Landmark data from the STAR trial comparing tamoxifen and Evista® (raloxifene) showed Evista was comparable to tamoxifen in reducing the risk of invasive breast cancer with fewer side effects. Now, with approval pending for Evista in this new setting, researchers had hoped to launch a follow-up phase III trial in April, known as the STELLAR trial, to compare the impact of Evista in high-risk women with the commonly used breast cancer prevention drug Femara® (letrozole). Budget cuts for the National Cancer Institute and questions about the trial’s $100 million price tag led the NCI to put the launch of the STELLAR trial on hold in March.
While both tamoxifen and Evista reduced the risk of invasive breast cancer by half in the STAR trial, Evista didn’t cause uterine cancer and blood clots, whereas tamoxifen did. “In various adjuvant trials, letrozole was more effective than tamoxifen in reducing breast cancers in the opposite breast,” says Lawrence Wickerham, MD, associate chairman of the NCI-funded National Surgical Adjuvant Breast and Bowel Project, sponsor of both the STAR and STELLAR trials. “The estimates are that letrozole may be able to reduce the risk of breast cancer from 70 to 75 percent in a group of healthy women at increased risk for the disease.” The STELLAR trial will also examine incidence of noninvasive breast cancers, as well as side effects, risk of non-breast cancers, quality of life and issues regarding bone, heart and circulatory system health.
The trial expects to recruit close to 13,000 high-risk postmenopausal women, and will follow them for five years. For more on breast cancer prevention, watch for CURE’s special issue on breast cancer in May.