WEDNESDAY, Jan. 5 (HealthDay News) -- Researchers have taken another step in the hunt to find a treatment for an aggressive, likely-to-recur form of breast cancer.
In a study published in the Jan. 5 online edition of the New England Journal of Medicine, the experimental drug iniparib not only shrank tumors and increased the time they took to progress, but also surprised researchers by prolonging survival in women with what's known as triple-negative breast cancer.
This type of breast cancer lacks receptors for estrogen and progesterone and doesn't have large quantities of HER-2/neu protein, which the most successful cancer therapies target. This means that many currently available drugs simply won't affect it.
"We were surprised [at the results] because triple-negative breast cancer is very difficult to treat," said study lead author Dr. Joyce O'Shaughnessy.
"The big, big surprise was survival," added O'Shaughnessy, who nevertheless stressed that the trial was small and preliminary.
The findings were enough to generate the interest of Dr. Lisa A. Carey, the co-author of an accompanying editorial.
"It is early, but it's really exciting because it's a new class of drugs. It isn't that often that we have a completely new approach to treating cancer," said Carey, medical director of the University of North Carolina Breast Center in Chapel Hill. "This is a new book. We've just opened it up."
Iniparib inhibits a pathway that helps repair DNA; researchers call it the poly(ADP-ribose) polymerase (PARP) pathway. If this chain is interrupted, cancer cells don't have the necessary tools to repair themselves.
"[PARP inhibitors] work by preventing the cells from repairing damage to their DNA," Carey explained.
A similar drug, in fact, has shown benefit in patients with BRCA 1 or BRCA 2 mutations predisposing them to breast and ovari
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