ABSTRACT
BACKGROUND: Adavosertib (AZD1775) is an inhibitor of the Wee1 kinase. The authors conducted a phase 1b trial to evaluate the safety of adavosertib in combination with definitive chemoradiotherapy for patients with newly diagnosed, intermediate-risk/high-risk, locally advanced head and neck squamous cell carcinoma (HNSCC). METHODS: Twelve patients with intermediate-risk/high-risk HNSCC were enrolled, including those with p16-negative tumors of the oropharynx, p16-positive tumors of the oropharynx with ≥10 tobacco pack-years, and tumors of the larynx/hypopharynx regardless of p16 status. All patients were treated with an 8-week course of concurrent intensity-modulated radiotherapy at 70 grays (Gy) (2 Gy daily in weeks 1-7), cisplatin 30 mg/m2 weekly (in weeks 1-7), and adavosertib (twice daily on Monday, Tuesday, and Wednesday of weeks 1, 2, 4, 5, 7, and 8). The primary objective was to determine the maximum tolerated dose and the recommended phase 2 dose of adavosertib given concurrently with radiation and cisplatin. Secondary objectives were to determine the 12-week objective response rate and progression-free and overall survival. RESULTS: Three patients (25%) experienced a dose-limiting toxicity, including febrile neutropenia (n = 2) and grade 4 thromboembolism (n = 1). Two dose-limiting toxicities occurred with adavosertib at 150 mg. The median follow-up was 14.7 months. The 12-week posttreatment objective response rate determined by positron emission tomography/computed tomography was 100%. The 1-year progression-free and overall survival rates were both 90%. The maximum tolerated dose of adavosertib was 100 mg. CONCLUSIONS: Adavosertib 100 mg (twice daily on Monday, Tuesday, and Wednesday of weeks 1, 2, 4, 5, 7, and 8), in combination with 70 Gy of intensity-modulated radiotherapy and cisplatin 30 mg/m2 , is the recommended phase 2 dose for patients with HNSCC.