Abstract LB120: Driver-specific MRD strategy associated with pathological response and predicted recurrence in stage III driver-mutant NSCLC receiving neoadjuvant treatment

Background: Postoperative driver gene-specific circulating tumor DNA (ctDNA) monitoring stratifies recurrence risk in resectable stage III driver-mutant NSCLC (NCT06443684). Whether driver-specific ctDNA MRD can evaluate neoadjuvant response and predict recurrence in stage III driver-mutant NSCLC remains to be defined. Methods: From 2022 to 2025, 203 resectable stage III NSCLC patients with tissue-confirmed driver mutations were prospectively enrolled at 14 centers in China (NCT06443684). Peripheral blood was collected before neoadjuvant therapy, preoperatively, 3 days and 1 month after surgery, and every 3 months until investigator-confirmed recurrence. ctDNA was analyzed using a 10-gene driver panel (LC10). This analysis focused on peri-neoadjuvant ctDNA dynamics and clinical outcomes among 82 patients who received neoadjuvant therapy followed by surgery. Results: Among the 82 neoadjuvant-treated patients, regimens included chemo-immunotherapy (57.3%), TKI (3rd-EGFR TKI/2nd or 3rd-ALK TKI, 39.0%), and chemotherapy alone (3.7%). Post-neoadjuvant ctDNA positivity was associated with a significantly lower MPR rate versus ctDNA negativity (0% vs 42.3%, p=0.004), whereas baseline ctDNA status was not associated with MPR (16.7% vs 21.2%). Post-neoadjuvant ctDNA molecular residual level (hGE/mL) positively correlated with residual viable tumor cells (R=0.332, p=0.009). Post-neoadjuvant ctDNA-positive patients had significantly shorter event-free survival (median EFS 11.4 vs 23.8 months; HR=8.82; p=0.009). For non-MPR patients, post-neoadjuvant negative ctDNA status also indicated favorable prognosis (median EFS 23.8 vs 4.7 months; HR=5.80; p=0.054). Compared with other regimens, neoadjuvant TKI was associated with a lower post-treatment ctDNA residual rate (0% vs 15.3%; p=0.05). Patients with persistent ctDNA positivity (baseline→post-neoadjuvant) had the shortest EFS (median 4.7 months), followed by negative→positive (23.8 months), while positive to negative and persistent negative ctDNA indicated disease free status(log-rank p<0.001). Conclusions: A driver-specific ctDNA MRD strategy provides a practical tool for neoadjuvant efficacy assessment and postoperative recurrence risk stratification for stage III driver-mutant NSCLC patients. Citation Format: Jian Hu, Xiao Teng, Ziming Li, Yu Qi, Feng Li, Qixun Chen, Changbin Zhu, Xing Li, Shun Lu. Driver-specific MRD strategy associated with pathological response and predicted recurrence in stage III driver-mutant NSCLC receiving neoadjuvant treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(8_Suppl):Abstract nr LB120.