Data from TAnDEM study have shown that the addition of Trastuzumab ( Herceptin ) to the hormonal therapy, Anastrozole ( Arimidex ), improves progression-free survival for patients whose advanced breast cancer is hormone receptor-positive, as well as HER2-positive.
Hormone receptor-positive breast cancer affects two-thirds1 of patients with breast cancer and is typically considered lower-risk due to successful treatment with hormonal therapies.
However, up to a quarter of these breast cancers are also HER2-positive,2 an aggressive form of the disease that requires special and immediate attention because the tumours are fast-growing and there is a higher likelihood of relapse.
The TAnDEM study is a randomised, Phase III trial, which evaluated Herceptin plus Arimidex versus Armidex alone as first-line therapy in postmenopausal women with advanced ( metastatic ), HER2-positive and hormone receptor-positive ( ER-positive and/or PR-positive ) breast cancer.
Enrolment to the trial began in 2001, and 208 HER2 and hormone receptor co-positive patients were enrolled at 134 sites in 25 countries across the world.
Arimidex was scheduled at a dose of 1 mg daily until progression.
Herceptin was administered in 2 mg/kg weekly doses ( after an initial loading dose of 4 mg/kg ) until disease progression.
According to the analysis, the primary efficacy endpoint was met, showing that patients who received Herceptin had a statistically significant improvement in progression-free survival. Overall safety data in both arms of the trial were acceptable given the known safety profile of each of the drugs in the advanced breast cancer setting.
Source: Roche, 2006