Head to head
Efruxifermin against Efimosfermin alfa
Two FGF21 analogues with different dosing intervals, weekly against monthly. Efimosfermin has FDA Breakthrough Therapy designation and phase 2 results; efruxifermin has phase 3 trials under way and a missed primary endpoint in cirrhosis behind it.
Column A
EfruxiferminEfruxifermin (EFX, AKR-001)
A weekly FGF21 analog that missed its 36-week primary endpoint in compensated MASH cirrhosis but improved fibrosis in 29% of patients by 96 weeks against 11% on placebo, with three Phase 3 SYNCHRONY trials under way.
Column B
Efimosfermin alfaEfimosfermin alfa (BOS-580)
GSK's once-monthly FGF21 analog, acquired for $1.2 billion upfront, with FDA Breakthrough Therapy designation for MASH and Phase 2 results published in 2026.
Side by side, on the facts we can check
| Attribute | Efruxifermin | Efimosfermin alfa |
|---|---|---|
| Category | Metabolic | Metabolic |
| FDA status | Investigational; Phase 3 | Investigational; Breakthrough Therapy designation |
| Half-life | Weekly subcutaneous dosing | Once-monthly dosing |
| Molecular weight | 92,108 Da (Fc-FGF21 fusion protein) | 89,093 Da (Fc-FGF21 fusion protein) |
| Mechanism | Long-acting FGF21 receptor agonism (FGFR1c/beta-klotho) that lowers liver fat, improves insulin sensitivity and reduces fibrosis. | Long-acting FGF21 receptor agonism that reduces liver fat, inflammation and fibrosis. |
| Human studies cited | 2 | 3 |
| Legal status, US | Investigational, not approved | Investigational, not approved |
Frequently asked questions
What is the difference between Efruxifermin and Efimosfermin alfa?
Efruxifermin: A weekly FGF21 analog that missed its 36-week primary endpoint in compensated MASH cirrhosis but improved fibrosis in 29% of patients by 96 weeks against 11% on placebo, with three Phase 3 SYNCHRONY trials under way. Efimosfermin alfa: GSK's once-monthly FGF21 analog, acquired for $1.2 billion upfront, with FDA Breakthrough Therapy designation for MASH and Phase 2 results published in 2026.
Which has stronger research evidence, Efruxifermin or Efimosfermin alfa?
This database does not grade compounds. It counts what was run in people: 2 of the 2 studies cited on the Efruxifermin profile were human work, against 3 of 3 for Efimosfermin alfa. Those counts are of our own citation lists and understate any larger literature, and neither is a recommendation.
Are Efruxifermin and Efimosfermin alfa FDA-approved?
Efruxifermin: Investigational; Phase 3. Efimosfermin alfa: Investigational; Breakthrough Therapy designation.
Related posts
Blog articles that cover Efruxifermin or Efimosfermin alfa, newest first.
Reviewed Sep 2026. This page sets two published records side by side. It is educational, it is not medical advice, and it contains no dosing protocols or recommendations for personal use.