Purpose: Promising results in a randomized phase II trial with the hypoxic cytotoxin tirapazamine (TPZ) combined with cisplatin (CIS) and radiation led to this phase III trial.
Patients and methods: Patients with previously untreated stage III or IV (excluding T1-2N1 and M1) squamous cell carcinoma of the oral cavity, oropharynx, hypopharynx, or larynx were randomly assigned to receive definitive radiotherapy (70 Gy in 7 weeks) concurrently with either CIS (100 mg/m(2)) on day 1 of weeks 1, 4, and 7 or CIS (75 mg/m(2)) plus TPZ (290 mg/m(2)/d) on day 1 of weeks 1, 4, and 7 and TPZ alone (160 mg/m(2)/d) on days 1, 3, and 5 of weeks 2 and 3 (TPZ/CIS). The primary end point was overall survival (OS). The planned sample size was 850, estimated to result in 334 deaths, which would provide 90% power to detect a difference in 2-year survival rates of 60% v 70% for CIS versus TPZ/CIS, respectively (hazard ratio = 0.69).
Results: Eight hundred sixty-one patients were accrued from 89 sites in 16 countries. In an intent-to-treat analysis, the 2-year OS rates were 65.7% for CIS and 66.2% for TPZ/CIS (TPZ/CIS--CIS: 95% CI, -5.9% to 6.9%). There were no significant differences in failure-free survival, time to locoregional failure, or quality of life as measured by Functional Assessment of Cancer Therapy-Head and Neck.
Conclusions: We found no evidence that the addition of TPZ to chemoradiotherapy, in patients with advanced head and neck cancer not selected for the presence of hypoxia, improves OS.