Patients with chronic myelogenous leukemia (CML) are finding new hope
in an experimental oral agent developed by Oregon Health Sciences
University researcher Brian Druker, MD, in collaboration with
scientists at Novartis Pharmaceuticals. Early clinical trials are
producing dramatic results with minimal side effects.
Unlike chemotherapy, which kills both normal and abnormal cells in an
attempt to eradicate the cancer, the compound STI-571 targets an
enzyme found only in leukemia cells. The result is a halt to the
progression of the disease.
Complete Normalization of Blood Counts
Dr. Druker presented the results of a phase I clinical trial at the
recent American Society of Hematology (ASH) conference in New
Orleans. The trial, conducted at Oregon Health Sciences University in
conjunction with Moshe Talpaz, MD, at M. D. Anderson Cancer Center in
Houston, and Charles Sawyers, MD, at the Jonsson Cancer Center at the
University of California, Los Angeles, involved CML patients who had
not responded to standard antileukemia treatment. Once an STI-571
dose of 300 mg or more was established, 31 of 31 patients in the
study showed a complete normalization of their blood counts,
signaling a remission of the disease. Moreover, in some cases, the
molecular cause of the disease seemed to disappear.
I congratulate these investigators on pushing forward the field
of rationally targeted cancer therapy, said Richard Klausner,
MD, director of the National Cancer Institute. While too soon
to evaluate the ultimate value of this agent for the standard
clinical approach to CML, their early data are very encouraging.
New Therapeutic Approach May Have Broader Applications
The early evidence of the effectiveness of agent STI-571
heralds a new approach to leukemia therapy and perhaps that of other
cancers as well, ie, the specific inactivation of the cancer-causing
protein in malignant cells, said Marshall Lichtman, MD,
executive vice president for research and medical affairs of the
Leukemia Society of America. These preliminary results should
engender excitement for researchers and physicians battling leukemia
and new hope for affected patients. The Leukemia Society of America,
on behalf of its donors and the patients we serve, is very pleased to
have played an integral role in supporting this landmark
The potential significance of this type of research extends
beyond leukemia, said Dr. Druker, whose research is supported
in part by the Leukemia Society and the National Cancer Institute.
One of the major goals of cancer research has been to identify
differences between cancer cells and normal cells so that these
differences can be targeted with more effective and less toxic
treatments. Thats exactly what weve seen happen in these
A phase II trial, which will introduce the compound to a broader
group of patients, is scheduled to begin in early 2000.