A Phase I Clinical Trial of AZD1775 in Combination with Neoadjuvant Weekly Docetaxel and Cisplatin before Definitive Therapy in Head and Neck Squamous Cell Carcinoma

Purpose: The WEE1 tyrosine kinase regulates G(2)-M transition and maintains genomic stability, particularly in p53-deficient tumors which require DNA repair after genotoxic therapy. Thus, a need arises to exploit the role of WEE1 inhibition in head and neck squamous cell carcinoma (HNSCC) mostly driven by tumor-suppressor loss. This completed phase I clinical trial represents the first published clinical experience using the WEE1 inhibitor, AZD1775, with cisplatin and docetaxel. Patients and Methods: We implemented an open-label phase I clinical trial using a 3+3 dose-escalation design for patients with stage III/IVB HNSCC with borderline-resectable or -unresectable disease, but who were candidates for definitive chemoradiation. Escalating AZD1775 was administered orally twice a day over 2.5 days on the first week, then in combination with fixed cisplatin (25 mg/m(2)) and docetaxel (35 mg/m(2)) for 3 additional weeks. The primary outcome measure was adverse events to establish MTD. Secondary measures included response rates, pharmacokinetics (PK), pharmacodynamics, and genomic data. Results: The MTD for AZD1775 was established at 150 mg orally twice per day for 2.5 days. RECISTv1.1 responses were seen in 5 of 10 patients; histologic adjustment revealed three additional responders. The only drug-limiting toxicity was grade 3 diarrhea. The PK C8hr target of 240 nmol/L was achieved on day 4 at all three doses tested. Pharmacodynamic analysis revealed a reduction in pY15-Cdk, and increases in gamma H2AX, CC3, and RPA32/RPA2 were noted in responders versus nonresponders. Conclusions: The triplet combination of AZD1775, cisplatin, and docetaxel is safe and tolerable. Preliminary results show promising antitumor efficacy in advanced HNSCC, meriting further investigation at the recommended phase II dose. (C) 2018 AACR.