1447P IMscin001 part 2 updated results: Efficacy, safety, immunogenicity and patient-reported outcomes (PROs) from the randomised phase III study of atezolizumab (atezo) subcutaneous (SC) vs intravenous (IV) in patients with locally advanced or metastatic non-small cell lung cancer (NSCLC)

IMscin001 Part 2 met its co-primary endpoints of non-inferior drug exposure for Cycle 1 Ctrough and AUC0-21d for atezo SC vs IV ( Burotto ESMO-IO 2022 ). Efficacy, safety and immunogenicity were similar between arms at primary analysis. Here, we report updated data. Cancer immunotherapy-naïve patients with locally advanced or metastatic NSCLC for whom platinum therapy had failed were randomised 2:1 to receive 1875 mg atezo SC or 1200 mg atezo IV q3w. Secondary endpoints were efficacy (OS, PFS, ORR, DOR), safety, immunogenicity and PROs. PROs were collected on Day 1 of Cycles 1-6 and then every second cycle until treatment discontinuation. Healthcare providers (HCPs) completed SC and SC vs IV perspective questionnaires after giving ≥3 doses of atezo SC or ≥3 doses of atezo SC and IV each, respectively. At data cut-off (16 Jan 2023; median follow-up: 9.5 mo), ≈60% of OS events had occurred. Median OS was 10.7 mo for SC vs 10.1 mo for IV; immunogenicity and safety were also similar between arms (Table). Mean PRO scores were within 10% between arms for global health status, role and physical functioning, and satisfaction with therapy. 90% (70/78) of HCPs reported that giving atezo SC was fairly easy/very easy, 85% (66/78) were satisfied/very satisfied with atezo SC and 75% (33/44) agreed that administering atezo SC could save time compared with IV.Table: 1447PSC (n=247)IV (n=124)Median administration time (95% CI), min7.1 (6.6, 7.4)40.0 (37.5, 45.0)EfficacyOS events, %5864OS, median (95% CI), mo10.7 (8.5, 13.8)10.1 (7.5, 12.1)Confirmed ORR, (95% CI), %11.0 (7.4, 15.6)10.5 (5.7, 17.3)Confirmed DOR, median (95% CI), mo15.1 (5.6, NE)11.2 (4.2, NE)Safety, %Any Grade AE8884Anaemia1917Dyspnoea1115Fatigue1213Grade 3/4 AE2131Grade 5 AE66Serious AE1927AE of special interest3128Hepatitis1214Hypothyroidism117Rash911AE leading to atezo discontinuation47Infusion-related reaction03Injection site reaction40Grade 1/240ImmunogenicityADA incidence, %2114NCT03735121. ADA, anti-drug antibody; NE, not estimable. Open table in a new tab NCT03735121. ADA, anti-drug antibody; NE, not estimable. At this updated analysis, OS data were mature and similar between arms. Safety was also similar and consistent with the atezo IV profile for approved indications. ADA incidence for both arms was in the historic range for atezo IV. PROs were similar for both arms, and HCPs reported easy/very easy administration and potential time savings for atezo SC. These results support atezo SC as an alternative to IV.