New Trial Tests Adding Two Type 2 Diabetes Drugs to Insulin for Type 1

People with Type 1 diabetes rely on insulin to survive, but insulin can lead to weight gain—making blood sugar control even harder to achieve. Researchers have wondered whether newer medications developed for Type 2 diabetes might help Type 1 patients reach their blood sugar targets without gaining more weight.

This new Phase 3 trial, called TTT1 (Triple Therapy for Type 1 Diabetes), is the first large-scale study to formally test whether adding two such medications to insulin therapy could work safely and effectively in Type 1 diabetes.

The study focuses on overweight and obese adults with Type 1 diabetes whose blood sugar (HbA1c) remains between 7.5% and 11.0% despite their current insulin therapy. The trial has two phases over one year.

In the first 26 weeks, about two-thirds of participants receive semaglutide (a GLP-1 receptor agonist) added to their insulin, while the remaining third continue standard insulin therapy alone. Semaglutide is gradually increased to 1.0 mg once weekly.

In the second 26 weeks, participants who received semaglutide are randomly assigned to also receive dapagliflozin (an SGLT2 inhibitor) or a placebo, both alongside their semaglutide and insulin. This allows researchers to test the full triple-therapy combination.

The main goal is to see whether adding dapagliflozin to semaglutide and insulin (triple therapy) improves blood sugar control better than semaglutide and insulin alone (dual therapy). The trial will also compare both approaches to standard insulin therapy.

Safety is a major focus. Researchers are carefully tracking rates of low blood sugar (hypoglycemia) and diabetic ketoacidosis—a serious condition that can develop when these medications are used in Type 1 diabetes. These safety concerns are why this trial is essential before wider use of these drugs in Type 1 patients.

The trial originally planned to enroll 114 participants but adjusted the target to 82 based on early data analysis. Results from the TTT1 trial will help determine whether GLP-1 receptor agonists and SGLT2 inhibitors have a role in Type 1 diabetes treatment, and under what conditions they might be safe to use.

Source: Diabetes, obesity & metabolism. Evidence type: PubMed indexed literature. Type1Cure is an information and intelligence hub, not a medical advice service. This article summarizes published research and does not provide diagnosis, treatment, or personal medical guidance. Always talk to your own care team before changing anything about your Type 1 diabetes management.