Trastuzumab and bevacizumab combined with docetaxel, oxaliplatin and capecitabine as first-line treatment of advanced HER2-positive gastric cancer: a multicenter phase II study

Summary: Objective To investigate the efficacy of bevacizumab and trastuzumab combined with docetaxel, oxaliplatin, and capecitabine (B-DOCT) as first-line treatment of advanced human epidermal growth factor receptor 2 (HER2)-positive gastric cancer (GC). Methods In this multicentre, single-arm, phase II study, tumor HER2 status was determined centrally prior to treatment. Patients with advanced HER2-positive adenocarcinoma of the stomach or gastroesophageal junction (immunohistochemistry 3+ or immunohistochemistry 2+/silver in-situ hybridization positive) were treated with six cycles of bevacizumab 7.5 mg/kg (day 1), docetaxel 50 mg/m² (day 1), oxaliplatin 100 mg/m² (day 1), capecitabine 850 mg/m² b.i.d. (days 1–14), and trastuzumab 6 mg/kg (day 1) every three weeks, followed by maintenance with bevacizumab, capecitabine, and trastuzumab until disease progression. The primary objective was to demonstrate an improvement of progression-free survival (PFS) to >7.6 months (observed in the ToGA trial) determined according to the lower limit of the 95 % confidence interval (CI). Secondary endpoints were safety, objective response rate (ORR), and overall survival (OS). Results Twenty-five patients with HER2-positive tumors were treated with B-DOCT between March 2011 and September 2014. At a median follow-up of 17 months, median PFS was 10.8 months (95%CI: 9.0–NA), OS was 17.9 months (95%CI: 12.4–NA). One-year PFS and OS were 52 % and 79 %, respectively. The ORR was 74 % (95%CI: 52–90 %). Two patients became resectable during treatment with B-DOCT and achieved a pathological complete response. The most common treatment-related grade ≥ 3 adverse events were: neutropenia (16 %), diarrhoea (16 %), and hypertension (16 %). Conclusions B-DOCT is a safe and active combination in HER2-positive GC, supporting further investigations of DOC with HER2/vascular endothelial growth factor (VEGF) inhibition in HER2-positive GC.