SAR341402 (SAR-Asp) was developed as a biosimilar/follow-on product to rapid-acting insulin NovoLog®/NovoRapid® (NN-Asp). This 6-month randomized, controlled, open-label, phase 3 study compared efficacy and safety of SAR-Asp and NN-Asp in adults with type 1 diabetes (T1D) or type 2 diabetes (T2D) also using insulin glargine (GLA100) as basal insulin. In total 597 adults with diabetes were randomized (1:1; 497 with T1D, 100 with T2D) to a multiple daily injection regimen of SAR-Asp or NN-Asp along with using once daily GLA100. Glucose targets levels were <180 mg/dL (2h-postprandial) and 80-130 mg/dL (fasting and pre-prandial) while avoiding hypoglycemia. Primary endpoint was HbA1c change (non-inferiority margin of 0.3%) from baseline to week 26 (tested for non-inferiority of SAR-Asp vs. NN-Asp). Immunogenicity was assessed by anti-insulin aspart antibody (AIA) status (positive/negative) and titers during the study. SAR-Asp was non-inferior to NN-Asp for change in HbA1c, with similar insulin dosages. There was no difference in the percentage of patients reporting hypoglycaemia. Immunogenicity and safety profiles (adverse events, hypersensitivity events and injection site reactions) were similar for SAR-Asp and NN-Asp (Table). We conclude that biosimilar/follow-on SAR-Asp is safe, effective and well-tolerated as insulin aspart in adults with T1D or T2D. Disclosure S.K. Garg: Advisory Panel; Self; Eli Lilly and Company, Roche Pharma, Sanofi-Aventis, Zealand Pharma A/S. Research Support; Self; Eli Lilly and Company, WebMD. K. Wernicke-Panten: Employee; Self; Sanofi-Aventis Deutschland GmbH. M. Wardecki: Employee; Self; Sanofi Research & Development. Stock/Shareholder; Self; Sanofi. D. Kramer: Employee; Self; Sanofi-Aventis Deutschland GmbH. Stock/Shareholder; Self; Sanofi-Aventis Deutschland GmbH. F. Delalande: None. V.N. Shah: Advisory Panel; Self; Sanofi US. Consultant; Self; Dexcom, Inc. E. Franek: Advisory Panel; Self; Boehringer Ingelheim International GmbH, Novartis AG, Novo Nordisk Inc. Speaker’s Bureau; Self; AstraZeneca, Bioton, Boehringer Ingelheim International GmbH, Medtronic, Novartis AG, Novo Nordisk Inc., Polfa Tarchomin S.A. K. Sadeharju: Research Support; Self; AstraZeneca, Bayer AG, ICON plc., Sanofi. T. Monchamp: Research Support; Self; Amarin Corporation, Novo Nordisk Inc., Sanofi, TrialNet. Funding Sanofi