At a median follow-up of 100 months, more than three years after the completion of treatment, Arimidex significantly reduced the risk of recurrence in comparison with tamoxifen in postmenopausal patients with hormone receptor-positive (HR+) breast cancer. A significant benefit of Arimidex on distant recurrence is now evident (HR+population p=0.027), and Arimidex is also shown to reduce the risk of distant metastases. Although there was no difference in overall survival, the impact of Arimidex at reducing distant metastases is important, as distant recurrence-free survival is an important predictor for survival related to breast cancer.
The availability of 100 months of follow-up data is also providing long-term information on the safety profile of five years of treatment with Arimidex. During the treatment period, Arimidex was associated with an increased incidence of joint symptoms and fractures (10% versus 7%). However, the 100-month analysis showed that fracture rates decreased after completion of treatment and were similar in both treatment arms.