Prognostic impact of baseline tumour immune infiltrate on disease-free survival in patients with completely resected, BRAFv600 mutation-positive melanoma receiving adjuvant vemurafenib.

Background We conducted a retrospective exploratory analysis to evaluate the effects of baseline tumour immune infiltrate on disease-free survival (DFS) outcomes in patients with fully resected stage IIC–IIIC melanoma receiving adjuvant vemurafenib monotherapy or placebo in the BRIM8 study. Patients and methods BRIM8 was a phase III, international, double-blind, randomised, placebo-controlled study. Eligible patients with BRAFV600 mutation–positive, completely resected melanoma were randomly assigned to oral vemurafenib (960 mg twice daily) or matching placebo for 52 weeks. The primary end point was DFS. The association of CD8+ T-cell infiltration and programmed death ligand 1 (PD-L1) expression with DFS, as measured by immunohistochemistry, was explored retrospectively. Results Four hundred ninety-eight patients were randomly assigned to receive adjuvant vemurafenib (n = 250) or placebo (n = 248); tumour samples were available for biomarker analysis for approximately 60% of patients. In the pooled biomarker population, placebo-treated patients with Conclusions The presence of CD8+ T cells and PD-L1+IC are favourable prognostic factors for DFS. Treatment with adjuvant vemurafenib may overcome the poor DFS prognosis associated with low CD8+ T-cell count or PD-L1 expression. ClinicalTrials.gov identifier NCT01667419