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Study Demonstrates That Arsenic Trioxide Is Active in Patients with Myelodysplasia
SEATTLE, June 6 /PRNewswire-FirstCall/ -- In an oral session at the 40th Annual Meeting of the American Society of Clinical Oncology, Dan Douer, M.D., University of Southern California/Norris Cancer Center, presented preliminary data from a U.S., multicenter, phase II clinical trial of TRISENOX® (arsenic trioxide) injection in a total of 67 patients with myelodysplasia (MDS). In his presentation, Douer concluded that single agent TRISENOX is active in both low- and high-risk disease. Among the 62 patients evaluable for efficacy, six of 29 low-risk patients (21 percent) achieved a major hematologic response and four of the 33 high-risk patients (12 percent) achieved a major response. In addition, TRISENOX treatment led to transfusion independence in five patients and a decrease of 50 percent or more in transfusion requirements in eight (13 percent) of all patients. Responses, which were observed in each of the cell lineages, lasted a median of approximately five months. TRISENOX is marketed by Cell Therapeutics, Inc. (CTI) (Nasdaq and Nuovo Mercato: CTIC).
"MDS is a disease of the bone marrow in which patients can become anemic and at risk for bleeding or infection as a result of the failure to produce red blood cells, platelets or infection fighting white blood cells. A major problem of this disease is that many patients require frequent transfusion of red cell and/or platelets. MDS patients, mostly high-risk patients, may also progress to acute leukemia, which is often rapidly fatal. Currently, there is only one approved treatment for MDS so there is a real need to find safe and effective, novel therapies for these patients," explained Douer. "TRISENOX has been shown to increase the number of red cells as well as the two other blood cell types in MDS patients. The fact that several responding patients no longer required transfusions is very significant. Responses were seen not only in low-risk but also in the sicker, high-risk patients who often need more transfusions and are more difficult to treat."
In addition to response rates, the trial was designed to determine the safety profile of single agent TRISENOX (0.25mg/kg/day) when administered on a five days per week, two weeks on, two weeks off dosing schedule. The results show that TRISENOX was generally well tolerated with mild to moderate reported adverse events. This trial has led to studies of TRISENOX using a twice weekly dosing schedule and studies in combination with other agents active in MDS.
TRISENOX® (arsenic trioxide) is marketed by Cell Therapeutics, Inc. (CTI) . TRISENOX® was approved for marketing in 2000 by the U.S. Food and Drug Administration to treat patients with relapsed or refractory Acute Promyelocytic Leukemia (APL), a rare, life-threatening form of cancer of the blood. TRISENOX® was granted marketing authorization from the European Commission in March 2002. APL, one of eight subtypes of acute myeloid leukemia (AML), represents 10-15 percent of the more than 20,000 patients diagnosed with AML each year. TRISENOX® is currently being studied in more than 40 clinical trials in a variety of cancers.
U.S. marketing approval for TRISENOX® was granted based on results from a U.S. multicenter study in which 40 relapsed APL patients were treated with TRISENOX® 0.15 mg/kg until bone marrow remission or a maximum of 60 days. Thirty-four patients (85 percent) achieved CR. When the results for these 40 patients were combined with those for the 12 patients in a pilot trial, an overall response rate of 87 percent was observed.
WARNING: TRISENOX® should be administered under the supervision of a physician who is experienced in the management of patients with acute leukemia. Some patients with acute promyelocytic leukemia (APL) treated with TRISENOX® have experienced APL differentiation syndrome - with symptoms similar to retinoic acid-acute promyelocytic leukemia (RA-APL) syndrome. Arsenic trioxide can cause QT prolongation (which can lead to torsade de pointes) and complete atrioventricular block.
The most common adverse events associated with TRISENOX® have been generally manageable, reversible and usually did not require interruption of therapy. These have included hypokalemia, hypermagnesemia, hyperglycemia and thrombocytopenia as reported in 13 percent of the patients (n=40). Abdominal pain, dyspnea, hypoxia, bone pain and neutropenia were reported in 10 percent of these patients, while arthralgia, febrile neutropenia and disseminated intravascular coagulation were reported in eight percent of patients.
Source: Cell Therapeutics, Inc.