[4466] Arsenic Trioxide (ATO) Downregulates the Expression of the AML1/MDS1/EVI-1 (AME) Oncoprotein and Induces Differentiation and Apoptosis in AME-Leukemic Cells. Session Type: Publication Only
David Shackelford, Samuel Waxman, Ruibao Ren. Department of Biology, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA, USA; Department of Medicine, Division of Hematology/Oncology, Mount Sinai School of Medicine, New York, NY, USA
Arsenic is an ancient drug, used for many centuries to treat a broad range of ailments including cancer but was largely abandoned in the early 20th century. In the 1990s arsenic trioxide (ATO) was rediscovered as an effective treatment for patients suffering from acute promyelocytic leukemia (APL). ATO has been shown to specifically target the fusion protein resulting from the t(15;17) translocation, PML/RARa, and subsequently stimulate differentiation and apoptosis of APL cells both in vitro and in vivo. The success in using ATO as a targeted therapy for APL underscores the importance of matching the right drug to patients with appropriate molecular targets. We previously reported that expression of the AML1/MDS1/EVI1 (AME) transcription factor fusion protein [a product of the human t(3;21)(q26;q22) translocation found as a secondary mutation in some cases of chronic myelogenous leukemia during the blast phase and in some patients with de novo and therapy-related myelodysplastic syndrome (MDS) and acute myelogenous leukemia (AML)] in mouse bone marrow cells by retroviral transduction impaired hematopoiesis and eventually induced an AML in mice. Our results established a causal role of AME in t(3;21)-positive myeloid malignancies. We went on to examine whether ATO could target AME. We found that ATO treatment downregulated forced-expressed AME protein in Bosc23 (a cell line derived from human 293 kidney cell line) and BM6-4 cells, a primary myeloid blast cell line derived from bone marrow of a mouse with AME-induced AML, in a dose dependent manner (within therapeutic relevant dosage range). We also found that ATO inhibited proliferation of BM6-4 cells, induced these cells to differentiate into macrophages and induced apoptosis in a dose dependent manner. Our results suggest that ATO could be used as a targeted therapy for t(3;21)-positive MDS and AML. The in vivo effect of ATO in the AME mouse model and mechanism of ATO-induced AME downregulation is under investigation. Such research may extend ATO therapy to other hematological malignancies and help to identify new therapeutic targets for human cancer.
Abstract #4466 appears in Blood, Volume 104, issue 11, November 16, 2004
Keywords: Arsenic trioxide|Acute myeloid leukemia|Differentiation therapy
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[4521] Safety Experience with Trisenox® (Arsenic Trioxide) Injection. Session Type: Publication Only
Joan Holman, Barbara Kirkhart, M. Scot Maxon, Cristina Oliva, Robert Earhart (Intr. by Jack Singer). Clinical Development, Cell Therapeutics, Inc., Seattle, WA, USA
Introduction: Trisenox®(arsenic trioxide) injection was approved in the United States in Sept 2000 and in the EU in March 2002 for the treatment of patients (pts) with relapsed or refractory acute promyelocytic leukemia (APL).
Aim: The aim of this analysis is to assess the safety profile of Trisenox®.
Methods: Safety information was gathered from monitored clinical trials and from spontaneous postmarketing reports.
Results: As of June 2004, approximately 3600 pts had received commercial drug for a variety of hematologic and nonhematologic cancers. In clinical trials or compassionate programs since the beginning of the Trisenox® development program, 808 pts [with APL (265), multiple myeloma (103), MDS (188), and other hematologic cancers or solid tumors (252)] have been treated. The overall safety experience for Trisenox® is therefore based on exposure of approximately 4400 pts. Postmarketing Experience: As of May 2004, 380 spontaneous postmarketing adverse event (AE) reports were received by CTI; 123 of these were serious AEs (SAEs), with 13 deaths, most due to disease progression or complications of the disease being treated. Trisenox® may have contributed to a death due to possible tumor lysis syndrome in a pt with MM, and 1 AML pt died with no cause reported. Most reported AEs are expected events that are listed in the Trisenox® product labeling. AEs reported for >15 pts were cytopenia (anemia, leukopenia, neutropenia, thrombocytopenia), pyrexia, prolonged QT interval, dyspnea, edema/wt gain, pain, hypotension, leukocytosis, rash, differentiation syndrome, nausea, asthenia/fatigue. Clinical Trial Experience: SAEs considered related to Trisenox® have been reported for 120 of 305 pts enrolled in clinical trials since US approval. This larger proportion of pts with SAEs likely reflects the monitored data in clinical trials compared to spontaneous postmarketing reports. Most of these SAEs are events listed in the Trisenox® label. AEs considered by investigators to be related to Trisenox® in 20% or more of the 233 pts with data received by CTI since US approval are pain (51%), nausea/vomiting (47%/23%), edema (43%), diarrhea (43%), fatigue/asthenia (37%/21%), pyrexia (36%), rash (34%), dyspnea (33%), gastrointestinal disorder (32%), headache (30%), cough (30%), upper respiratory symptoms (27%), abdominal pain (26%), anorexia (23%), lower respiratory disorders (22%), any cardiac arrhythmia (21%), hemorrhage (21%), viral infection (21%). As disease symptoms diminish, adverse events generally decrease in incidence and severity with continued use of Trisenox®. Few pts require interruption of therapy. A recent report of transient arrhythmias in pts continuously monitored during treatment with a non-Trisenox® formulation of arsenic trioxide (Unnikrishnan, Br J Haematol 2004;124:610-7) does not reflect the safety experience in pts treated with Trisenox® and managed in accordance with the product labeling.
