A Study of Tirzepatide (LY3298176) Versus Semaglutide Once Weekly as Add-on Therapy to Metformin in Participants With Type 2 Diabetes - SURPASS-2
Contribution To Literature:
The SURPASS-2 trial showed that tirzepatide is superior to semaglutide (both administered subcutaneously once-weekly) in improving glycemic control among patients with type 2 diabetes who were receiving metformin.
Description:
The goal of the trial was to assess the safety and efficacy of tirzepatide versus semaglutide among patients with type 2 diabetes, who had been inadequately controlled with metformin monotherapy.
Study Design
Patients were randomized in an open-label 1:1:1:1 fashion to either tirzepatide 5 mg (n = 470), tirzepatide 10 mg (n = 469), tirzepatide 15 mg (n = 470), or semaglutide 1 mg (n = 469) for 40 weeks. Both drugs were administered as a subcutaneous injection once a week. Tirzepatide was initiated at a dose of 2.5 mg once weekly, and the doses were increased by 2.5 mg every 4 weeks until the randomly assigned dose was reached. Semaglutide was initiated at a dose of 0.25 mg once weekly, and the dose was doubled every 4 weeks until 1 mg was reached.
- Total number screened: 2,526
- Total number of enrollees: 1,878
- Duration of follow-up: 40 weeks
- Mean patient age: 56.6 years
- Percentage female: 53%
Inclusion criteria:
- Age ≥18 years
- Type 2 diabetes
- Glycated hemoglobin (HbA1c) 7.0-10.5%
- Inadequate glycemic control on metformin (≥1500 mg/day)
- Stable body weight over 3 months
Exclusion criteria:
- Type 1 diabetes
- Estimated glomerular filtration rate <45 ml/min/1.73 m2
- History of pancreatitis
- History of any of the following: nonproliferative diabetic retinopathy that warranted urgent treatment, proliferative diabetic retinopathy, or diabetic maculopathy
Other salient features/characteristics (mean):
- Body weight: 93.7 kg (206.6 lbs)
- HbA1c: 8.3%
- Duration of type 2 diabetes: 8.6 years
- Waist circumference: 109.3 cm (40.5 inches)
- Blood pressure: 130/79 mm Hg
Principal Findings:
The primary endpoint, change in HbA1c levels from baseline to 40 weeks for tirzepatide 5 mg, tirzepatide 10 mg, tirzepatide 15 mg, or semaglutide 1 mg, was: -2.01% vs. -2.24% vs. -2.3% vs. -1.86%; p = 0.02, p < 0.001, p < 0.001, respectively.
Secondary outcomes:
- Change in body weight: -7.6 vs. -9.3 vs. -11.2 vs. -5.7 kg (p < 0.001) for all doses of tirzepatide vs. semaglutide
- Change in LDL-C: -7.7 vs. -5.6 vs. -5.2 vs. -6.4 mg/dl (p > 0.05)
- All-cause mortality: 0.9% vs. 0.9% vs. 0.9% vs. 0.2% (p > 0.05)
- Pancreatitis: 0% vs. 0.4% vs. 0.4% vs. 0.6% (p > 0.05)
- Hypoglycemia: 0.6% vs. 0.2% vs. 1.7% vs. 0.4% (p > 0.05)
- Increase in pulse rate: 2.3 vs. 2.2 vs. 2.6 vs. 2.5 bpm (p > 0.05)
Interpretation:
The results of this trial indicate that injectable once a week tirzepatide is superior to semaglutide in improving glycemic control among patients with type 2 diabetes who were receiving metformin.
Semaglutide is a selective GLP-1 (glucagon-like peptide) agonist, with established efficacy in improving glycemic control and weight reduction (SUSTAIN [several] and STEP 2 trials). Tirzepatide is a novel dual glucose-dependent insulinotropic polypeptide–GLP-1 receptor agonist. This trial suggests that the glycemic and weight loss efficacy may be higher with tirzepatide compared with low-dose semaglutide (1 mg). The most frequent side effects were gastrointestinal related. Both agents appear to increase the resting pulse rate; the clinical impact of this finding is unclear. Two large cardiovascular outcomes trials of tirzepatide are ongoing.
References:
Frías JP, Davies MJ, Rosenstock J, et al. Tirzepatide Versus Semaglutide Once Weekly in Patients With Type 2 Diabetes. N Engl J Med 2021;385:503-15.
Editorial: Tuttle KR. Breaking New Ground With Incretin Therapy in Diabetes. N Engl J Med 2021;385:560-1.
Presented by Dr. Juan P. Frías at the Virtual 81st Scientific Sessions of the American Diabetes Association (June 25-29, 2021).
Clinical Topics: Diabetes and Cardiometabolic Disease, Dyslipidemia, Prevention, Lipid Metabolism, Nonstatins
Keywords: Blood Pressure, Cholesterol, LDL, Diabetes Mellitus, Type 2, Diabetic Retinopathy, Glucagon-Like Peptide 1, Heart Rate, Hypoglycemia, Metabolic Syndrome, Metformin, Primary Prevention, Waist Circumference, Weight Loss
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