Candidates For Standard Induction Therapy Research Articles

Abstract 981: BCL-2 inhibitor APG-2575 and homoharringtonine (HHT) synergistically induces apoptosis and inhibits tumor growth in preclinical models of acute myeloid leukemia and myelodysplastic syndromes (AML/MDS)

Abstract The AML treatment landscape has improved dramatically in the past decade, with improved objective response rates and overall survival after treatment with newly approved targeted therapies. BCL-2 inhibition combined with a hypomethylating agent or low-dose cytosine arabinoside (Ara-C) is also effective in previously untreated elderly patients who are not candidates for standard induction therapy. However, the effect of BCL-2 inhibition is commonly weakened when tumor cells upregulate antiapoptotic protein MCL-1 to escape apoptosis. Thus, combination therapy is introduced to suppress MCL-1 levels. HHT (omacetaxine mepesuccinate) has been widely used in Chinese patients with AML for 30 years. As an inhibitor of protein synthesis, HHT decreases MCL-1. This study investigated the effect of combining clinical stage BCL-2 selective inhibitor APG-2575 with HHT in AML and MDS cells, as well as murine xenograft tumor models. In AML (MV-4-11, OCI-AML-3) and MDS (SKM-1) cell lines, single-agent HHT exerted stronger antiproliferative and apoptogenic activities compared to APG-2575 (as assessed by Cell Titer Glo assay or flow cytometry). When combined, these treatments synergistically inhibited cellular proliferation and induced apoptosis. In a mouse xenograft tumor model derived from MV-4-11 cells, APG-2575 demonstrated limited antitumor activity, with a T/C (Treated/Control tumor volume %) value of 63% whereas HHT showed stronger activity, with T/C equal to 30%. Most importantly, these antitumor effects were potentiated when APG-2575 and HHT were combined, yielding a T/C value of 3% and partial regression in all treated tumors. Mechanistically, BCL-2 inhibition with APG-2575 decreased BCL-2:BIM complexes and but increased MCL-1:BIM complexes, as liberated BIM was re-sequestered by MCL-1. On the other hand, concomitant treatment with HHT abolished induction of MCL-1:BIM complexes. Besides BIM complexes, MCL-1:PUMA and MCL-1:BAK pairings also decreased after exposure to HHT. The decrease in MCL-1 complex coincided with its downregulation at protein levels. Thus, under such an MCL-1-supressed condition facilitated by HHT treatment, the freed proapoptotic proteins (BIM, PUMA, BAK) more potently manifested apoptotic signals triggered by APG-2575. In summary, APG-2575 synergizes with HHT to potentiate antitumor activity in preclinical models of AML/MDS. HHT suppresses MCL-1 protein, preventing or abolishing formation of MCL-1:BIM, MCL-1:PUMA, and MCL-1:BAK complexes, and hence allowing prodeath proteins to fully engage in tumor cell apoptosis induction. Our results provide scientific rationale for clinical development of APG-2575 plus HHT in patients with AML/MDS. Citation Format: Douglas D. Fang, Qiuqiong Tang, Yanhui Kong, Tao Rong, Qixin Wang, Jing Deng, Dajun Yang, Yifan Zhai. BCL-2 inhibitor APG-2575 and homoharringtonine (HHT) synergistically induces apoptosis and inhibits tumor growth in preclinical models of acute myeloid leukemia and myelodysplastic syndromes (AML/MDS) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 981.

Di-O-lauroyl-decitabine-lipid nanocapsules: toward extending decitabine activity.

BackgroundAcute myeloid leukemia mainly affects adult patients. Complete remission for patients younger than 60 years, who are candidates for standard induction therapy, is achieved in 60%–80% of cases. However, the prognosis is still poor for older patients, who are unfit for intensive chemotherapy, and only a few therapies are available. Hypomethylating agents, such as decitabine, are approved for such patients. The current dosing regimen consists of one administration per day, for 5 days, each 4 weeks.MethodsHere, we present the synthesis of a decitabine prodrug, combined with its encapsulation into a lipid-based nanocapsule formulation. Decitabine (C12)2 was synthetized, then loaded into nanocapsules. Its stability in phosphate buffer ans human plasma was checked. Its activity was evaluated by Cell proliferation assays and cell-cycle analysis on human erythroleukemia cells. Then its pharmacokinetics was determined on a rat model.ResultsDecitabine (C12)2 was obtained with a yield of 50%. Drug loading into nanocarriers of 27.45±0.05 nm was 5.8±0.5 mg/mL. The stability of decitabine was improved and its activity on leukemia cells was not altered. Finally, pharmacokinetics studies showed a prolonged mean residence time of the drug.ConclusionDecitabine (C12)2 as a prodrug showed high encapsulation efficiency, a good stability in plasma with no impact on its activity on leukemia cells and improved pharmacokinetics.

