News: Tibolone prevents osteoporotic fractures but increases stroke risk

Tibolone, a drug already approved to treat menopausal symptoms and prevent osteoporosis in many countries, prevents vertebral and other fractures in osteoporotic women but increases the risk of stroke, according to a report in the Aug. 14 issue of the New England Journal of Medicine.

Steven R. Cummings, MD, from the University of California San Francisco, and colleagues randomly assigned 4,538 women (60–85 years old) with negative bone mineral density at the hip or spine and evidence of a vertebral fracture to 1.25 mg of tibolone per day or placebo.

The researchers found that, over a median treatment period of 34 months, the tibolone group had a significantly lower risk of vertebral fractures (70 vs.
126 cases per 1,000 person-years, relative hazard [RH] 0.55) and a significantly lower risk of non-vertebral fractures (122 vs. 166 cases per 1,000 person-years, RH, 0.74). The tibolone group also had a significantly lower risk of invasive breast cancer (RH, 0.32) and colon cancer (RH, 0.31), but a higher risk of stroke (RH, 2.19), leading to early termination of the study. Both groups had similar risks of coronary heart disease and venous thromboembolism, the report indicates.

The study was supported by Organon. The authors of the study and editorial report a financial relationship with the pharmaceutical industry.

Cummings SR, Ettinger B, Delmas PD, et al. The effects of tibolone in older postmenopausal women. N Engl J Med. 2008;359:697-708.