A phase I study of tirapazamine in combination with radiation and weekly cisplatin in patients with locally advanced cervical cancer
5543 Background and Purpose: Hypoxia is an adverse prognostic factor in locoregionally advanced cervical cancer treated with radiation. GOG are currently studying the hypoxic cytotoxin, tirapazamine (TPZ) in combination with biweekly intermediate dose cisplatin (CIS) and radiation in a large phase III trial. The aim of this phase I study was to develop a better tolerated regimen that added TPZ to the standard regimen of radiation and weekly low dose CIS. Methods: Eligible patients had previously untreated carcinoma of the cervix, Stages IB2 - IVA. The starting schedule was radiotherapy (45 to 50.4 Gy external beam radiation followed by brachytherapy), with concomitant weekly CIS 40 mg/m2 weeks 1–6 and weekly TPZ 290 mg/m2 (prior to CIS) in weeks 1–5. Results: Between 3/05 and 7/06 eleven patients were enrolled, median age (range) 52 (31–65), squamous cell carcinoma 10, adenocarcinoma 1, 1B2–5, IIA-1, IIB-3, IIIB- 1, IVA-1. The first 2 patients on dose level 1 experienced a dose limiting toxicity (DLT), one grade 3 ALT (SGPT) elevation and grade 4 pulmonary embolism and one grade 3 ototoxicity. Doses were decreased to dose level -1 CIS 30 mg/m2 and TPZ 260 mg/m2. Three patients were treated without any DLTs. Six patients were then treated on dose level -1a, CIS 35 mg/m2 and TPZ 260 mg/m2, with 2 DLTs: grade 3 neutropenia with dose omission and grade 4 pulmonary embolism with major hemodynamic compromise. The sixth patient on dose level -1a withdrew from the trial in week 2 after being advised about the DLTs observed on this dose level. 3 additional patients will be accrued on dose level -1 to confirm safety of this dose level. One patient has relapsed in pelvic nodes, all other patients remain disease-free with a median followup of 10 months (range 5 - 21) Conclusions: The combination of weekly TPZ and CIS with radiation for locally advanced cervical cancer was associated with more toxicity than anticipated with the recommended dose level being TPZ 260 mg/m2, CIS 30 mg/m2. No significant financial relationships to disclose.