Treatment with PD-(L)1 blockade can produce remarkably durable responses in non-small cell lung cancer (NSCLC) patients. However, a significant fraction of long-term responders ultimately progress and predictors of late progression are unknown. We hypothesized that circulating tumor DNA (ctDNA) analysis of long-term responders to PD-(L)1 blockade may differentiate those who will achieve ongoing benefit from those at risk of eventual progression.In patients with advanced NSCLC achieving long-term benefit from PD-(L)1 blockade (PFS=12 months), plasma was collected at a surveillance timepoint late during/after treatment to interrogate ctDNA by Cancer Personalized Profiling by Deep Sequencing (CAPP-Seq). Tumor tissue was available for 24 patients and was profiled by whole-exome sequencing (n=18) or by targeted sequencing (n=6).31 NSCLC patients with long-term benefit to PD-(L)1 blockade were identified and ctDNA was analyzed in surveillance blood samples collected at a median of 26.7 months after initiation of therapy. Nine patients also had baseline plasma samples available, and all had detectable ctDNA prior to therapy initiation. At the surveillance timepoint, 27 patients had undetectable ctDNA and 25 (93%) have remained progression-free; by contrast, all four patients with detectable ctDNA eventually progressed (Fisher's p<0.0001; PPV 1 [95% CI 0.51-1]; NPV 0.93 [95% CI 0.80-0.99]).ctDNA analysis can noninvasively identify minimal residual disease in patients with long-term responses to PD-(L)1 and predict the risk of eventual progression. If validated, ctDNA surveillance may facilitate personalization of the duration of immune checkpoint blockade and enable early intervention in patients at high risk for progression.
View details for DOI 10.1158/1078-0432.CCR-19-3418
View details for PubMedID 32046999