Herceptin+Arimidex Improves HER2+ B/C Survival

[Tom]

Trastuzumab plus anastrozole improves HER2+ breast cancer survival

Martha Kerr
Reuters Health
Posting Date: December 15, 2006



Last Updated: 2006-12-15 16:36:05 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Adding trastuzumab (Herceptin, Genentech Inc., South San Francisco) to anastrozole (Arimidex, AstraZeneca, London) improves disease control and prolongs survival in women with advanced HER-2-positive breast cancer who choose to not undergo chemotherapy, investigators with the TAnDEM trial, reported this week at the 29th annual San Antonio Breast Cancer Symposium.

Principal investigator Dr. John R. Mackey of the University of Alberta Cross Cancer Institute in Edmonton, Alberta, presented the phase III results of 207 postmenopausal women from 22 countries with HER-2 node-positive metastatic breast cancer. Some women with estrogen receptor-negative or progesterone receptor-positive cancers were also included. All women had previously received tamoxifen, which failed to control their disease.

Women were randomized to anastrozole, 1 mg/day orally; or anastrazole plus trastuzumab, 4 mg/kg intravenously on day 1, then 2 mg/kg IV once a week; until disease progression.

The response rate was 20.6% with anastrazole plus trastuzumab compared with 6.8% with anastrazole alone.

Time to tumor progression was doubled with combination therapy. It was 2.4 months with anastrazole alone and 4.8 months with combination therapy. Median survival time was 23.9 months with monotherapy and 28.5 months with combination therapy, for an increase of 4.6 months. All of these findings were significant.

"The combination clearly improves disease control," Dr. Mackey told Reuters Health in an interview after his presentation in San Antonio, Texas. "The clinical benefit (of combination therapy) of about 6 months was somewhat diluted because patients were allowed to cross over to the Herceptin arm after the benefit was seen," he commented. "We think the clinical benefits would have been more statistically significant" without a cross-over option.

"This is not the standard of care," Dr. Mackey said. "The standard is trastuzumab plus chemotherapy. But a regimen of anastrazole plus trastuzumab gives women who want to avoid or postpone chemotherapy another option."

"We've learned with the TAnDEM trial that HER-2-positive disease is very resistant to treatment, and that you need to add Herceptin to improve survival without chemotherapy."