Response rates and survival to systemic therapy after immune checkpoint inhibitor failure in recurrent/metastatic head and neck squamous cell carcinoma

Objectives: Prior reports have demonstrated a potential enhancement in overall response rate (ORR) to chemotherapy after exposure to immunotherapy. The goal of this study was to evaluate the ORR and survival to chemotherapy and/or targeted therapy in head and neck squamous cell carcinoma (HNSCC) patients who progressed on immune checkpoint inhibitors (ICI). Materials and Methods: We retrospectively collected clinical and pathologic data from patients with recurrent/metastatic HNSCC who progressed on ICI and subsequently received chemotherapy or targeted therapy. ORR was assessed by RECIST version 1.1. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method. Results: A total of 43 patients met criteria for inclusion. The majority were male (91%) and former smokers (60%). Most patients received ICI as first-line (58.14%); the vast majority was platinum exposed (90.7%). The ORR to ICI was 21%. The ORR to systemic therapy before ICI was 47%, and the ORR after ICI failure was 42%. After progression on ICI, the median PFS and OS on the subsequent line of therapy were 4.2 and 8.4 months respectively. Conclusion: In our cohort of recurrent/metastatic HNSCC patients, the ORR and OS to systemic therapy after progression on ICI were higher than historical controls for second-line or beyond. Further investigations are warranted to better characterize optimal sequencing and combination strategies.