A phase II trial of trastuzumab (H) + capecitabine (X) as first-line treatment in patients (pts) with HER2-positive metastatic breast cancer (MBC)

10615 Background: The addition of H to a taxane provides significant clinical benefit, including prolonged survival, in HER2-positive MBC. H adds little to the toxicity of taxanes alone. As monotherapy, X has consistently high activity and favorable safety. The addition of X to docetaxel extends survival in MBC. Preliminary data [Bangemann et al. 2000] indicated that the combination of H + X is effective and well-tolerated for intensively pretreated HER2-positive MBC (ORR 47%). The current study evaluated the efficacy and safety of H + X in first-line MBC. Methods: 72 pts of a planned population of 100 pts were enrolled between Mar03 and Dec05. All pts had measurable (WHO criteria), HER2-positive (IHC 3+ or IHC 2+/FISH positive) and untreated MBC, KPS ≥60, and adequate organ function. H was administered as a 4mg/kg loading dose followed by 2mg/kg i.v. weekly (until disease progression) and X 1250mg/m2 bid d1–14 q3w (max 6 cycles). The primary endpoint was progression-free survival (PFS). Results: Baseline...