Zoledronic acid did not improve disease free survival among women with stage 2/3 breast cancer according to results of the Adjuvant Treatment with Zoledronic Acid in Stage 2/3 Breast Cancer (AZURE) trial, which was presented at the 33rd Annual CTRC-AACR San Antonio Breast Cancer Symposium.
“In the larger population, we did not see a difference,” said Robert Coleman, M.D., professor of medical oncology at the University of Sheffield in England.
However, among 1101 patients who were five years post-menopause, about 30 percent of the overall group, there was a 29 percent improvement in overall survival. Coleman stressed that this was a secondary outcome, so it could not be considered conclusive, but it did present the largest unanswered question.
“To see a survival advantage like this is quite remarkable, and the difference in outcome between this group and the younger population is unlikely to be a chance finding. We will clearly want to investigate further in this population,” he said.
The AZURE trial included 3,360 patients with stage II/III breast cancer from 174 centers. Coleman and colleagues randomly assigned the patients to standard therapy or to standard therapy plus zoledronic acid. The primary outcome was disease free survival.
The researchers found no difference in disease free survival in the overall population.
“This will likely dissuade clinicians from giving adjuvant bisphosphonates on a routine basis to younger women taking adjuvant chemotherapy because, although the drug is generally well tolerated, there is a small risk of osteonecrosis of the jaw,” said Coleman.
The researchers identified 17 (1.1%) confirmed cases of osteonecrosis of the jaw over the duration of the study period.
These results do not impact on the current useage of zoledronic acid for the treatment of metastatic bone disease across a broad range of cancers.
Date: December 14, 2010
Source: American Association for Cancer Research
Filed Under: Drug Discovery