Trial results comparing the efficacy and safety of switching from weekly dulaglutide to weekly tirzepatide in adult participants with Type 2 Diabetes were posted on ClinicalTrials.gov on 2025-08-03. The study found that switching to tirzepatide resulted in a significantly greater least squares mean change from baseline in HbA1c of -1.59 percentage of HbA1c compared to -0.69 percentage of HbA1c for dulaglutide, and a greater weight loss of -11.0 kilograms (kg) versus -3.6 kilograms (kg).
Background
Type 2 Diabetes is a chronic metabolic disorder characterized by high blood sugar, often leading to serious health complications if not effectively managed. Treatment strategies typically focus on glycemic control and weight management, with various pharmacological agents available to help patients achieve their therapeutic goals.
Trial design
This completed PHASE4 study (NCT05564039), titled "A Study of Tirzepatide (LY3298176) in Adult Participants With Type 2 Diabetes Switching From Dulaglutide (SURPASS-SWITCH)," enrolled 282 participants with Type 2 Diabetes. The main purpose was to investigate the efficacy and safety of switching from weekly dulaglutide to weekly tirzepatide compared to increasing the dulaglutide dose. Participants were randomized to either receive 15 mg Tirzepatide or an increased dose of 4.5 mg Dulaglutide or Maximum Tolerated Dose (MTD).
Key results
Key measurements from the trial demonstrated significant differences between the tirzepatide and dulaglutide groups:
- Change From Baseline in HbA1c: The 15 mg Tirzepatide or MTD group showed a least squares mean change of -1.59 percentage of HbA1c (Standard Error: 0.073), while the 4.5 mg Dulaglutide or MTD group showed a change of -0.69 percentage of HbA1c (Standard Error: 0.074). The LS Mean difference was -0.9 (95% CI: -1.1 to -0.69) with a p-value of 0.0001.
- Change From Baseline in Body Weight: Participants in the 15 mg Tirzepatide or MTD group experienced a least squares mean change of -11.0 kilograms (kg) (Standard Error: 0.48), compared to -3.6 kilograms (kg) (Standard Error: 0.49) in the 4.5 mg Dulaglutide or MTD group. The LS Mean difference was -7.4 (95% CI: -8.7 to -6.0) with a p-value of 0.0001.
- Percentage of Participants Who Achieved HbA1c <7%: 84.21 percentage of participants in the 15 mg Tirzepatide or MTD group achieved this target, versus 52.38 percentage of participants in the 4.5 mg Dulaglutide or MTD group. The Odds Ratio was 7.13 (95% CI: 3.82 to 13.32) with a p-value of 0.0001.
- Percentage of Participants Who Achieved HbA1c <=6.5%: 73.88 percentage of participants in the 15 mg Tirzepatide or MTD group reached this target, compared to 22.73 percentage of participants in the 4.5 mg Dulaglutide or MTD group. The Odds Ratio was 12.24 (95% CI: 6.51 to 23.02) with a p-value of 0.0001.
- Percentage of Participants Who Achieved HbA1c <5.7%: 21.64 percentage of participants in the 15 mg Tirzepatide or MTD group achieved this target, versus 2.27 percentage of participants in the 4.5 mg Dulaglutide or MTD group. The Odds Ratio was 15.34 (95% CI: 4.58 to 51.36) with a p-value of 0.0001.
- Percentage of Participants Who Achieve Weight Loss From Baseline of ≥5%: 84.33 percentage of participants in the 15 mg Tirzepatide or MTD group achieved this, compared to 37.40 percentage of participants in the 4.5 mg Dulaglutide or MTD group. The Odds Ratio was 9.31 (95% CI: 5.11 to 16.98) with a p-value of 0.0001.
What this means
The results indicate that switching from dulaglutide to tirzepatide leads to significantly superior improvements in glycemic control, as evidenced by greater HbA1c reductions and higher rates of achieving glycemic targets. Additionally, patients switching to tirzepatide experienced substantially greater body weight loss. These findings suggest that tirzepatide offers a considerable clinical benefit for adult participants with Type 2 Diabetes who are already on dulaglutide and may require further improvements in their metabolic control.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT05564039, titled "A Study of Tirzepatide (LY3298176) in Adult Participants With Type 2 Diabetes Switching From Dulaglutide (SURPASS-SWITCH)," were posted on 2025-08-03 on clinicaltrials.gov.