Efficacy and safety of subcutaneous and intravenous administration of atezolizumab in patients with non-small cell lung cancer, including early-stage, locally advanced or metastatic disease: Updated results of the IMscin001 and IMscin002 randomized studies

BACKGROUND: Subcutaneous (SC) and intravenous (IV) atezolizumab is approved for the treatment of several solid tumors. Part 2 of IMscin001 (NCT03735121) met its co-primary endpoints and demonstrated non-inferior drug exposure at cycle 1 with atezolizumab SC versus atezolizumab IV in patients with non-small cell lung cancer (NSCLC). Efficacy, safety and drug immunogenicity were similar for both atezolizumab formulations. Primary results from IMscin002 (NCT05171777) demonstrated higher preference for atezolizumab SC over atezolizumab IV amongst patients with NSCLC. We now report updated efficacy, safety and drug immunogenicity results from IMscin001 (part 2) and IMscin002. METHODS: Patients were randomized 2:1 (IMscin001) and 1:1 (IMscin002) to receive 1875 mg atezolizumab SC or 1200 mg atezolizumab IV every three weeks. In IMscin002, patients switched formulations after cycle 3 and chose a formulation for the continuation period after cycle 6. Overall survival (OS) in IMscin001, ongoing clinical benefit after cycle 16 in IMscin002, plus safety and drug immunogenicity (both studies), were secondary/exploratory endpoints. RESULTS: In IMscin001, at data cutoff (November 22, 2024), 247 patients were randomized to atezolizumab SC and 124 to atezolizumab IV; median OS was 10.9 and 10.1 months, respectively (hazard ratio: 1.00, 95% CI: 0.78-1.27). In IMscin002, at data cutoff (October 25, 2024), 179 patients were randomized, of whom 115 and 43 patients had completed the crossover and continuation periods, respectively; 65.4% (117/179) of patients had metastatic disease. Ongoing clinical benefit after cycle 16 was observed in 44.7% (80/179) of patients. In both studies, no new or unexpected safety signals were identified. The combined incidence of treatment-emergent anti-drug antibodies was 20.0% (atezolizumab SC) and 21.1% (atezolizumab IV). CONCLUSIONS: Updated results from IMscin001 (part 2) and IMscin002 show similar efficacy, safety and drug immunogenicity for atezolizumab SC and IV. No new or unexpected safety signals were reported and switching between atezolizumab formulations was well tolerated. CLINICAL TRIAL REGISTRATION NUMBER: IMscin001 (NCT03735121); IMscin002 (NCT05171777).