Multicenter phase II study of trastuzumab with S-1 plus oxaliplatin for chemotherapy-naïve, HER2-positive advanced gastric cancer

Gastric Cancer. 2019 Nov;22(6):1238-1246. doi: 10.1007/s10120-019-00973-5. Epub 2019 May 17.

Abstract

Background: Trastuzumab with cisplatin and fluoropyrimidines improves overall survival (OS) in patients with HER2-positive advanced gastric cancer (AGC). S-1 plus oxaliplatin (SOX) is one of the standard regimens for HER2-negative AGC in Japan. However, few studies have evaluated trastuzumab combined with SOX in patients with HER2-positive AGC.

Methods: This was a multicenter, phase II study conducted at 10 institutions in Japan. Patients with HER2-positive AGC received S-1 twice a day on days 1-14 and oxaliplatin and trastuzumab on day 1 of a 21-day cycle. The primary endpoint was the confirmed overall response rate (ORR), and the secondary endpoints were OS, progression-free survival (PFS), and safety. The sample size was 75 to have 90% power with an alpha error of 0.1 (one-sided), expecting an ORR of 65% and threshold of 50%.

Results: From June 2015 to January 2018, 75 patients were enrolled. The ORR was 70.7% [95% confidence interval (CI) 59.0-80.6]. The median OS and PFS were estimated as 18.1 months (95% CI 15.6-26.5) and 8.8 months (95% CI 7.4-12.2), respectively. The major grade 3 or 4 adverse events were sensory neuropathy (16.0%) and neutropenia (10.7%).

Conclusions: Trastuzumab with SOX had promising activity with well-tolerated toxicities for patients with HER2-positive AGC.

Clinical trial registration: UMIN000017602.

Keywords: Advanced gastric cancer; HER2-positive; Oxaliplatin; S-1; Trastuzumab.

Publication types

  • Clinical Trial, Phase II
  • Multicenter Study

MeSH terms

  • Adult
  • Aged
  • Antineoplastic Combined Chemotherapy Protocols / administration & dosage*
  • Antineoplastic Combined Chemotherapy Protocols / adverse effects
  • Drug Combinations
  • Female
  • Humans
  • Japan
  • Male
  • Middle Aged
  • Oxaliplatin / administration & dosage
  • Oxonic Acid / administration & dosage
  • Progression-Free Survival
  • Prospective Studies
  • Receptor, ErbB-2 / metabolism
  • Stomach Neoplasms / drug therapy*
  • Stomach Neoplasms / pathology
  • Survival Rate
  • Tegafur / administration & dosage
  • Trastuzumab / administration & dosage
  • Treatment Outcome
  • Young Adult

Substances

  • Drug Combinations
  • Oxaliplatin
  • S 1 (combination)
  • Tegafur
  • Oxonic Acid
  • ERBB2 protein, human
  • Receptor, ErbB-2
  • Trastuzumab