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Antibody-Targeted Chemotherapy-Induced Remission and Stem Cell Transplantation Prolong Disease-Free Survival for Leukemia Patients

Fred Hutchinson Cancer Research Center Researcher Presents Study Results at the American Society of Hematology Meeting in San Francisco

Patients with acute myeloid leukemia (AML) who achieve remission with the antibody-targeted chemotherapy agent Mylotarg™ (gemtuzumab ozogamicin for injection) have prolonged disease-free survival following stem cell transplantation according to research presented today at the annual meeting of the American Society of Hematology (ASH). These early data, from clinical studies conducted at the Fred Hutchinson Cancer Research Center and other centers, suggest that pre-transplant therapy with Mylotarg can enable patients to receive curative therapy in the form of hematopoietic stem cell transplantation.

AML is among the most serious forms of adult leukemia, with a relatively high fatality rate. It is an aggressive form of cancer in which certain white blood cells become cancerous and rapidly accumulate in the bone marrow, preventing normal marrow from growing and functioning properly. Most AML patients undergo intensive chemotherapy to achieve complete remission, and some also must undergo bone marrow transplants. Because standard chemotherapy drugs to treat AML are non-specific – destroying normal as well as malignant cells – patients who receive the therapy tend to become very sick.

"Intensive chemotherapy is a real challenge for most patients. Mylotarg is different because it has enabled us to achieve remissions with less severe side effects," said Eric Sievers, M.D., of Fred Hutchinson Cancer Research Center. "Our study shows that if a patient achieves remission with Mylotarg and subsequently receives a hematopoietic stem cell transplant, they have an excellent chance of prolonged disease-free survival."

Twenty-two patients with AML in first relapse who achieved remissions with Mylotarg received hematopoietic stem cell transplantation (HSCT). Eleven patients received allogeneic and 11 received autologous hematopoietic stem cell transplants. A majority of patients were alive without leukemia one year after the transplant. At the time of data cutoff, the median relapse-free survival for the 22 patients was 17.4 months after transplant.

"We believe that hematopoietic stem cell transplants appear to cause fewer complications than bone marrow transplants and that Mylotarg appears to cause fewer severe side effects than standard chemotherapy," Sievers continued. "This study shows us that we can offer our high-risk patients tolerable treatment that may prolong their chances of survival."

Researchers at the Fred Hutchinson Cancer Research Center, and eleven other leading leukemia centers, including University of Chicago Medical Center, MD Anderson Cancer Center, The University of Pennsylvania Cancer Center, Wayne State University, and the City of Hope Medical Center, are working with Wyeth-Ayerst Laboratories and Celltech Chiroscience to study Mylotarg, an antibody-drug conjugate that targets chemotherapy treatment to leukemia cells. Mylotarg was approved by the U.S. Food and Drug Administration on May 18, 2000, and is manufactured by Wyeth-Ayerst Laboratories.

The Fred Hutchinson Cancer Research Center is an independent, non-profit research institution dedicated to the development and advancement of biomedical technology to eliminate cancer and other potentially fatal diseases. Recognized internationally for its pioneering work in bone marrow transplantation, the Center has four scientific divisions collaborating to form a unique environment for conducting basic and applied science. One of 35 National Cancer Institute-designated comprehensive cancer centers in the country, it is the only one in the Northwest. Visit the Hutchinson Center web site for more information at www.fhcrc.org.

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For information about Wyeth-Ayerst Laboratories, contact: Douglas Petkus, 610/902-7336.

Mylotarg™:Mylotarg is a trademark of American Home Products Corp.

CONTACT: Susan Edmonds
sedmonds@fhcrc.org
(206) 667-2896

EMBARGOED FOR RELEASE
Dec. 3, 2000, 4:30PM PST