic cytokines, granulocyte-macrophage colony-stimulating factor (GM-CSF), has elicited anti-tumour immune responses in animal studies and clinical trials. However, the clinical efficacy has been limited, with local GM-CSF levels being therapeutically insufficient and systemic toxicity being a limiting factor.

METHODS

To address these problems we have developed a novel GM-CSF expression vector, pAD-HotAmp-GM-CSF, which can provide high levels of GM-CSF expression, and induction of cytokine expression to limited tissue areas. This expression system combines inducible and amplifying elements in a single multi-genic construct. The first transcriptional unit contains the inducible element, the heat shock protein 70B (HSP70B) promoter that regulates expression of the transcription-activating factor tat.

RESULTS

Upon the binding of tat to the second promoter, the HIV2 long terminal repeat amplifies downstream gene expression of the therapeutic cytokine GM-CSF. Moderate hyperthermia at 42 degrees C for 30 min induced GM-CSF expression in pAD-HotAmp-GM-CSF that was over 2.5- and 2.8-fold higher than levels reached with HSP70B promoter alone and the prototypical human cytomegalovirus promoter.

CONCLUSIONS

Thus, the inducible amplifier vector, pAD-HotAmp-GM-CSF, represents a novel system for regulated and enhanced GM-CSF expression, which enables both greater efficacy and safety in cytokine immunotherapy of cancer.

A pharmacodynamic study of 5-azacytidine in the P39 cell line

OBJECTIVE

5-azacytidine (azacytidine), a DNA hypomethylating agent, was recently approved as the first therapeutic agent for the treatment of myelodysplastic syndromes. The present subcutaneous dosing schedule, 75 mg/m(2) for 7/28 days, is based on early clinical studies and may constitute a practical problem for patients. The present in vitro study aimed at evaluating the pharmacodynamics of azacytidine, thereby providing a rationale for clinical dose-finding studies.

METHODS

P39 cells were incubated with 0.1, 0.5, and 1 microM azacytidine daily for 24, 48, and 72 hours, followed by 48 hours in drug-free medium. The effects of azacytidine on cell growth, proliferation, apoptosis, cell cycle status, and promoter methylation of E-cadherin, ER, and HIC genes were studied.

RESULTS

Azacytidine decreased cell growth and proliferation, increased apoptosis, and affected cell cycle status in a dose-dependent manner. However, the exposure time, 24 to 72 hours, at doses between 0.5 and 1 microM, did not significantly affect any of these variables. Using first-order exponential pharmacokinetic model, we found that the effect of 1, 2, or 3 microM over 24 hours did not differ from that of 0.5 to 1 microM given over 48 to 72 hours. Induction of promoter hypomethylation was observed already after 24 hours of exposure with >or=0.5 microM azacytidine with no clear dose-effect relationship.

CONCLUSION

Our results indicate that optimal cellular effects of azacytidine might be achieved by shorter exposure times. The model provides information about the relation between azacytidine dose intensity and exposure time on malignant myeloid cells, which could serve as a rationale for further clinical development of practical, safe, and cost-effective dosing schedules.

Angiogenesis in relation to clinical stage, apoptosis and prognostic score in myelodysplastic syndromes

The International Prognostic Scoring System (IPSS), based on the number of cytopenias, percentage of bone marrow blasts and cytogenetics, is an important prognostic tool for patients with myelodysplastic syndrome (MDS). In addition, factors such as high bone marrow cellularity and lactate dehydrogenase levels have been associated with an adverse outcome, spontaneously and after chemotherapy. Recently, increased bone marrow angiogenesis, measured as, e.g. microvascular density (MVD), was reported to be more intense in high-risk than in low-risk MDS. To assess the prognostic role of MVD in MDS, a cohort of 56 patients, thoroughly investigated for various clinical and morphological parameters, were followed-up for survival > or =60 months after the diagnostic analysis. As a group MDS patients had higher MVD compared to healthy controls (p<0.02). The highest median MVD value was observed in the RAEB group, but there was no overall significant difference between the FAB groups. No significant correlations were observed between MVD and peripheral blood counts, bone marrow cellularity, percentage of bone marrow blasts and CD34 positive cells, apoptotic index (TUNEL), proliferation index (MIB-1), erythroid index, FAB group and IPSS score. MVD was not correlated to overall survival. In contrast, bone marrow blast count <5%, low or normal cellularity, as well as a high erythroid index, indicated a favorable survival. Thus, our data do not support an important prognostic role of angiogenesis, reflected by microvessel density, in the myelodysplastic syndromes.

