Background: Automated insulin delivery systems improve glycemic control including time spent in, below and above range (TIR, TBR and TAR, respectively) in people with T1D. A next generation system, the MiniMedTM AHCL system, that offers a target set point (SP) of 100 or 120mg/dL, autocorrects to 120mg/dL every 5 mins and has fewer Auto Mode exits, was evaluated. Methods: A 16-site, single-arm, in-home trial of the AHCL system in 39 adolescents (14-21yrs) and 118 adults (≥22yrs) with T1D was conducted. After a baseline period of sensor-integrated pump, HCL feature, or predictive low glucose feature use (~14 days), the AHCL feature was enabled with a 100 or 120mg/dL SP for ~45 days and then the other SP for ~45 days. Study endpoints included safety events, change in A1C, sensor glucose (SG), %TIR, %TBR and %TAR. Results: There were no DKA or severe hypoglycemia episodes during the study period. Auto Mode was used ≥95% of the time; autocorrection was 22% of daily bolus. The table shows outcomes (mean±SD) for the overall group and each age group at baseline and study period (100 and 120mg/dL SP), and at the 100mg/dL SP. Best glycemic results (SG of 141±8.8mg/dL, TIR of 78.8±5.5% and TBR of 2.6±2.0%; N=29) were seen with a 100mg/dL SP and active insulin time of 120 minutes. Conclusion: These pivotal trial data demonstrate that AHCL is safe and significantly improved A1C and SG in subjects aged ≥14 years with T1D. Disclosure A.L. Carlson: Consultant; Self; Medtronic. Research Support; Self; Abbott, Dexcom, Inc., Eli Lilly and Company, Insulet Corporation, Medtronic, Novo Nordisk A/S, Sanofi, UnitedHealth Group. B.W. Bode: Advisory Panel; Self; Medtronic, Novo Nordisk A/S. Consultant; Self; Eli Lilly and Company, Medtronic, Novo Nordisk A/S. Research Support; Self; Abbott, Advance, Boehringer Ingelheim Pharmaceuticals, Inc., Dexcom, Inc., Diasome Pharmaceuticals, Inc., Eli Lilly and Company, Insulet Corporation, Janssen Pharmaceuticals, Inc., MannKind Corporation, Medtronic, National Institutes of Health, Nova Biomedical, Novo Nordisk A/S, Provention Bio, Inc., Sanofi, Senseonics. Speaker’s Bureau; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company, Janssen Pharmaceuticals, Inc., MannKind Corporation, Medtronic, Novo Nordisk A/S, Sanofi, Senseonics. Stock/Shareholder; Self; Aseko. R.L. Brazg: None. M.P. Christiansen: Research Support; Self; Abbott, Ascensia Diabetes Care, Biolinq, Dexcom, Inc., Eli Lilly and Company, Lexicon Pharmaceuticals, Inc., Medtronic, Merck & Co., Inc., Novo Nordisk A/S, Sanofi-Aventis, Senseonics, ViroMed Laboratories, Xeris Pharmaceuticals, Inc. S.K. Garg: Advisory Panel; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company, Medtronic, Novo Nordisk A/S, Roche Diagnostics France. Research Support; Self; Dexcom, Inc., Eli Lilly and Company, Medtronic. K. Kaiserman: Advisory Panel; Self; Medtronic. Consultant; Self; Medtronic. Research Support; Self; Medtronic. Speaker’s Bureau; Self; Medtronic. M. Kipnes: None. D.R. Liljenquist: None. A. Philis-Tsimikas: Advisory Panel; Self; Lilly Diabetes, Medtronic, Novo Nordisk A/S, Sanofi. Employee; Spouse/Partner; Ionis Pharmaceuticals, Inc. Research Support; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Dexcom, Inc., Lilly Diabetes, Medtronic, Novo Nordisk A/S, Sanofi. R. Pop-Busui: Advisory Panel; Self; Boehringer Ingelheim Pharmaceuticals, Inc. Consultant; Self; Bayer Healthcare Pharmaceuticals Inc., Novo Nordisk Inc. Research Support; Self; AstraZeneca. Other Relationship; Self; American Diabetes Association. J. Sherr: Advisory Panel; Self; Bigfoot Biomedical, Cecelia Health. Consultant; Self; Eli Lilly and Company, Lexicon Pharmaceuticals, Inc., Medtronic, Sanofi, T1D Exchange. D.I. Shulman: Advisory Panel; Self; Medtronic. K.K. Singh: None. R.H. Slover: None. J. Thrasher: Advisory Panel; Self; Lexicon Pharmaceuticals, Inc., Novo Nordisk Inc., Sanofi. Board Member; Self; Medtronic. Consultant; Self; Medtronic. Research Support; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Bristol-Myers Squibb, Eli Lilly and Company, Lexicon Pharmaceuticals, Inc., Medtronic, Mylan, Novo Nordisk Inc., Sanofi. Speaker’s Bureau; Self; AstraZeneca, Janssen Pharmaceuticals, Inc., Medtronic, Sanofi. X. Chen: Employee; Self; Medtronic. B. Grosman: Employee; Self; Medtronic. S.W. Lee: Employee; Self; Medtronic. L.J. Lintereur: Employee; Self; Medtronic. M. Liu: Employee; Self; Medtronic. N. Parikh: None. A.S. Rhinehart: Employee; Self; Glytec, Medtronic. Stock/Shareholder; Self; Dexcom, Inc., Glytec, Lexicon Pharmaceuticals, Inc., MannKind Corporation, Tandem Diabetes Care. F. Peng: None. A. Roy: Employee; Self; Medtronic. J. Shin: Employee; Self; Medtronic. D. Wu: None. R. Vigersky: Employee; Self; Medtronic.