START: S-1 plus docetaxel improved survival in subset of patients with advanced gastric cancer
2011 Gastrointestinal Cancers Symposium
SAN FRANCISCO — The combination of S-1 plus docetaxel failed to meet the primary endpoint of 25% improvement in OS for all patients with advanced gastric cancer in the START study, but patients who had non-measureable disease did see a significant improvement in OS and time to progression on the regimen.
“The combination of S-1 and docetaxel did not meet the primary endpoint of prolongation of OS,” said Yeul Hong Kim, MD, PhD, with the Korea University College of Medicine in Seoul, South Korea. “However, the use of second-line therapy was quite common in Japan and Korea, so we think this high percentage of use of second-line or third-line or even fourth-line therapy could impact on these results.”
Kim presented the results Thursday during the 2011 Gastrointestinal Cancers Symposium.
S-1 combined with cisplatin is a standard treatment for advanced gastric cancer in Japan, but because that regimen requires hospitalization, Kim and colleagues conducted START, a prospective, randomized phase 3 trial conducted in Japan and Korea, to determine if S-1 plus docetaxel could extend OS. The trial was designed to have 90% power to detect an improvement in OS from 300 to 400 days.
Patients in the study arm (n=314) were assigned to 40 mg/m2 IV docetaxel on day 1 along with twice daily 40 mg/m2 S-1 for 14 days followed by 7 days rest. Patients in the control arm (n=314) were assigned to 28 days of S-1 followed by 14 days rest.
At 2 years follow-up, Kim said median survival time was 390 days in the study group and 334 days in the control group (HR=0.88). However, time to progression was superior in the experimental group (160 days vs. 126) days and the difference was statistically significant (HR=0.74).
The response rate was 30.3% in the study arm and 18.4% in the control arm.
Additionally, a subset analysis showed that in patients with non-measurable disease, median survival time was 523 days for the S-1 plus docetaxel group compared with 335 days for the control group (P=.0018). Kim said time to progression was also significantly superior for the experimental arm in this subset of patients (P=.0045).
“This study demonstrates that docetaxel plus S-1 is an effective combination therapy for outpatient treatment of AGC and this is a quite promising, non-platinum containing regimen for the treatment of gastric cancer,” Kim said. – by Jason Harris
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Dr. Kim reported no relevant financial disclosures.
The statistically significant results of the SPIRITS trial make S-1 plus cisplatin the preferred regimen for most patients in East Asia. In patients with renal insufficiency or other contraindications to platinum, S-1 plus docetaxel seems to be a reasonable alternative. The difference in survival between measurable and non-measurable cohorts is interesting and merits further investigation in future trials, particularly for docetaxel.
– Peter C. Enzinger, MD
Clinical Director, the Gastrointestinal Cancer Center at Dana-Farber Cancer Institute
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