Role of cytokines in the treatment of acute leukemias: a review

Myeloid growth factors, such as granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor, have been used to decrease the duration of chemotherapy-induced neutropenia and thereby reduce the incidence and severity of infections in various regimens used to treat acute myeloid leukemia and acute lymphoblastic leukemia. These growth factors have also been used to recruit dormant myeloid leukemia cells into the S phase of cell cycle in order to increase their susceptibility to the antileukemic effects of agents such as cytarabine. Multiple prospective randomized trials have examined the benefit and safety of the addition of growth factors before, during, and after chemotherapy. A reduction in the duration of neutropenia has been the most consistent finding; this has not been associated with stimulation of leukemia cells, the main concern of using this strategy. Unfortunately, few studies have reported a benefit in prolonging the duration of disease-free survival or overall survival. Other cytokines, including interleukins and thrombopoietin, have also been evaluated for their theoretical ability to recruit immune mechanisms to eradicate residual leukemia burden after chemotherapy, and to stimulate platelet production. In this review, we summarize the clinical experience with these growth factors in treating acute leukemias.

Management of patients with higher risk myelodysplastic syndromes

Higher risk myelodysplastic syndromes (MDS) include patients in the Intermediate-2 and high-risk categories of the International Prognostic Scoring System, as well as patients with MDS secondary to radiation or chemical exposure. Ideally, the goal of therapy is to alter the natural history of disease in these patients to achieve cure or durable remission. High-intensity chemotherapy can achieve moderate rates of complete remission, however, durability of remission and overall survival tend to be short. Hematopoietic stem cell transplantation (HSCT) offers the possibility of cure, with long-term disease-free survival inversely related to age. Patients who are elderly or have poor functional status are candidates for reduced intensity HSCT, although this is still an experimental modality. Azacitidine is a hypomethylating agent that is a reasonable option for many patients ineligible for high-intensity therapies. Other therapies, such as immunomodulatory agents, arsenic trioxide, and farnesyl transferase inhibitors have thus far shown limited usefulness in higher risk MDS. This paper reviews the various therapeutic options for higher risk MDS, providing rationale for specific management approaches for these patients.

Update on supportive care and new therapies: immunomodulatory drugs, growth factors and epigenetic-acting agents

Patients with "low-risk" myelodysplastic syndrome (MDS) are mostly treated with approaches aiming to reduce the negative consequences of ineffective hematopoiesis. Transfusion therapy should be tailored to allow adequate oxygenation and optimal quality of life, and may lead to the need for iron chelation therapy. Growth factors (erythropoietin and granulocyte colony-stimulating factor [G-CSF]) may induce long-lasting improvement of hemoglobin levels and does not increase the risk for leukemic transformation. Growth factors should be offered to defined subgroups of patients. Immunosuppression with anti-thymoglobulin or cyclosporine A may be an alternative for younger patients with refractory anemia (RA). The new immunomodulating compound lenalidomide, CC5013, is very active in the 5q- syndrome and is under evaluation for other low-risk MDS subtypes. "High-risk" MDS is associated with poor survival and high risk for leukemic transformation. The DNA hypomethylating compounds azacytidine and decitabine may offer improved long-term outcomes in this group of patients, although there has so far been no effect on survival rates. The efficacy of farnesyl transferase inhibitors has been evaluated in a series of phase II trials. The overall response rate was low, but the majority of responses were CRs. Finally, a number of new drugs directed to various biological and genetic targets are entering clinical trials.

Granulocyte-macrophage colony-stimulating factor to increase efficacy of mitoxantrone, etoposide and cytarabine in previously untreated elderly patients with acute myeloid leukaemia: a Swedish multicentre randomized trial

A total of 110 patients, aged 64 years or over, with de novo acute myeloid leukaemia (AML) and white blood cell counts <50 x 109/l were treated with 3 d of cytarabine 1 g/m2 twice daily, mitoxantrone 12 mg/m2 and etoposide 200 mg/m2, randomized with or without the addition of granulocyte-macrophage colony-stimulating factor (GM-CSF) 200 microg/m2. The primary aim was to evaluate the effect of GM-CSF on the remission rate. Secondary aims included comparison of duration of remission, survival and infectious complications and the impact of maintenance therapy with thioguanine. Complete remission (CR) was achieved by 64% of patients without GM-CSF, and by 65% of patients who received GM-CSF, the median remission duration was 13 vs. 6 months, the median overall survival (OS) was 14 vs. 9 months, the mean time to neutrophil recovery was 25 vs. 17 d (P = 0.03) and the number of positive blood cultures was 46 vs. 39 (P = 0.05) respectively. The impact of thioguanine remains unanswered since only 30 patients remained in CR after consolidation therapy. We conclude that induction therapy is feasible with acceptable toxicity in elderly patients with AML, albeit with a high relapse rate and short OS. GM-CSF prior to, and in combination with, induction treatment reduced the time to neutrophil recovery and the number of neutropenic septicaemia cases but did not improve the OS of AML in the elderly.