Media Contact: Kelli StauningTelephone: 310-423-3674 or 423-4767E-mail: [email protected]
LOS ANGELES, CA (April 1, 2001) -- Researchers at Cedars-Sinai Medical Center report that very low doses of a potent new drug called zoledronic acid reduces the complications that arise from multiple myeloma and breast cancer that has spread to the bone. The study, published in the April 1st issue of the journal, Cancer, shows that a five-minute infusion of zoledronic acid works as effectively as much higher doses of a similar therapy called pamidronate, which is given over a two-hour time period. Bone metastasis occurs in approximately 50 percent of patients with cancers that have spread to other parts of the body, but is particularly prevalent in multiple myeloma and metastatic cancers of the breast, prostate, lung, kidney and thyroid.
"Not only was zoledronic acid effective in much lower doses, but we could give the drug to patients over a much shorter time period than we could with pamidronate,' said James Berenson, M.D., Director of the Multiple Myeloma and Bone Metastases Program at Cedars-Sinai Medical Center. "This means a more potent and convenient alternative for patients battling with the debilitating effects of cancers that have spread to the bone."
Both zoledronic acid and pamidronate are types of bisphosphonates -- compounds that work by slowing the production of cells that destroy bone. Under normal conditions, cells called osteoclasts remove old bone, while cells called osteoblasts then begin building new bone. But when cancer spreads, the normal balance of the cells is disturbed and the osteoclasts are more active, causing bone fractures, pain, spinal cord compression (bone collapsing onto the spine) and hypercalcemia (an excess of calcium in the blood).
To help alleviate these complications, radiation therapy to the bone is often required. But radiation causes side effects, such as extreme fatigue and lower levels of infection fighting white blood cells. Alternatively, bisphosphonates cause fewer and less serious side effects, that include flu-like symptoms and some bone pain and can be given safely to patients receiving simultaneous chemotherapy or hormone therapy. Thus, pamidronate and other bisphosphonates have been increasingly used as safe and effective treatments for the skeletal complications due to cancers that have spread.
To determine whether zoledronic acid, the newest of the bisphosphonate compounds, was as effective as pamidronate in reducing bone complications, the investigators evaluated 280 patients with bone metastases due to metastatic breast cancer or multiple myeloma, a cancer of the infection fighting plasma cells in the bone marrow. Earlier studies by Dr. Berenson and his colleagues had already shown that lower doses of zoledronic acid were safe and reduced the indicators of bone loss such as excess calcium in patients whose cancer had spread to the bone.
In this study, patients were evaluated over a 10-month period and were divided into groups that received either 0.4, 2.0 or 4.0 milligrams of zoledronic acid infused over a five-minute period or, 90 milligrams of pamidronate, infused over a two-hour period. Both drugs were given to patients once a month. The investigators determined that either treatment was effective if the need for radiation therapy to bone was reduced to less than 30 percent of patients in each group.
Although some patients discontinued treatment due to death or other complications due to their cancer, approximately 76 percent of patients in the three groups receiving zoledronic acid and 82 percent receiving pamidronate completed at least six months of the study. Among these patients, the investigators found that treatment with zoledronic acid at doses of 2.0 and 4.0 milligrams was as effective as the much higher dose of pamidronate in reducing the need for radiation to bone. Of the patients receiving zoledronic acid, 19 percent receiving 2.0 milligrams received radiation to bone, while 21 percent received radiation in the 4.0 milligram group. Of those patients receiving pamidronate, 18 percent received radiation to bone. The lowest dose of zoledronic acid was found to be significantly less effective than the higher doses of zoledronic acid or pamedronate, with 24 percent receiving radiation to bone.
"We found that the proportion of patients receiving radiation to bone in the zoledronic acid group was very comparable to those patients receiving the much higher dose of pamidronate," added Dr. Berenson. "Complications such as fractures, spinal cord compression - or bone collapsing onto the spinal cord - and hypercalcemia occurred less frequently in the patients receiving the higher doses of zoledronic acid."
In addition, the investigators found that the higher doses of zoledronic acid increased bone density in the spine by almost 10 percent.
"Zoledronic acid may provide a much more convenient and effective therapy for overcoming the skeletal complications of bone metastases," said Dr. Berenson.
Currently, Dr. Berenson and his team are conducting phase III clinical trials to further compare the effects of zoledronic acid and pamidronate in bone metastases.
Cedars-Sinai Medical Center is one of the largest and finest non-profit hospitals in the Western United States. For the fifth straight two-year period, Cedars-Sinai has been named Southern California's gold standard in health care in an independent survey. Cedars-Sinai is internationally renowned for its diagnostic and treatment capabilities and its broad spectrum of programs and services, as well as breakthrough biomedical research and superlative medical education. The Medical Center ranks among the top seven non-university hospitals in the nation for its research activities.
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For media information and to arrange interviews, please contact Kelli Stauning at 310-423-3674 or via e-mail at [email protected].
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