Background: Immune checkpoint inhibitor (ICI) therapy has significantly improved outcomes across a range of malignancies. While infections are a well-known contributor to morbidity and mortality amongst patients receiving systemic chemotherapy regimens, little is known about the impact of infections on patients receiving ICI therapy. This study aims to assess incidence, risk factors, and outcomes in patients who develop infections while on pembrolizumab-based therapies for non-small cell lung cancer (NSCLC). Methods: Patients receiving pembrolizumab for stage III/IV NSCLC from 1/1/2017-8/1/2021 across seven hospitals were identified. Incidence and type of infection were characterized. Covariates including baseline demographics, treatment information, treatment toxicities, and immunosuppressive use were collected and compared between infected and non-infected patients. Outcomes included the rate of infections, all-cause hospital admissions, median number of treatment cycles, overall survival (OS), and progression free survival (PFS). Univariable and multivariable analysis with reported odds ratio (OR) and 95% confidence intervals (CI) were utilized to evaluate infection risks. OS and PFS were analyzed by Kaplan–Meier analysis and tested by log-rank test. p-value < 0.05 was considered statistically significant. Results: There were 243 NSCLC patients that met the inclusion criteria. Of these, 111 (45.7%) had one documented infection, and 36 (14.8%) had two or more. Compared to non-infected patients, infected patients had significantly more all-cause Emergency Department (ED) [37 (33.3%) vs. 26 (19.7%), p = 0.016], hospital [87 (78.4%) vs. 53 (40.1%), p < 0.001], and ICU visits [26 (23.4%) vs. 5 (3.8%), p < 0.001], and had poorer median OS (11.53 [95% CI 6.4–16.7] vs. 21.03 [95% CI: 14.7–24.2] months, p = 0.033). On multivariable analysis, anti-infective therapy (OR 3.32, [95% CI: 1.26–8.76], p = 0.015) and ECOG of >1 (OR 5.79, [95% CI 1.72–19.47], p = 0.005) at ICI initiation conferred an increased risk for infections. At last evaluation, 74 (66.7%) infected and 70 (53.0%) non-infected patients died (p = 0.041). Conclusion: Infections occurred in nearly half of patients receiving pembrolizumab-based therapies for NSCLC. Infected patients had frequent hospitalizations, treatment delays, and poorer survival. ECOG status and anti-infective use at ICI initiation conferred a higher infection risk. Infection prevention and control strategies are needed to ameliorate the risk for infections in patients receiving ICIs.

4573 Background: Over the past decade, studies have shown the benefit of immune checkpoint inhibitors (IO) in patients with advanced urothelial cancer. These agents work by reconditioning the adaptive anti-cancer immune response within the tumor microenvironment. Immune-related adverse events have been well documented, but there is limited data evaluating infections in patients treated with IO. We performed a retrospective analysis to assess the incidence of infection and its effect on morbidity and mortality in patients treated with pembrolizumab for advanced urothelial cancer. Methods: Data was collected from a network of 7 hospitals for patients who received pembrolizumab for advanced urothelial cancer from 1/1/2017-8/1/2021. Date of last follow up was 12/1/2021. Covariates compared among infected and non-infected cohorts included age, gender, race, comorbidities, ECOG, anti-infective therapy at IO initiation, and line of therapy (1L, 2L, > 2L). Univariable analysis with reported odds ratio (OR) and 95% confidence interval (CI) was used to assess risk factors for infection. Outcome measures included all-cause emergency department (ED) visits, inpatient and intensive care unit (ICU) admissions, median number of IO cycles, and overall survival (OS). OS was evaluated using the Kaplan-Meier model. All analyses were deemed statistically significant if the p-value was < 0.05. Results: A total of 51 patients were identified. Of these, 34 (66.7%) had at least one documented infection and 17 (33.3%) had no reported infections. Baseline characteristics were similar across cohorts. Compared to non-infected patients, infected patients received fewer cycles of IO (median 4 vs 8, p = 0.016). At last follow-up, 20 (58.8%) patients in the infected cohort and 4 (23.5%) in the non-infected cohort died (p = 0.017). Median OS was 7.4 months (95% CI: 3.4-24.9) among patients with infection while not reached in those without infection (p = 0.014). ED visits (p = 1.00), inpatient admissions (p = 0.21), and ICU admissions (p = 0.17) did not significantly differ between cohorts. Univariable analysis did not identify significant risks among covariates. Conclusions: The incidence of infection in patients treated with pembrolizumab for advanced urothelial cancer is high and associated with fewer cycles of IO therapy and shorter OS. Further study of infectious process prevention is of value to maximize immunotherapy benefit.

