Results of the long-awaited AZURE trial prove negative.
Significant benefit in post-menopausal women will need further study.
Researchers said clinicians should be cautious about this investigational use in the adjuvant setting in premenopausal women.
SAN ANTONIO - Zoledronic acid did not improve disease free survival among women with stage II/III breast cancer according to results of the Adjuvant Treatment with Zoledronic Acid in Stage II/III 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.
Follow the AACR on Twitter @AACR, and throughout the meeting using the hash tag #SABCS. Recordings of the teleconferences and video interviews with researchers will be posted to the AACR website throughout the meeting: www.aacr.org/page23506.aspx.
The mission of the CTRC-AACR San Antonio Breast Cancer Symposium is to produce a unique and comprehensive scientific meeting that encompasses the full spectrum of breast cancer research, facilitating the rapid translation of new knowledge into better care for breast cancer patients. The Cancer Therapy & Research Center (CTRC) at The University of Texas Health Science Center at San Antonio, the American Association for Cancer Research (AACR) and Baylor College of Medicine are joint sponsors of the San Antonio Breast Cancer Symposium. This collaboration utilizes the clinical strengths of the CTRC and Baylor, and the AACRs scientific prestige in basic, translational and clinical cancer research to expedite the delivery of the latest scientific advances to the clinic. The 33rd annual symposium is expected to draw nearly 9,000 participants from more than 90 countries.
In San Antonio, Dec. 8-12: