Comparison of characteristics and outcomes among veterans receiving first-line immunotherapy versus chemotherapy for stage IV non-small cell lung cancer

e19295 Background: Immunotherapy (IO) has revolutionized the treatment paradigm for patients with advanced non-small cell lung cancer (NSCLC). Study objectives were to evaluate utilization of IO as first-line (1L) therapy and compare clinical characteristics between patients receiving IO and those receiving CT in 1L setting. Methods: Using the U.S. Department of Veterans Affairs corporate data warehouse, patients with stage IV NSCLC diagnosed 2012-2017 and initiated non-targeted systemic therapy within 120 days of diagnosis were selected. Unadjusted descriptive statistics were used to compare patient characteristics, inpatient and outpatient clinic visits, and prevalence of select adverse events (AE) between patients receiving IO monotherapy and CT. Kaplan-Meier and Cox regression approaches with and without propensity score matching (PSM) were used for overall survival (OS) analyses. OS was calculated from treatment initiation date to death or end of study period in June 2019. Results: 4609 patients were included in the analysis: 3.4% (n = 156) received IO monotherapy, 96% (n = 4426) received CT, and 0.6% (n = 27) received IO+CT (IO+CT not included in analysis). IO patients were older than CT patients (median age 69 vs. 66 years, p < 0.0001) and more frequently resided in the Midwest and West regions whereas CT patients were more likely to live in the Northeast and South (p = 0.0024). There were no significant differences in IO and CT by other demographic and clinical characteristics. Estimated median OS was 7.5 months (95% CI 7.2-7.7) for CT and 7.9 months (95% CI 5.3-12.6) for IO patients. The unadjusted HR for IO compared to CT patients was 0.81 (95% CI 0.67-0.98). With 1:4 PSM (144 and 559 patients matched in the IO and CT groups, respectively), the HR was 0.75 (95% CI 0.60-0.93). The mean number of outpatient visits for IO and CT patients were 47 and 36, respectively (p = 0.003). No difference in number of hospitalizations or length of hospital stays between the two groups was observed. Common AEs in the IO group were dyspnea (58%), colitis/enterocolitis (42%), and anemia (30%). Common AEs among CT patients were colitis/enterocolitis (36%), anemia (32%), and nausea/vomiting (31%). Conclusions: In a real-world 1L setting among veterans with NSCLC, improvement in OS was observed among patients receiving IO monotherapy compared to those receiving CT, and IO patients had a greater number of outpatient visits. Continued assessment of treatment patterns and impact of IO are needed as the use of IO continues to expand.