Trial Combining Pembrolizumab and Cesium 131 Brachytherapy With Salvage Surgery in HNSCC

This study is a non-randomized, single-arm, multi-institutional phase 1b/II study

including patients with locally recurrent head and neck cancer eligible for resection.

Patients who are identified to be eligible for surgical resection will be screened and

consented to receive one 200mg IV dose of pembrolizumab followed by salvage surgery. At

the time of surgery, they will have Cesium131 seeds implanted. Two to six weeks after

surgery, subjects will be started on 200 mg IV of pembrolizumab to be continued every 3

weeks for 6 months. The phase 1b part will enroll 3 patients for a safety run-in,

followed by the phase 2 part if no DLTs are seen in these 3 patients. Phase 2 will be

used to estimate the 2-year DFS in comparison to a benchmark selected based on a

historical control. For correlative studies, archived tissue and surgical specimen will

be evaluated by H&E and IHC for immune phenotype. Blood samples will also be collected as

shown in schema above for correlative studies (blood will be collected for correlatives

and biomarkers before and after the first of pembrolizumab, before starting adjuvant

pembrolizumab and at completion of 6 month course of adjuvant pembrolizumab). Patients

will be followed approximately every 3 weeks during treatment for the first 6 months,

then monthly for 3 months following treatment and then every 3 months thereafter for 24

months for disease free survival (DFS) and overall survival (OS).