Longitudinal Monitoring of ctDNA in Patients with Melanoma and Brain Metastases Treated with Immune Checkpoint Inhibitors

Abstract

Purpose: Brain involvement occurs in the majority of patients with metastatic melanoma. The potential of circulating tumor DNA (ctDNA) for surveillance and monitoring systemic therapy response in patients with melanoma brain metastases merits investigation. Experimental Design: This study examined circulating BRAF, NRAS, and c-KIT mutations in patients with melanoma with active brain metastases receiving PD-1 inhibitor–based therapy. Intracranial and extracranial disease volumes were measured using the sum of product of diameters, and response assessment performed using RECIST. Longitudinal plasma samples were analyzed for ctDNA over the first 12 weeks of treatment (threshold 2.5 copies/mL p..