About a Dozen New Weight Loss Drugs Aim to Promote Muscle Growth

About a dozen drugmakers are developing new weight-loss treatments aimed at preserving muscle, and industry analysts, clinical trial experts, and doctors say they may also need to demonstrate additional health benefits beyond the numbers on a scale to get approved.

The drugs are being tested to complement or replace the wildly popular Wegovy from Novo Nordisk and Eli Lilly’s Zepbound, which in trials helped patients lose 15% to 20% of their weight, but also caused a decline in muscle that some doctors find concerning. In trials of Wegovy, up to 40% of weight loss was from a decrease in lean or fat-free mass, rather than excess fat.

New Approaches

These experimental medicines are still a few years from possible approval.

While weight loss drugs from Novo Nordisk and Eli Lilly helped patients lose 15% to 20% of their weight, it also decreased their muscle mass. REUTERS

The dozen new drugs, including those furthest along in development from Eli Lilly, Regeneron, Scholar Rock, and Veru, target proteins tied to muscle preservation or growth. Wegovy and Zepbound target the GLP-1 protein to help control appetite.

Veru was first with results in January from a 168-person trial, showing its enobosarm helped older patients lose 71% less muscle when taken with Wegovy. Data on Lilly’s muscle mass-preserving drug, bimagrumab, is due this year.

Targeting Muscle Growth

These new weight loss drugs target the myostatin protein, which promotes muscle growth and decreases fat due to its constant source of energy. Getty Images/iStockphoto

Veru, whose drug targets androgen receptor cells to promote muscle growth, will use stair climb ability as a late-stage trial goal.

Lilly, which acquired bimagrumab with its $1.9 billion purchase of biotech Versanis, is testing the drug alone and in combination with Zepbound, and will complete a study with Novo’s Wegovy begun prior to the 2023 acquisition.

Future Outlook

Westport, Connecticut-based New England Consulting Group estimates the drugs could collectively bring in $1 billion to $5 billion a year by the end of the decade. Analysts have projected obesity drugs sales reaching $150 billion a year by the early 2030s.

Some doctors say drugs that improve muscle mass could benefit older or infirm people at greater risk of falls and fractures. A higher portion of muscle can also help patients keep weight off for longer, experts say.

“If the narrative shifts from amount of weight lost over to how long someone can actually keep that weight loss off, that might be a powerful story,” said Riley McCarthy, senior project manager at NECG.

FDA Considerations

How the Food and Drug Administration will approach measuring the benefits of these drugs for the purpose of approving them is uncertain.

FDA draft guidelines published in January say loss of lean mass is not harmful, but still suggest measuring trial participants’ muscle-to-fat ratio at least twice. It advised companies testing muscle preservation to consult with the agency early about their chosen methods.

It is unlikely for the Food and Drug Administration to approve a weight loss drug due to its muscle preservation. REUTERS

Analysts and clinical trial experts expressed doubts on whether FDA would approve a drug solely on muscle-mass effect.

“There’s a real uphill battle to get something like that approved because the FDA does not approve drugs on the basis of muscle building or muscle preservation in this (obesity) setting,” said BMO Capital Markets analyst Evan Seigerman.

Future treatments will need to show benefits such as fewer side effects and improved heart health, he added.

FAQs

Q: What are the new weight loss drugs targeting?

A: The new drugs target proteins tied to muscle preservation or growth, such as myostatin and activin.

Q: How do these drugs work?

A: They promote muscle growth and decrease fat due to their constant source of energy.

Q: What are the potential benefits of these drugs?

A: They may benefit older or infirm people at greater risk of falls and fractures, and help patients keep weight off for longer.

Q: How likely is FDA approval?

A: Analysts and clinical trial experts are uncertain about FDA approval, as the agency may require additional health benefits beyond weight loss.

Q: What are some of the key players in the development of these drugs?

A: Eli Lilly, Regeneron, Scholar Rock, and Veru are among the companies developing these new weight loss drugs.