Phase I/II Study of the Aurora Kinase A Inhibitor Alisertib and Pembrolizumab in Refractory, Rb-Deficient Head and Neck Squamous Cell Carcinomas

Abstract Purpose: Effective therapy for recurrent head and neck squamous cell carcinoma (HNSCC) that is refractory to chemotherapy and immunotherapy is a considerable need. Aurora kinase A inhibition leads to apoptosis and immunogenic cell death in preclinical models of human papilloma virus (HPV)–driven cancers. Patients and Methods: Alisertib was administered orally twice daily on days 1–7 and pembrolizumab on day 1 of a 21-day cycle to adults with advanced solid tumors (phase I) or with immunotherapy- and platinum-resistant, HPV-positive HNSCC (phase II). Results: The recommended phase II alisertib dose was 40 mg, which had only the expected toxicity including cytopenia that led to dose reductions in two phase II patients at cycles 13 and 16. We saw no objective responses, but the combination led to prolonged stable disease (SD) in several patients, including two of 10 phase I patients (8 and 27 months). Eight of the 15 HPV-positive patients had SD, of which four (heavily pretreated) had ≥6 months, with median overall and progression-free survival durations of 16.8 and 1.4 months, respectively. In circulating immune cells and plasma, patients with SD had markedly higher levels of HLA de novo resistance–expressing NK cells than did progressive disease patients who demonstrated a more immunosuppressive and inflammatory profile. Pharmacokinetics did not indicate any significant drug-drug interactions between pembrolizumab and alisertib. Conclusions: The combination of alisertib and pembrolizumab was well tolerated and led to prolonged SD in some immunotherapy-resistant patients, supporting our hypothesis that Aurora kinase A inhibition can reverse immunotherapy resistance of retinoblastoma protein–deficient HNSCC.