Conclusion: With >4400 pts exposed to Trisenox®, the postmarketing AEs reported are generally similar to those observed in clinical trials and listed in the product labeling. The risk/benefit profile of Trisenox® when pts are managed in accordance with the product label remains acceptable.
Abstract #4521 appears in Blood, Volume 104, issue 11, November 16, 2004
Keywords: Safety|Adverse reaction|Acute promyelocytic leukemia
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[4582] Phase II Study of Arsenic Trioxide Plus Ascorbic Acid for Relapsed and Refractory Lymphoid Malignancies: A Wisconsin Oncology Network Study. Session Type: Publication Only
Brad S. Kahl, Harish G. Ahuja, Federico A. Sanchez, Gilberto A. Rodrigues, Peter M. Voorhees, Emily A. Stevens, Jamie Smith, Nancy Turman, KyungMann Kim, Howard H. Bailey. Medicine, University of Wisconsin Comprehensive Cancer Center, Madison, WI, USA; UW Cancer Center, Wausau, WI, USA; Regional Cancer Center, Waukesha, WI, USA
Introduction: Arsenic trioxide (AT) has impressive single agent activity in relapsed acute promyelocytic leukemia. It also has activity in myelodysplastic syndromes and multiple myeloma. In vitro data has suggested increased cytotoxicity when combined with agents that deplete intracellular glutathione, forming the rationale for combination studies. Ascorbic acid (AA) can deplete intracellular glutathione and may potentiate the cytotoxicity of AT. Upon this basis, we initiated a phase II study of arsenic trioxide plus ascorbic acid for relapsed/refracory lymphoid malignancies. Arsenic trioxide was administered at a dose of 0.25 mg/kg IV over one hour M-F for one week and then 2X/week for 5 weeks. Each arsenic infusion was followed by an infusion of 1000 mg ascorbic acid over 15 minutes. Each 6-week cycle was followed by a two-week rest period before repeating the cycle. Treatment was continued until best response plus two cycles or progressive disease.
Patient characteristics: Median age 70.5 (37-88). Gender 10M, 6F. Histologies CLL/SLL (4), Follicular (3), Mantle Cell (3), DLBCL (2), Burkitt (2), Marginal Zone (1), Hairy Cell (1). Median # Prior therapies 4 (2-13). Refractory to prior treatment 13/16. Median ECOG PS 1 (0-2). B symptoms 3/16. Elevated LDH 8/16. Elevated B2M 13/16.
Results: Median number of completed cycles 1 (0-4). Eight patients did not complete cycle #1, six due to progressive disease (PD) and 2 due to toxicity. Of the 2 patients coming off for toxicity, one patient with known coronary artery disease suffered a myocardial infarction on the 4th day of treatment and expired from congestive heart failure and the other experienced repeated grade 4 hyperglycemia. Six patients completed one cycle of therapy and were removed for PD. One patient completed 3 cycles of therapy before experiencing PD. One patient with mantle cell lymphoma received 4 cycles of therapy and achieved a CRu. The overall response rate was 6% (1/16). The responding patient’s treatment was stopped after 4 cycles for MD/patient preference and she experienced PD 5 months after completion of therapy. Grade 3 toxicities included thrombocytopenia (2 patients), anemia (3), neutropenia (1), stomatitis (1), anorexia (1), and elevated LFTs (1). Grade 4 toxicities included neutropenia (2) and hyperglycemia (1).
Conclusions: AT plus AA in this dosing schedule had modest toxicity but limited antitumor activity. The data should be interpreted in the context of our heavily treated, essentially refractory patient population. Our trial had a two-stage design, and was closed due to lack of activity at the first stage analysis. Other doses and schedules may prove to be more efficacious.
