Regeneron stock: CIDEB data deepen focus on MASH pipeline

Published on 11/11/2026 at 14:13 | Editorial responsibility: Rafael Müller, Editor-in-Chief AD HOC NEWS

Regeneron stock stays in focus after CIDEB siRNA cut liver fat in an early MASLD trial. Further studies are recruiting.

CIDEB data sharpen pipeline focus

A single dose produced sustained liver-fat reductions through week 36 in an early MASLD trial.
Regeneron is evaluating CIDEB siRNA in additional Phase 2a, Phase 2b and Phase 3 studies.
The treatment remains investigational and has not received regulatory approval.

Regeneron, US75886F1075, Illustration mit AI erstellt.

Regeneron Pharmaceuticals reported on Sunday, November 8, that a single dose of investigational CIDEB siRNA produced sustained liver-fat reductions in adults with metabolic dysfunction-associated steatotic liver disease, or MASLD. The results were presented at the 2026 meeting of the American Association for the Study of Liver Diseases and published simultaneously in the New England Journal of Medicine.

According to the company's November 8 release, liver fat fell by 58% to 80% at week 36 among recipients of CIDEB siRNA, measured by magnetic resonance imaging-proton density fat fraction. The reduction had reached 49% to 72% at week six, while the placebo group recorded a mean decrease of 2.9% at week 36.

Early results support further testing

The Phase 1/2 trial evaluated one subcutaneous dose at four dose levels in 30 participants receiving CIDEB siRNA and compared them with 10 placebo recipients. Safety and tolerability were the primary objectives; liver fat and liver-injury markers were secondary measures.

Liver fat fell below 5% in 62% of CIDEB siRNA recipients at week 36, compared with none of the placebo recipients. Regeneron also said 93% of treated participants achieved at least a 30% reduction in liver fat, a threshold linked to histological MASH resolution. Alanine aminotransferase levels declined across all doses, while aspartate aminotransferase changes moved in the same direction.

The findings are encouraging but remain early-stage. Regeneron said overall adverse-event rates were generally similar between the treatment and placebo groups and that all adverse events were mild or moderate except for one severe, serious hyperglycemia event that was not attributed to the study drug. No trial discontinuations occurred in the CIDEB siRNA groups.

Longer-term safety and histological outcomes are being evaluated in ongoing Phase 2a, Phase 2b and Phase 3 trials. The company's release states that CIDEB siRNA is investigational and that its safety and efficacy have not been evaluated by a regulatory authority. That leaves later-stage efficacy, durability and safety results as the main development hurdles for the program.

Investor attention turns to the pipeline

Regeneron had scheduled a virtual MASH pipeline roundtable for Tuesday, November 10, at 8:30 a.m. Eastern time. The event page lists the webcast and supporting presentation. Investors will be watching for updates on trial recruitment, dosing strategy and the path toward later-stage studies.