Data for the September 2021 submission to eLife. This is the source data for multivariate regression. Progression free survival outcome.Blood samples from 56 HNSCC patients were prospectively obtained within a Phase 2 clinical trial (NCT02633800), before and after the first treatment cycle of platinum-based chemotherapy, to identify biological covariates predictive of outcome.The baseline dataset contained 42 covariates (29 laboratory parameters at baseline, C1, and 13 clinical characteristics). The second, a combined predictive dataset, consists of 71 covariates, i.e. the 42 baseline covariates and a further 29 derived from the change in lab-based parameters between C1 and C2, measured by log fold change (LFC) of the variable of interest.Drug: 1 = patient was given Patritumab, 0 = drug was not givenAge: Patient age in years at baselineSex: 1 = Female, 0 = MaleSite: one-hot encoded site of primary cancerPrev.Cetux: Cetuximab given previouslyHPV.status: 1 = positiveHereg.status: 1 = positiveSmoking: 2 = Current, 1 = Ex smoker, 0 = Never smoked