Lilly halts one bimagrumab trial in diabetes, citing strategic business reasons
Lilly stopped one mid-stage test of a muscle-preserving drug for people with obesity and type 2 diabetes, while a separate study in non-diabetic obesity continues.
Eli Lilly has stopped a Phase 2 trial of its experimental muscle-sparing drug bimagrumab in people with obesity and type 2 diabetes, citing "strategic business reasons," according to a federal database [1]. The trial stoppage was first reported by Bloomberg [1].
In an email, a Lilly spokesperson said company executives "routinely evaluate our clinical development programs to optimize the potential for each product," and noted that a separate trial testing bimagrumab in people with obesity who do not have diabetes is still running [1].
The canceled study was one of two Phase 2 trials of bimagrumab, which is being tested alone or with Lilly's marketed obesity drug Zepbound (tirzepatide) [1]. The halted study was expected to enroll 180 people and finish in late 2026 [1]. Lilly has not disclosed whether any data collected before the stop will be published.
Why muscle loss is the focus
Bimagrumab is one of several drugs in development designed to protect muscle in people taking weight loss medicines such as Zepbound and Novo Nordisk's Wegovy (semaglutide), which can reduce lean mass along with fat [1]. One reason is that a suppressed appetite and slower digestion can lead people to eat less protein [1]. The hope is that muscle-sparing drugs could preserve muscle without blunting the weight loss that GLP-1 medicines are known for [1].
According to BioPharma Dive, Regeneron Pharmaceuticals, Biohaven, Scholar Rock and Veru also have muscle-sparing obesity drugs in development [1]. Bimagrumab was originally discovered by Novartis and tested against rare muscle-wasting conditions such as sarcopenia and inclusion body myositis [1]. Novartis licensed it to the biotech startup Versanis Bio, which launched in 2021, and Lilly bought Versanis for up to $1.9 billion two years later [1].
The remaining bimagrumab study is listed in a federal database as recruiting patients who receive either a placebo or several dosing regimens of bimagrumab, with or without Zepbound [1]. It is measuring how well the regimens stimulate weight loss and preserve muscle mass, with initial results expected around April 2026 [1].
A shifting regulatory signal
The FDA appears to be indicating that drugs like bimagrumab may need to do more than improve muscle composition [1]. Veru said earlier the same week that the agency "now guides that incremental weight loss" over a GLP-1 drug alone "is an acceptable primary endpoint to support approval" [1]. Veru's shares fell 3% on Tuesday after that announcement and another 3% on Thursday [1]. BioPharma Dive reported that at least one biotech has said additive weight loss effects are an approval requirement, suggesting higher clearance standards have been set by the FDA [1].
Why it matters for patients
Nothing changes for people taking currently approved GLP-1 medicines. Bimagrumab is not approved for any use, and the halted study involved an experimental combination, not a marketed product [1]. Ozempic, Wegovy and Rybelsus are brand names for semaglutide; Mounjaro and Zepbound are brand names for tirzepatide.
The practical question for patients is whether muscle-preserving options will eventually be available alongside weight loss drugs. That remains unresolved: one of two Phase 2 trials for bimagrumab has been stopped, and no approved product in this class exists yet [1].
How much muscle people actually lose while taking GLP-1 medicines, and whether adding a second drug safely prevents it, is still being studied. The trial that continues is designed to measure both weight loss and muscle preservation, so its results should give the clearest picture so far [1].
What happens next
The continuing Phase 2 trial of bimagrumab, with or without Zepbound, is listed as recruiting and has initial results expected around April 2026 [1]. Lilly has not said what will happen to the diabetes-focused study beyond its cancellation, and the company has not disclosed whether the decision affects other bimagrumab programs [1]. Several other companies are running their own muscle-sparing programs, and the FDA's stated position on what those drugs must show for approval could shape how quickly any of them reach patients [1].
Sources
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