Dennis Black, PhD


April 25, 2003


What is the current feeling and evidence regarding long-term use (> 5 years) of raloxifene?

Robert C. Post, MD

Response From the Expert

No studies have evaluated the effects of > 4 years of treatment with raloxifene; any extrapolation beyond 4 years is not strictly evidence-based. Given that caveat, with respect to osteoporosis, the recently published results from 4 years of follow-up in the Multiple Outcomes of Raloxifene Evaluation (MORE) trial showed that raloxifene continued to reduce risk of vertebral fracture by about 35% and did not reduce the risk of nonvertebral or hip fractures. In terms of bone mineral density (BMD), the maximum effect of raloxifene vs placebo was attained after about 2 years, with about 2% increase in BMD at the hip and 2.5% at the spine. After 2 years, BMD at the hip began to decline but remained about 2% above placebo for at least 4 years. Presumably, continued use of raloxifene after 4 years would result in a continued advantage of about 2% compared with use of no medication.[1]

Data on the effects of treatment with nitrogen-containing bisphosphonates for as long as 10 years are available and suggest that BMD at both the hip and spine either continues to increase or at least remains relatively constant for at least that length of time.[2] However, there are no good fracture trials that have evaluated the effects of treatment longer than about 4 or 5 years.

In terms of primary prevention of breast cancer, data from the study of 4 years of raloxifene use suggest a continued reduction in risk.[3] Again, no studies have evaluated the effect of > 4 years of raloxifene.

However, there are some data for tamoxifen in the context of secondary prevention that suggest that after 5 years tamoxifen may be ineffective or even harmful.[4] A large trial of tamoxifen vs raloxifene (STAR) is ongoing and will compare these 2 drugs with each other (no placebo) over 8 years for the prevention of breast cancer.


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