GSK’s Efimosfermin receives dual fast-track designations for MASH treatment

UK—GSK plc has secured two major regulatory designations for efimosfermin, its once-monthly investigational therapy for metabolic dysfunction-associated steatohepatitis (MASH), strengthening the company’s push into liver disease treatment.

The US Food and Drug Administration (FDA) has granted the medicine Breakthrough Therapy Designation, while the European Medicines Agency (EMA) has awarded it Priority Medicines (PRIME) Designation.

Both pathways are designed to accelerate the development and review of promising therapies for serious diseases with limited treatment options.

MASH, formerly known as non-alcoholic steatohepatitis (NASH), is a progressive liver disease linked to fat buildup, inflammation, and scarring in the liver.

It can lead to cirrhosis, liver failure, liver cancer, and the need for liver transplantation.

Regulatory boost for development

The FDA grants Breakthrough Therapy status when early clinical evidence suggests a medicine may offer substantial improvement over currently available therapies.

Likewise, the EMA’s PRIME programme supports medicines that could meet major unmet medical needs by offering early scientific and regulatory guidance.

These recognitions may help speed up efimosfermin’s clinical development and future review processes in both the United States and Europe.

GSK highlights unmet need

Kaivan Khavandi, Senior Vice President and Head of R&D for Respiratory, Immunology & Inflammation, as well as Head of Translational and Development Sciences at GSK, said MASH affects millions of people worldwide and remains one of the leading causes of liver transplantation in the US and Europe.

He noted that treatment options remain limited for many patients and are currently unavailable for those with the most advanced stage of the disease.

He added that the new designations reflect growing momentum in GSK’s liver disease programme and recognition of efimosfermin’s potential.

According to Khavandi, the therapy could help improve standards of care by directly targeting liver fibrosis, the scarring process that drives disease progression.

Clinical trial evidence

The regulatory decisions were supported by data from patients with moderate-to-advanced fibrosis (F2/F3) and cirrhotic fibrosis (F4).

In a Phase II study involving F2/F3 patients, efimosfermin showed improvement in liver fibrosis and resolution of MASH after 48 weeks of treatment compared with placebo. Researchers also reported a favourable safety profile.

Most side effects were mild and temporary, with nausea, vomiting, and diarrhoea among the most commonly reported events.

Phase III programme underway

Efimosfermin has now moved into Phase III development through the ZENITH-1 and ZENITH-2 trials, which are evaluating its safety and effectiveness in patients with F2/F3 fibrosis.

GSK also expects to begin Phase III studies this year in patients with cirrhotic MASH (F4), a group with no approved liver-specific treatment options.

Growing global burden

MASH affects up to 5% of the global population and continues to place increasing pressure on healthcare systems.

Fibrosis remains the strongest predictor of serious complications, making treatments that reduce scarring a major focus for researchers and drugmakers.