WEDNESDAY, Dec. 5 (HealthDay News) -- An experimental cancer drug may delay the progression of some advanced breast cancers, while a double dose of an existing cancer drug could help women live longer, according to separate studies reported Wednesday.
In one study, of nearly 200 women, researchers tested the effects of adding the experimental drug -- known for now as PD 0332991 -- to Femara (letrozole), a hormonal therapy already used to treat certain breast cancers.
They found that women on the combination had a much longer "progression-free survival" -- the time a cancer patient lives with the disease without it getting worse. For women on the combination therapy, that period was typically 26 months, versus less than eight months among women given Femara alone.
"That's a dramatic difference," said lead researcher Dr. Richard Finn, associate professor of medicine at the University of California, Los Angeles, Jonsson Comprehensive Cancer Center.
Finn noted that in oncology clinical trials, success is measured in very small steps. A new drug might extend patients' lives by a matter of a couple of months, for instance.
The women in the trial all had advanced cancer that had spread beyond the breast. Their tumors were also estrogen-receptor positive, which means the cancer depends on estrogen to feed its growth and spread.
"ER-positive breast cancer is the most common form of breast cancer," Finn said. "And while we do have effective therapies for it, we still need to improve upon them."
The experimental drug is made by Pfizer, Inc., which also funded the trial. A larger trial is set to start next year, but Finn said these early results are "encouraging."
He was scheduled to present the findings Wednesday at the 2012 San Antonio Breast Cancer Symposium in Texas. Data and conclusions of studies released at medical meetings are considered preliminary, sin
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