Phase II study of trastuzumab and cisplatin as first-line therapy in patients with HER2-positive advanced gastric or gastroesophageal junction cancer

HER2 over-expression and/or amplification are present in 9-38% of gastric or gastroesophageal junction (GEJ) cancers and are correlated to poor outcome. We conducted a multicentre phase II trial to evaluate trastuzumab in combination with cisplatin in patients with untreated HER2-positive advanced gastric or GEJ cancer. Chemo-na < ve patients with measurable, non-resectable, advanced or metastatic gastric or GEJ adenocarcinoma, with HER2 over-expression and/or amplification (IHC 3+, or IHC 2+ and FISH+), age a parts per thousand yen18 years, ECOG a parts per thousand currency sign2, left ventricle ejection fraction a parts per thousand yen50% and adequate organ function were eligible. Treatment consisted of trastuzumab (8 mg/kg on cycle 1 day 1 as loading; 6 mg/kg in subsequent cycles) and cisplatin (75 mg/m(2)), both intravenously on day 1, every 21 days. Twenty-two out of 228 patients (10%) were HER2-positive and were included in this phase II trial. The median age was 66 years and ECOG 0/1 was 41%/59%. The median number of cycles was 4 (range 1-41). The confirmed ORR was 32% and disease control was achieved in 64% of patients. Median time to progression was 5.1 months. Grade 3 adverse events included asthenia (27%), neutropenia (18%), anorexia (14%), diarrhoea (9%) and abdominal pain (9%). There were no grade 4 toxicities or treatment-related deaths. Higher baseline HER extracellular domain (ECD) levels were associated with better outcome in terms of response and survival. Trastuzumab in combination with cisplatin is an active regimen and has a favourable toxicity profile in advanced HER2-positive gastric or gastroesophageal cancers.