Akero Therapeutics, Inc. released preliminary topline week 96 results from HARMONY, a Phase 2b study evaluating the efficacy and safety of its lead product candidate efruxifermin (EFX) in patients with pre-cirrhotic metabolic dysfunction-associated steatohepatitis (MASH), fibrosis stage 2 or 3 (F2-F3). The study previously met its primary endpoint of =1 stage improvement in fibrosis with no worsening of MASH after 24 weeks of treatment for both the 50mg EFX (41%) and 28mg EFX (39%) dose groups, compared to 20% for the placebo arm. At week 96, the response rates on this endpoint increased to 75% (p<0.001) for 50mg EFX and 46% (p=0.07) for 28mg EFX, compared to 24% for placebo.

The study also met additional histology endpoints at week 96?notably 36% (p<0.01) and 31% (p<0.01) of patients treated with 50mg EFX and 28mg EFX experienced a 2-stage improvement in fibrosis without worsening of MASH?which is more than 10-fold the placebo rate of 3%. Results for all of the histological endpoints are summarized in the table below, based on either the primary analysis (patients with baseline and week 96 biopsies) or intent-to-treat (ITT) analysis (all randomized and dosed patients, with missing data imputed as non-response). The placebo-adjusted effect size on fibrosis improvement without worsening of MASH (EFX response rate minus placebo response rate) more than doubled between week 24 and week 96 for the 50mg EFX group, with a slight increase observed for the 28mg EFX group.

Specifically, the placebo-adjusted effect sizes for fibrosis improvement without worsening of MASH grew from 21% to 52% between week 24 and week 96 for 50mg EFX and from 20% to 22% for 28mg EFX. Highly statistically significant results for 50mg EFX at week 96 are notable because (1) the study was not fully powered at week 96 and (2) the placebo rate increased rather than decreased. An increase in treatment rate for placebo means that the increases in effect size are attributable to higher EFX treatment responses rather than a decline in placebo rate.

Analysis of the evolution of responses between weeks 24 and 96 indicated not only broader fibrosis improvement without worsening of MASH but also sustained response, particularly at 50mg EFX. Among those patients with available week 96 biopsies whose fibrosis improved at week 24, 92% and 83% of the 50mg and 28mg EFX groups remained responders, respectively, compared to 40% for placebo. Analysis of a subset of patients with baseline F3 fibrosis who had week 96 biopsies showed EFX?s potential to treat patients with more advanced fibrosis, who are generally considered to be at higher risk of progression to cirrhosis.

For this advanced F3 patient population, 68% (p<0.001) and 40% (p=0.053) of the 50mg EFX and 28mg EFX groups, respectively, experienced at least a one-stage improvement in fibrosis without worsening of MASH, compared to 14% for placebo. EFX was reported to be generally well-tolerated. There were no deaths.

Fifteen serious adverse events were reported, which were generally balanced across dose groups. Across both EFX groups, the most frequent adverse events (AEs) were grade 1 or 2 gastrointestinal events (diarrhea, nausea, and increased appetite), which were transient in nature. A total of three patients treated with EFX were discontinued due to AEs between week 24 and week 96 (two in the 28mg group and one in the 50mg group), compared with none for placebo.

In October of 2023, Akero reported week 36 results for the SYMMETRY study, a Phase 2b trial in patients with compensated cirrhosis (F4) due to MASH, Child-Pugh class A. The SYMMETRY study was designed to include a second biopsy after 96 weeks of treatment, for which the results remain on track to be reported in the first quarter of 2025.