Aromasin Side Effects: Bone Loss and Fractures. The breast-cancer drug Aromasin, used in trials to prevent the cancer from developing in postmenopausal women, worsened bone loss in these women and raised their risk for fractures, a new study finds. The study was published in the Feb. 6 online edition of The Lancet Oncology.
Pfizer Inc, the world’s biggest drug maker, manufactures the drug.
On the other hand, the drug, also known by its chemical name exemestane, significantly reduced the recurrence of cancer—and lowered the chance that a woman with a high risk of getting breast cancer would actually end up getting it.
That, in turn, was what researchers found last year when they conducted a large study of 4,600 healthy women at risk of developing breast cancer.
That study, published in the New England Journal of Medicine, showed that women taking Aromasin had a lower risk of developing breast cancer than women taking a placebo, and that risk was 65 percent lower. It also showed that for every 94 women who took the drug for three years, one cancer was prevented.
Following up those findings in the new study, Canadian researchers examined the drug’s bone-density loss side effects more closely. Researchers, led by Dr. Angela Cheung, director of the osteoporosis program at Toronto’s University Health Network, looked at bone loss among more than 4,500 women who took part in the first trial.
Of this number, 351 women without osteoporosis were chosen in the new analysis, 176 given exemestane and 175 given a placebo.
Researchers found that after two years, the women taking exemestane suffered about three times more loss of cortical bone than those taking a placebo. Cortical bone is the bone’s outer shell that provides most bone support, and its loss accounts for about 80 percent of fractures in older people.
The results go against earlier studies that suggested exemestane, a third-generation aromatase inhibitor, might help stimulate bone growth. The researchers in fact, had set out to prove that Aromasin might result in less bone loss than other similar drugs.
Read more about Aromasin side effects after the jump.