A phase II study of decitabine and gemtuzumab ozogamicin in newly diagnosed and relapsed acute myeloid leukemia and high-risk myelodysplastic syndrome

Decitabine may open the chromatin structure of leukemia cells making them accessible to the calicheamicin epitope of gemtuzumab ozogamicin (GO). A total of 110 patients (median age 70 years; range 27-89 years) were treated with decitabine and GO in a trial designed on model-based futility to accommodate subject heterogeneity: group 1: relapsed/refractory acute myeloid leukemia (AML) with complete remission duration (CRD) <1 year (N=28, 25%); group 2: relapsed/refractory AML with CRD ⩾1 year (N=5, 5%); group 3: untreated AML unfit for intensive chemotherapy or untreated myelodysplastic syndrome (MDS) or untreated myelofibrosis (MF; N=57, 52%); and group 4: AML evolving from MDS or relapsed/refractory MDS or MF (N=20, 18%). Treatment consisted of decitabine 20 mg/m(2) daily for 5 days and GO 3 mg/m(2) on day 5. Post-induction therapy included five cycles of decitabine+GO followed by decitabine alone. Complete remission (CR)/CR with incomplete count recovery was achieved in 39 (35%) patients; group 1= 5/28 (17%), group 2=3/5 (60%), group 3=24/57 (42%) and group 4=7/20 (35%). The 8-week mortality in groups 3 and 4 was 16% and 10%, respectively. Common drug-related adverse events included nausea, mucositis and hemorrhage. Decitabine and GO improved the response rate but not overall survival compared with historical outcomes in untreated AML ⩾60 years.

A prognostic score for patients with lower risk myelodysplastic syndrome

Current prognostic models for myelodysplastic syndromes (MDS) do not allow the identification of patients with lower risk disease and poor prognosis that may benefit from early therapeutic intervention. We evaluated the characteristics of 856 patients with low or intermediate-1 disease by the International Prognostic Scoring System. Mean follow-up was 19.6 months (range 1-262). Of these patients, 87 (10%) transformed to acute myelogenous leukemia, and 429 (50%) had died. By multivariate analysis, characteristics associated with worse survival (P<0.01) were low platelets, anemia, older age, higher percent of marrow blasts and poor-risk cytogenetics. Although not included in the model, higher ferritin (P=0.007) and beta2-microglobulin (P<0.001) levels were associated with worse prognosis. This allowed the development of a scoring system in which patients could be grouped in three categories: category 1 (n=182, 21%) with a median survival of 80.3 months (95% CI 68-NA); category 2 (n=408, 48%) with a median survival of 26.6 months (95% CI 22-32) and category 3 (n=265, 31%) with a median survival of 14.2 months (95% CI 13-18). In summary, this analysis indicates that it is possible to identify patients with lower risk MDS and poor prognosis who may benefit from early intervention.

A new prognostic score for patients with lower-risk myelodysplastic syndrome (MDS) allows the identification of a subset of patients with poor prognosis

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Background: Current prognostic models of MDS do not allow the identification of patients (pts) with lower risk disease and poor prognosis. Methods: We evaluated the characteristics of 898 pts with low or intermediate-1 disease by IPSS referred at MDACC from 1976 to 2005. Distributions of OS and progression-free-survival (PFS) were estimated by the method of Kaplan and Meier and compared between subgroups using the log rank test. Cox proportional hazards regression model was used to assess the ability of patient characteristics to predict OS and PFS, with goodness-of-fit assessed by Martingale residual plots, the Grambsch-Therneau test, Schoenfeld residual plots, and the likelihood ratio (LR) test. Multiple patient characteristics were evaluated including ferritin and β2- microglobulin, but these last two were not included in the multivariate model because their values were only known for a subset of patients.None of the patients had received chemotherapy prior to referral. Results: Median age was 66 years (range 16–94), and 65% had diploid cytogenetics. Only 88 pts (10%) transformed to AML and 388 (43%) had died. By multivariate analysis, characteristics associated with a worse OS were low platelets, anemia, older age, higher percent of marrow blasts and poor risk cytogenetics. Although not included in the model, higher ferritin (p=0.03) and β2-microglobulin (p=0.001) levels were associated with worse prognosis.These allowed the development of a scoring system in which patients could be grouped in 3 categories. Patients in category 1 (score less than 0.7) (n=22%) had a median survival of 69 months (95% CI 55-NA) and a 4-year OS of 67%, in category 2 (score 0.7–1.2) (n=40%) of 25 months (95% CI 18–31) and a 4-year survival of 28%, and in category 3 (score more than 1.2) (n=38%) of 17 months (95% CI 15–20), and a 4 -year survival of 12%. The model could segregate patients in each IPSS category (low and int-1). A subset of patients with intermediate-1 risk treated with decitabine could also be stratified by the model. Conclusions: This data indicates that it is possible to identify patients with lower-risk MDS and poor prognosis that may benefit from early therapeutic intervention.

