Oral Semaglutide Versus Empagliflozin in Patients With Type 2 Diabetes Uncontrolled on Metformin: The PIONEER 2 Trial

OBJECTIVE: Efficacy and safety of the glucagon-like peptide 1 (GLP-1) analog oral semaglutide and the sodium-glucose cotransporter 2 inhibitor empagliflozin were compared in patients with type 2 diabetes uncontrolled on metformin. RESEARCH DESIGN AND METHODS: Patients were randomized to once-daily open-label treatment with oral semaglutide 14 mg (n = 412) or empagliflozin 25 mg (n = 410) in a 52-week trial. Key end points were change from baseline to week 26 in HbA1c (primary) and body weight (confirmatory secondary). Two estimands addressed efficacy-related questions: treatment policy (regardless of trial product discontinuation or rescue medication) and trial product (on trial product without rescue medication) in all randomized patients. RESULTS: Four-hundred (97.1%) patients in the oral semaglutide group and 387 (94.4%) in the empagliflozin group completed the trial. Oral semaglutide provided superior reductions in HbA1c versus empagliflozin at week 26 (treatment policy -1.3 vs. -0.9% [-14 vs. -9 mmol/mol], estimated treatment difference [ETD] -0.4% [95% CI -0.6, -0.3%] [-5 mmol/mol (-6, -3 mmol/mol)]; P < 0.0001). The treatment difference in HbA1c significantly favored oral semaglutide at week 26 for the trial product estimand (-1.4 vs. -0.9% [-15 vs. -9 mmol/mol], ETD -0.5% [95% CI -0.7, -0.4%] [-6 mmol/mol (-7, -5 mmol/mol)]; P < 0.0001) and at week 52 for both estimands (P < 0.0001). Superior weight loss was not confirmed at week 26 (treatment policy), but oral semaglutide was significantly better than empagliflozin at week 52 (trial product -4.7 vs. -3.8 kg; P = 0.0114). Gastrointestinal adverse events were more common with oral semaglutide. CONCLUSIONS: Oral semaglutide was superior to empagliflozin in reducing HbA1c but not body weight at 26 weeks in patients with type 2 diabetes uncontrolled on metformin. At week 52, HbA1c and body weight (trial product estimand) were significantly reduced versus empagliflozin. Oral semaglutide was well tolerated within the established safety profile of GLP-1 receptor agonists.