Tirzepatide once weekly for the treatment of obesity in people with type 2 diabetes (SURMOUNT-2)

The SURMOUNT-2 trial, published in The Lancet, was a phase 3, randomized, double-blind, placebo-controlled study that evaluated tirzepatide specifically in adults with obesity and type 2 diabetes — a population that typically shows a lower response to pharmacological weight loss. Participants were randomized to tirzepatide 10 mg, 15 mg, or weekly placebo for 72 weeks.

The results demonstrated clinically significant weight loss: -12.8% with tirzepatide 10 mg and -14.7% with tirzepatide 15 mg, compared to only -3.2% with placebo (p<0.001 for both doses). Additionally, there was substantial improvement in glycemic control, with significant reductions in HbA1c.

• Approximately 40% of participants on tirzepatide 15 mg achieved ≥15% weight loss
• Mean HbA1c decreased significantly in both tirzepatide groups
• Improvements were observed in blood pressure, triglycerides, and waist circumference
• The safety profile was consistent with prior trials, with predominantly gastrointestinal events

SURMOUNT-2 complemented the findings of SURMOUNT-1 by demonstrating that tirzepatide maintains robust efficacy even in the presence of type 2 diabetes, a condition that frequently attenuates the response to anti-obesity therapies. The results reinforced tirzepatide's position as a reference treatment for patients with the combination of obesity and diabetes, simultaneously addressing both conditions.