No significant financial relationships to disclose.

Effect of hematologic improvement (HI) on survival in patients (pts) given targeted therapy (TT) as initial treatment of acute myeloid leukemia (AML) or high-risk myelodysplastic syndrome (HR-MDS)

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Background: Recent years have seen the introduction of TT for pts with AML and HR- MDS (> 10% marrow blasts). New criteria, less stringent than those for CR, for response to these agents have been promulgated, giving rise to the response category HI. However, the effect of achieving HI on survival is uncertain. Methods: 180 pts, median age 73, with AML or HR-MDS received TT, most commonly decitabine (69 pts), from 2000–2006. Treatment-related death occurred in 11%, CR in 28%, CRp in 6%, and 55% (99 pts) were resistant. We examined survival in these 99 according to whether TT produced HI, blood count criteria for which were as defined by the International Working Group (IWG) for MDS. Initially, we, unlike the IWG, did not require any duration of HI, however; in subsequent analyses, we required durations of = 4 weeks (HI-4) and, like the IWG, = 8 weeks (HI-8). Results: Survival time dated from start of TT was similar in the 32 pts who achieved HI and the 67 who did not. However, the 13 pts with HI-8 lived longer than those with shorter or no HI (48% vs. 11% at 2 years, p=0.01) as did the 14 with HI-4 (p=0.01). Because HI-4 and HI-8 pts had to live long enough to achieve and maintain HI, we re-did the analysis including only the 84 pts who lived = 67 days from start of TT, the median time needed to observe HI-4. This analysis, which included HI-4, age, and cytogenetics as predictors of survival, indicated that HI-4 was the strongest predictor of longer survival (HR 0.34, 95% CI 0.13–0.86, p=0.02). Results were analogous when we limited the analysis to the 68 pts who lived at least 138 days, by which time 75% of HI-4 pts had achieved HI (p=0.06). Conclusions: Our results suggest that HI-4 (or HI-8 as defined by the IWG) following TT confers a survival benefit in AML or HR-MDS.

No significant financial relationships to disclose.

Levels of soluble HLA-I and beta2M in patients with acute myeloid leukemia and advanced myelodysplastic syndrome: association with clinical behavior and outcome of induction therapy

beta-2 Microglobulin (beta2M), a subunit of human leukocyte antigen-class I (HLA-I), is well established as a marker of prognosis in various solid tumors and hematologic malignancies. The prognostic role of intact free-circulating HLA-I (sHLA-I) is less well understood. We compared the clinical relevance of plasma levels of sHLA-I and beta2M in patients with acute myeloid leukemia (AML; n=209) or advanced myelodysplastic syndrome (MDS; n=98). sHLA-1 and beta2M levels were significantly higher in AML and MDS patients than in control subjects, but did not differ significantly between the two disease groups. In AML patients, multivariate analysis showed both sHLA-1 and beta2-M to be highly predictive of complete remission (CR), survival and duration of complete response (CRD). In MDS, the predictive value of the two markers differed substantially from one another: beta2M was associated with survival, CR and CRD, whereas sHLA-I was not. These findings not only establish the role of sHLA-I as a tumor marker in AML but also support that MDS is clinically and biologically distinct from AML. sHLA-I has been reported to be an immunomodulator inhibiting the cytotoxic effects of T-lymphocytes, which may offset its predictive value for disease aggressiveness in patients with MDS.

