Neoadjuvant presurgical PD-1 inhibition in oral cavity squamous cell carcinoma.

Abstract

2574 Background: Oral cavity squamous cell carcinoma (OCSCC) is a highly prevalent surgically-treated subset of head and neck cancer with frequent recurrence and poor survival. Immunotherapy has demonstrated efficacy in recurrent/metastatic head and neck cancer, but has not been validated in the neoadjuvant presurgical setting. Methods: A Simon two stage design was used in this single-arm, Phase II clinical trial with a preplanned analysis after completion of stage one. The first stage included 9 patients with stage II-IVA OCSCC who received 3-4 biweekly doses of 3mg/kg Nivolumab (anti-programmed death 1 [PD-1]) followed by definitive surgical resection for cure. The primary endpoint was overall response rate to treatment. Secondary endpoints were safety and feasibility. Results: Presurgical Nivolumab therapy resulted in an overall response rate of 44% (95% CI: 14-79%) with four patients having >30% reduction in tumor size consistent with partial response. An additional patient had stable disease while the remaining four patients progressed through treatment. Neoadjuvant Nivolumab was not associated with delays in definitive surgical treatment. There were no grade 3-4 adverse events and no treatment interruptions. At median follow up of 10 months (2-16), there were 4 recurrences in 3 patients and one death. Objective response by RECIST 1.1 criteria on interval imaging predicated eventual pathologic response in 100% of patients. Conclusions: Neoadjuvant presurgical PD-1 blockade is associated with encouraging response rate and demonstrates feasibility and safety for OCSCC. Clinical trial information: NCT03021993.