Pfizer Inc today announced new, longer-term data from the Intergroup Exemestane Study (IES) showing that women who switched to AROMASIN® (exemestane tablets) after taking tamoxifen for two to three years experienced a significant reduction (18%) in the risk of disease-free survival (DFS) events. In addition, IES showed that AROMASIN prolonged overall survival (OS) in the ER+/unknown population with a 14% reduction in the risk of dying. These results demonstrate that the benefits of treatment are maintained in long term follow-up. These results were presented at the joint ECCO 15/ESMO 34 meeting in Berlin, Germany.
“These new, long-term follow-up data of the IES demonstrate a significant survival benefit for patients who switched to AROMASIN compared to those who stayed on tamoxifen,” said Charles Coombes, head of the oncology department at Imperial College, London, UK and principal investigator of the IES. “These findings are important to patients and physicians alike as they reaffirm their confidence in switching to AROMASIN after two to three years of tamoxifen.”
IES is a landmark trial with the longest follow-up of endocrine treatment in the adjuvant switch setting. It is a randomized, double-blind, multinational trial of postmenopausal women with early breast cancer. IES evaluates the clinical benefits of switching 2,352 patients to AROMASIN after two to three years of tamoxifen versus continuing 2,372 patients on tamoxifen for a full five years of therapy. The primary endpoint of the study was DFS in the intent-to-treat (ITT)population. Within the IES, 97% of the study population was oestrogen-receptor positive/unknown.
In postmenopausal women with early breast cancer at a median follow-up of 91 months, switching to AROMASIN after two to three years of tamoxifen, for a total of five years of treatment, was shown to result in a: