Efimosfermin Receives Breakthrough Designation for Treatment of MASH

GSK’s investigational liver therapy, efimosfermin, was given both Breakthrough Therapy and European Medicines Agency Priority Medicines (PRIME) designations for its use among patients with metabolic dysfunction-associated steatohepatitis (MASH), according to a GSK news release.¹

“MASH affects millions of people worldwide and is one of the leading causes of liver transplant in the US and Europe, but treatment options are limited for most and non-existent for those with the most advanced form of disease,” said Kaivan Khavandi, MD, MRCP, PhD, senior vice president of research and development in head respiratory, immunology and inflammation, and head of translational and development sciences at GSK. “These designations recognize efimosfermin’s potential and reflect GSK’s accelerating momentum in liver health.”

This significant regulatory momentum in GSK’s liver health pipeline follows phase 2 data demonstrating that once-monthly efimosfermin improved liver fibrosis and achieved MASH resolution in patients with moderate-to-advanced disease.¹

READ MORE: New Data Show Semaglutide’s Liver Benefits Not Exclusively Tied to Weight Loss

For the pharmacy community, these designations signal that the landscape of metabolic liver care is rapidly shifting from a field once considered a “graveyard” for drug development into a new era of diverse, targeted pharmacological interventions, according to a study in the International Journal of Translational Medicine.²

The urgency for these therapies is underscored by the fact that MASH, formerly known as nonalcoholic steatohepatitis (NASH), is now a leading cause of liver transplantation in the US and Europe. While early stages of metabolic dysfunction-associated steatotic liver disease (MASLD) may be asymptomatic, the progression to MASH involves lobular inflammation and hepatocyte ballooning—which can lead to cirrhosis, liver failure, and hepatocellular carcinoma.^1-3

Efimosfermin, an FGF21 analogue, addresses this by regulating metabolic pathways to decrease liver fat and reverse fibrosis. It joins a robust pipeline of other novel agents, such as ION224, the first enzyme-targeting drug that blocks DGAT2 to interrupt fat accumulation and inflammation at the source.^1,3

Pharmacists’ Role in Addressing Evolving MASH Guidelines, Therapies

Pharmacists are increasingly positioned at the forefront of this therapeutic revolution, particularly as specialized hepatology resources face projected scarcities.^4,5

The recent FDA approval of resmetirom (Rezdiffra)—a thyroid hormone receptor-beta agonist—and updated practice guidance from the American Association for the Study of Liver Diseases (AASLD) regarding semaglutide therapy illustrate the growing complexity of MASH management.^2,6

AASLD’s new guidance provides clinicians and pharmacists with evidence-based criteria for patient selection and monitoring when utilizing glucagon-like peptide-1 (GLP-1) receptor agonists for MASH patients with moderate-to-advanced fibrosis.⁶

As the industry moves toward next-generation polyagonists—drugs like tirzepatide and retatrutide, that target multiple receptors simultaneously—pharmacists will play a critical role in personalized therapy and adherence. While these polyagonists show potent results in liver fat reduction, they also introduce new clinical challenges, such as the potential loss of lean muscle mass during rapid weight loss, according to a recent Drug Topics article.⁵

Pharmacists are essential for counseling patients on precision nutrition and monitoring for rare but serious adverse effects like gallbladder disease. Similarly, for patients on efimosfermin, pharmacists must manage and educate on well-tolerated but common gastrointestinal side effects, including nausea and diarrhea.^1,5

Beyond medication management, however, pharmacists in community settings are becoming vital facilitators in early screening and detection.⁴

By utilizing non-invasive tools such as portable ultrasound devices, FibroScan, and validated risk calculators like the FIB-4 or NAFLD Fibrosis Score, pharmacists can identify high-risk individuals and initiate necessary referrals to specialists. This proactive role is especially important given that MASH is often a silent disease that can progress for years without symptoms.^2-4

How This Designation Informs the Future of MASH Treatment

The ongoing phase 3 ZENITH trials for efimosfermin, along with late-phase studies for various drug classes including PPAR agonists and sodium-glucose cotransporter 2 (SGLT2) inhibitors, suggest that the future of MASH treatment may eventually involve combination regimens to target the disease’s multifaceted nature.^1,2

By bridging the gap between innovative science and holistic patient care, pharmacists are uniquely positioned to guide patients through this shift toward life-saving, liver-protecting therapies. This evolving role ensures that as new treatments like efimosfermin move toward official approval, the health care system is prepared to identify, treat, and monitor the millions affected by this chronic liver condition.^4,5

“We believe efimosfermin has the potential to significantly advance the standard of care by directly targeting liver fibrosis,” concluded GSK’s Khavandi, according to the release.¹

READ MORE: FDA Updates Resource Center

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REFERENCES

1. GSK’s investigational liver therapy, efimosfermin, receives US FDA Breakthrough Therapy and EMA Priority Medicines (PRIME) designations for MASH. News Release. GSK. April 27, 2026. Accessed April 27, 2026. https://www.gsk.com/en-gb/media/press-releases/gsk-s-investigational-liver-therapy-efimosfermin-receives-us-fda-breakthrough-therapy/

2. Dinerman S, Shu Y. Therapeutic strategies for MASH: an update on drug candidates under investigation in late-phase clinical trials. Int J Transl Med (Basel). 2025 Mar;5(1):7. doi: 10.3390/ijtm5010007.

3. Aquinde L. First enzyme-targeting drug reverses liver damage in MASH. UC San Diego Health. August 27, 2025. Accessed April 27, 2026. https://health.ucsd.edu/news/press-releases/2025-08-27-first-enzyme-targeting-drug-reverses-liver-damage-in-mash/

4. Syed-Abdul MM. Expanding pharmacists’ role in the management of non-alcoholic fatty liver disease. Pharmacy (Basel). 2023 Sep 21;11(5):151. doi: 10.3390/pharmacy11050151.

5. Nowosielski B. Pharmacists can lead shift toward liver-protecting polyagonists. Drug Topics. March 16, 2026. Accessed April 27, 2026. https://www.drugtopics.com/view/pharmacists-can-lead-shift-toward-liver-protecting-polyagonists

6. AASLD announces update to metabolic dysfunction‐associated steatotic liver disease (MASLD) practice guidance. News Release. American Association for the Study of Liver Diseases. November 7, 2025. Accessed April 27, 2026. https://www.aasld.org/aasld-announces-update-metabolic-dysfunction-associated-steatotic-liver-disease-masld-practice