F. Giles

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.

Antithymocyte of 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 40u2009mg/kg/day daily intravenously (i.v.) for 4 days; cyclosporine daily orally for 6 months with levels titrated between 200 and 400u2009mg/dl; and methylprednisone 1u2009mg/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.

Plasma hepatocyte growth factor is a prognostic factor in patients with acute myeloid leukemia but not in patients with myelodysplastic syndrome

Hepatocyte growth factor (HGF) is a potent angiogenic factor. The aim of our study was to evaluate plasma HGF levels and their prognostic significance in patients with newly diagnosed acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). The sandwich enzyme immunoassay technique was used to quantify HGF in stored samples obtained before treatment from patients with AML (59 patients) and MDS (42 patients) treated at The University of Texas MD Anderson Cancer Center. HGF levels were significantly higher in patients with AML or MDS than in healthy individuals (P < 0.0001). Higher HGF levels in both AML and MDS correlated significantly with white blood cell (P = 0.000001 for both groups) and monocyte counts (P = 0.0004 and 0.003, respectively), and with poor performance status (P = 0.03 and 0.001, respectively). Using Cox proportional hazard model and HGF levels as a continuous variable, plasma levels of HGF correlated with shorter survival of AML (P = 0.001), but not MDS (P = 0.34) patients. No significant correlation was observed between HGF levels and complete remission rate or duration. In the multivariate analysis HGF retained its significance as prognostic factor in AML (P = 0.02), along with age (P = 0.0005).

The novel tyrosine kinase inhibitor EXEL-0862 induces apoptosis in human FIP1L1-PDGFR-α-expressing cells through caspase-3-mediated cleavage of Mcl-1

The FIP1-like-1 (FIP1L1)-platelet-derived growth factor receptor-alpha (FIP1L1-PDGFR-α) fusion kinase causes hypereosinophilic syndrome (HES) in a defined subset of patients. Imatinib mesylate is a potent inhibitor of ABL but also of PDGFR-α, and has been associated with durable hematologic responses in patients with HES. However, development of mutations in the tyrosine kinase domain may hamper the activity of tyrosine kinase inhibitors (TKIs), which suggests that novel agents are warranted to prevent or overcome resistance. We evaluated the efficacy of the novel TKI EXEL-0862 in FIP1L1-PDGFR-α-expressing cell lines and in cells from a patient with HES harboring the FIP1L1-PDGFR-α gene. EXEL-0862 inhibited the proliferation of EOL-1 and imatinib-resistant T674I FIP1L1-PDGFR-α-expressing cells and resulted in potent inhibition of the phosphorylation of PDGFR-α and downstream proteins STAT3 and Erk1/2, both in vitro and ex vivo. Moreover, EXEL-0862 induced apoptotic death in EOL-1 cells and imatinib-resistant T674I FIP1L1-PDGFR-α-expressing cells, and resulted in significant downregulation of the antiapoptotic protein Mcl-1 through a caspase-dependent mechanism. Our data establish EXEL-0862 as a solid candidate for the targeted treatment of patients with FIP1L1-PDGFR-α-positive HES.

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 (Pu2009=u20090.02) 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 (Pu2009=u2009<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.

Variations in the detection of ZAP‐70 in chronic lymphocytic leukemia: Comparison with IgVH mutation analysis

Lack of immunoglobulin heavy chain genes (IgVH) mutation in patients with chronic lymphocytic leukemia (CLL) is associated with rapid disease progression and shorter survival. The zeta‐chain (T‐cell receptor) associated protein kinase 70 kDa (ZAP‐70) has been reported to be a surrogate marker for IgVH mutation status, and its expression in leukemic cells correlates with unmutated IgVH. However, ZAP‐70 detection by flow cytometry varies significantly dependant on the antibodies used, the method of performing the assay, and the condition of the cells in the specimen. The clinical value of ZAP‐70 testing when samples are shipped under poorly controlled conditions is not known. Furthermore, testing in a research environment may differ from testing in a routine clinical laboratory. We validated an assay for ZAP‐70 by comparing results with clinical outcome and the mutation status of the IgVH. Using stored samples, we show significant correlation between ZAP‐70 expression and clinical outcome as well as IgVH mutation at a cut‐off point of 15%. While positive samples (>15% positivity) remain positive when kept in the laboratory environment for 48 h after initial testing, results obtained from samples from CLL patients tested after shipping at room temperature for routine testing showed no correlation with IgVH mutation status when 15% cut‐off was used. In these samples, cut‐point of 10% correlated with the IgVH mutation (P = 0.0001). This data suggests that although ZAP‐70 positivity correlates with IgVH mutation status and survival, variations in sample handling and preparation may influence results. We show that IgVH mutation results, unlike ZAP‐70 remain correlated with CD38 expression and β‐2 microglobulin in shipped samples, and ZAP‐70 testing should not be used as the sole criterion for stratifying patients for therapy.

Levels of soluble HLA-I and β2M in patients with acute myeloid leukemia and advanced myelodysplastic syndrome : association with clinical behavior and outcome of induction therapy

β-2 Microglobulin (β2M), 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 β2M in patients with acute myeloid leukemia (AML; n=209) or advanced myelodysplastic syndrome (MDS; n=98). sHLA-1 and β2M 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 β2-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: β2M 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.

Hemizygous/homozygous and heterozygous JAK2 mutation detected in plasma of patients with myeloproliferative diseases: correlation with clinical behaviour

other patients’. Perhaps the cut-off points could be increased to 5%, but at the risk of including more aggressive cases. The reference range of most laboratories for bone marrow blasts is less than 2% or 3%. Cases with ‡3% bone marrow blasts, but <5%, could provisionally be placed in a myelodysplastic/ myeloproliferative disease, unclassifiable category pending further follow up. The criterion of normal cytogenetics is also based on the data. All 13 RST cases in which a cytogenetic study was performed had a normal karyotype. Abnormal cytogenetics would probably predict a more aggressive clinical course. The rationale is analogous to the ‘5q) syndrome’ where only an isolated 5q deletion is allowed to place a patient in that relatively indolent disease category. The series of 16 RST patients that I reported (Shaw, 2005) is but one contribution of new knowledge upon which modifications of the World Health Organization classification scheme can be based.

Cloretazine for the treatment of acute myeloid leukemia.

Cloretazine is a new sulfonylhydrazine alkylating agent with antileukemic activity. Phase I studies have shown myelosuppression to be the dose limiting toxicity in both solid tumors and leukemias. A large Phase II study of single agent cloretazine (600 mg/m²) confirmed its activity in patients with relapsed acute myeloid leukemia, and in elderly patients with previously untreated acute myeloid leukemia or myelodysplastic syndrome. It also confirmed the limited nonhematological toxicity, even in elderly patients. Cloretazine can be safely combined with cytarabine, and this combination regimen is currently being tested in a large Phase III study in patients with relapsed acute myeloid leukemia. Cloretazine is a promising new antileukemic agent that may be incorporated into an intensive combination regimen.