Tirzepatide Trial In Adults With Type 1 Diabetes Reports Weight Loss

Key Takeaways:

• A randomized 12-week trial in adults with type 1 diabetes and obesity reported greater weight loss with tirzepatide than placebo (estimated treatment difference, -8.7 kg [95% CI, -12.0 to -5.5]; P < 0.0001).
• Investigators also reported an HbA1c difference versus placebo of -0.4% (95% CI, -0.7 to 0.0; P = 0.05) and a reduction in total daily insulin dose versus placebo of -35.1% (95% CI, -46.5 to -21.3; P = 0.0002) over 12 weeks.
• No significant adverse events were reported in either group, and the safety finding was limited to short-term trial reporting.

Investigators conducted a 12-week phase 2, double-blind, placebo-controlled trial in adults with type 1 diabetes and BMI greater than 30 kg/m2. The active-treatment group received once-weekly subcutaneous tirzepatide at 2.5 mg for 4 weeks, then 5.0 mg for 8 weeks. The primary end point was change in body weight at 12 weeks. Twenty-two of 24 participants completed the study, framing this as a short-term randomized comparison focused primarily on body-weight change.

In the results, mean body-weight change after 12 weeks was -10.3 kg with tirzepatide and -0.7 kg with placebo. The estimated treatment difference between groups was -8.7 kg (95% CI, -12.0 to -5.5; P < 0.0001). The abstract also reported 8.8% weight loss at 12 weeks with tirzepatide. The study reported that 100% and 45% of participants in the tirzepatide group achieved at least 5% and 10% weight loss, respectively, compared with 9% and 0% in the placebo group. Weight reduction was the main reported between-group difference over 12 weeks.

The abstract also reported an HbA1c improvement with tirzepatide versus placebo (mean difference, -0.4% [95% CI, -0.7 to 0.0]; P = 0.05) over 12 weeks. Investigators reported a reduced total daily insulin dose (-24.2 units/day with tirzepatide vs -0.3 units/day with placebo; difference from baseline vs placebo, -35.1% [95% CI, -46.5 to -21.3]; P = 0.0002). These glycemic and insulin-dose changes were reported alongside the primary weight outcome and broadened the short-term clinical picture beyond weight alone.

Investigators reported that no significant adverse events occurred in either treatment group during the study. Safety outcomes were summarized over the 12-week trial period.

The investigators conclude that tirzepatide was associated with greater short-term weight loss than placebo in adults with type 1 diabetes and obesity. The abstract reported an HbA1c difference versus placebo of -0.4% (95% CI, -0.7 to 0.0; P = 0.05) and a reduction in total daily insulin dose versus placebo of -35.1% (95% CI, -46.5 to -21.3; P = 0.0002) over 12 weeks. No significant adverse events were reported, aligning with the limited safety description provided for both groups. The trial remained small and brief, with 24 randomized participants and follow-up confined to 12 weeks. These findings remain short-term observations from a phase 2 randomized study.