Abstract #4582 appears in Blood, Volume 104, issue 11, November 16, 2004
Keywords: Arsenic trioxide|Lymphoid malignancy|Phase II
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[4706] Study on Mechanisms of Telomerase Regulation in Arsenic Trioxide Inducing Apoptosis in Myelodysplasia Cell Line. Session Type: Publication Only
Hongyan Tong, Jie Jin, Weilai Xu, Wenbin Qian, Maofang Lin. Hematology Department, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
The telomerase activity can be down regulated by arsenic trioxide (As2O3), which is regarded as an apoptotic induction agent, is confirmed in many kinds of tumor cells. To investigate the mechanisms of telomerase regulation and to explore the correlation of As2O3 inducing apoptosis and telomerase regulation in MUTZ-1 cells, which are established as a high-risk myelodysplasia Cell line that derived from a MDS patient (FAB subtype refractory anemia with excess of blasts), a quantitative assessment of the telomerase activity by TRAP-ELISA and detection of the expression levels of hTERT, TRF1 (TTAGGG repeat binding factor 1), TRF2 (TTAGGG repeat binding factor 2), bcl-2, bax mRNA were performed, together with the assessment of the apoptosis by means of translocation of phosphatidylserine (PS) through flow cytometry assay. The results indicated that a typical apoptotic cell group distribution of DNA content was represented in the MUTZ-1 cells after being exposed to As2O3 at the range of concentration from 1µmol/L to 8µmol/L in a dose-dependent manner (r=0.736, P<0.001) and time-dependent manner (r=0.674, p<0.05), and the telomerase activity was down-regulated in a time-dependent manner (r=-0.976,P=0.024), and the expression level of hTERT mRNA in MUTZ-1 cells was represented in a dose-dependent manner (r=-0.892,P=0.042) and time-dependent manner (r=-1.000,P=0.04), after the cells were treated by As2O3 at the dosage as above. It was showed that a significant correlation between the decreased telomerase activity and the increased percentage of apoptotic cells in the treated cells (r=0.938,P=0.018), and there was a strong relationship between the telomerase activity and the mRNA expression of hTERT gene (r=0.783,P=0.022). However, As2O3 has no obvious effect on the expression level of TRF1 mRNA and TRF2 mRNA, which were regarded as two telomere-binding proteins. Further findings indicated that the inhibition of telomerase activity in MUTZ-1 cells was accompanied with down-regulated mRNA expression of bcl-2 gene (densitometry readings: 0.255±0.017 vs 0.466±0.069, P<0.05) and decreased ration of bcl-2/bax (densitometry reading ratios: 0.890±0.083 vs 0.546±0.014, P<0.05) at the dosage of 4µmol/L for 24 hours. These observations suggest that the apoptosis induced by As2O3 on MUTZ- 1 cells might be mediated through the inhibition of telomerase activity regulated by expression of hTERT gene, which implies that may be one of the mechanisms of As2O3 inducing apoptosis in MUTZ-1 cells.
Abstract #4706 appears in Blood, Volume 104, issue 11, November 16, 2004
Keywords: hTERT|BCL2|
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[4710] Arsenic Trioxide (Trisenox®) with/without Thalidomide in Patients with Myelodysplastic Syndromes (MDS) Produces Hematologic Improvement (HI). Session Type: Publication Only
Azra Raza, Laurie Lisak, Jennifer Billmeier, Samreen Akbar, Khalid Washeed, Mohammad Mumtaz, Poluru Reddy, Naomi Galili. Medicine/MDS Center, Rush University Medical Center, Chicago, IL, USA
In a previous clinical trial, we have shown that 7/28 MDS patients, belonging to IPSS intermediate and high risk categories, responded to a combination of Trisenox® and thalidomide including a complete hematologic and cytogenetic remission. Two trilineage responses were seen in patients with inv(3) abnormality. It was not clear whether the responses were due to the combination or to either drug alone. In the present study, we treated 30 MDS patients with Trisenox® (5 days of loading dose at 0.25mg/kg IV over 2 hours followed by twice weekly dose) for 6 months followed by the addition of thalidomide (100mg po qday x 3 months). The Median age was 71 years (19 males, 11 females). FAB types: RA 3 patients, RARS 2, RAEB 14, RAEB-t 8, CMMoL 2, Unclassified 1. IPSS: Low 0 patients, Int-1 10, Int-2 7, High 13. Two, 1,1 and 4 patients had abnormalities affecting chromosomes 5, 7, 8, and 20, while 12 patients showed a complex karyotype. Therapy was fairly well tolerated and median number of cycles was 3. Five patients showed a variety of hematologic responses as judged by the IWG criteria (1 trilineage, 1 cytogenetic and change in FAB type due to decrease in blasts, 1 ANC and reduction in blasts, and 2 with 50% reduction in blasts). Among the responders, 1 had 47 XX, +8(16 metaphases), del(X)(q22q25),del(3)(q25q27)(4 metaphases), 3 had a normal karyotype, and 1 had del(20q). Three of the partial responders were started on thalidomide, but all stopped within 2 months. Following response, the first patient showed disappearance of the clone bearing the chromosome 3 abnormality, confirming the sensitivity of these cells to Trisenox® as reported in our previous trial. Interestingly, 3/5 responders showed an increase in WBC/ANC and 1 in platelets as well (12, 22 and 90,000/ul), without any evidence of a differentiation syndrome. One also had an increase in platelets from ~50,000/ul to 966,000/ul. Blasts were 11, 24 and 28% in these 3 patients prior to therapy and decreased to 4, 6 and 24% respectively after treatment. It was concluded that the twice-daily dose of arsenic trioxide was well tolerated, and some patients converted their disease to a more myeloproliferative type picture.
Abstract #4710 appears in Blood, Volume 104, issue 11, November 16, 2004
Keywords: MDS|Arsenic trioxide|Thalidomide
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