Ablation plus immunotherapy in advanced NSCLC patients who develop oligo-residual disease after anti–PD-1/L1 therapy: Updated results from the BOOSTER trial.

8563 Background: Local consolidative therapy (LCT) has been demonstrated to augment the survival benefits of immunotherapy in non-small cell lung cancer (NSCLC) patients with oligo-residual disease (ORD) in the phase2 BOOSTER Trial (ChiCTR2000032479) as previously reported (2024 WCLC OA05.03; Signal Transduction and Targeted Therapy 2025). Here we report updated data with longer follow-up. Methods: This randomized, phase 2 trial enrolled patients with advanced NSCLC who developed oligo-residual disease after anti-PD-1/L1 therapy, defined as partial response or stable disease as the best response with residual tumors confined to a maximum of three organs and five lesions. Participants were randomly assigned (2:1) to receive ablation (thermal ablation or cryoablation) plus immunotherapy or immunotherapy maintenance alone. The primary endpoint was progression-free survival (PFS). The secondary endpoints were overall survival (OS), safety, patterns of disease progression and immunogenic changes after ablation. Results: Among 65 patients enrolled, the full analysis set finally included 42 patients in ablation plus immunotherapy group and 20 patients in immunotherapy maintenance group. In this updated data cutoff (December 2025) compared to the prior data cutoff (March 2024), median duration of follow-up has increased from 17.8 months to 28.9 months. Patients receiving ablation were associated with significantly longer PFS than those without ablation (median 28.1 vs. 12.8 months, p < 0.001, HR = 0.310, 95%CI 0.169–0.596). The median OS was not reached in either group. The 48-months OS rate were 79.0% (95% CI, 59.5–90.0) in ablation group and 67.6% (95% CI, 41.3–84.1) in the without ablation group. Updated subgroup analysis further suggested a trend of superior efficacy of cryoablation (n=13) compared with thermal ablation (n=29), with a median PFS of 37.6 versus 22.4 months, respectively (p=0.028). The safety profile of ablation combining with immunotherapy was similar to previously reported, and most of the adverse events were well managed. Conclusions: With extended follow up, the updated data suggested that the addition of local consolidative ablation confers durable clinical benefit in patients with advanced NSCLC who develop ORD after anti-PD-1/L1 therapy. Cryoablation was associated with potentially superior survival outcomes compared with thermal ablation. Clinical trial information: ChiCTR2000032479.