Regeneron Pharmaceuticals said on Monday its experimental weight-loss drug combination helped preserve muscle mass in a mid-stage study.

The drug candidate, trevogrumab, in combination with Novo Nordisk's popular obesity drug Wegovy, chemically known as semaglutide, helped patients preserve muscle and increase fat loss in patients, Regeneron said.

The combination helped preserve up to 80% of the lean mass compared to semaglutide alone, according to interim data from the study.

However, a triple combination of Novo's semaglutide, Regeneron's trevogrumab and experimental antibody garetosmab led to a substantially higher rate of discontinuation due to tolerability issues and other side effects, Regeneron said.

The full data set will be available later this year, the drugmaker said.