Phase 1/2 Study of the Aurora Kinase A Inhibitor Alisertib and Pembrolizumab in Refractory, Rb-Deficient Head and Neck Squamous Cell Carcinomas.

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.

Experimental design: 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 1) or with immunotherapy- and platinum-resistant, HPV-positive HNSCC (phase 2).

Results: The recommended phase 2 alisertib dose was 40 mg which had only the expected toxicity including cytopenia that led to dose reductions in two phase 2 patients at cycles 13 and 16. We saw no objective responses, but the combination led to prolonged stable disease (SD) in several patients, including 2 of 10 phase 1 patients (8 and 27 months). Eight of the 15 HPV-positive patients had SD; four of them (heavily pretreated) for ≥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-DR-expressing natural killer 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.