crystal structure of the ERalpha ligand-binding domain complexed with lasofoxifene: image via wikimedia.org A drug that's been in and out of the FDA's pipeline has re-surfaced as its newest tests reveal its performance in studies of 8,556 women with osteoporosis. Lasofoxifene, an osteoporosis drug being marketed by Pfizer, showed some amazing results in reducing the risks associated with breast cancer, heart disease and stroke!
The Postmenopausal Evaluation And Risk-Reduction With Lasofoxifene
(PEARL) a 5-year study sponsored by Pfizer, tested the drug lasofoxifene at
twice the current recommended dose - .50 mg. per day instead of .25 mg. per day - to determine its impact on risk of
hip and back fractures, but also to test the drug's performance in protecting against estrogen related breast cancers, strokes, and heart attacks.
The study participants, between the ages of 59 and 80, were randomly divided into three groups; a placebo group, women taking .25 mg. of lasofoxifene, and women taking .50 mg. of lasofoxifene. The double dose of lasofoxifene was successful at reducing vertebral fractures by 42 percent and non-vertebral fractures by 24 percent. But there was more positive news....
Lasofoxifene, like tamoxifen and raloxifene, is a selective estrogen receptor modulator (SERM). SERMs have been shown to reduce estrogen related breast cancers in post menopausal women. Lasofoxifene was shown, in this study, to be as effective as the other SERMs in reducing breast cancer risk (79 percent reduced risk of cancer from any source and 83 percent reduced risk of estrogen related breast cancers), but unlike tamoxifen, lasofoxifene does not appear to increase risk for endometrial cancer.
Additionally, lasofoxifene reduced incidents of coronary events by 32 percent and incidents of stroke by 36 percent. However, there was an increased risk of venous thromboembolism compared to the other SERMs, but it was posited that the risk may have been higher in the PEARL group because they were on average 10 years older than those tested in the other SERM groups.
Lasofoxifene reduced breast cancers dramatically over a 5 - year period in women taking .50 mg of the drug.: image via ecancermedicalscience.com
Victor G. Vogel, MD, of the Geisinger Medical Center and an editor of the Journal of the National Cancer Institute, called the reductions in breast cancer and stroke incidence "dramatic" and considered that, though more data about the long-term effects of lasofoxifene was needed, the drug just may be the "tipping point in breast cancer prevention."
ECancerMedicalScience, Eureka Alert, The New England Journal of Medicine