2113 - COPD, Pneumonia and Diabetes: Common Comorbidities Influence Pneumonitis Risk after ChemoRT and Adjuvant Durvalumab in Stage III Non Small Cell Lung Cancer

K. C. Ohaegbulam¹, C. Anderson², R. F. Thompson³, and T. Mitin³; ¹Department of Radiation Medicine, Oregon Health and Science University, Portland, OR, ²Portland VA Medical Center, Portlando, OR, ³Department of Radiation Medicine, Oregon Health & Science University, Portland, OR

Purpose/Objective(s): In the Phase III PACIFIC trial, patients with unresectable stage III NSCLC who had not progressed after ChemoRT received 12 months of durvalumab. Updated OS and PFS showed 42.9% survival at 5 years, favoring durvalumab. However, adverse events (AEs), notably pneumonitis, radiation pneumonitis, and pneumonia, led to discontinuation in 15.4% and 9.8% of durvalumab and placebo patients, respectively. Identifying prognostic factors for treatment-related pneumonitis is crucial. We aimed to explore these factors in patients receiving CRT followed by durvalumab.

Materials/

Methods: We conducted a retrospective cohort study using US Veterans Health Administration data with data extracted from 2017 through 2022. NSCLC patients receiving sequential or concurrent ChemoRT followed by Durvalumab were included. Pneumonitis diagnoses post-durvalumab initiation were identified via ICD codes. Pneumonitis severity was determined using CTCAE criteria. Covariate comorbidities were evaluated. Kaplan-Meier and Cox Proportional Hazards models were used for analysis.

Results: Among 1524 stage III NSCLC receiving CRT followed by durvalumab, 216 patients (14%) developed pneumonitis. Patients diagnosed with pneumonia within one year of NSCLC diagnosis had significantly higher pneumonitis incidence (p <.005). Treatment with antibiotics, particularly macrolides and/or tetracycline, also increased pneumonitis incidence significantly (p <.005). Furthermore, COPD severity was a significant risk factor for pneumonitis development (p = 0.04). In addition to pulmonary comorbidities, diabetes, notably uncontrolled (hemoglobin A1c > 8), tended to associate with higher rates of pneumonitis grades 1-2 (p=0.18) and grades 3-5 (p=0.19) upon multi-variable analysis (MVA).

Conclusion: Common comorbidities like COPD, pneumonia, and diabetes may significantly contribute to pneumonitis development in Stage III NSCLC patients receiving CRT followed by durvalumab. These findings emphasize the importance of medical education and therapeutic management of these ailments in this patient population to improve clinical outcomes and prognoses.