Phase II Study of the Effectiveness and Safety of Trastuzumab and Paclitaxel for Taxane- and Trastuzumab-naïve Patients with HER2-positive, Previously Treated, Advanced, or Recurrent Gastric Cancer (JFMC45-1102)

Paclitaxel is a standard second-line gastric cancer treatment in Japan. Trastuzumab could be active as second-line chemotherapy for taxane/trastuzumab-naïve patients with epidermal growth factor 2 (HER2)-positive advanced gastric cancer. Patients aged ≥20 years with HER2-positive, previously treated (except for trastuzumab and taxane), unresectable or recurrent gastric adenocarcinoma underwent combined trastuzumab (first and subsequent doses of 8 and 6 mg kg , respectively, every 3 weeks) and paclitaxel (days 1, 8, 15, every 4 weeks) treatment. Study endpoints were best overall response, progression-free survival, overall survival, and safety. From September 2011 to March 2012, 47 Japanese patients were enrolled. Forty patients discontinued treatment after a median of 128.5 (range 4-486) days. Complete and partial responses were obtained in one and 16 patients (response rate of 37% [95% CI 23-52]), respectively. Median progression-free survival and overall survival were 5.1 (95% CI 3.8-6.5) and 17.1 (95% CI 13.5-18.6) months, respectively. Grade 3/4 adverse events were neutropenia (32.6%), leukopenia (17.4%), anemia (15.2%) and hypoalbuminemia (8.7%). There was no clinically significant cardiotoxicity or cumulative toxicity. Three (disturbed consciousness, pulmonary fibrosis, and rapid disease progression) grade 5 events occurred. In conclusion, trastuzumab combined with paclitaxel was well tolerated and was a promising regimen for patients with HER2-positive, previously treated, advanced or recurrent gastric cancer.