We have previously conducted phase II studies to evaluate the effect of adding docetaxel to base treatment with S-1 plus cisplatin (DCS) to further improve the therapeutic response; both a very high response rate (87.1%) and a promising median survival time (687 days) in patients with unresectable advanced gastric cancer were noted (Y. Sato et al. Cancer Chemother Pharmacol. 2009); however, it also showed a high incidence of grade 3/4 toxicity. With the aim of reducing toxicities, we conducted a phase II study of modified DCS (mDCS), using a reduced dose of docetaxel, and evaluated the clinical efficacy and adverse events of this regimen.
Patients with unresectable gastric cancer received chemotherapy with S-1 (40 mg/m2 b.i.d) on days 1–14, and docetaxel (50 mg/m2) plus cisplatin (60 mg/m2) on day 8 every 3 weeks. The primary endpoint was the response rate (RR). Overall (OS) and progression-free survival (PFS), and toxicities were also evaluated.
Forty-nine patients were enrolled from November 2011 to April 2014, and 47 were eligible. The overall RR was 78.8%, including two cases of a complete response (4.3%), and 35 cases of a partial response (74.5%). Ten cases had stable disease (21.3%) but none showed progressive disease. Of the 47 cases, 16 cases (34.0%) underwent curative conversion surgery. The median PFS was 350 days (95% CI; 238–406 days) and median OS was 561 days (95% CI; 401–783 days). Grade 3/4 neutropenia developed in 76.6%, and febrile neutropenia in 31.9%, of patients. Non-hematological grade 3/4 adverse events were anorexia (23.4%), nausea (4.3%), and diarrhea (8.5%).
mDCS therapy showed high clinical efficacy and fewer toxicities, but careful management of these is still essential.
Clinical trial identification
Legal entity responsible for the study
Tokushima-Hokkaido cancer therapy clinical trial group, Tetsuji Takayama
All authors have declared no conflicts of interest.