Los
Angeles, CA (5/18/98)- Favorable results with a new antibody therapy
against breast cancer, HER-2/neu (Herceptin), herald a new era of
treatment based on molecular targeting of tumor cells, reported researchers
at the annual meeting of the American Society of Clinical Oncology.
The HER-2/neu proto-oncogene encodes a growth factor receptor that is
overexpressed in 20-30% of metastatic breast cancers. This overexpression
is associated with decreased survival and decreased relapse-free periods.
The anti-HER2 antibody is designed to block this receptor.
The long-awaited results from a large clinical trial of Herceptin combined
with chemotherapy regimens (paclitaxel or anthracycline plus cyclophosphamide)
compared to chemotherapy alone indicate that adding this antibody to chemotherapy
did increase the clinical benefit by slowing the progression of the cancer
and increasing tumor shrinkage, reported Dennis Slamon MD. PhD, UCLA School
of Medicine, division of Hematology/Oncology.
Adding Herceptin to standard chemotherapy increased the amount of time
before the disease spreads by approximately three months, and increased
tumor response rates by 23-32%, depending on the chemotherapy regimen used,
without significant side effects.
Results of a second, large trial looking at the efficacy and safety
of Herceptin treatment alone in patients with metastatic disease who had
undergone prior chemotherapy regimens also appears to produce clinical
benefit.
"We are at a very exciting point where what we have learned in the laboratory
about the molecular basis for cancer can be translated into clinical trials,
and eventually used in patients," said Lori J.Goldstein, MD, Director of
the Breast Cancer Research Program at Fox Chase Cancer Center, Philadelphia,
at an ASCO press conference.
"These studies, especially the approach utilizing HER2/Neu, show that
molecular targeting can effectively fight advanced breast cancer, and that
biotherapy can be used to augment current therapy. These approaches are
showing clinical significance not just in the treatment of breast cancer,
but also, perhaps, in early detection and prevention," added Dr. Goldstein.
Nearly a third of women with breast cancer have tumors that overexpress
HER2. Now that there is a treatment available for this group of high-risk
patients, it is likely that screening for HER2 overexpression will become
much more common than it is now. This in turn might allow earlier treatment
of patients with one of the most aggressive forms of breast cancer known.
HER-2/neu is also overexpressed in a number of other cancer types including
endometrial cancer, gastric cancer and prostate cancer. A preliminary clinical
study using a different version of the HER-2/neu antibody showed some improvement
in patients with prostate and kidney cancer.
"Our investment in cancer research is clearly paying off with a host
of exciting new approaches to treating the disease," said Lynn M. Schuchter,
MD, of the University of Pennsylvania Cancer Center. "Efforts over the
last 15 years to understand the biology of cancer - the cellular,
molecular and genetic basis for the disease - are now making their way
from the laboratory to the bedside."
Herceptin is still considered an investigational new drug, not yet approved
for general use. However, the drug has been granted 'fast track' status
and is expected to gain approval by the end of the year. Meanwhile, patients
eligible for treatment via clinical trial can obtain information by calling
the National Cancer Institute at 800-4-CANCER.
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