Enasidenib Monotherapy Is Effective and Well-Tolerated in Patients with Previously Untreated Mutant- IDH2 (m IDH2) Acute Myeloid Leukemia (AML)

Enasidenib Monotherapy Is Effective and Well-Tolerated in Patients with Previously Untreated Mutant- IDH2 (m IDH2) Acute Myeloid Leukemia (AML)

Phase I Trial of Targeted Alpha-Particle Therapy with Actinium-225 (225Ac)-Lintuzumab and Low-Dose Cytarabine (LDAC) in Patients Age 60 or Older with Untreated Acute Myeloid Leukemia (AML)

Background:225Ac-lintuzumab is a radioimmunoconjugate composed of 225Ac (t½=10 days), which emits 4 α-particles, linked to a humanized anti-CD33 monoclonal antibody. Short-ranged (50-80 µm), high-energy (~100 keV/µm) α particle-emitting isotopes such as 225Ac may result in more specific tumor cell kill and less damage to normal tissues than β-emitters. An initial phase I trial in 20 patients with relapsed/refractory AML showed that a single infusion of 225Ac-lintuzumab is safe at doses ≤ 3 µCi/kg and has anti-leukemic activity (Jurcic et al. ASH, 2011). We conducted a multicenter, phase I dose-escalation trial to determine the maximum tolerated dose (MTD), toxicity, and biological activity of fractionated-dose 225Ac-lintuzumab in combination with LDAC.Patients and Methods: Patients ≥ 60 years with untreated AML not candidates for standard induction therapy (e.g., antecedent hematologic disorder, poor-risk cytogenetic or molecular features, and significant comorbidities) were eligible. Patients received LDAC 20 mg twice a day for 10 days every 4-6 weeks for up to 12 cycles. During Cycle 1, 2 fractions of 225Ac-lintuzumab were given 1 week apart, beginning 4-7 days following completion of LDAC. To prevent radiation-induced nephrotoxicity, patients were given furosemide while receiving 225Ac-lintuzumab then spironolactone for 1 year afterward. Four dose levels of 225Ac-lintuzumab were studied using a 3+3 design. Dose escalation proceeded if < 33% of patients in a cohort experienced dose-limiting toxicity (DLT).Results: Eighteen patients (median age, 77 years; range, 68-87 years) completed therapy. Twelve (67%) had prior myelodysplastic syndrome (MDS), for which 10 (83%) received therapy with hypomethylating agents (n=9) or allogeneic hematopoietic cell transplantation (n=1). One patient (6%) had chronic myeloid leukemia in molecular remission prior to developing AML. Eleven patients (61%) had intermediate-risk and 7 (39%) had poor-risk disease by NCCN criteria. Median CD33 expression was 81% (range, 30-100%). 225Ac-lintuzumab was given at 0.5 (n=3), 1 (n=6), 1.5 (n=3), or 2 (n=6) μCi/kg/fraction. Up to 4 cycles of LDAC were administered. Two patients experienced DLT (grade 4 thrombocytopenia with marrow aplasia for > 6 weeks following therapy), one each in the 1 and 2 µCi/kg/fraction cohorts. Although the MTD was not reached, 2 µCi/kg/fraction was chosen as the phase II dose to limit prolonged myelosuppression. Hematologic toxicities included grade 4 neutropenia (n=5) and thrombocytopenia (n=9). Grade 3/4 non-hematologic toxicities included febrile neutropenia (n=6), pneumonia (n=5), other infections (n=3), atrial fibrillation/syncope (n=1), transient creatinine increase (n=1), generalized fatigue (n=1), hypokalemia (n=1), mucositis (n=1), and rectal hemorrhage (n=1). Thirty- and 60-day mortality rates were 0% and 17%, respectively. Eleven of 14 patients (79%) evaluated after Cycle 1 had bone marrow blast reductions (mean reduction, 66%; range, 19-100%). Objective responses (2 CR, 1 CRp, 2 CRi) were seen in 5 of the 18 patients (28%), but only at doses ≥ 1 µCi/kg/fraction (Table 1). One of the responders received 15 cycles of azacitidine for prior MDS. All responses occurred after 1 cycle of therapy, in contrast to historical data with LDAC alone, where the median time to response was 3 cycles. Median progression-free survival (PFS) for all patients was 2.7 months (range, 1.0-31.8+ months). Median overall survival (OS) was 5.6 months (range, 1.6-32+ months). Median response duration was 5.6 months (range, 4.9-32+ months). Peripheral blood blast counts were a strong predictor of response. Among 38 patients treated in the current and initial phase I trials, responses were seen in 8 of 19 patients (42%) with blast counts < 200/µL, compared with 0 of 17 patients with blast counts ≥ 200/µL (P=0.002). This difference is likely due to decreased marrow targeting in patients with higher circulating blast counts when the subsaturating antibody doses used in this trial are given.Conclusions: Fractionated-dose 225Ac-linutuzmab can be safely combined with LDAC and induce remission in older patients with untreated AML. A phase II trial of 225Ac-lintuzumab monotherapy at 2 µCi/kg/fraction using hydroxyurea, if needed, to lower peripheral blast counts prior toadministration will be undertaken to determine response rate, PFS, and OS in this patient population. [Display omitted] DisclosuresJurcic:Forma Therapeutics: Research Funding; Seattle Genetics: Research Funding; Kura Oncology: Research Funding; Celgene: Research Funding; Novartis: Membership on an entity’s Board of Directors or advisory committees; Bayer: Consultancy; Alexion Pharmaceuticals: Consultancy; Merck & Co.: Consultancy; Astellas: Research Funding; Actinium Pharmaceuticals, Inc.: Research Funding; Daiichi-Sankyo: Research Funding. Levy:Janssen: Speakers Bureau; Actinium Pharmaceuticals, Inc.: Research Funding; Seattle Genetics: Research Funding; Amgen: Speakers Bureau; Takeda Pharmaceuticals International Co.: Speakers Bureau. Park:Amgen: Consultancy; Genentech/Roche: Research Funding; Juno Therapeutics: Consultancy, Research Funding. Ravandi:Actinium Pharmaceuticals, Inc.: Research Funding. Perl:Actinium Pharmaceuticals, Inc.: Research Funding; Seattle Genetics: Consultancy. Smith:Actinium Pharmaceuticals, Inc.: Research Funding. Cicic:Actinium Pharmaceuticals, Inc.: Employment, Equity Ownership. Scheinberg:Actinium Pharmaceuticals, Inc.: Equity Ownership, Patents & Royalties: Ac-225-Lintuzumab.

