A two-arm randomized open-label prospective design superiority phase III clinical trial to compare the efficacy of docetaxel-oxaliplatin-capecitabine/5 fluorouracil (DOC/F) followed by docetaxel versus CAPOX/mFOLFOX-7 in advanced gastric cancers (DOC-GC study).

Abstract

LBA248 Background: The choice of optimal chemotherapy in advanced (unresectable/metastatic) gastroesophageal junction and gastric (GEJ/G) adenocarcinomas remains undecided with regard to the addition of docetaxel to a FOLFOX/CAPOX backbone in improving outcomes with equipoise with regard to the optimal duration of chemotherapy as well. Methods: The DOC GC study is a multicentric open-label, randomized controlled phase III trial, in adults ≥18 years with advanced GEJ/G adenocarcinoma and adequate end-organ function. Patients were randomized 1:1 to one of two arms: Arm A - modified CAPOX (3 weekly) or modified FOLFOX-7 (2 weekly) for a maximum of 6 months and then observation OR Arm B: modified FLOT (5-FU/leucovorin /Oxaliplatin/Docetaxel) or DOX (docetaxel/oxaliplatin/capecitabine) every 2 weeks for a maximum of four months followed by Docetaxel (60mg/m2) every 3 weeks till disease progression, unacceptable toxicity, or patient's decision to withdraw. The primary endpoint of the study is Overall survival (OS), as calculated by Kaplan-Meier method, while key secondary endpoints include Progression-free survival, and adverse event rates. Results: Of the 324 patients randomized between July 2020 and November 2022, 305 patients were evaluable for analysis (Arm A: 156; Arm B: 149). With a median follow-up time of 19.2 months (95% CI: 16.5 – 21.9) for the entire cohort, the median OS was 10.1 months (95%: 9.2-10.9) in Arm A and 8.9 months (95% CI: 7.3-10.5) in arm B and this difference was not statistically significant [p=0.70]. There were no statistical differences in median PFS between the two arms [Arm A: 7.1 months (95% CI: 6.1-8.1); Arm B: 6.2 months (95% CI: 5.7 – 6.8); p=0.39]. An increased proportion of grade 3/4 neutropenia (21% vs. 5.1%; p<0.001) was seen in patients in Arm B, with other treatment related side effects being comparable between the two arms. A greater proportion of patients in Arm A tended to receive second line therapy compared to Arm B (38% vs. 26%; p=0.07). Conclusions: The addition of docetaxel to a doublet regimen comprising 5-fluorouracil/capecitabine and oxaliplatin did not improve overall survival in patients with advanced GEJ/G cancers. Continuing chemotherapy beyond six months also does not appear to improve survival in this group of cancers. Clinical trial information: CTRI/2020/03/023944 .