FULVESTANT-ANASTRAZOLE COMBINATION OF NO BENEFIT

NEW YORK (Reuters Health) Mar 14 - In women with a first relapse of endocrine-responsive breast cancer, a combination of fulvestrant and anastrozole was no more effective than anastrozole monotherapy in a phase III trial.
The approach had looked quite promising. Dr. Jonas Bergh, who headed the study, told Reuters Health by email that because fulvestrant is a specific blocker of the estrogen receptor alpha, it "should have the potential to be very interesting for the management of breast cancer patients with endocrine sensitive disease."
"The dual blockade with fulvestrant and the aromatase inhibitor anastrozole should be even better compared with anastrozole alone, as the preclinical studies have demonstrated, but we failed to demonstrate that in our patients," he added.
In a February 27th online paper in the Journal of Clinical Oncology, Dr. Bergh of the Karolinska Institutet and University Hospital, Stockholm, Sweden and colleagues report on a randomized trial in which 514 women received fulvestrant with or without anastrozole.
The women were either postmenopausal, or premenopausal and receiving a gonadotropin-releasing hormone agonist, with estrogen receptor- and/or progesterone receptor-positive disease at first relapse after primary treatment of localized disease. About a third were anti-estrogen naive. Only eight had received an aromatase inhibitor. The median length of follow-up was 8.9 months.
The median time to progression was 10.8 months in the combination group and 10.2 months in those on monotherapy. Corresponding median overall survival was 37.8 and 38.2 months.
Although there were 11 deaths due to adverse events in the combination patients and 5 in the monotherapy group, no causal relationship was seen with the study drugs.
Thus, say the investigators, no advantages were observed "in this population of individuals with a relatively high proportion of previous adjuvant antiestrogen exposure."
Dr. Bergh thinks the approach may still have some value. "Data from other studies demonstrate that the fulvestrant should have been used at a higher dose," he said, "and the patient population to be treated need(s) to (be) further refined."
The study was sponsored by Astra Zeneca, which markets fulvestrant as Faslodex and anastrozole as Arimidex.
SOURCE: http://bit.ly/yWtQGH
J Clin Oncol 2012.