CLAG-based induction therapy in previously untreated high risk acute myeloid leukemia patients

The CLAG regimen is highly active in patients with relapsed and/or refractory acute myeloid leukemia (AML). We administered CLAG-based chemotherapy to 20 previously untreated AML patients who were poor candidates for standard induction therapy. Responding patients received further CLAG as post-remission therapy followed by additional therapy that was tailored to their AML subtype. Patients were considered poor candidates for standard therapy due to either cardiac disease, prior chemotherapy for another malignancy, prior myeloproliferative disease, or myelodysplastic syndrome that had progressed after hypomethylator therapy. Overall, thirteen patients had a complete response (CR) to the first cycle of therapy (65%), one patient had a CR without platelet recovery, and 3 patients had a partial response (PR). Two of the patients with PR converted to CR after further therapy. The median duration of response has not been reached; the mean duration of response is 36.8 months (95% CI 28.8–44.8 months). Median overall survival (including deaths from all causes) is 29.0 months (95% CI 18.0–46.0 months). Patients with de novo AML had a CR rate of 90.9% and a median overall survival of 38.5 months. CLAG-based therapy is a well-tolerated, efficacious induction strategy in previously-untreated patients with high risk AML. CLAG-based regimens should be studied in a broader group of newly diagnosed AML patients.

