Regeneron Chief Flags Health Risks with Popular Weight-Loss Medications Like Ozempic, Says Company Targets Muscle Preservation For Its Obesity Drugs

George Yancopoulos, co-founder and chief scientific officer of Regeneron Pharmaceuticals Inc REGN, has voiced concerns that the popular GLP-1s class of weight-loss drugs may lead to unintended health risks, particularly rapid muscle loss.

Yancopoulos warned that unless this side effect is mitigated, these treatments could ultimately cause “more harm than good.” Clinical studies indicate that patients using GLP-1s, such as Novo Nordisk A/S’ NVO Ozempic and Wegovy, experience muscle loss much faster than those who lose weight through diet and exercise.

U.S. pharmacy claims data analysis reveals that only one in four patients prescribed Wegovy and Ozempic continue their treatment after two years.

In the Financial Times report, Yancopoulos emphasized that patients often regain weight but with a higher fat-to-muscle ratio, which Yancopoulos described as “adding insult to injury.”

He expressed concerns that GLP-1s may trigger body composition changes that could lead to more harm than benefit in the long run when used in the real world.

A study published in the Journal of the American Medical Association (JAMA) revealed that patients, on average, achieved only a 3.7% weight reduction after one year on the drugs—lower than the results reported in controlled trials.

Regeneron is researching muscle-preserving treatments to pair with these weight-loss medications.

Regeneron is conducting a Phase 2 trial for trevogrumab, which blocks the hormone myostatin to promote muscle growth, in combination with Wegovy (semaglutide).

Topline results are expected in the second half of 2025.

In June, Regeneron released multiple ascending dose data from a Phase 1 study evaluating garetosmab (anti-activin A) and trevogrumab on body composition in healthy volunteers (n=34).

The data demonstrated that combination therapy led to greater-than-additive increases in lean mass while decreasing fat mass in healthy participants.

In 2023, Eli Lilly And Co LLY acquired Versanis Bio for up to $1.925 billion in cash, bolstering its product profile of obesity-curbing drugs.

Eli Lilly said bimagrumab can reduce fat mass while preserving muscle mass for people with obesity and obesity-related complications.

According to FT, Yancopoulos hinted that Regeneron is considering entering the GLP-1 space by developing its drug version despite the concern. However, he remains cautious, stating that GLP-1s may not be the ultimate solution to metabolic disease.

Price Action: REGN stock is down 0.23% tot $1,010.51 at the last check on Monday.

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