Soluble phosphorylated fms-like tyrosine kinase III. FLT3 protein in patients with acute myeloid leukemia (AML)

FLT3 ligand (FL) has a significant role in the proliferation and differentiation of hematopoietic cells. Mutations in the FLT3 receptor gene have been reported in 30% of patients with AML. We investigated whether abnormal phosphorylation of FLT3 may be more common in AML. We evaluated FLT3 protein and its phosphorylation in the plasma from 85 patients with AML, 16 patients with myelodysplastic syndrome (MDS) and 5 patients with acute lymphoblastic leukemia (ALL). There were no significant differences in the level of plasma FLT3 protein level in the different diseases (p=0.57). AML patients had a significantly higher level of phospho-FLT3:FLT3 ratio (p=0.02). FLT3-ITD and FLT3 point mutations were present in 27 (32%) of the AML patients. Phosphorylated FLT3 was significantly higher in the plasma from patients with FLT3 mutation (p=0.002). Overall, there was no correlation between survival and the plasma level of FLT3 protein or its phosphorylated form. However, amongst the patients without FLT3 mutations, those with a higher level of phosphorylated FLT3 had a significantly shorter duration of remission (p=0.04). Other mechanisms may be responsible for abnormal phosphorylation of FLT3 and inhibitors of FLT3 should also be investigated in patients without mutations.

Clinical outcomes and rates of molecular remission with all-trans retinoic acid (ATRA) and arsenic trioxide (As2O3) combination therapy in newly diagnosed acute promyelocytic leukemia (APL)

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Background: ATRA and anthracyclines provide durable remissions in patients with untreated APL. As2O 3 has improved outcomes in untreated and relapsed/refractory APL. The aim of this study was to determine the rates of complete response (CR) and molecular remission with ATRA and As2O 3 combination therapy in untreated APL. Methods: From 2/02 to 1/06, 53 patients with untreated APL received ATRA 45 mg/m2 daily and As2O 3 0.15 mg/kg IV 1-hr infusion daily starting on day 10. Patients with WBC>10×109/L also received gemtuzumab ozogamicin (GO) 9 mg/m2 on day 1 and/or idarubicin 12 mg/m2 on days 1–4. Patients in CR received As2O 3 0.15 mg/kg IV on days 1–5 weekly for 4 weeks on and 4 weeks off and ATRA 45 mg/m2 daily for 2 weeks on and 2 weeks off (for 28 weeks). Polymerase chain reaction (PCR) testing for PML-RARα (sensitivity level, 10−4) was performed every 3 months from CR for 2 years. Patients with molecular relapse received GO 9 mg/m2 once monthly for 3 months in addition to ATRA and As2O 3 as in postremission therapy. If PCR became negative, only the single dose of GO was given. Results: The median age was 46 years; and 20% of patients were Sanz low risk, 40% intermediate, and 40% high risk. The CR rate was 91% (low risk 91%, intermediate 95%, high risk 86%). The median follow-up in surviving patients was 1.6 years. Six patients died during induction, and 2 died in CR from other cancers. The 1-yr survival rate was 88%. Three patients relapsed (at 9, 9, and 16 months). The 1-yr failure-free survival (FFS) rate in responding patients was 94% (high risk 86%, other risk 100%). Molecular remission rates are shown in the Table . Grade 3–4 nonhematologic toxicities were infections (n=16), neurologic (n=4), cardiac arrhythmias (n=4), APL differentiation syndrome (n=4), and headache (n=2). Conclusions: ATRA plus As2O 3 results in high rates of CR, molecular remission, FFS, and survival and is an alternative to ATRA and idarubicin combination therapy in low-risk APL.

[Table: see text]

No significant financial relationships to disclose.

