Purpose: This study sought to determine the maximum tolerated dose (MTD) of oral etoposide in combination with radiotherapy in head and neck squamous cell carcinoma (HNSCC).
Patients and methods: Phase I, multicenter, open-labelled, non-comparative and dose escalating trial. Patients with locally advanced HNSCC were enrolled onto cohorts of escalating dose of etoposide. Oral etoposide was administered on five consecutive days every week for 7 weeks (7 treatment cycles) in combination with daily radiotherapy (70 Gy /35 fractions). Two dose levels (25 mg/day and 50 mg/day) of etoposide were planned and three to six patients were to be enrolled at each level according to the potential DLTs.
Results: Fourteen patients were allocated to two dose levels: 25 mg/day (3) and 50 mg/day (11). Cisplatin was contra-indicated in all the patients included. Only one patient (50 mg/day) presents a grade 4 neutropenia (DLT), no other DLTs were observed. The most frequently adverse events (AEs) were radiomucositis. Two deaths before 3 months of end of treatment were not related to treatment. Seven patients were still alive with a median follow-up of 30 months (12-58 months). Nine patients had a complete response (CR) at 3 months after the radiotherapy; Among the 9 patients, 3 patients had a local relapse; one patient with local and distant relapse.
Conclusion: Due to only one DLT experienced, it is possible to a dose of 50 mg/day for phase II studies, however this should be considered with caution.