For the majority of people who begin taking GLP-1 medicines with the hope of shedding weight, the drugs can really feel nearly miraculous: Cravings are quieted. Exercise can turn out to be simpler and extra enjoyable. Pounds that stubbornly remained for years lastly dissipate.
But for a smaller subset of people, the medicines don’t assist with weight loss. Clinical trials counsel about 10 to fifteen% of people who attempt GLP-1s, resembling Wegovy and Zepbound, are “non-responders” with regards to substantial weight loss. A study revealed final week recommended genetics might play a task.
But analysis, together with new findings revealed Tuesday, is additionally persevering with to color an image of GLP-1 medicines’ advantages impartial of weight loss. Clinical trials in heart health, for instance, have recommended the medicines can scale back the danger of coronary heart assaults and strokes, and enhance outcomes in heart failure, even when contributors don’t lose weight – or, in some instances, probably even when contributors achieve weight.
The newest findings make clear how the drugs might enhance liver well being. Wegovy, made by Novo Nordisk and primarily based on the lively ingredient semaglutide, was approved by the US Food and Drug Administration in August for a severe liver illness known as metabolic dysfunction-associated steatohepatitis, or MASH, estimated to have an effect on about 6% of US adults. It was shown in a scientific trial to assist dramatically enhance markers of the illness.
“For the most part, I think the dogma is that this improvement is driven by weight loss,” mentioned Dr. Daniel Drucker, a pioneer of GLP-1 analysis at the University of Toronto whose lab produced the new research. “But we have seen hints in our lab that weight loss isn’t the whole story.”
Drucker argues the mounting proof ought to change the approach well being insurers and authorities applications think about whether or not to pay for the medicines: as a substitute of assessing weight loss as a measure of their success, they need to consider their different advantages “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,” mentioned Dr. Jody Dushay, who prescribes the medicines in her observe 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 eight% of sufferers in her observe are what she calls “weight non-responders” to GLP-1s. The drugs are so named for the hormone they mimic, which performs a task in insulin secretion, abdomen emptying and urge for food.
“But with the increasing number of indications for these medications,” Dushay advised NCS in an e-mail, “we are going to see (or, we need to look for!) benefits in people who do not meet weight loss ‘responder’ criteria.”
Drucker’s research, led by postdoctoral fellow Dr. Maria Gonzalez-Rellan, sought to know why semaglutide appeared to enhance markers of MASH no matter whether or not contributors misplaced weight in scientific trials.
The analysis workforce did this, partly, by creating basically “weight non-responders” out of lab mice, eliminating GLP-1 receptors in the mind in a gaggle of them to make it in order that they don’t lose weight with GLP-1 medicines, Drucker mentioned.
“That allows us to then say, ‘OK, if we prevent weight loss, because that’s mediated by the brain, do we still see the benefits of GLP-1 and improving liver health?’ ” he defined. “And the answer is: Absolutely, we see substantial benefits, even in the absence of weight loss.”
The workforce recognized a gaggle of cells in the liver that, when stimulated by GLP-1, kickstart a course of that communicates with the immune system to “quiet down inflammation,” Drucker mentioned. “It’s this very rare population of blood vessel cells that’s driving the reduction of inflammation.”
To additional validate their findings, the group studied what occurred when mice engineered to lack GLP-1 receptors in these liver cells misplaced a considerable quantity of weight: no liver enchancment.
“It’s elegant work,” mentioned Dr. Harlan Krumholz, a heart specialist and professor at Yale School of Medicine who wasn’t concerned in the research.
He identified, although, that since the research was performed in mice, it may possibly’t be mentioned with certainty that the similar mechanisms are at play in people.
“But we can now say that this is a biologically plausible explanation for why some benefits of these drugs appear to extend beyond simple weight reduction,” Krumholz added.
The capability of GLP-1 medicines to tamp down irritation could also be a key motive they assist with coronary heart circumstances and kidney disease in methods impartial of weight loss as nicely.
A research of outcomes from a serious cardiovascular outcomes trial of Wegovy in 2024 discovered that its capability to cut back the danger of people having a second coronary heart assault or stroke wasn’t depending on how a lot weight people misplaced.
The research creator, Professor John Deanfield from University College London, suggested “positive impacts on blood sugar, blood pressure, or inflammation, as well as direct effects on the heart muscle and blood vessels,” could also be at play.
That’s to not say weight loss doesn’t additionally assist – and is doubtless a key driver of enchancment in circumstances together with arthritis and sleep apnea, mentioned Drucker, who has acquired consulting and talking charges from firms that make GLP-1 medicines.
But the new findings add to the physique of proof suggesting the medicines may very well be utilized in extra tailor-made methods, bearing in mind their typically substantial prices and negative effects, which might embrace nausea and different gastrointestinal signs.
“It’s very important to understand: should we be trying to maximize the weight loss, and sometimes that means using the highest doses of the medicine, and sometimes that means more side effects?” Drucker mentioned. “Or, in this case with metabolic liver disease, we could only use a smaller dose of the medicine and not have so much of the adverse events, and it wouldn’t cost the patient as much money because they’re not taking as much of the drug.”
“So,” Drucker added, “it’s really clinically relevant to understand how these medicines work in every one of these conditions.”