The decision to stop the Phase IIb study was driven by “strategic business reasons,” according to a federal clinical trials database.
Eli Lilly has pulled the plug on a Phase IIb trial that was testing the investigational antibody bimagrumab in combination with Zepbound to improve weight loss.
According to a federal clinical trials database, the termination was due to “strategic business reasons.” The page does not provide additional details regarding the discontinuation. Lilly did not respond to BioSpace‘s request for comment by the time of publication.
The Phase IIb trial was evaluating bimagrumab alone and in combination with the blockbuster weight-loss drug tirzepatide, marketed as Zepbound for weight loss. It had an initial enrollment target of 180 patients who had type 2 diabetes and overweight or obese. The study was primarily designed to assess change in body weight over 36 weeks, but it was also meant to look specifically at how much body fat and visceral adipose tissue patients lost after treatment with bimagrumab.
These specific secondary outcomes are in line with bimagrumab’s mechanism of action. The antibody works by binding to activin/myostatin type II receptors, in turn helping to promote the formation of muscle. The drug is being proposed not just to help patients lose pounds, but also to improve the quality of weight loss by preserving lean mass.
In June, Lilly released Phase IIb data showing that bimagrumab indeed helped maintain muscle mass in patients undergoing treatment with Novo Nordisk’s semaglutide. At 72 weeks, patients on the combo regimen lost 22.1% of their body weight, with 92.8% of this weight loss attributable to fat loss. In comparison, semaglutide alone resulted in a 15.7% drop in weight, 71.8% of which was fat.
Notably, patients on bimagrumab alone lost 10.8% of their weight over 72 weeks, all of which was fat.
Aside from bimagrumab, Lilly’s push to preserve muscle during weight loss includes a recent deal with California-based Juvena Therapeutics. The pharma in June bet up to $650 million—including an undisclosed upfront commitment—to leverage the biotech’s AI platform to discover and develop novel drugs that could help maintain both muscle mass and function during weight-loss.
Joining Lilly in the muscle-preservation space is Regeneron, which in June released Phase II data for the investigational antibody trevogrumab, touting a 51.3% boost in muscle preservation versus semaglutide monotherapy. Adding on another therapy, dubbed garetosmab, increased preserved muscle to 80.9% relative to semaglutide.
That same month, Scholar Rock announced that apitegromab, when used alongside Lilly’s tirzepatide, preserves 55% more muscle mass than tirzepatide alone.
