Regeneron reports up to 80% liver‑fat reduction in early CIDEB siRNA trial

Regeneron Pharmaceuticals disclosed that a single dose of its CIDEB siRNA candidate lowered liver fat by as much as 80% after 36 weeks in a Phase 1/2 study of adults with metabolic dysfunction‑associated steatohepatitis (MASLD). The company said the trial showed no clear treatment‑related effects on glucose or hemoglobin A1C and noted one serious hyperglycaemic event that was judged unrelated to the drug. Regeneron also highlighted a rare loss‑of‑function CIDEB variant present in about one in 500 people that is linked to a 43% lower risk of liver disease and 22% lower liver fat, and it estimated the U.S. MASH market at roughly $1 billion now, potentially expanding to $15 billion by 2035.

If the liver‑fat reduction translates into clinical benefit, the candidate could address a large, growing market, adding a new revenue stream for Regeneron. The market‑size estimate of $1 billion today and $15 billion by 2035, cited by the company, underscores the financial upside.

  • 1A single dose of CIDEB siRNA reduced liver fat by up to 80% at 36 weeks in a Phase 1/2 trial.
  • 2The trial showed no clear treatment‑related effects on glucose or hemoglobin A1C.
  • 3One serious hyperglycaemic event occurred in a patient with pre‑existing diabetes and was assessed as unrelated to the study drug.
  • 4Regeneron identified a rare loss‑of‑function CIDEB variant in approximately one in 500 people, associated with a 43% lower risk of liver disease and 22% lower liver fat.
  • 5The company estimates the U.S. MASH market at about $1 billion in net sales now and projects it could reach $15 billion or more by 2035.
  • 6MASH affects roughly 13 million U.S. adults, with an addressable population of 5 million to 5.5 million adults with F2 or F3 fibrosis.

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