Semaglutide and tirzepatide treatment lead to significant weight loss and improve blood sugar control in individuals with type 1 diabetes (T1D) who are living with overweight or obesity, research presented at the annual meeting of the European Association for the Study of Diabetes (EASD) held in Madrid, Spain (9–13 September) has found.

The two relatively new drugs are approved to treat type 2 diabetes and for weight loss. In type 2 diabetes, they help the body produce more insulin when needed. They also reduce the amount of glucose produced by the liver and slow down the digestion of food, all of which help lower blood sugar levels.

And, while they aren’t approved to treat T1D, they are increasingly being prescribed for this purpose, typically in patients who are living with overweight or obesity.

“Some of the mechanisms through which semaglutide and tirzepatide lower blood sugar in type 2 diabetes are also likely to be relevant in type 1 diabetes,” says study leader Dr. Janet Snell-Bergeon, of the University of Colorado Anschutz Medical Campus, Aurora, Colorado, U.S..

“In addition, an increasing number of adults with type 1 diabetes are living with overweight or obesity. These conditions can lead to insulin resistance, which makes it more difficult for people who have type 1 diabetes to control their blood sugar. Therefore, these drugs may be particularly beneficial for these patients.

“However, there is, as yet, a lack of data on how effective they are in this group.”

To address this, Dr. Snell-Bergeon and colleagues assessed the effectiveness of the two drugs in T1D patients at a diabetes clinic in the US.

The retrospective study involved reviewing the medical charts of 100 adults with T1D, 50 who were prescribed semaglutide and 50 who were prescribed tirzepatide. The majority (84% of those prescribed semaglutide and 100% of those prescribed tirzepatide) were living with overweight or obesity.

The participants were matched by computer for age, sex, diabetes duration, body mass index (BMI) and glycated hemoglobin (HbA1c—a measure of how well blood sugar is controlled) with 50 controls—T1D patients not prescribed weight loss medication.

Data were collected at baseline (prior to initiation of weight loss medication) and then for up to one year for each participant.

Mean age (40 vs. 41 years), sex (71 vs. 72 % female), diabetes duration (26 vs. 27 years), BMI (34 vs. 34kg/m²) and HbA1c (7.3% vs. 7.3%) did not differ between those receiving the drugs and the controls, respectively.

All of the participants were taking insulin for their diabetes. Insulin pumps were used by 75% of those receiving the drugs and 80% of controls. The remainder injected insulin multiple times daily.

The results show that those in the semaglutide and tirzepatide groups lost significantly more weight than the controls.

Almost all of those treated with the drugs lost at least 5% of their body weight (77% of semaglutide users, 93% of tirzepatide users), compared to 14% of the controls.

And 47% of those receiving semaglutide and 87% of those receiving tirzepatide lost at least 10% of their body weight. (None of the controls lost more than 10%.)

The patients taking tirzepatide lost more than twice as much weight as those taking semaglutide.

Those taking semaglutide lost 9.1% of their body weight on average over 12 months, which equates to 19.2lb (8.7kg). Their BMI decreased by 3kg/m², on average over 12 months.

The patients taking tirzepatide lost 21.4% of their body weight, on average after 12 months of use, which equates to 49.4lb (22.4kg). Their BMI decreased by 7.5kg/m², on average after 12 months.

Dr. Snell-Bergeon says, “This amount of weight loss has been seen in other studies of these drugs and is likely to lower the risk of a number of consequences of obesity including heart disease and insulin resistance.”

In contrast, the controls had gained a small amount of weight (0.4%), on average, after 12 months.

Blood sugar, or glycemic control, improved by a similar amount in those taking the drugs.

There was no difference in weight loss between those who used insulin pumps and those who had injections.

However, the patients in the tirzepatide group were able to reduce the amount of insulin they took.

When their lower body weight was taken into account, by examining daily insulin dose per kg of body weight, insulin dose had decreased by 0.13 units/kg/day after 12 months of treatment—a reduction of 18%.

Dr. Snell-Bergeon says, “This is a substantial reduction and is an indication that insulin resistance has improved.”

There were no reported hospitalizations from severe hypoglycemia or ketosis, complications of diabetes which can occur when diabetes isn’t being adequately controlled, during the study period.

The researchers conclude that semaglutide and tirzepatide both led to large amounts of weight loss and improved blood sugar control in patients with T1D, even among people using automated insulin delivery systems.

Dr. Snell Bergeon adds, “A growing number of individuals with type 1 diabetes are living with obesity, partly because the intensive insulin therapy that is required to manage blood sugar levels can cause weight gain.

“Semaglutide and tirzepatide can lead to significant weight loss in these patients and improve their blood sugar levels, which could reduce their risk of complications of obesity and diabetes, including heart disease and eye, nerve and kidney problems.

“These drugs could be a valuable addition to insulin in the treatment of type 1 diabetes. However, larger, prospective trials are now needed to fully evaluate their safety and efficacy in type 1 diabetes patients living with overweight and obesity.”