Delaying therapy in Pts age ≥ 65 with untreated AML

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186 pts age ≥ 65 with untreated normal karyotype AML given ara-C-containing Rx at MDA from 1996–2005 had course 1(C1) CR and death rates of 57% and 13%, while in 133 pts with abnormalities of chromosomes 5 and/or 7 (−5/−7) the C1 CR rate was essentially identical to the C1 death rate (30% and 27%). Knowledge of cytogenetics, while thus valuable in planning Rx, may not be available for ≥ 1 week after presentation, raising questions as to the advisability of waiting this long to begin Rx. We previously reported a multivariate analysis in 197 pts, median age 64 and with presenting WBC < 50,000, given idarubicin + ara-C for untreated AML at M.D. Anderson between 2001- and 2004, finding that the independent predictors of CR were age and cytogenetics but not the number of days from MDA presentation to MDA Rx (Estey et al. 2004 ASH meeting,abstract #879). Because Rx was delayed for > 1 week in only small numbers of older pts we now extend these observations to 684 pts age ≥ 65 with untreated AML and presenting WBC < 50,000 given induction Rx (± ara-C) at MDA since 1996. Time from MDA presentation to Rx was < 1 week in 423, 1–2 weeks in 126, 2 weeks-1 month in 80, and > 1 month in 55. This time was not affected by age, bilirubin, creatinine, or by whether induction Rx contained ara-C. However, 7% of pts Rxed within 2 weeks of diagnosis had performance status 3–4 vs. only 1% of pts Rxed after a delay of > 14 days (p = 0.008), leading us to limit analysis to pts with performance status 0–2. Results were as follows: Although CR rates were higher, results were qualitatively similar considering only pts given ara-C-containing Rx. Recognizing the potential influence of unrecorded covariates, the data suggest that delay of Rx in pts age ≥ 64 with untreated AML, WBC count < 50,000, and performance status < 3 does not affect outcome of induction therapy, a possibility given more credence by the several days that elapse between diagnosis of AML by referring physicians and MDA presentation. Delaying Rx allows knowledge of cytogenetic status, thus permitting investigational Rx, or supportive care only, to be directed to pts with -5/-7.

[Table: see text]

No significant financial relationships to disclose.

Reproducibility of diagnosis in patients with myelodysplastic syndrome

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Background: The myelodysplastic syndromes (MDS) have been considered notoriously difficult with regard to reliability of diagnosis and proper classification. The diagnosis and subclassification of MDS is based on hematopathology studies on the peripheral blood and marrow, along with cytogenetic and clinical information. Determination of single or multiple lineage dysplasia, percentage of myeloblasts, grading of cellularity, fibrosis, and iron content are essential for establishing the diagnosis of MDS. Methods: We reviewed the diagnosis of 112 patients who were referred to MD Anderson Cancer Center (MDACC) with an outside diagnosis of MDS. Results: Between July and December 2005, 112 patients were referred to MDACC with a diagnosis of MDS (bone marrow blast percentage <30%). Upon review of bone marrow studies performed at MDACC, diagnosis of MDS was confirmed in 83 patients. Acute myelogenous leukemia (AML) was diagnosed in 11 patients, and 3 patients were diagnosed to have myeloproliferative disorder (MPD) or chronic myelomonocytic leukemia (CMML). Alternate diagnosis offered in 18 patients included other cause of anemia (6), normal marrow (3), large granular lymphocyte leukemia (2), uncertain (2), immune thrombocytopenia (1), and multiple myeloma (1). Excluding 14 patients with AML or MPD/CMML (since they may represent natural progression of disease), diagnosis other than MDS was established in 15% (18/98) of patients. Conclusions: Upon review, diagnosis other than MDS is made in a significant percentage of patients referred with a diagnosis of MDS. As such, repeat blood and marrow workup and evaluation by more than one hematopathologist increases the accuracy of diagnosis in MDS and should be mandatory for clinical trials in MDS.

No significant financial relationships to disclose.

