Purpose: The aims of this dose-escalating phase I study were to determine the maximum tolerable dose (MTD) and recommended dose (RD) of 5-fluorouracil (5-FU), docetaxel, and nedaplatin (UDON) combination therapy for future phase II studies, and to evaluate the safety and efficacy of this regimen in patients with untreated recurrent or metastatic esophageal cancer.
Methods: Patients were administered 5-FU on days 1-5, docetaxel on days 1 and 15, and nedaplatin on day 1 at 4-week intervals. The dose levels of 5-FU/docetaxel/nedaplatin were escalated as follows (mg/m(2)): level 1, 800/30/80; level 2, 800/30/90; and level 3, 800/35/90. Toxicity was evaluated using Common Terminology Criteria for Adverse Events version 4.0.
Results: Overall, nine patients were enrolled in this study. All patients had an Eastern Cooperative Oncology Group performance status of 0 or 1 and were diagnosed with squamous cell carcinoma. No dose-limiting toxicity was observed at any level, and planned dose escalation was completed without reaching the MTD. No grade 4 or higher toxicity was observed in this study. The observed grade 3 hematological toxicities included neutropenia in five patients (55.6 %) and leukopenia in three patients (33.3 %). None of the patients developed febrile neutropenia, and no grade 3 or 4 non-hematological toxicities were observed. The overall response rate was 77.8 %, including two complete responses, and the disease control rate was 100 %.
Conclusion: The RD of UDON was identified as level 3. The good tolerability and high antitumor efficacy of this regimen warrant further evaluation in this setting.