Combination of trastuzumab and letrozole after resistance to sequential trastuzumab and aromatase inhibitor monotherapies in patients with estrogen receptor-positive, HER-2-positive advanced breast cancer: a proof-of-concept trial (SAKK 23/03)

Köberle D, Thürlimann B, Pilop C, Crowe S, Öhlschlegel C, von Moos R, Zaman K, Pagani O, Jost L, Ruhstaller T, Swiss Group for Clinical Cancer Research (SAKK). Combination of trastuzumab and letrozole after resistance to sequential trastuzumab and aromatase inhibitor monotherapies in patients with estrogen receptor-positive, HER-2-positive advanced breast cancer: a proof-of-concept trial (SAKK 23/03). Endocr Relat Cancer 2011; 18:257-64.