BRAF and melanoma: ,107,108 In the CAcTUS clinical trial, a BRAF V600 ddPCR assay was used to guide a switch from targeted to immune therapy when ctDNA VAF had fallen by ≥80% to provide preliminary data on whether response to an initial run-in of mitogen-activated protein kinase-targeted treatment resulted in improved outcomes for patients with advanced melanoma; final results are awaited.109