5-Fluorouracil Response and Optimization STudy (The FROST Trial)

This randomized phase II trial will characterize the efficacy, adverse event (AE) profile, and safety of two regimens of 5-FU given as 2L+ treatment to patients with RM-HNSCC. Eligible patients for this trial will have previously received platinum and PD-1 inhibitor therapy. The experimental regimen (Arm 1) will comprise the two days every two weeks (2D-Q2W) regimen of 5-FU. The standard regimen (Arm 2) will consist of the four days every three weeks (4D-Q3W) regimen of 5-FU. The primary hypotheses is that each regimen of 5-FU will result in an ORR of 10% of greater assessed by RECIST v1.1 criteria. The study will also describe treatment-related AEs assessed by CTCAE v5.0, dose interruptions, discontinuations, and modifications in each regimen.