Gemcitabine, vinorelbine and trastuzumab combination (GemVinT) as second-third line therapy for HER-2 overexpressing metastatic breast cancer (MBC)

759 Background: The addition of Trastuzumab (T) to chemotherapy as first-line therapy is associated with significant improvement in response rate (RR), time to progression (TTP) and overall survival (OS), in HER-2 overexpressing MBC. However, the efficacy of T combined with chemotherapy is presently object of evaluation in MBC pretreated with chemotherapy ± T. We evaluated in this phase II study the safety and efficacy of GemVinT as second-third line therapy for HER-2 overexpressing MBC, pretreated with anthracyclines and/or taxanes and/or T. Methods: Eligible patients had HER-2 positive disease (ICH 2+ or 3+), PS ≤ 2, normal LVEF. Pts were treated with weekly T (4 mg/Kg on day 1 and then 2 mg/Kg), in combination with Gem (800 mg/m2) and Vin (25 mg/m2) on days 1 and 8, every 21 days. Pts were re-staged every 3 cycles. Results: 26 pts were enrolled onto the study, median age 58 years (range 41–74), median ECOG PS 0 (range 2–0), median number of metastatic sites 3 (range 1–8), prior first line chemotherapy 90% or second line 10%, prior T treatment (35%). Twenty-three patients are evaluable for toxicity and response. Treatment was well tolerated: grade 4 neutropenia in 2 pts, grade 3 thrombocytopenia in 1 pt, grade 3 anemia in 1 pt and grade 3 asthenia in 2 pts were observed. Nine pts achieved an objective response (1 complete response and 8 partial response: RR of 39.1%): 8/9 of the responsive pts were T-naïve and Herceptest 3+. Noteworthy, four objective responses were observed in patients with brain metastasis. Seven patients had stable disease (30.4%). Median TTP was 6 months (range 2–15), median OS was 9 months (range 5–28). Conclusions: GemVinT is a safe and active regimen in this subgroup of poor prognosis pts. The recruitment is ongoing. No significant financial relationships to disclose.