Evista Decreases Risk of Breast Cancer in Postmenopausal Women

October 4, 2006

Evista Decreases Risk of Breast Cancer in Postmenopausal Women

Raloxifene (sold under brand name Evista) has been show to lower postmenopausal women’s risk of developing invasive breast cancer – regardless of their risk level for developing the disease.

The same study also showed that raloxifene may reduce breast cancer risk in women with a family history of the disease to levels similar to women with no affected family members.

Results of the study were published in Clinical Cancer Research on September 1 and reported on Newswise online on September 13.

Women with no family history of breast cancer who took raloxifene had a 58% reduction in breast cancer risk (compared with placebo), and women with a family history of the disease had an 89% reduction in risk.

Raloxifene (Evista), is not approved by the US Food and Drug Administration as preventative treatment for breast cancer.

Differences in Benefit

The researchers noted that the reason for raloxifene’s apparent superior protection in women genetically predisposed to breast cancer was clear:

“We don’t know what to make of this observation,” Marc E Lippman, MD, professor in the Department of Internal Medicine at the University of Michigan and the study’s lead author, reportedly said.

“It could be due to chance, or there may be other factors at work that we don’t know about. But our bottom-line analysis as to why raloxifene universally reduces the risk of developing invasive cancer in women without a family history is that it interferes with the duration and concentration of estrogen, which acts as a tumor promoter in the majority of breast cancers.”

MORE and CORE Clinical Trials

Dr Lippman and colleagues analyzed data from two trials: MORE (Multiple Outcomes of Raloxifene Evaluation) and CORE (Continuing Outcomes Relevant to Evista).

MORE was the first large trial of raloxifene and included 7,705 postmenopausal women with osteoporosis. MORE’s primary endpoint was the raloxifene’s ability to prevent vertebral fractures; the secondary endpoint raloxifene’s effect on breast cancer development. Results were announced in 1999, at which point the trial was extended four more years to continue to evaluate raloxifene’s effect on breast cancer incidence in 4,011 of the original participants.

Results of the first trial showed raloxifene was associated with a 72% reduction in invasive breast cancer incidence after four years, compared with placebo. Results of the second trial, known as CORE, showed raloxifene was associated with a 66% reduction in invasive breast cancer incidence after eight years’ treatment.

The current study examined the effects of raloxifene treatment on breast cancer risk using data from both MORE and CORE.

Overall, the researchers found that raloxifene reduced breast cancer risk in women at low and high risk of breast cancer.

“In each variable commonly associated with a higher risk for developing breast cancer - age older than 65, age at menopause, a body mass index greater than 25, higher estradiol levels, prior use of estrogen replacement and a family history of breast cancer - use of raloxifene reduced incidence of breast cancer when compared to a placebo drug,” Dr Lippman reportedly said.

“But it also reduced incidence in each of those variables that should have lowered risk, such as younger age, later menopause, etc., compared to use of a placebo drug. We don’t define the lowest limit of risk, the point at which toxicity associated with use of raloxifene outweighs the benefits.”

Dr Lippman noted that he could not make a general comparison of raloxifene’s effects in this study with tamoxifen – that, although his team’s findings were published shortly after results from the 19,747-participant STAR trial (evaluating tamoxifen vs. raloxifene in reducing breast cancer risk), the MORE, CORE and STAR clinical trials should not be directly compared.

“These studies looked at two different groups of women,” Dr Lippman reportedly said. “Women enrolled in STAR were at high risk for developing breast cancer, so presumably they had higher levels of estrogen in general. Women who participated in MORE and CORE were older and had osteoporoses and it is assumed that these women generally have lower levels of estrogen, because that is a risk factor for development of the disorder.”

Sources:
Raloxifene Reduces Breast Cancer Risk in Postmenopausal Women at All Risk Levels, American Association for Cancer Research (AACR), reported by Newswise, September 13, 2006.
Effect of Raloxifene on the Incidence of Invasive Breast Cancer in Postmenopausal Women with Osteoporosis Categorized by Breast Cancer Risk. Marc E Lippman et al, Clinical Cancer Research, volume 12, pages 5242-5247, September 1, 2006.

Latest Pharma Industry News...

Pharma Industry News Archive

More News Resources

Daily MedNews
Pharma Industry News
New Drug Applications
New Drug Approvals
Clinical Trial Results
Generic Drug Approvals
Monthly Update Archive