Background: IMpower110 (NCT02409342) evaluated atezo (anti–PD-L1) monotherapy as 1L treatment in PD-L1–selected patients (pts) with metastatic NSCLC and met its primary endpoint with statistically significant and clinically meaningful OS benefit in TC3 or IC3 wild-type (WT; EGFR/ALK-negative) pts. PROs were prespecified endpoints to assess pt perspectives on overall clinical benefit. Methods: Pts were randomized 1:1 to receive atezo 1200 mg IV q3w (Arm A) or platinum-based chemo (Arm B; 4 or 6 21-day cycles). Arm B non-squamous pts received cisplatin (cis) 75 mg/m² or carboplatin (carbo) AUC 6 + pemetrexed 500 mg/m² IV q3w; Arm B squamous pts received cis 75 mg/m² + gemcitabine (gem) 1250 mg/m² or carbo AUC 5 + gem 1000 mg/m² IV q3w. PROs were assessed by the EORTC Quality of Life Questionnaire Core 30 (QLQ-C30) and lung cancer module QLQ-LC13. Time to confirmed deterioration (TTD) in QLQ-LC13 lung cancer symptoms (secondary endpoint) and change from baseline (BL) in global health status (GHS), functioning and lung cancer symptoms (exploratory endpoints) were analyzed in TC3 or IC3-WT pts. Clinically meaningful change was defined as a ≥10-point deterioration from BL. Results: Completion rates at BL (atezo, n = 107; chemo, n = 98) were high in both arms for the QLC-C30 (90% atezo, 86% chemo) and the QLC-LC13 (89% atezo, 85% chemo), and remained > 80% at most visits. Mean BL scores for GHS, physical functioning, and role functioning were moderate, symptom burden was low, and all were similar in both arms. No differences in TTD were seen between arms for cough (HR, 0.98; 95% CI: 0.48, 2.03), chest pain (HR, 1.02; 95% CI: 0.47, 2.22), dyspnea (HR, 0.96, 95% CI: 0.57, 1.60), and 3-symptom composite score (HR, 0.92; 95% CI: 0.59, 1.44). Mean change in physical function from BL to wk 42 was modestly improved with atezo and greater than or similar to chemo. No clinically meaningful worsening in dyspnea, cough or chest pain was seen with atezo vs chemo. Mean change in cough and chest pain from BL numerically improved immediately after start of treatment and was maintained to wk 48 with atezo. Fatigue and nausea/vomiting scores numerically improved immediately with atezo and were maintained to wk 48. Conclusions: QLQ-C30 and QLQ-LC13 completion rates were high at BL and most study visits. TTD of lung cancer-related symptoms was similar in both arms, indicating pts’ low BL symptom burden was maintained for a similar duration. Pts receiving atezo vs chemo sustained numerical improvements in physical function and no worsening in lung cancer-related symptoms. Clinical trial information: NCT02409342.