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9043 Background: Older individuals with advanced/metastatic NSCLC have inferior outcomes compared to younger patients. Aside from baseline comorbidities and treatment-limiting toxicities, identifying factors that impact overall survival (OS) in this population is needed. The aim of this study is to assess characteristics impacting outcomes in patients ≥80 years with NSCLC using the NCDB. Methods: Adults ≥80 years with NSCLC, stage III/IV disease, diagnosed between 2015-2018, and available demographic data were included. Age, sex, race, insurance status, hospital subtype, Charelson-Deyvo comorbidity (CDCC) index, cancer stage (III/IV), geographic region in the United States (US), and histologic NSCLC subtypes were compared. Kaplan-Meier methodology assessed differences in median OS, and differences were compared using hazard ratios (HR) with 95% confidence intervals (CI). Pearson Chi-Squared test assessed the significance of covariates, and a p value < 0.05 was considered statistically significant. Results: There were 42,356 patients included. Median age was 83 (80-90) years, 20,422 were (48.2%) female, 35,653 (84.2%) were white, 37,738 (89.1%) had medicare coverage, 11,055 (26.1%) received treatment at an academic hospital, and 14,383 (33.9%) received care in the southern United States. Treatment at an academic hospital (HR: 0.91 [95% CI: 0.87, 0.95], p < 0.001), females (HR: 0.82 [95% CI 0.81, 0.84], p < 0.001), Medicaid (HR: 0.77 [95% CI: 0.65, 0.93], p = 0.005) vs no insurance, and adenocarcinoma (HR: 0.79 [95% CI: 0.74, 0.84], p < 0.001) or squamous cell carcinoma (HR: 0.84 [95% CI: 0.80, 0.90, p < 0.001] had better outcomes. Patients in the Northeastern (HR: 0.90 [95% CI: 0.87, 0.93], p < 0.001), Southern (HR: 0.92 [95% CI: 0.89, 0.94], p < 0.001), and Western (HR: 0.89 [95% CI: 0.88, 0.93], p < 0.001) US had better OS compared to the Midwest. Compared to whites, patients who were black (HR: 0.92 [95% CI: 0.88, 0.85], p < 0.001), Asian (HR: 0.77 [95% CI: 0.72, 0.82], p < 0.001), Hispanic (HR: 0.83 [95% CI: 0.78, 0.88], p < 0.001), or other (HR: 0.88 [95% CI: 0.79, 0.97) had better outcomes. Per year increase in age (HR 1.009 [95% CI: 1.006, 1.013], p < 0.001), patients with CDCC score of 1 (HR: 1.16 [95% CI: 1.14, 1.19], p < 0.001), 2 (HR: 1.22 [95% CI: 1.18, 1.27], p < 0.001), and ≥3 (HR: 1.33 [95% CI: 1.284, 1.380], p < 0.001) vs 0, and stage IV NSCLC (HR: 1.83 [95% CI: 1.79, 1.88], p = 0.000) had poorer survival. Conclusions: White race, males, uninsured status, receipt of treatment in the Midwest, community hospital treatment, large cell histology, advancing age, stage IV disease, and increasing CDCC score all had poorer outcomes in adults ≥80 years with advanced NSCLC. These factors should be taken into consideration when discussing the diagnosis, management, and expectations of the disease course with patients in the geriatric age group.

9042 Background: Treatment of advanced/metastatic NSCLC in older patients is hindered by performance status, comorbidities, and treatment toxicities. Moreover, whether multiagent chemotherapy in combination with immune checkpoint inhibitor (ICI) therapy outweighs a conservative approach is controversial. This study aims to assess treatment patterns and outcomes in patients ≥80 years with NSCLC through data provided by the national cancer database (NCDB). Methods: Adults ≥80 years with stage III/IV NSCLC, available treatment data, and diagnosis between 2015-2018 were included. Patients were stratified by therapy including none, ICI alone, chemotherapy alone, and chemotherapy+ICI; radiation and surgical management was also assessed. Median overall survival (OS) was evaluated by Kaplan-Meier survival methods, and differences were assessed by hazard ratios (HR) and 95% confidence intervals (CI). The mean difference in OS was compared between systemic therapy arms. Pearson Chi-Squared tests assessed the significance of treatment differences, with a p-value of < 0.05 considered statistically significant. Results: There were 42,356 patients included; 29,698 (70.1%) had stage IV disease and 26,314 (62.1%) had adenocarcinoma. A total of 3,248 (7.7%) received ICI, 11,505 (27.2%) received chemotherapy, 2,393 (5.6%) received chemotherapy+ICI, and 25,210 (59.5%) received no therapy. Median OS for no therapy, ICI, chemotherapy, and chemotherapy+ICI was 2.63 (95% CI: 2.57, 2.69), 10.68 (95% CI: 9.96, 11.39), 12.35 (95% CI: 11.98, 12.72), and 14.03 (95% CI: 13.87, 14.88) months, respectively. Compared to no therapy, ICI alone (HR: 0.377 [95% CI: 0.361, 0.393], p = 0.000), chemotherapy alone (HR: 0.439 [95% CI: 0.426, 0.452], p = 0.000), and chemotherapy+ICI (HR: 0.345 [95% CI 0.328, 0.363], p = 0.000) improved OS. Compared to ICI, chemotherapy and chemotherapy+ICI had a longer mean OS difference of 2.48 (95% CI 1.82, 3.13) (p < 0.001) and 1.9 (95% CI 1.01, 2.78 (p < 0.001) months, respectively. In chemotherapy alone, the median OS was 1.12 months (95% CI: 0.55, 1.70) (p < 0.001) longer with multiagent vs single agent. There was no difference between chemotherapy vs chemotherapy+ICI (0.57 months [95% CI: 0.16, 1.31], p = 0.234), or for ICI+single agent vs ICI+multiagent (0.67 months [95% CI -1.18, 2.54], p = 1.00). Treatment with radiation (HR: 0.664 [95% CI: 0.649, 0.679], p < 0.001), primary-sit(HR: 0.495 [95% CI: 0.465, 0.527], p < 0.001) and non-primary surgery (HR: 0.867 [95% CI: 0.811, 0.927], p < 0.001), and receipt of ICI vs no ICI (HR: 0.912 [95% CI 0.873, 0.954], p < 0.001) improved OS. Conclusions: Patients ≥80 years with NSCLC derived most benefit from multiagent chemotherapy or chemotherapy+ICI, with no OS difference between ICI+single or ICI+multiagent therapy. ICI alone and no therapy had inferior OS. Future trials to corroborate this finding would benefit the elderly population.