Proteomic signatures of acute myeloid leukemia (AML) distinguishes different outcome groups across cytogenetics and identified potential therapy targets

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Background: Cytogenetics (CG) guide AML treatment but reliable markers predicting response and relapse within CG groups are missing. We therefore determined whether functional proteomic signatures can classify AML into groups with different outcomes and risk of relapse. Method: Using Reverse Phase Protein Array, total and phospho-site specific expression of 37 proteins in 73 primary AML was measured. Outcomes in the set were comprised equally of primary refractory (PR), relapsed (Rel) and continuous complete remission (CCR) patients. Cell lysates were spotted on nitrocellulose coated slides, probed with validated antibodies, expression intensities were quantified, data was standardized and analyzed for correlations using different clustering approaches. Results: Unsupervised hierarchical clustering based on Pearsons’ correlation distance yielded 4 large clusters. Subsequent perturbation bootstrap re-sampling arranged samples into four classes that correlated with initial response to therapy and risk of relapse (see Table ). Protein profiles in each of he 4 classes differed. Cytogenetic marker distribution were similar across the 4 clusters. Class 1 and 4 demonstrated a similar predictive value of patient outcome as cytogenetics. In classes at highest risk of relapse (2, 3) different proteins were predictive of response. In class 2, the most discriminatory proteins predicting CCR were elevated AMPK, p27, 4-EBP1, BclXL. In class 3, relapsed patients had elevated PTEN, phospho-Stat3, total Stat3, and phospho-PKCα compared to CCR patients. Conclusion: Pretreatment protein expression signatures divide AML into classes that predict for initial achievement of CR and subsequent relapse independent of CG. Poteomic profiling may suggest potential therapy targets as opposed to CG or transcriptional profiling. These preliminary results need to be confirmed in formal training and test sets prior to changing patient management.

[Table: see text]

No significant financial relationships to disclose.

Combination therapy with arsenic trioxide (ATO), all-trans retinoic acid (ATRA), and gemtuzumab ozogamycin (GO) in relapsed acute promyelocytic leukemia (APL)

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Background: Relapse occurs in 20 to 30% of patients with APL treated with ATRA. ATO is an effective agent for salvage of APL relapse, and GO has shown activity in APL due to the high expression of CD33. Methods: We investigated the efficacy of a combination regimen of ATO, ATRA and mylotarg in 8 patients with APL in 1st relapse. All patients had been previously treated with regimens that included ATRA and chemotherapy. Patients received ATO 0.15 mg/kg intravenously until marrow complete remission (CR). Once in marrow CR patient was observed until CR. Once CR was achieved or 60 days from the start of induction therapy, consolidation therapy was initiated with 1) ATO 0.15 mg/kg intravenously for 5 days per week for 4 weeks, repeated every 8 weeks for total of 5 courses, 2) ATRA 45mg/m2 orally twice daily 10 days per month for 10 months, and 3) GO 9 mg/m2 intravenously monthly for 10 months. Patients then received maintenance with 1) idarubicin 8mg/m2daily on day 1 and 2 every month for 3 months, 2) ATRA 45mg/m2orally daily 10 days per month for 14 months, 3) 6-MP 50 mg orally 3 times per day for 11 months and methotrexate 15mg/m2 orally once a week for 11 months. Results: The median age is 51years (range, 18–68 years), median WBC count 1.9 ×109/L (range 0.9–7.7 ×109/L), platelets 71 ×109/L (range, 6–164 ×109/L). The median duration of 1st CR was 7 months (range, 3 to 17 months). Seven patients achieved CR with median time to remission of 8 weeks (range 3–15 weeks). One patient achieved marrow CR after 3 weeks of therapy but is too early to evaluate for CR. All 7 are still in CR after a median follow up of 36+ months (range, 1+ to 51+ months). All seven patients achieved molecular remission. All patients had myelosuppression but there was no grade 3–4 extramedullary toxicity. Two patients died, one died secondary to complication related to metastatic lung adenocarcinoma, and the other patient died of sepsis. Conclusions: We concluded that the combination of ATO, ATRA and mylotarg is effective and may achieve durable remissions in many patients with APL in first relapse. It should be considered as an effective alternative to allogeneic or autologous transplant.

