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Higher fulvestrant dose improved survival in advanced breast cancer
SAN ANTONIO — A 500-mg dose of fulvestrant was linked to increased survival duration and a lower mortality risk than the standard 250-mg dose, according to findings presented here.
Angelo Di Leo, MD, of the Hospital of Prato in Italy, presented the findings of the Comparison of Faslodex in Recurrent or Metastatic Breast Cancer (CONFIRM) trial at the 2012 CTRC-AACR San Antonio Breast Cancer Symposium.
“There were 736 patients, all of whom were menopausal and had advanced ER-positive disease,” Di Leo said. “They were randomly assigned to the standard 250-mg dose or the experimental 500-mg dose. The study was placebo-controlled.”
There were 362 patients in the higher-dose group, who received fulvestrant (Faslodex, AstraZeneca) on days 0, 14 and 28 and every 28 days thereafter, and 374 patients in the lower-dose group who received the drug every 28 days.
Di Leo highlighted 2010 results, which indicated that the 500-mg dose was superior in terms of PFS and OS.
“That study was presented when 50% of the patients had died,” Di Leo said. “We saw superiority of the 500-mg dose, but it did not reach statistical significance.”
The current survival analysis was conducted when 75% of patients had died. “We continue to see a numerical superiority,” Di Leo said. He noted a 4.1-month increase in median OS and a 19% reduction in mortality in the higher-dose group.
“The P value seems to be statistically significant, but this is a nominal P value because we didn’t have enough statistical power to form an analysis between study arcs,” Di Leo said.
He suggested that the two analyses led to the same conclusion of an increased survival benefit of the 500-mg dose.
“We observed no differences in terms of serious adverse events between the two treatment groups,” Di Leo said, adding that there were few events in both arms. “The safety results do not support any clinically relevant difference between fulvestrant 250 mg and 500 mg, and they are consistent with previously reported safety profile information on the 500-mg dose.”
Patients were randomly assigned between February 2005 and August 2007 and were culled from 128 centers in 17 countries.
For more information:
Di Leo A. #S1-4. Presented at: the 2012 CTRC-AACR San Antonio Breast Cancer Symposium; Dec. 4-8, 2012; San Antonio.
Disclosure: Di Leo reports being a speaker for and receiving research grants and honoraria from AstraZeneca.