Efficacy of Immune Checkpoint Inhibitor Plus Chemotherapy in Patients With ROS1-Rearranged Advanced Lung Adenocarcinoma: A Multicenter, Retrospective Cohort Study

PURPOSE Immune checkpoint inhibitors (ICIs) exert robust antitumor activity in non–small-cell lung cancer (NSCLC) without actionable mutations. Apart from isolated case reports, the efficacy of PD-1 blockade in ROS1-rearranged NSCLC is currently unknown. METHODS This retrospective cohort study included 23 patients with ROS1-rearranged advanced lung adenocarcinoma who received ICI plus chemotherapy regardless of the treatment setting. ICI plus chemotherapy was received as a later-line regimen by 14 patients, as the first-line regimen by six patients, and after chemoradiotherapy by three patients. RESULTS All three patients who received chemoradiotherapy followed by ICI plus chemotherapy achieved partial response (PR) and had a progression-free survival (PFS) of >17.9 months. Of the six patients who received first-line ICI plus chemotherapy, five patients achieved PR and one had stable disease (SD), with a median PFS of 24.3 months (95% CI, 4.9 to 43.7). Of the 14 previously treated patients who received later-line ICI plus chemotherapy, the Objective Response Rate (ORR) was 28.6%, the Disease Control Rate (DCR) was 92.9%, and the median PFS was 5.8 months (95% CI, 0.2 to 9.4). The median time on ICI therapy was 10.0 months (95% CI, 1.5 to 32.5). The duration of response was 24.3 months (95% CI, 5.4 to 43.2) and 4.8 months (95% CI, 2.3 to 12.7) for first-line (n = 5) and subsequent-line (n = 4) ICI plus chemotherapy, respectively. Of the 10 patients with brain metastasis before receiving ICI plus chemotherapy, four patients achieved intracranial PR and five patients achieved intracranial SD, achieving an intracranial ORR of 40.0% and an intracranial DCR of 90.0%. Conclusion Our retrospective study provides real-world clinical evidence that ROS1-rearranged NSCLCs benefit from ICI plus chemotherapy in any treatment setting, including patients who present with brain metastasis.