No significant financial relationships to disclose.

Quantitative single cell determination of ERK phosphorylation and regulation in relapsed and refractory primary acute myeloid leukemia

We investigated the constitutive activation of the MEK/ERK pathway in acute myelogenous leukemia (AML) via a flow cytometric technique to quantitate expression of phosphorylated ERK (p-ERK). A total of 42 AML samples (16 newly diagnosed, 26 relapsed/refractory) were analyzed. Normal bone marrow CD34+ cells (n = 10) had little or no expression of p-ERK, while G-CSF-mobilized CD34+ cells exhibited enhanced p-ERK levels. Markedly elevated p-ERK levels were found in 83.3% of the AML samples, with no differences observed between the newly diagnosed and relapsed/refractory samples. Treatment with a MEK inhibitor resulted in significantly decreased p-ERK levels in both the newly diagnosed and relapsed/refractory samples, which was associated with growth arrest, but not apoptosis induction. In summary, we defined conditions for the analysis of MAPK signaling in primary AML samples. Normal CD34+ cells expressed very low levels of p-ERK, and increased p-ERK levels were found in normal G-CSF-stimulated circulating CD34+ cells. Constitutively high p-ERK levels observed in the majority of AML samples suggest deregulation of this pathway that appears to be independent of disease status. The ability of ERK inhibition to promote growth arrest rather than apoptosis suggests that clinical trials of MEK/ERK inhibitors may be more effective when combined with chemotherapy.

Outcome in patients with nonleukemic granulocytic sarcoma treated with chemotherapy with or without radiotherapy

Granulocytic sarcoma (GS) is an extramedullary tumor composed of immature myeloid cells. The objectives of this study were to describe the frequency, presenting characteristics, and survival in patients with nonleukemic GS by conducting a review of all untreated patients presenting to the MD Anderson Cancer Center between January 1990 and June 2002. In all, 21 patients with nonleukemic GS, 1520 patients with acute myeloid leukemia (AML), and 402 patients with high-risk myelodysplastic syndrome (MDS) were identified. GS occurred in 1.4% of patients with AML, and 1.1% of patients with AML or high-risk MDSs. The median patient age was 57 years (range, 7-81). Among 20 patients with available cytogenetics in tissue and/or bone marrow, six had chromosome 8 abnormalities. The median follow-up of surviving patients is 12 months (range, 7-75). In all, 20 patients were treated. Patients were treated with AML-type chemotherapy (n=16), chemotherapy and radiotherapy (n=3), or radiotherapy alone (n=1). A total of 13 patients (65%) achieved complete remission and one patient (5%) achieved partial remission. The median overall survival was 20 months (range, 1-75), median overall failure-free survival was 12 months (range, 1-75). The median survival of patients with chromosome 8 abnormalities was 12 months compared with 40 months of those without (P=0.17). Novel therapies for patients with GS are required.

Better detection of FLT3 internal tandem duplication using peripheral blood plasma DNA

Somatic mutation of the FLT3 gene as an internal tandem duplication (ITD) of the juxtamembrane domain-coding sequence causes constitutive tyrosine phosphorylation and activation. Tumor-specific DNA has been documented in the sera of patients with solid tumors even when it is in an early stage. We compared the detection of FLT3 ITD in DNA extracted from cells of bone marrow (BM) aspirations with DNA extracted from peripheral blood (PB) plasma in patients newly diagnosed with acute myeloid leukemia (AML; 85 patients), myelodysplastic syndrome (MDS; 16 patients), and acute lymphocytic leukemia (ALL; 16 patients). FLT3 ITD was detected in 18 (21%) AML samples and in one (6%) MDS sample in both cellular and plasma DNA but in none of the ALL samples. Hemizygous/homozygous FLT3 ITD was detected in five (28%) of the FLT3 ITD-positive AML using plasma DNA, whereas only four of these cases showed hemizygous/homozygous FLT3 ITD using cellular DNA. The presence of FLT3 ITD was associated with significantly shorter survival (P = 0.02) when only patients younger than 50 years of age (48 AML+MDS patients) were considered. This finding was independent of cytogenetics in this age group. However, patients with the FLT3 ITD hemizygous/homozygous phenotype had even shorter survival (P = <0.001). As expected, the presence of FLT3 ITD correlated with higher white blood cell (WBC) counts. These data demonstrate that plasma DNA is a reliable alternative resource for detecting FLT3ITD, especially the hemizygous/homozygous genotype. Furthermore, the data derived from this study support the notion that the presence of FLT3 ITD in conjunction with the absence of the wild-type FLT3 allele predicts an especially poor prognosis for patients with AML.

