Eli Lilly Halts Muscle Mass Drug Trial in Surprise Setback

Pharma giant Eli Lilly pulls the plug on experimental treatment aimed at preserving muscle mass—raising questions about the future of metabolic therapeutics.

Clinical Roadblock Hits Big Pharma

The decision to stop the trial mid-stream signals deeper challenges in developing drugs that target muscle preservation. Lilly isn't disclosing specific data behind the halt, but industry watchers note the failure adds to recent stumbles in metabolic disease research.

Wall Street's reaction was predictably muted—because when you're printing money from weight-loss drugs, who needs muscle mass anyway?

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The study was a Phase 2 clinical trial testing the drug Bimagrumab, alone and in combination with Eli Lilly’s existing Zepbound weight-loss medicine. The study that was halted also included people with Type 2 diabetes. Eli Lilly said the trial was canceled for “strategic business reasons,” and that it often decides to stop clinical trials after evaluating them and the potential of drug candidates.

The medication Bimagrumab is designed to preserve muscle in people taking weight-loss medications such as Zepbound. Obesity drugs can have a side effect that cuts lean mass as well as burns fat. The clinical trial involving Bimagrumab appears to have not gone as planned or hoped.

Improving Treatments

Eli Lilly has said that it wants to build on the success of Zepbound with new medicines that can address its limitations and side effects. Among those weaknesses are the loss of muscle that can occur in people taking obesity drugs, in part because a suppressed appetite leads them to consume less protein.

The clinical trial that Eli Lilly terminated was expected to enroll 180 people and finish in late 2026. The trial had been measuring how well Bimagrumab stimulates weight loss and preserves muscle mass. Initial results had been expected in April 2026.

Is LLY Stock a Buy?

The stock of Eli Lilly has a consensus Strong Buy rating among 20 Wall Street analysts. That rating is based on 16 Buy and four Hold recommendations issued in the last three months. The average LLY price target of $909.31 implies 26.77% upside from current levels.