For a study, researchers sought to understand that Dostarlimab, a PD-1 inhibitor, showed anticancer efficacy in 67 patients with recurrent/advanced NSCLC in a Phase I trial, with an irORR of 26.9% (2 complete responses) across all PD-L1 status subgroups. With 11.9% of patients reporting Grade ≥3 TRAEs, Dostarlimab’s had an acceptable safety profile. In the ongoing Phase I, multi-center, open-label, two different (dose escalation and cohort expansion) GARNET research, dostarlimab, an anti-programmed cell death protein-1 antibody, was being studied in recurrent/advanced solid malignancies, including non-small cell lung cancer (NSCLC) (NCT02715284). An interim analysis of individuals with recurrent/advanced NSCLC who progressed after platinum-based treatment was presented here. For more than two years, patients were given dostarlimab (500 mg IV every three weeks [Q3W] for Cycles 1–4, then 1000 mg Q6W) until disease progression or unacceptable toxicity. The primary objectives were the immune-related objective response rate (irORR) per investigator-assessed irRECIST and safety. As of July 8, 2019, 67 patients with recurrent/advanced NSCLC had been enrolled and treated with dostarlimab; the majority had a PD-L1 tumor proportion score (TPS) of less than 1% (35.8% of patients) or PD-L1 TPS 1–49% (29.9% of patients); 7.5% had a PD-L1 TPS of more than or equal to 50%, and 26.9% had unknown PD-L1 TPS status. Between visits, the median time was 13.8 months (0.0–22.6). The irORR was 26.9%, with two complete and 16 partial responses. The average response time was 11.6 months (2.8–19.4). About 2/24 (16.7%) patients with PD-L1 TPS of less than 1%, 4/20 (20.0%) patients with PD-L1 TPS 1–49%, and 2/5 (40.0%) patients with PD-L1 TPS of more than or equal to 50% showed responses. The most prevalent Grade of more than or equal to 3 treatment-related treatment-emergent adverse events (TRAE) was fatigue (4.5%). In 28.4% of patients, immune-related TRAEs (of any grade) were found. Dostarlimab showed promising anticancer activity in advanced/recurrent NSCLC that progressed after platinum-based chemotherapy and across all PD-L1 subgroups and had a good safety profile.