More cell death in refractory anemia with excess blasts in transformation than in acute myeloid leukemia

Refractory anemia with excess blasts in transformation (RAEB-T) is a subgroup of myelodysplastic syndrome (MDS) in which the bone marrow blast count ranges from 20% to 30%. The recently proposed World Health Organization Classification of Hematologic Malignancies eliminated this category from MDS by lowering the blast count cutoff for acute myeloid leukemia (AML) from 30% to 20%. However, MDS is distinguished from AML by a significant increase in apoptosis. To investigate the difference in apoptosis between RAEB-T, AML, and other categories of MDS, we prospectively analyzed fresh bone marrow samples using the Annexin V and mitochondrial potential assays. There was a significantly higher level of apoptosis in RAEB-T than in AML according to both assays, while no significant differences between RAEB-T and other categories of MDS were noted. The data suggest that RAEB-T is more likely to be an advanced stage of MDS and biologically different from AML.

Chemotherapy only compared to chemotherapy followed by transplantation in high risk myelodysplastic syndrome and secondary acute myeloid leukemia; two parallel studies adjusted for various prognostic factors

Comparisons of the effectiveness of chemotherapy and transplantation in AML in first complete remission (CR) have focused almost exclusively on patients with de novo disease. Here we used Cox modelling to compare these strategies in patients with MDS and s-AML treated by the Leukemia Group of the EORTC or at the MD Anderson Cancer Center. All patients were aged 15-60. The 184 EORTC patients received conventional dose ara-C + idarubicin + etoposide for remission induction, and after one consolidation course, were scheduled to receive an allograft, or an autograft if a sibling donor was unavailable. The 215 MDA patients received various high-dose ara-C containing induction regimens, and in CR, continued to receive these regimens at reduced dose for 6-12 months. CR rates were 54% EORTC and 63% MDA (P = 0.09). Sixty-five of the 100 EORTC patients who entered CR received a transplant in first CR. Disease-free survival in patients achieving CR was superior in the EORTC cohort, the 4-years DFS rates were 28.9% (s.e. = 4.8%) EORTC vs 17.3% (s.e. = 3.7%) MDA (P = 0.017). Survival from CR was not significantly different in the EORTC and MDA groups, as was survival from start of treatment. After accounting for prognostic factors the conclusions were unchanged. Despite various problems with the analysis discussed below, the data suggest that neither transplantation nor chemotherapy, as currently practised, can be unequivocally recommended for these patients in first CR and that questions as to the superior modality may be less important than the need to improve results with both.

Antibody-targeted chemotherapy of older patients with acute myeloid leukemia in first relapse using Mylotarg (gemtuzumab ozogamicin)

