Type 2 Diabetes

Tirzepatide outperforms insulin lispro in treating type 2 diabetes

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In a Phase 3b clinical trial involving 1428 adults with type 2 diabetes already on basal insulin, tirzepatide, administered as a once-weekly subcutaneous injection, demonstrated significant advantages over prandial thrice-daily insulin lispro.

Tirzepatide resulted in a substantial reduction in HbA1c levels, greater weight loss, and a higher percentage of participants achieving the target HbA1c level of less than 7.0%. In addition, tirzepatide showed a lower risk of hypoglycemia compared to insulin lispro.

Participants in this trial were randomly assigned to receive either tirzepatide in 5 mg, 10 mg, or 15 mg doses, or prandial thrice-daily insulin lispro.

At the 52-week mark, the estimated mean change from baseline in HbA1c with tirzepatide was a significant -2.1%, compared to -1.1% with insulin lispro. This translated to mean HbA1c levels of 6.7% versus 7.7%, respectively. The trial not only met noninferiority criteria but also achieved statistical superiority.

The trial also revealed a substantial reduction in body weight. Participants on tirzepatide experienced an estimated mean change of -9.0 kg from baseline, whereas those on insulin lispro saw an increase of 3.2 kg. This resulted in an estimated treatment difference of -12.2 kg.

Overall, 68% of participants on tirzepatide achieved the target HbA1c level of <7.0%, while only 36% of those on insulin lispro did.

The most common adverse events associated with tirzepatide were mild to moderate gastrointestinal symptoms, including nausea (14%-26%), diarrhea (11%-15%), and vomiting (5%-13%). Notably, hypoglycemia event rates were significantly lower with tirzepatide, at 0.4 events per patient-year, compared to 4.4 events per patient-year with insulin lispro.

Rosenstock J, Frías JP, Rodbard HW, et al. Tirzepatide vs Insulin Lispro Added to Basal Insulin in Type 2 Diabetes: The SURPASS-6 Randomized Clinical Trial. JAMA. Published online October 03, 2023. doi:10.1001/jama.2023.20294