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Scholar Rock's drug helps Zepbound patients retain more muscle in trial
By Christy Santhosh and Padmanabhan Ananthan - 6/18/2025
By Christy Santhosh and Padmanabhan Ananthan
(Reuters) -Scholar Rock said on Wednesday a combination of its experimental drug and Eli Lilly's weight-loss treatment Zepbound helped overweight patients preserve significantly more lean mass in a mid-stage study, sending its shares up 15%.
The Massachusetts-based biotech is among the dozen or so companies racing to develop treatments that can help people shed weight without losing muscle, as they look to enter the potential $150 billion weight-loss drug market dominated by Novo Nordisk and Eli Lilly.
The reduction of muscle accompanying weight-loss drugs such as Lilly's Zepbound and Novo's Wegovy has left some doctors concerned about a possible decrease in overall strength, especially in older patients.
In Scholar Rock's study, patients who received a combination of tirzepatide - the active ingredient in Zepbound - and Scholar's apitegromab lost 3.4 pounds of lean mass after 24 weeks, compared with those on tirzepatide alone, who lost 7.6 pounds of lean mass.
However, total fat loss and weight change were consistent across both groups.
Analysts have said the regulatory path forward for treatments aimed at muscle preservation remains unclear, as the Food and Drug Administration requires them to show additional weight loss or other benefits to be approved.
Another injectable drug from Regeneron and an oral treatment by Veru have also helped patients preserve more lean mass when used in combination with Novo Nordisk's Wegovy during mid-stage trials, but these remain a few years away from approval. Regeneron's drug combination has also shown additional weight loss in a study.
Truist analyst Srikripa Devarakonda said the data from apitegromab shows a superior safety profile than Regeneron's drug as none of the patients in Scholar's trial discontinued treatment or experienced severe side effects.
Investors are more closely focused on a U.S. regulatory decision for apitegromab to treat a genetic condition known as spinal muscular atrophy, which is expected by September.
(Reporting by Christy Santhosh and Padmanabhan Ananthan in Bengaluru; Editing by Devika Syamnath)