Last Updated: 2010-12-09 16:36:27 -0400 (Reuters Health)
By Bill Berkrot
NEW YORK (Reuters) - The Novartis osteoporosis drug Zometa failed to improve disease free survival of early breast cancer patients in a large clinical trial, but some benefit was observed in older patients who took the medicine, researchers said.
The long-awaited results of the 3,360-patient trial called Azure will likely increase comfort in prescribing the medicine to post-menopausal patients with early stage breast cancer, but eliminate younger patients whose disease has not spread as candidates for the drug, researchers said.
The primary goal of the five-year study was an improvement in disease-free survival in women with localized stage II/III breast cancer who had undergone surgery.
The addition of Zometa to standard therapy, typically chemotherapy, made no difference to survival in the study's overall population, according to data presented on Thursday at the annual San Antonio Breast Cancer Symposium.
"This will be a surprise to most people. I think most people expected this to be a positive trial, but it isn't," Dr. Robert Coleman, the study's lead investigator, said in a telephone interview, calling the result "disappointing."
But among the 1,101 patients in the trial who were five years post-menopause there was a 29 percent improvement in overall survival over standard chemotherapy alone.
"To see a survival advantage like this is quite remarkable," said Coleman, professor of medical oncology at the University of Sheffield in England.
"The older patients are performing very, very differently from the rest of the population. We believe that probably is a true effect," Coleman said, noting that post-menopausal patients have very low levels of reproductive hormones.
"It's probably going to need further validation before it can be a standard approach to all older women. I think we'll get that kind of data from other trials expected to report in the next one to two years," Coleman said.
Zometa, known chemically as zoledronic acid, is an intravenous drug from a widely used class of osteoporosis medicines called bisphosphonates. It is increasingly being prescribed to help reduce or delay fractures and other skeletal complications in a variety of cancers that have spread to the bones.
Some 65 percent to 75 percent of breast cancer recurrences occur in the bones.
But researchers concluded that the results do not support routine use of Zometa in the management of early breast cancer following surgery, especially in pre-menopausal patients.
"It's a great drug if the cancer has already spread to the bones, but in this adjuvant (early, post surgery) setting we wouldn't give it to a younger patient," Coleman said.
He said the data should help tip the balance in favor of Zometa use in that older population since the drug also prevents bone loss due to osteoporosis, "and perhaps it will do some good for the cancer as well."
Among those taking the Novartis drug there were 17 confirmed cases - about 1 percent - of osteonecrosis of the jaw, a serious condition in which the jaw bone can die due to lack of blood flow. The condition has been associated with use of bisphosphonates. About half of those 17 patients healed, Coleman said.
"Clearly it's another reason not to give the drug in a younger patient because we can't show any benefit and there is more chance of harm," Coleman said.
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