Higher Dose of Breast Cancer Drug Associated with Longer Survival ► NCI Cancer Bulletin for December 11, 2012 - National Cancer Institute

NCI Cancer Bulletin for December 11, 2012 - National Cancer Institute

Higher Dose of Breast Cancer Drug Associated with Longer Survival

Women with advanced breast cancer who receive a higher dose of the drug fulvestrant (Faslodex) live longer than women who receive a lower dose, according to updated findings from a large clinical trial. The higher dose, 500 mg, has been in clinical use for a decade, but the new results provide evidence of a survival benefit for some women.
The trial, called CONFIRM, tested the two doses of fulvestrant in postmenopausal women with estrogen receptor (ER)-positive metastatic breast cancer whose cancer had recurred or progressed after previous treatment with endocrine therapy, such as tamoxifen (Nolvadex). Women who received 500 mg of fulvestrant lived for a median of 26.4 months, whereas women who received 250 mg lived for a median of 22.3 months, a statistically significant difference of more than 4 months.
The findings were presented December 5 at the San Antonio Breast Cancer Symposium (SABCS).
More than 700 women were enrolled in the international trial, which randomly assigned participants to receive 500 mg of fulvestrant or 250 mg, the dose initially approved by the Food and Drug Administration (FDA) in 2002.
The FDA approved the 500 mg dose in 2010, based on initial results from the CONFIRM trial that showed a statistically significant improvement in progression-free survival. Overall survival was also improved in the high-dose group, but the difference at that time was not statistically significant.
With longer follow-up, the overall survival benefit became statistically significant. But, the overall survival finding is from an unplanned exploratory analysis, warned the trial's lead investigator, Dr. Angelo Di Leo of the Hospital of Prato in Italy, during an SABCS press briefing.
Even so, when the results of the initial and updated analyses are compared, the two analyses "are perfectly consistent," he continued, "leading to the same conclusion that there is an increased benefit in terms of survival for patients receiving 500 mg" of fulvestrant.
Women who received the higher fulvestrant dose had a slightly higher rate of adverse side effects (8.9 percent versus 6.7 percent), but the difference was not statistically significant.
Following the FDA's 2010 approval, the 500 mg dose became the standard of care for this patient group, "so this study does not change current practice," said Dr. Claudine Isaacs of the Georgetown Lombardi Comprehensive Cancer Center. "However, it does provide further support for this dose and suggests that it may have a survival benefit."