Home›The Library›Efruxifermin

Efruxifermin

Written by The Peptide Record editorialClinical review not yet completedLast reviewed 15 September 2026Funding No ads, no affiliate links, no vendor payment

Efruxifermin is a real, Phase 3 fibroblast growth factor 21 (FGF21) analog for MASH-related liver fibrosis and cirrhosis — not approved anywhere yet, but real enough that Novo Nordisk paid up to $5.2 billion for the company developing it in December 2025. Its own pivotal cirrhosis trial is a genuinely mixed result worth knowing before treating this as simple good news: it missed its own primary statistical endpoint at 36 weeks, then reported a real, statistically significant cirrhosis-reversal signal at 96 weeks.

In brief

Should you care? Yes if you're tracking the MASH/fatty-liver-disease drug space — efruxifermin is a genuinely instructive case of a drug that missed its own primary statistical endpoint and still attracted a multibillion-dollar acquisition, which is worth understanding rather than skipping past.

The short version

Efruxifermin (EFX) is an Fc-FGF21 fusion protein from Akero Therapeutics — a different drug class from the GLP-1/glucagon peptides covered elsewhere on this site.
Its Phase 2b SYMMETRY trial missed its 36-week primary endpoint (fibrosis improvement without worsening of MASH, not statistically significant) but reported a real 96-week cirrhosis-reversal result (39% vs. 15% on placebo, P=.009).
Novo Nordisk acquired Akero for up to $5.2 billion (announced 9 October 2025, completed 9 December 2025) specifically to get this molecule.
Not approved anywhere — the Phase 3 SYNCHRONY program (three separate trials) is ongoing.

What it is, and the mechanism

Efruxifermin (EFX) is a fusion protein pairing an engineered, longer-acting variant of fibroblast growth factor 21 (FGF21) — a natural metabolic hormone — with an antibody Fc fragment, extending its half-life to once-weekly subcutaneous dosing. It was developed by Akero Therapeutics for metabolic dysfunction-associated steatohepatitis (MASH, formerly called NASH), a liver disease with no FGF21-class drug approved anywhere yet. Unlike the GLP-1-family peptides covered elsewhere on this site, FGF21 analogs act directly on liver fat, inflammation and fibrosis rather than primarily through appetite suppression.

The Phase 2b SYMMETRY trial: a mixed result

SYMMETRY (ClinicalTrials.gov NCT05039450), Akero's Phase 2b trial in patients with compensated cirrhosis (fibrosis stage F4) caused by MASH, randomized patients to 28mg or 50mg efruxifermin weekly or placebo. Its pre-specified primary endpoint — at least one stage of fibrosis improvement without worsening of MASH at week 36 — was not met at a statistically significant level (Noureddin M, Rinella ME, Chalasani NP, Neff GW, Lucas KJ, et al., N Engl J Med 2025;392(24):2413-2424, DOI 10.1056/NEJMoa2502242, PMID 40341827). At week 96, however, the trial reported a real, statistically significant secondary result: 39% of patients on the 50mg dose with paired biopsies had reversal of cirrhosis with no worsening of MASH, versus 15% on placebo (P=.009).

Phase 3, and the Novo Nordisk acquisition

Akero is running three Phase 3 trials under the SYNCHRONY name: SYNCHRONY Histology (pre-cirrhotic F2/F3 MASH), SYNCHRONY Real-World (a broader, non-invasively diagnosed MASH/MASLD population, with topline data anticipated in the first half of 2026), and SYNCHRONY Outcomes (compensated F4 cirrhosis). On 9 October 2025, Novo Nordisk announced a definitive agreement to acquire Akero for $54 per share in cash (about $4.7 billion) plus a contingent value right of up to $6 per share (roughly $0.5 billion more) payable if efruxifermin reaches full US regulatory approval for MASH cirrhosis by 30 June 2031 — a deal that closed on 9 December 2025. Efruxifermin is now a Novo Nordisk asset, developed alongside the company's GLP-1 franchise rather than in competition with it.

A drug missing its own primary endpoint and still driving a multibillion-dollar acquisition is not a contradiction once the full picture is in view: the week-96 cirrhosis-reversal finding, the size of the addressable MASH-cirrhosis market, and two other FGF21 analogs (covered below) attracting comparable acquisition interest from Roche and GSK in the same 12-month window all point to genuine institutional confidence in the drug class — which is a different thing from proof that any single molecule, including this one, will ultimately reach approval.

What's not yet resolved

Efruxifermin is not approved anywhere, and the 96-week cirrhosis-reversal figure driving most of the current optimism is a secondary, not primary, trial result — real and specific, but not yet a confirmed regulatory pathway until the ongoing Phase 3 SYNCHRONY trials report their own biopsy-confirmed results. As of this review, no regulatory filing has been submitted anywhere for any efruxifermin indication, and current trial-status details should be checked directly against Akero/Novo Nordisk's own disclosures rather than assumed from this page.

References

Noureddin M, Rinella ME, Chalasani NP, Neff GW, Lucas KJ, et al., "Efruxifermin in Compensated Liver Cirrhosis Caused by MASH," N Engl J Med 2025;392(24):2413-2424, DOI 10.1056/NEJMoa2502242, PMID 40341827 (SYMMETRY).
ClinicalTrials.gov, NCT05039450 ("Symmetry") — Akero Therapeutics-sponsored Phase 2b trial record.
Novo Nordisk, "Novo Nordisk enters into a definitive agreement to acquire Akero Therapeutics," company announcement, 9 October 2025; Novo Nordisk, "Novo Nordisk has completed its acquisition of Akero Therapeutics," 9 December 2025 — both company-reported, corroborated by contemporaneous trade coverage (BioPharma Dive, PharmExec, C&EN).
Akero Therapeutics investor disclosures on the Phase 3 SYNCHRONY program (Histology, Real-World and Outcomes trials) — company-reported; check Akero/Novo Nordisk's own current disclosures before relying on this page for trial status.