Publication Date:
2017-10-03
Description:
Purpose: Tumor mutational burden detected by tissue next-generation sequencing (NGS) correlates with checkpoint inhibitor response. However, tissue biopsy may be costly and invasive. We sought to investigate the association between hypermutated blood-derived circulating tumor DNA (ctDNA) and checkpoint inhibitor response. Experimental Design: We assessed 69 patients with diverse malignancies who received checkpoint inhibitor–based immunotherapy and blood-derived ctDNA NGS testing (54–70 genes). Rates of stable disease (SD) ≥6 months, partial and complete response (PR, CR), progression-free survival (PFS), and overall survival (OS) were assessed based on total and VUS alterations. Results: Statistically significant improvement in PFS was associated with high versus low alteration number in variants of unknown significance (VUS, 〉3 alterations versus VUS ≤3 alterations), SD ≥6 months/PR/CR 45% versus 15%, respectively; P = 0.014. Similar results were seen with high versus low total alteration number (characterized plus VUS, ≥6 vs. 〈6). Statistically significant OS improvement was also associated with high VUS alteration status. Two-month landmark analysis showed that responders versus nonresponders with VUS 〉3 had a median PFS of 23 versus 2.3 months ( P = 0.0004). Conclusions: Given the association of alteration number on liquid biopsy and checkpoint inhibitor–based immunotherapy outcomes, further investigation of hypermutated ctDNA as a predictive biomarker is warranted. Clin Cancer Res; 23(19); 5729–36. ©2017 AACR .
Print ISSN:
1078-0432
Electronic ISSN:
1557-3265
Topics:
Medicine
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