Association between circulating tumor DNA (ctDNA) and recurrence-free survival (RFS) in patients (pts) with resected stage III melanoma: An exploratory analysis of SWOG S1404.

• DOI: 10.1200/jco.2024.42.16_suppl.9564
• Publication Date: 2024-07-03T20:08:42Z
• Authors: Michael Brian LaP...; David Marcano; Megan Othus; Allie Grossmann; Vasily N. Aushev; Bharat Sridhar; Derrick Renner; Himanshu Sethi; Minetta C. Liu; Ahmad A. Tarhini; John M. Kirkwood; Kenneth F. Grossmann; James Moon; Hongli Li; Sandeep H. Mashru; Nikhil I. Khushalani; Elad Sharon; Larissa A. Korde; Antoni Ribas; Sapna Pradyuman P...
• Keywords: Circulating tumor DNA; Exploratory analysis

9564 Background: Our exploratory study aimed to understand the association between presence of ctDNA after definitive surgical resection and RFS in pts with stage III melanoma treated adjuvant immunotherapy. Methods: This included 92 resected enrolled a phase 3 trial (NCT02506153) that evaluated efficacy pembrolizumab compared interferon alfa-2b or ipilimumab IIIA(N2a)-IV melanoma. Personalized, tumor-informed assays (Signatera) were run on banked plasma samples (median: 3.8 mL) collected at up 5 time points resection: pre-adjuvant treatment (pre-Tx), 1, 3, 6, 12 months Tx initiation recurrence. was measured from randomization (pre-Tx) first recurrence death. A case-control design used: 50% within 2 yrs alive without for > yrs. Conditional logistic regression pre-Tx groups. Results: Of pts, 10 did not pass quality control. analyzed total 245 82 pts. No significant differences demographics, including stage, number + lymph nodes, BRAF status, existed who ctDNA+ ctDNA- pre-Tx. 7 (70.0%) had disease 33 72 (45.8%) (p = 0.19). 2-yr 30% 54% (HR 1.75; 95% CI: 0.78, 3.94; p 0.18). yrs, all assessed. The other transiently cleared during Tx, turning back prior recur immunotherapy remained later points. All 39 Among 29 having timepoints available analysis near (end-of-Tx on-progression timepoints), 22 (75.9%) ctDNA+. Conclusions: In this study, incidence low, potentially related limited yield. However, positivity rate increased subsequent serial testing. might help identify early patients setting, but further studies larger cohorts accounting effect more uniform pre-analytic collection are needed.