Time Magazine includes drug in May 28 cover story on new cancer breakthroughs
The University of Maryland Greenebaum Cancer Center has begun to study a new drug called Iressa that has shown promising results in treating lung and prostate cancer patients. The new study, sponsored by the National Cancer Institute, is looking at the drug 's effectiveness in treating kidney cancer patients.
"This is a very exciting drug that in preliminary testing has shown very promising results against two solid tumors," says Nancy Dawson, M.D., an internationally known prostate cancer expert who heads the Division of Genitourinary Oncology at the University of Maryland Greenebaum Cancer Center. She also is a professor of medicine at the University of Maryland School of Medicine.
"In the laboratory and in animals, Iressa has not just slowed the growth of cancer cells, but has resulted in shrinkage of tumors," says Dr. Dawson. She adds that a kidney tumor in one of her patients has shrunk after just one month of treatment with Iressa.
The University of Maryland Greenebaum Cancer Center and Memorial Sloan-Kettering are the only two sites nationwide offering Iressa (also known as ZD 1839) as a potential treatment option for inoperable kidney cancer, a rapidly fatal cancer for which there are few treatment options or effective therapies.
"Of the estimated 31,000 new cases of renal cell carcinoma diagnosed annually in the United States, one-third will have inoperable or incurable disease, and about 12,000 patients will die," points out Dr. Dawson. "Complete responses occur infrequently and many patients will die in less than one year. Chemotherapy is generally ineffective and novel approaches in both previously untreated patients, as well as patients failing standard immunotherapy, are needed."
Iressa is classified as an STI, a signal transduction inhibitor, which blocks signals within the cancer cells to prevent a series of chemical reactions that cause the cell to grow and divide. STI 's are "designer" drugs created in laboratories, based on many years of research in cell biology and genetics that have helped identify the triggers that make some cancers develop and grow. The growth of these cancers appears to rely heavily on the activation of one particular enzyme and STIs are strategically produced to counter that effect. They appear to quash that growth activity in ways never seen before, by turning off those triggers so that cells will not reproduce.
"Chemists can make drugs that fit perfectly into these receptor sites," explains Dr. Dawson, likening it to a lock and key mechanism. "The growth factor can 't bind because it 's blocked by this drug, which is designed specifically to fit into the pocket of these receptor sites. And, in theory, if that receptor is critical to cancer growth, blocking that receptor should result in those cancer cells dying."
Cancer specialists worldwide are excited at the prospect of this new approach, as evidenced by a variety of presentations and reports delivered at this year 's annual American Society of Clinical Oncologists conference held last month. Similar drugs, such as Gleevec, approved by the U.S. Food and Drug Administration just two weeks ago for chronic myeloid leukemia, work by the same principle, as do Rituxin, Tarceva and Herceptin.
All are pills, taken orally, often in the comfort of the patient 's home and with minimal side effects. All are "targeted" therapies that attack cancer cells only, sparing non-cancerous tissues, unlike traditional radiation and chemotherapy. Studies have not been conducted long enough to determine the overall success, and challenges remain in finding multi-drug combinations, as most do not work singly or without long-term administration.
"Patients have to take these medications daily," acknowledges Dr. Dawson. "These pills will not be a quick fix, nor a cure, but they may be a tremendous step forward in terms of treatment options that result in improved quality of life for patients with kidney cancer."
Dr. Dawson, previously chief of the Hematology/Oncology division at Walter Reed Army Medical Center and a senior investigator at the National Cancer Institute, sits on the editorial board of the Journal of Clinical Oncology, among other publications, and is a reviewer for several prestigious medical journals, including the American Journal of Medicine and the New England Journal of Medicine.
Anyone interested in more information about the Iressa clinical trial for kidney cancer should contact 1-800-492-5538.