By Meg Tirrell, CNN
(CNN) — For the majority of people who start taking GLP-1 medicines with the hope of losing weight, the drugs can feel almost miraculous: Cravings are quieted. Exercise can become easier and more fun. Pounds that stubbornly remained for years finally dissipate.
But for a smaller subset of people, the medicines don’t help with weight loss. Clinical trials suggest about 10 to 15% of people who try GLP-1s, such as Wegovy and Zepbound, are “non-responders” when it comes to substantial weight loss. A study published last week suggested genetics may play a role.
But research, including new findings published Tuesday, is also continuing to paint a picture of GLP-1 medicines’ benefits independent of weight loss. Clinical trials in heart health, for example, have suggested the medicines can reduce the risk of heart attacks and strokes, and improve outcomes in heart failure, even when participants don’t lose weight – or, in some cases, possibly even if participants gain weight.
The latest findings shed light on how the drugs may improve liver health. Wegovy, made by Novo Nordisk and based on the active ingredient semaglutide, was approved by the US Food and Drug Administration in August for a serious liver disease called metabolic dysfunction-associated steatohepatitis, or MASH, estimated to affect about 6% of US adults. It was shown in a clinical trial to help dramatically improve markers of the disease.
“For the most part, I think the dogma is that this improvement is driven by weight loss,” said Dr. Daniel Drucker, a pioneer of GLP-1 research at the University of Toronto whose lab produced the new study. “But we have seen hints in our lab that weight loss isn’t the whole story.”
Drucker argues the mounting evidence should change the way health insurers and government programs consider whether to pay for the medicines: instead of assessing weight loss as a measure of their success, they should take into account their other benefits “across a wide range of very serious diseases.”
“Insurance companies have historically required at least 5% weight loss after three to four months of treatment in order to continue covering GLP-1 treatment,” said Dr. Jody Dushay, who prescribes the medicines in her practice at Beth Israel Deaconess Medical Center in Boston. “With new information about metabolic benefits separate from weight loss, this will definitely need to be reconsidered.”
She estimates that about 5 to 8% of patients in her practice are what she calls “weight non-responders” to GLP-1s. The drugs are so named for the hormone they mimic, which plays a role in insulin secretion, stomach emptying and appetite.
“But with the increasing number of indications for these medications,” Dushay told CNN in an email, “we are going to see (or, we need to look for!) benefits in people who do not meet weight loss ‘responder’ criteria.”
‘Elegant work’
Drucker’s study, led by postdoctoral fellow Dr. Maria Gonzalez-Rellan, sought to understand why semaglutide appeared to improve markers of MASH regardless of whether participants lost weight in clinical trials.
The research team did this, in part, by creating essentially “weight non-responders” out of lab mice, eliminating GLP-1 receptors in the brain in a group of them to make it so they don’t lose weight with GLP-1 medicines, Drucker said.