A government study showed raloxifene was safer than tamoxifen.

A government study showed raloxifene was safer than tamoxifen.
WASHINGTON (AP) -- A newer drug prevents breast cancer in older, high-risk women just as well as today's standby tamoxifen -- but with fewer side effects, the National Cancer Institute announced Monday.
Called raloxifene, the newer drug already is sold to treat bone-thinning osteoporosis.
But the striking new results, from a government study of nearly 20,000 women, suggest that raloxifene may supplant its older cousin as the first choice for breast cancer prevention in postmenopausal women at high risk of developing the disease.
"Now women have a choice," Dr. Leslie Ford, NCI's cancer prevention chief, said in an interview Monday. "It's good news, because we're giving you a choice with fewer side effects."
Manufacturer Eli Lilly & amp; Co., which sells raloxifene under the brand name Evista, plans to seek Food and Drug Administration approval for the new use.
Until now, tamoxifen has been the only drug approved to reduce the chances of breast cancer striking high-risk women.
Both drugs are "selective estrogen response modulators" -- they act like the estrogen hormone in some tissues but like an anti-estrogen in others.
Here are problems
Estrogen can fuel certain breast cancers, making tamoxifen a longtime top choice both to prevent the disease's return in women with estrogen-sensitive tumors and to reduce the odds that it will strike high-risk women in the first place.
However, tamoxifen causes some rare but serious side effects: It acts like an estrogen in the uterus and bloodstream, thus increasing users' risk of getting uterine cancer or a life-threatening blood clot.
Raloxifene is a close chemical relative, and earlier research suggested that it might help breast cancer, too. So the NCI launched the $88 million study to compare the two.
Taking either tamoxifen or raloxifene daily for up to five years cut in half women's chances of developing invasive breast cancer, NCI announced Monday.
Raloxifene caused the same side effects, but not as many. Raloxifene users had 36 percent fewer uterine cancers and 29 percent fewer blood clots, according to initial results of the "Study of Tamoxifen and Raloxifene," or STAR project. Raloxifene users also suffered fewer vision-blocking cataracts.
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