Abstracts

Zoledronic acid does not prolong survival for women with early breast cancer

Intravenous zoledronic acid should not be offered routinely to women with early breast cancer, say researchers, after a large trial found it had no discernible effect on recurrence or survival over five years. The trial, which was sponsored by Novartis, tested the drug in 3 360 women with T1, T2, or T3 tumours. Almost all had axillary spread. Results were clear, and the trial stopped early after an interim analysis and a median follow-up of 59 months.

Just over 1% of the women treated with zoledronic acid developed osteonecrosis of the jaw (17/1 681), an unexpectedly high incidence of a well-known and serious side-effect. The authors blame their intensive treatment schedule – 4 mg infusions starting monthly and decreasing to twice yearly for a total of five years. No cases of osteonecrosis of the jaw were seen in controls, who had standard treatment without zoledronic acid.

Most of the women in this trial had postoperative chemotherapy. They also had radiotherapy and endocrine treatments as appropriate, according to local protocols. Almost identical proportions of women in each group were alive and disease free after five years (76.9% v. 77.1%; adjusted hazard ratio 0.98, 95% confidence interval (CI) 0.85 - 1.13).

Subgroup analyses hinted at a small but significant survival advantage for postmenopausal women given zoledronic acid. The drug’s effects may depend on background values of reproductive hormones, say the authors.

Coleman RE, et al. N Engl J Med 2011;doi:10.1056/nejmoa1105195.

Bridget Farham