A Phase I Trial of a Pharmacodynamically-Conceived Decitabine and Thioguanine Combination in Patients with Advanced Myeloid Malignancies

Background: Using a chemosensitivity screening assay, we previously demonstrated that decitabine and thioguanine combinations can rescue therapeutic efficacy in primary leukemia cells isolated from patients with relapsed and refractory acute myeloid leukemia (AML). Although both decitabine and thioguanine have single-agent anti-leukemic activity, they have not previously been used concurrently. To test the safety and preliminarily assess possible additive/synergistic activity of this combination, we are performing a Phase I dose escalation trial of thioguanine given with decitabine.Patients and Methods: Patients with untreated AML over 60 years who are not suitable candidates for standard induction therapy, as well as those with relapsed/refractory AML, advanced myelodysplastic syndrome, and chronic myelomonocytic leukemia (CMML) are eligible. Three thioguanine dose levels are being evaluated: 80, 120, and 160 mg/m2/day, given in two divided doses on Days 1-12 of each induction course for up to two cycles and Days 1-7 of maintenance cycles. Decitabine 20 mg/m2 is administered IV on Days 3-12 during induction cycles and on Days 3-7 during maintenance cycles. In addition to standard safety measures and clinical outcomes, the biologic activity of the combination is assessed by patient specific pharmacodynamic measures. These measures include an in vitro chemosensitivity assay, genome-wide analysis of DNA methylation changes, and BH3 profiling in order to measure the degree to which samples are primed to undergo apoptotic cell death.Results: Six patients (median age, 69 yrs; range, 66–83 yrs) with newly diagnosed AML (n=2), relapsed/refractory AML (n=3), and newly diagnosed CMML (n=1) have been treated to date with thioguanine at the 80 mg/m2 dose. Dose-limiting toxicity was seen in one patient who developed acute renal failure (ARF) requiring hemodialysis. Infectious complications were the most common toxicity and included two episodes of grade 3 neutropenic colitis in one patient, grade 3 pseudomonal bacteremia, grade 3 staphylococcal bacteremia, and a dental infection requiring extraction. No other grade 3–4 non-hematologic toxicities were observed. Three patients remain on active treatment three to seven months from the initiation of therapy. Two patients were removed from study due to disease progression (n=1) and grade 4 ARF noted above (n=1). A patient with CMML was removed to undergo allogeneic hematopoietic stem cell transplantation after achieving a hematologic remission with red cell transfusion independence and platelet count normalization. The median number of cycles administered was 3 (range, 1-5). Bone marrow blast reductions to less than 5% were seen in all 4 evaluable patients with AML and included 1 CR and 1 CRi. The overall response rate in this high risk patient population was 67% (4 of 6 patients). Importantly, the patient who achieved a CR was 83 years old with relapsed disease following 4 previous cycles of single-agent decitabine therapy, demonstrating that this regimen can rescue previous hypomethylating agent failures. Clinical activity was well-correlated with the in vitro cytotoxicity assays. The chemosensitivity assay results for thioguanine on pre-treatment mononuclear cells directly correlated with clinical outcome in both response to therapy and clinical resistance. BH3 profiling was also performed on pre-treatment myeloblasts. Significant apoptotic priming corresponded to good initial clinical response. In addition, in the single patient who responded and subsequently relapsed, decreased apoptotic priming was observed in the relapsed sample, suggesting that the thioguanine/decitabine regimen applies selective pressure for reduction in apoptotic priming. Detailed analysis of treatment-related changes in DNA methylation will be presented and compared to prior work showing decitabine-induced hypomethylation in CD34+ leukemic cells during single agent therapy with decitabine.Conclusions: Combination decitabine and thioguanine has been well-tolerated and has shown surprising anti-leukemic activity at the lowest dose level studied. Importantly, the in vitro chemosensitivity testing and BH3 profiling accurately predicted the observed clinical responses while also confirming the etiology of the loss of therapeutic response. Accrual to this trial continues at higher dose levels to determine the maximum tolerated dose. DisclosuresLetai:AbbVie, Inc: Consultancy, Research Funding; Tetralogic: Consultancy, Research Funding.

Hypomethylating agents as first-line therapy in acute myeloid leukemia (AML).

7084 Background: Hypomethylating agents are used in older AML patients (pts) who are not considered candidates for standard induction therapy. However, data regarding their efficacy remains unclear. Methods: We retrospectively evaluated a cohort of 24 consecutive AML pts who were placed on hypomethylation therapy at diagnosis between October 2010 and June 2012 at Markey Cancer Center. Results: Baseline characteristics of the patients are described in table 1. Response rate (CR+PR) was 45.8%. Median number of infections were 1 (8 pts), 2 (5 pts), 3 (4 pts).Median hospital admissions required were 1 (10 pts), 2 (4 pts), 3 (5 pts), 4 or greater (2 pts). Average length of hospital stay was 10.3 days (0-37 days). Median units of packed red cell and platelet transfusions were 10 and 11 units (Range=0-64 and 0-78) respectively. After a median follow up of 145.5 days, 13 pts had died. Cause of death was AML (6 pts), infection and end organ failure (7pts).Median overall survival (OS) was 9.7 months (95%CI: 3.2-16.5 months). On multivariate analysis, blast count less than 30% was borderline significantly associated with better OS (P=0.05). However after addition of average hospital stay in the model only age (HR=1.3, CI=1.06- 1.67), gender (HR=11.5, CI=1.2, 110.5), and average hospital stay were significantly associated with OS (HR=1.2, CI = 1.04- 1.32). Conclusions: In this cohort of pts the median OS was 9.7 months. Older pts and those with longer average hospital stay had a higher mortality. Better selection of pts in a larger cohort who are likely to gain more benefit from these agents may impact outcomes. [Table: see text]

Decitabine: A Review of its Use in Older Patients with Acute Myeloid Leukaemia

Decitabine (Dacogen(®)) is a deoxynucleoside analogue of cytidine that selectively inhibits DNA methyltransferases. Decitabine administered at a dose of 20 mg/m(2) by a 1-h intravenous infusion for 5 consecutive days of a 4-week cycle has been approved by the European Medicines Agency (EMA) for use in adult patients aged ≥65 years with de novo or secondary acute myeloid leukaemia (AML) who are not candidates for standard induction therapy. Decitabine, compared with treatment choice (cytarabine or supportive care), did not result in a statistically significant improvement in median overall survival (OS) in older patients with AML at the pre-specified primary endpoint of a pivotal phase III trial. However, the improvement in OS was considered by the EMA to be clinically meaningful. After a further year of follow-up, an analysis of the mature survival data demonstrated a statistical significance in median OS in favour of decitabine over treatment choice. Complete remission (CR) rates in the phase III trial were significantly improved with decitabine versus treatment choice. The overall safety profile of decitabine in older patients with AML was generally similar to that of cytarabine, with pyrexia, thrombocytopenia and anaemia being the most commonly reported adverse events. In conclusion, low-dose decitabine may be considered as an effective and generally well tolerated alternative treatment to cytarabine or supportive care in older patients with AML who are not candidates for standard induction therapy.

Pre-Screening for Low Methyl Guanine Methyltransferase (MGMT) Expression Results in High Response Rates to Temozolomide (TMZ) Therapy in AML and MDS Patients.

