A study investigating whether the osteoporosis-fighting drug Evista could be used as an alterative to tamoxifen for preventing breast cancer found Evista did prevent cancer, but raised the risk of blood clots and fatal strokes in women taking the drug. Evista also did not lower the risk of death, hospitalization, or heart attack.

The study, which involved 10,101 post-menopausal women in 26 countries including the U.S. was published in the July 13, 2006 edition of the New England Journal of Medicine and paid for by Eli Lilly and Co., makers of Evista . Participants either had clogged arteries or multiple heart risk factors and the study was designed to test whether Evista would both lower their risk of getting breast cancer and lower their risk of heart disease. After an average of five years on either Evista or placebo, Evista users had one-third fewer cases of breast cancer, and about half the number of invasive breast cancers; but 59 of 5,044 Evista users had fatal strokes compared to 39 on placebo. This represents a 49 percent greater risk of fatal strokes for patients on Evista . Blood clots in veins, which can potentially travel to the lungs and cause death, were found in 103 women on Evista but only 71 women on placebo.

Marcia Stefanick, disease-prevention researcher at Stanford University School of medicine, said in an editorial in the journal that the “moderate” breast-cancer prevention benefits of Evista “do not seem to justify the risks” of taking the drug for women already prone to heart problems. Dr. Marisa Weiss, a breast-cancer specialist who founded the web site breastcancer.org, agreed. “The cardiac benefit wasn’t there,” Dr. Weiss said. “The side effects were.”

Source: “Cancer drug increases heart risks,” Associated Press,” July 13, 2006, accessed July 17, 2006.