We analyzed the safety and efficacy of Mylotarg (gemtuzumab ozogamicin, an antibody-targeted chemotherapy consisting of a humanized anti-CD33 antibody linked to calicheamicin, a potent antitumor antibiotic) in the treatment of 101 patients > or =60 years of age with acute myeloid leukemia (AML) in untreated first relapse in three open-label trials. Mylotarg is administered as a 2-h intravenous infusion at 9 mg/m(2) for two doses with 14 days between doses. The overall remission rate was 28%, with complete remission (CR) in 13% of patients and complete remission with incomplete platelet recovery (CRp) in 15%. Median survival was 5.4 months for all patients and 14.5 months and 11.8 months for patients achieving CR and CRp, respectively. CD33 antigen is present on normal hematopoietic progenitor cells; thus, an expected high incidence of grade 3 or 4 neutropenia (99%) and thrombocytopenia (99%) was observed. The incidences of grade 3 or 4 elevations of bilirubin and hepatic transaminases were 24% and 15%, respectively. There was a low incidence of grade 3 or 4 mucositis (4%) and infections (27%) and no treatment-related cardiotoxicity, cerebellar toxicity, or alopecia. Mylotarg is an effective treatment for older patients with CD33-positive AML in first relapse and has acceptable toxicity.

Reducing mortality associated with immediate treatment complications of adult leukemias

Analysis of data from 806 patients with newly diagnosed adult acute myelocytic leukemia (AML) (not including acute promyelocytic leukemia [APL] patients) treated at M.D. Anderson Cancer Center from 1995 through 1999 indicated that among patients entering a particular week of induction therapy, mortality rates were 6%, 8%, 6%, 9%, and 6% during weeks 1 to 2, 3 to 4, 5 to 6, 7 to 8, and 9 to 10, respectively. Because the mortality rate was not higher in the period immediately after treatment began, a definition of the period covered by the term "immediate" is somewhat arbitrary rather than "biologic," as might be the case if the early weeks were distinguished by a particularly high mortality rate. M.D. Anderson researchers have focused on the treatment complications and deaths occurring in the first 4 weeks after the beginning of induction therapy. In the first week, infection contributed to 71% of the deaths and pulmonary hemorrhage associated with diffuse alveolar damage contributed to 44%; the incidence of infection rose while the incidence of hemorrhage decreased during weeks 2 to 4. The associations between 4-week mortality rates with age, performance status, and white blood cell (WBC) count are well known. Study data suggest that elevated pretreatment levels of uric acid and tumor necrosis factor-alpha (TNF-alpha) levels are similarly associated with 4-week mortality. The prognostic significance of hyperuricemia appears independent of WBC, creatinine, and TNF-alpha. M.D. Anderson investigators have studied the roles of pheresis, TNF-alpha receptor-blocking agents, continuous venovenous dialysis, and newer antifungal agents in reducing early mortality. In particular, data from a retrospective M.D. Anderson analysis of pheresis (146 patients with WBC > 50,000 +/- microL) suggest that the value of this procedure is questionable. Preliminary data also point to the potential value of the TNF-alpha alpha receptor blocker etanercept (Enbrel, Immunex Corp, Seattle, WA) in patients at high risk of early death. Data from a randomized M.D. Anderson trial suggest that oral fluconazole plus itraconazole capsules are equivalent to liposomal amphotericin in antifungal prophylaxis. Because neither alternative appears satisfactory, researchers at M.D. Anderson are examining the role of intravenous itraconazole, which produces higher concentrations than itraconazole capsules in prophylaxis, and the role of FK 463 in treatment of fungal infections.

Therapeutic targeting of the MEK/MAPK signal transduction module in acute myeloid leukemia

The mitogen-activated protein kinase (MAPK) pathway regulates growth and survival of many cell types, and its constitutive activation has been implicated in the pathogenesis of a variety of malignancies. In this study we demonstrate that small-molecule MEK inhibitors (PD98059 and PD184352) profoundly impair cell growth and survival of acute myeloid leukemia (AML) cell lines and primary samples with constitutive MAPK activation. These agents abrogate the clonogenicity of leukemic cells but have minimal effects on normal hematopoietic progenitors. MEK blockade also results in sensitization to spontaneous and drug-induced apoptosis. At a molecular level, these effects correlate with modulation of the expression of cyclin-dependent kinase inhibitors (p27(Kip1) and p21(Waf1/CIP1)) and antiapoptotic proteins of the inhibitor of apoptosis proteins (IAP) and Bcl-2 families. Interruption of constitutive MEK/MAPK signaling therefore represents a promising therapeutic strategy in AML.