Retreatment with trastuzumab after progression on lapatinib-based therapy in heavily pretreated HER2-positive metastatic breast cancer: A monoinstitutional experience.

Abstract

1082 Background: Continuing trastuzumab (T) in association with a different cytotoxic agent (CA) is a common practice in metastatic breast cancer (MBC) showing progression on T plus chemotherapy. Lapatinib plus Capecitabine (L-X) is another option in that setting. Little data is available about the efficacy of retreatment with T after L. Preclinical data(Scaltriti et al, 2009) suggest the possibility of a further response to T after L. Methods: From April 2007 to March 2009, we treated 58 HER2-positive MBC patients (pts) who had developed progression after antracycline, taxane, and T-based regimens with L-X as part of an expanded access program and thereafter with commercial drug. Of these 58 pts, 21 were retreated, at progression on L-X, with T combined with a different CA (mostly gemcitabine). The outcome of these 21 pts was retrospectively evaluated. Results: The median number of treatment lines, including the adjuvant setting, was 5 (ranging from 2 to 8). The median duration of previous T treatment (g...