Intergroup Exemestane Study

21 July 2011


This study compared five years of tamoxifen with two-three years tamoxifen followed by the aromatase inhibitor exemestane.

Scientific Title

BIG 2-97/IBCSG 16-98: Intergroup Exemestane Study

Randomised double-blind trial in postmenopausal women with primary breast cancer who have received adjuvant tamoxifen for 2-3 years, comparing subsequent adjuvant exemestane treatment with further tamoxifen.


Tamoxifen, taken for five years, at the time of this trial, was the standard hormonal treatment for postmenopausal women with primary, oestrogen receptor-positive breast cancer. Despite this treatment, however, some patients relapse.


This research showed that switching from tamoxifen after two to three years of treatment to exemestane, significantly reduced breast cancer recurrence. Exemestane also showed a modest but significant reduction in the risk of death for women who switched to treatment with exemestane. This was the first adjuvant aromatase inhibitor trial to show a survival benefit.

Main Publications

Disease-related outcomes with long-term follow-up: An updated analysis of the Intergroup Exemestane Study. Bliss JM, Kilburn LS, Coleman RE, Forbes JF, Coates AS, Jones SE, Jassem J, Delozier T, Andersen J, Paridaens R, van de Velde CJH, L√łnning PE, Morden J, Reise J, Cisar L, Menschik T, Coombes RC. J Clin Oncol. 2012; 30(7):709-717.