REG - GSK PLC - Efimosfermin granted US/EU regulatory designations

GSKAnnouncement

Today 12:00

For best results when printing this announcement, please click on link below:
https://newsfile.refinitiv.com/getnewsfile/v1/story?guid=urn:newsml:reuters.com:20260427:nRSa0447Ca&default-theme=true

RNS Number : 0447C  GSK PLC  27 April 2026

Issued: 27 April 2026, London UK

 

GSK's investigational liver therapy, efimosfermin, receives US FDA
Breakthrough Therapy and EMA Priority Medicines (PRIME) designations for MASH

 

·   Phase II data show once-monthly efimosfermin improved liver fibrosis
(scarring), a key driver of disease progression in metabolic
dysfunction-associated steatohepatitis (MASH)

·   MASH is a leading cause of liver transplant in the US and Europe

·   Designations recognise potential for efimosfermin to address
significant unmet medical need and reflect momentum in GSK's liver health
pipeline

 

 

 

GSK plc (LSE/NYSE: GSK) today announced that efimosfermin, a once-monthly
investigational liver therapy, has

been granted Breakthrough Therapy Designation by the US Food and Drug
Administration (FDA) and Priority Medicines (PRIME) Designation by the
European Medicines Agency (EMA) for the treatment of MASH.

 

The FDA designation is designed to expedite the development and review of
medicines for serious conditions, where preliminary clinical evidence
indicates the potential for substantial improvement over available therapy.(1)
The EMA designation provides scientific and regulatory support for medicines
that have the potential to address significant unmet medical need.(2)

 

Kaivan Khavandi, SVP, R&D Head Respiratory, Immunology & Inflammation
(RI&I), and Head of Translational & Development Sciences, GSK, said:
"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. These
designations recognise efimosfermin's potential and reflect GSK's accelerating
momentum in liver health. We believe efimosfermin has the potential to
significantly advance the standard of care by directly targeting liver
fibrosis."

 

The two designations were supported by data from MASH patients with moderate
to advanced (F2/F3) and cirrhotic (F4) fibrosis. This includes phase II data
at 48 weeks for F2/F3 patients who showed fibrosis improvement and MASH
resolution with once-monthly efimosfermin versus placebo. Data also confirmed
a well-tolerated safety profile with mild, transient adverse events, including
nausea, vomiting, and diarrhoea.(3,4) Efimosfermin is currently in phase III
with the ZENITH-1 and ZENITH-2 trials investigating efficacy and safety in
MASH patients with F2/F3 fibrosis. Phase III trials in MASH patients with F4
fibrosis are expected to start this year.

 

MASH is a chronic, progressive liver disease that affects up to 5% of the
global population and is a leading cause of liver transplants in both the US
and Europe.(5-7) The buildup of scar tissue, or fibrosis, is a key predictor
of serious outcomes for patients, including cirrhosis, liver failure and liver
cancer.(8) Currently, liver-specific treatment options are limited for those
with moderate to advanced fibrosis and there are no approved treatments for
cirrhotic MASH (F4).(8)

( )

About efimosfermin
Efimosfermin is an investigational, once-monthly subcutaneous injection of a
long-acting variant of FGF21 that is designed to regulate key metabolic
pathways to decrease liver fat, ameliorate liver inflammation, and reverse
liver fibrosis in patients with MASH. Efimosfermin is currently in trials for
moderate to advanced fibrosis, including cirrhosis, and is not available for
prescription anywhere in the world.

 

About GSK research in hepatology

GSK is extending its expertise in inflammation to develop a next wave of
innovation for the millions of people

affected by chronic and life-threatening fibro-inflammatory liver conditions.
Harnessing the science of the immune

system and advanced technologies, GSK is committed to advancing its hepatology
pipeline with potential therapies

for chronic hepatitis B, metabolic dysfunction-associated steatohepatitis
(MASH) and alcohol-associated liver disease (ALD).

 

About GSK
GSK is a global biopharma company with a purpose to unite science, technology,
and talent to get ahead of disease together. Find out more at gsk.com.

 

 GSK enquiries
 Media:               Tim Foley            +44 (0) 20 8047 5502  (London)
                      Sarah Clements       +44 (0) 20 8047 5502  (London)
                      Kathleen Quinn       +1 202 603 5003       (Washington DC)
                      Sydney Dodson-Nease  +1 215 370 4680       (Philadelphia)

 Investor Relations:  Constantin Fest      +44 (0) 7831 826525   (London)
                      James Dodwell        +44 (0) 20 8047 2406  (London)
                      Mick Readey          +44 (0) 7990 339653   (London)
                      Steph Mountifield    +44 (0) 7796 707505   (London)
                      Sam Piper            +44 (0) 7824 525779   (London)
                      Jeff McLaughlin      +1 215 751 7002       (Philadelphia)
                      Frannie DeFranco     +1 215 751 3126       (Philadelphia)

 

Cautionary statement regarding forward-looking statements

GSK cautions investors that any forward-looking statements or projections made
by GSK, including those made in this announcement, are subject to risks and
uncertainties that may cause actual results to differ materially from those
projected. Such factors include, but are not limited to, those described in
the "Risk Factors" section in GSK's Annual Report on Form 20-F for 2025.

 

Registered in England & Wales:

No. 3888792

 

Registered Office:

79 New Oxford Street

London

WC1A 1DG

 

References

1 U.S. Food & Drug Administration. Breakthrough Therapy. Available at:
https://www.fda.gov/patients/fast-track-breakthrough-therapy-accelerated-approval-priority-review/breakthrough-therapy
(https://www.fda.gov/patients/fast-track-breakthrough-therapy-accelerated-approval-priority-review/breakthrough-therapy)
. Last accessed: 16 April 2026.

2 European Medicines Agency. PRIME: Priority Medicines. Available
at: https://www.ema.europa.eu/en/human-regulatory-overview/research-development/prime-priority-medicines
(https://www.ema.europa.eu/en/human-regulatory-overview/research-development/prime-priority-medicines)
. Last accessed: 16 April 2026.

3 Noureddin M, Kowdley K, Odrljin T et al. Efimosfermin alfa (BOS-580) once
per month in people with metabolic dysfunction-associated steatohepatitis with
F2 or F3 fibrosis: results from a 24-week, randomised, double-blind,
placebo-controlled, phase 2 trial. Lancet, 2026; 407: 794-804.

4 Once-Monthly Efimosfermin Alfa for Up to 48 Weeks in MASH With F2/F3
Fibrosis: Results From a Phase 2, Open-Label Extension Study. Gastroenterol
Hepatol (N Y). 2025 Dec;21(12 Suppl 11):7-9. PMID: 41660650; PMCID:
PMC12879048.

5 Povsic M, et al. A Structured Literature Review of the Epidemiology and
Disease Burden of Non-Alcoholic Steatohepatitis (NASH). Advances in Therapy.
2019;36(7):1574-94. DOI: 10.1007/s12325-019-00960-3.

6 Paklar N, Mijic M, Filipec-Kanizaj T. The Outcomes of Liver Transplantation
in Severe Metabolic Dysfunction-Associated Steatotic Liver Disease Patients.
Biomedicines. 2023;11(11):3096.

7 Younossi Z, Germani G, Wong R, et al. Steatotic liver disease is the
dominant indication for liver transplantation in both Europe and the United
States: Trends and outcomes in the past 2 decades. Liver Transplantation.
2026;32(4):549-557. DOI: 10.1097/LVT.0000000000000688.

8 Miller DM, McCauley KF, Dunham-Snary KJ. Metabolic Dysfunction-Associated
Steatotic Liver Disease (MASLD): Mechanisms, Clinical Implications and
Therapeutic Advances. Int J Mol Sci. 2024;25(10):5487. Available
at: https://pmc.ncbi.nlm.nih.gov/articles/PMC12627968/
(https://pmc.ncbi.nlm.nih.gov/articles/PMC12627968/) . Last accessed: 16 April
2026.

 

 

This information is provided by RNS, the news service of the London Stock Exchange. RNS is approved by the Financial Conduct Authority to act as a Primary Information Provider in the United Kingdom. Terms and conditions relating to the use and distribution of this information may apply. For further information, please contact
rns@lseg.com (mailto:rns@lseg.com)
 or visit
www.rns.com (http://www.rns.com/)
.

RNS may use your IP address to confirm compliance with the terms and conditions, to analyse how you engage with the information contained in this communication, and to share such analysis on an anonymised basis with others as part of our commercial services. For further information about how RNS and the London Stock Exchange use the personal data you provide us, please see our
Privacy Policy (https://www.lseg.com/privacy-and-cookie-policy)
.   END  MSCKZGZDLNRGVZG



            Copyright 2019 Regulatory News Service, all rights reserved