Abstract 422 Introduction:Many patients with acute myeloid leukemia (AML) and high-risk myelodysplasia (MDS) are not suitable candidates for standard induction therapy, and newer treatment approaches are needed. TMZ anti-tumor activity is attributed to methylation of DNA, leading to the formation of O6-methylguanine that eventually leads to apoptosis. Expression of MethylGuanine DNA MethylTransferase (MGMT) restores normal guanine, decreasing DNA alkylation and thus anti-tumor activity of TMZ. Brandwein et al. (Leukemia 2007;21:821–4) previously demonstrated that response to TMZ in AML patients could be correlated with low MGMT expression. Thus MGMT expression prescreening could be used to identify patients more likely to respond to TMZ and provide an alternative for patients who are not candidates for standard induction therapy. Methods:We conducted a prospective multicenter study of patients with previously untreated AML and high risk MDS who were not candidates for standard induction therapy. Patient selection was based on MGMT expression as determined by Western blot in bone marrow or peripheral blood. Screening was performed by comparing the expression ratio between MGMT and b-actin protein levels. Patients with a ratio <0.25 were eligible to receive TMZ therapy 200 mg/m2/day × 7 days. Patients achieving a complete response (CR) could receive up to 12 monthly cycles of temozolomide 200 mg/m2/day × 5 days. Partial responders received a modified schedule of temozolomide 100 mg/m2/day × 21 days. Results:MGMT expression was tested in 188 patients; median age was 75 years old (range 46–94 years);62% were male. Primary diagnoses were AML (86%) and MDS (14%). Low or weak MGMT expression was detected in 46% of patient that were therefore potential candidates for TMZ therapy. Responses were evaluated in 42 patients, and were divided into 4 categories: Complete (CR/CRp), Morphologic Leukemia-Free State (MLFS), Partial (PR) Minimal (MR). Response was observed in 74% of cases including 29% CR, 10% MLFS, 19% PR and 17% MR. Prognostic factors associated with a higher response rate to temozolomide included MDS presentation, ECOG PS 0 and favorable/standard cytogenetic risk group. Induction and post-remission cycles were well-tolerated and most patients could be successfully treated on an outpatient basis.Patient who reached CR/CRp had a significantly longer median survival (>18 months) compared to those who reached MLFS, PR and MR (5.6 months). Median duration of therapy for patients reaching CR/CRp was 255 days and a majority (80%) became transfusion independent. Grade 3 and 4 toxicities were rare with the most common being fatigue (17%) and diarrhea (6%). Discussion:Pre-selection of patients based on MGMT expression level was associated with a higher response rate to TMZ as compared to previously reported unselected patients. Complete response was associated with increased survival and treatment had a favorable toxicity profile even in frail elderly patients. Targeted therapy with TMZ is feasible in patients with low MGMT expression and represents a new option for AML and MDS patients who are not candidate for standard induction therapy. Disclosures:Brandwein:Merck: Research Funding. Off Label Use: Temozolomide therapy for AML and MDS. Kassis:Merck: Research Funding. Leber:Merck: Research Funding. Howson-Jan:Merck: Research Funding. Minden:Merck: Research Funding. Galarneau:Merck: Employment. Pouliot:Merck: Employment.

Pilot Study of Low Dose Melphalan and Bortezomib for Treatment of Acute Myelogenous Leukemia and High-Risk Myelodysplastic Syndromes.

Elderly patients with AML (>60) have a poor prognosis due to high risk cytogenetics and a high incidence of secondary AML. Comorbid conditions make induction therapy more risky and less effective. There is a need for less toxic and more effective treatment for these patients. The combination of bortezomib (B) and melphalan (M) demonstrate synergistic cytotoxicity in vitro against AML cell lines providing a rationale for this combination in patients with AML. We report the initial results of a pilot study of low-dose M and B for the treatment of patients with AML and high-risk myelodysplastic syndromes. Eligibility requirements included a diagnosis of AML or high-risk MDS and subjects were not candidates for standard induction therapy or had failed therapy. Strata 1 included patients who had received no previous therapy and strata 2 patients with refractory or relapsed disease. Treatment consisted of M (2mg) oral daily dose and B (1.0mg/M2) on day 1, 4, 8 &11 of a 28 day cycle. Ten patients have been enrolled. Median age was 69 (range 54–79), 8 patients w/ AML and 2 w/ refractory MDS. Five patients were previously treated (strata 2); regimens included induction (7(3), auto SCT (1) and azacytadine (2). Cytogenetic abnormalities were present in 70% of patient specimens. To date 25 cycles of treatment have been given (range 1–6). Six patients are evaluable for response. Two patients (both with MDS) were withdrawn after 1 cycle for cytopenias. Two patients with AML achieved CR by bone marrow morphology. One patient, a 78 year old man with multiple cytogenetic abnormalities and no previous treatment achieved remission with normalization of cytogentetics after 4 cycles. A 74 year old man who had failed previous therapy for his AML achieved a morphologic remission with persistent cytogenetic abnormalities after 6 cycles. Three patients required admission for management of febrile episodes in association with neutropenia that were disease related. There were no treatment related admissions or grade 3/4 non hematologic toxicity events. The 74 year old man who achieved a CR with no “in hospital” days while on study had previously failed to respond to two induction attempts which required a 44 day hospitalization. Accrual continues. In summary, the combination of low dose oral melphalan with low dose bortezomib appears to be a novel, active and well tolerated outpatient treatment for elderly patients with high risk MDS and AML.