Sequential Chemotherapy With Xelox Follows by TX to Treat Gastric Cancer

• objective tumor response rate [ Time Frame: 2 year ] [ Designated as safety issue: No ]
  Analysis for the objective response rate will be conducted on both the intention-to-treat (ITT) and evaluable data sets. Response will be assessed by Response Evaluation Criteria in Solid Tumor (RECIST 1.1).The analysis will be in descriptive statistics, presented by point estimate and 95% confidence interval for the efficacy variable (Objective tumor response rate)
  
  

• the progression-free survival, overall survival, toxicity profiles [ Time Frame: 2 year ] [ Designated as safety issue: Yes ]

  The progression-free survival is defined as the duration between the time from the date of randomization to the date of first observed progressive disease or death due to any cause. The overall survival is defined as the duration between the time from the date of randomization to the date of death due to any cause.

  Toxicity profiles: measure numbers of participants with adverse events. Treatment toxicity will be graded by NCI Common Toxicity Criteria Version 4.0 (CTC,v4.0) for safety evaluation.

  
  

Gastric cancer is one of the most frequent cancer types in Taiwan. Advanced gastric cancer is incurable. Although chemotherapy can improve survival and maintain quality of life for patients with advanced gastric cancer, optimal chemotherapy for this disease has not been defined.

Cytotoxic agents commonly used in this disease include platinum compounds, fluoropyrimidines and taxanes. A phase III (V325) study showed that adding docetaxel to cisplatin and 5-FU (TCF) improved response rates, progression-free survival (PFS), and overall survival (OS). Although the TCF regimen improved clinical outcomes, it was associated with substantial toxicity particularly that related to myelosuppression, with a 29% incidence of febrile neutropenia or neutropenic infection1. Several modifications to the TCF regimen have been made to maintain efficacy and reduce toxicity.

Cunningham et al. evaluated the impact of substituting oxaliplatin for cisplatin and capecitabine for 5-FU in the epirubicin, cisplatin, and 5-FU (ECF) regimen. Oxaliplatin as compared with cisplatin demonstrated comparable efficacy, with a lower incidence of myelosuppression, thromboembolic complications, and nephrotoxicity. The combination of docetaxel and oxaliplatin has been evaluated in gastric cancer with moderate activities in four phase II trials.

A different way of including all active agents in the first line treatment of advanced gastric cancer is to use them sequentially. Sequential schedules may maximize the dose-intensity of each single agent and avoid the overlapping toxicity caused by the concomitant administration of active drugs. Two studies using sequential strategy to treat advanced gastric cancer were reported.7-8 One used docetaxel after PELF regimen, the other used cisplatin plus 5-Fluorouracil / leucovorin (5-FU/LV) followed by irinotecan plus 5-FU/LV, followed by docetaxel plus 5-FU/LV. Both studies shown that sequential approach produced a good treatment efficacy with manageable toxicities in the management of advanced gastric cancer.

In our hospital, we had completed two phase II studies in advanced gastric cancer, including XELOX (capecitabine plus oxaliplatin) and a modified TCF regimen (docetaxel plus cisplatin and oral tegafur/uracil plus leucovorin). After analyzing these results, the median time to response, time to progression and overall survival were around 3, 6, and 10 months, respectively. Overall response rate was around 50% for each.

Based on the above considerations and our previous experiences, we hence initiate this phase II study to evaluate the feasibility and the anti-tumor activity of a new strategy consists of two sequential regimens involving XELOX and TX in unresectable gastric cancer.