149P POSITION: Characterising risk factors and outcomes in patients (pts) with stage III unresectable non-small cell lung cancer (uNSCLC) who fail to complete concurrent chemoradiotherapy (cCRT) or progress during or shortly after cCRT

PACIFIC established consolidation durvalumab as standard of care for pts with Stage III uNSCLC and no progression after complete cCRT. POSITION aims to identify factors associated with failure to complete cCRT and progression during or shortly after cCRT. A retrospective cohort study was conducted using a US-based real-world dataset (Tempus). Eligible pts had Stage III uNSCLC diagnosed from 2010 to 2021 and received cCRT without durvalumab. Pts had incomplete cCRT (Group A), progressed during/within 42 days of complete cCRT (Group B) or completed cCRT without progression (Group C). Descriptive statistics were applied to pt characteristics/disposition. Median overall survival (mOS) was estimated by Kaplan-Meier analysis. Multivariable logistic regression was used to identify factors associated with incomplete cCRT and progression during or shortly after cCRT. Overall, 2076 pts comprised Groups A (n=477; 23.0%), B (n=264; 12.7%), and C (n=1335; 64.3%). Median age was 65 yrs (range, 34-86) and 55.2% were male. Higher proportions of Group A and B (vs Group C) had ECOG PS ≥2 (21.2%, 20.0%, vs 16.1%), Stage III B/C NSCLC at diagnosis (43.5%, 48.9%, vs 39.7%), and Charlson Comorbidity Index (CCI) ≥1 (40.0%, 32.6%, vs 31.8%). From CRT initiation, mOS (95% CI) was 21.6 mo (17.2, 28.0) for Group A, 10.1 mo (7.2, 12.5) for Group B, and 32.4 mo (29.8, 34.6) for Group C. Black race (odds ratio [OR]: 1.67 [95% CI: 1.22, 2.28]) and higher CCI (CCI=1 OR: 1.39 [95% CI: 1.05, 1.83]; CCI≥2 OR: 1.57 [95% CI: 1.11, 2.19]) were associated with higher risks of incomplete cCRT. Among pts who completed cCRT, Stage III B/C NSCLC at diagnosis (OR: 1.63 [95% CI: 1.20, 2.23]) and cerebrovascular (OR: 2.49 [95% CI: 1.06, 5.49]) or renal (OR: 3.50 [95% CI: 1.32, 8.81]) comorbidities were associated with progression during or shortly after cCRT. Per these analyses, pts who do not complete and/or progress during or shortly after cCRT (Groups A and B) appear frailer (vs Group C), with poor PS and high comorbidity burden. Pts with incomplete cCRT (Group A) are also more likely to be Black. Clinical trials focusing on these pts are warranted.