Paweletz CP, Heavey GA, Kuang Y, Durlacher E, Kheoh T, Chao RC, Spira AI, Leventakos K, Johnson ML, Ignatius Ou SH, Riely GJ, Anderes K, Yang W, Christensen JG, Jänne PA. Early Changes in Circulating Cell-Free KRAS G12C Predict Response to Adagrasib in KRAS Mutant Non-Small Cell Lung Cancer Patients.
Clin Cancer Res 2023;
29:3074-3080. [PMID:
37279096 PMCID:
PMC10527102 DOI:
10.1158/1078-0432.ccr-23-0795]
[Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/25/2023] [Accepted: 06/02/2023] [Indexed: 06/08/2023]
Abstract
PURPOSE
Non-invasive monitoring of circulating tumor DNA (ctDNA) has the potential to be a readily available measure for early prediction of clinical response. Here, we report on early ctDNA changes of KRAS G12C in a Phase 2 trial of adagrasib in patients with advanced, KRAS G12C-mutant lung cancer.
EXPERIMENTAL DESIGN
We performed serial droplet digital PCR (ddPCR) and plasma NGS on 60 KRAS G12C-mutant patients with lung cancer that participated in cohort A of the KRYSTAL-1 clinical trial. We analyzed the change in ctDNA at 2 specific intervals: Between cycles 1 and 2 and at cycle 4. Changes in ctDNA were compared with clinical and radiographic response.
RESULTS
We found that, in general, a maximal response in KRAS G12C ctDNA levels could be observed during the initial approximately 3-week treatment period, well before the first scan at approximately 6 weeks. 35 patients (89.7%) exhibited a decrease in KRAS G12C cfDNA >90% and 33 patients (84.6%) achieved complete clearance by cycle 2. Patients with complete ctDNA clearance at cycle 2 showed an improved objective response rate (ORR) compared with patients with incomplete ctDNA clearance (60.6% vs. 33.3%). Furthermore, complete ctDNA clearance at cycle 4 was associated with an improved overall survival (14.7 vs. 5.4 months) and progression-free survival (HR, 0.3).
CONCLUSIONS
These results support using early plasma response of KRAS G12C assessed at approximately 3 weeks to anticipate the likelihood of a favorable objective clinical response.
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