Two studies published this summer have found that the injected diabetes drug pramlintide (brand name Symlin) may help obese people lose weight.
Pramlintide is a synthetic analog of the hormone amylin, which is usually secreted by the pancreas along with insulin in response to meals. In the body, amylin works with insulin to control the rise in blood glucose levels after eating. People with diabetes whose pancreases don’t produce enough insulin (or any insulin) also don’t produce enough amylin at mealtimes.
Pramlintide was approved by the U.S. Food and Drug Administration (FDA) in March 2005 for use in people with Type 1 diabetes and people with Type 2 diabetes who use insulin. Pramlintide helps control blood glucose levels by several mechanisms, including slowing stomach emptying. This action can also help people feel more full and eat less food.
Previously published studies have shown that using pramlintide can help people with Type 2 diabetes, who are often overweight, lower both their HbA1c levels and their weight. Now, two new studies have looked specifically at pramlintide’s role in helping obese people lose weight.
In one study, published in the August issue of The Journal of Clinical Endocrinology and Metabolism, researchers recruited 204 people with an average body-mass index (BMI) of 37.8 (a BMI over 30 is classified as obese). These people were randomly assigned to take injections of either pramlintide or a placebo three times a day before meals for four months. Both groups also received lifestyle interventions aimed at weight loss.
Compared with the placebo group, the participants who received pramlintide lost about eight pounds and almost 1 1/2 inches from their waistlines. Also, a greater percentage of the pramlintide group (31%) lost 5% or more of their body weight compared to 2% of the placebo group, and a substantially higher percentage of people in the pramlintide group reported better appetite control and improved well-being. Nausea was the most common side effect associated with pramlintide, and both groups had a similar percentage of withdrawal from the study: 29% of the pramlintide group and 25% of the placebo group.
Another study, published in the American Journal of Physiology - Endocrinology and Metabolism in August looked at 88 obese people randomly assigned to inject either pramlintide or a placebo before each meal for six weeks. Over this period, the people who received pramlintide ate between 500 and 750 fewer calories per day than the people who received the placebo. They also ate smaller portions and were less likely to binge eat when presented with food such as pizza, soda, and ice cream during “fast food challenges.” At the end of the study period, members of the pramlintide group had lost an average 2% of their body weight while members of the placebo group had gained a small amount of weight.
Both studies received funding from Amylin Pharmaceuticals, Inc., which manufactures pramlintide.
FDA approval for pramlintide purely as a weight-loss drug is probably still years in the future; meanwhile, other studies are under way to test the weight-loss effects of combining pramlintide with other drugs and synthetic hormones. For people with diabetes who are overweight and use insulin, however, pramlintide may be able to help them lose weight in addition to helping control postmeal blood glucose levels.