Docetaxel and nedaplatin twice a week with concurrent definitive radiotherapy in inoperable esophageal squamous cell carcinoma: A phase I trial (GASTO-1021).

Purpose: This phase I trial aimed to determine the maximal tolerated dose (MTD) of incorporating a twice-weekly docetaxel and nedaplatin regimen into definitive concurrent chemoradiotherapy (CCRT) as radiosensitizers in patients with inoperable esophageal squamous cell carcinoma (ESCC).

Methods: The CCRT regimen included docetaxel (5 mg/m, 10 mg/m, or 15 mg/m) and nedaplatin (5 mg/m, 10 mg/m, or 15 mg/m) twice-weekly based on the traditional 3 + 3 dose escalation strategy, and radiotherapy (64 Gy in 32 fractions). The primary goals were to determine the MTD of concurrent chemotherapy and the dose limiting toxicities (DLTs). In-field objective response rate (ORR) was investigated.

Results: Fifteen patients had been recruited and analyzed. DLT involving persistent grade 3 esophagitis over 1 week was observed in all three patients (3/3) at dose level 3 (15 mg/m), and two patients (2/6) experienced DLTs in the dose level 2 (10 mg/m) due to esophageal fistula and persistent grade 3 esophagitis over 1 week, while one patient (1/6) treated at dose level 1 (5 mg/m) exhibited DLT owing to Grade 3 increased liver enzymes, suggesting a MTD of 5 mg/m. The in-filed ORR was both 100% in all patients and those receiving MTD. The 1-year loco-regional recurrence-free survival rate was 83.3%, 83.3% and 66.7% in dose level 1, 2, and 3, respectively.

Conclusions: The MTD of twice-weekly docetaxel and nedaplatin regimen was 5 mg/m in inoperable ESCC patients treated with definitive CCRT. Low dose concurrent docetaxel and nedaplatin showed promising radiosensitizing effect on in-filed disease control and good tolerability.