Switching to tirzepatide reduces HbA1c, weight in adults with T2D

In people with type 2 diabetes (T2D) with inadequate control, switching to tirzepatide results in additional reductions in haemoglobin A1c (HbA1c) and body weight compared with escalating dulaglutide dose, reports a study.

This multicentre, randomized, open-label, phase 4 trial (SURPASS-SWITCH) was conducted in 38 sites across five countries. Participants included adults with HbA1c ≥7 percent to ≤9.5 percent, stable body weight, BMI ≥25 kg/m², receiving a stable dose of dulaglutide (0.75 or 1.5 mg) for at least 6 months and 0–3 oral antihyperglycaemic medications for at least 3 months. 

A total of 282 eligible participants either switched to tirzepatide (n=139) or had a dose escalation of dulaglutide to 4.5 mg or maximum tolerated dose (MTD; n=143). Change from baseline in HbA1c at week 40 was the primary endpoint, while the change from baseline in weight at week 40 was secondary.

At week 40, the change in HbA1c from baseline was –1.44 percent with tirzepatide 15 mg or MTD and –0.67 percent with dulaglutide 4.5 mg or MTD (estimated treatment difference, –0.77 percent, 95 percent confidence interval [CI], –0.98 percent to –0.56 percent; p<0.001).

The change in weight at week 40 was also greater with tirzepatide than with dulaglutide (–10.5 vs –3.6 kg; estimated treatment difference, –6.9 kg, 95 percent CI, –8.3 to –5.5; p<0.001).

Ten patients in each treatment group reported serious adverse events (7.2 percent vs 7.0 percent). Nausea and diarrhoea were the most common treatment-emergent adverse events.

This study was limited by its open-label design, according to the investigators.

Tirzepatide is a once-weekly glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonist approved for the treatment of T2D or obesity.