Consistent efficacy of efruxifermin across PNPLA3 genotypes in phase 2b trials in MASH

Efruxifermin is a long-acting, bivalent Fc-FGF21 analog in development for the treatment of moderate to advanced fibrosis and cirrhosis due to metabolic dysfunction–associated steatohepatitis (MASH). FGF21 is a hormone expressed predominantly in the liver that reduces liver fat, suppresses hepatic fibrogenesis, and improves insulin sensitivity.¹ In randomized controlled phase 2b trials, efruxifermin administration for 96 weeks improved fibrosis compared with placebo in individuals with MASH and stage 2 or 3 fibrosis (F2/F3)² as well as compensated cirrhosis (F4c).³ Efruxifermin also improved noninvasive measures of fibrosis as well as markers of liver and whole-body metabolic health.

The patatin-like phospholipase domain-containing 3 (PNPLA3) rs738409 C>G (I148M) variant is the most well-established genetic risk factor for chronic liver disease susceptibility and progression.^4,5 The PNPLA3 G-allele is associated with increased hepatic fat, elevated liver enzymes, and fibrosis, as well as a higher risk of metabolic dysfunction–associated steatotic liver disease (MASLD) and MASH, cirrhosis, hepatocellular carcinoma, hepatic decompensation, and mortality.^5,6 Given the higher risk of disease progression in individuals with MASH carrying the G-allele, we evaluated the response to efruxifermin by PNPLA3 genotype in participants with MASH and F2/F3 or F4c in phase 2b trials.

This post hoc analysis included participants from phase 2b randomized placebo-controlled trials of efruxifermin who consented to genotyping. All research was conducted in accordance with the principles of the Declaration of Helsinki and applicable laws and regulations. All participants provided written informed consent. The HARMONY trial (NCT04767529) included participants with biopsy-defined MASH and F2/F3 fibrosis.² The SYMMETRY trial (NCT05039450) enrolled adults with biopsy-defined F4 fibrosis and MASH (~80% of the trial population) or clinical MASH diagnosis.³ Participants were randomly assigned (1:1:1) to efruxifermin 28 mg, efruxifermin 50 mg, or a matching placebo administered subcutaneously once per week for 96 weeks. The primary outcome was the proportion of participants with fibrosis improvement, defined as a fibrosis decrease of ≥1 stage without MASH worsening, as described previously.^2,3 HARMONY participants were genotyped using the Infinium Global Screening Array v3 (Illumina). SYMMETRY participants were genotyped using blended genome/exome sequencing, with exome variants called using DRAGEN v4 (Illumina) and whole genome variants imputed using GLIMPSE2.

Participants were grouped by PNPLA3 rs738409 genotype, defined as CC (ancestral) or by the presence of the high-risk PNPLA3 G-allele (CG or GG). An interaction model was used to assess if PNPLA3 genotype modified the treatment effect on fibrosis improvement, defined as ≥1 stage fibrosis decrease without MASH worsening, evaluated by liver histology at week 96. Participants with missing data were excluded from analyses.

In phase 2b trials of efruxifermin, 90% (115/128) of enrolled participants with F2/F3 MASH and 78% (142/181) with F4c MASH consented to genotyping (Supplemental Table S1, http://links.lww.com/HEP/K487). Of these, 26% (68/257) were PNPLA3 CC genotype (ancestral), 46% (117/257) were CG genotype (heterozygous), and 28% (72/257) were GG genotype (homozygous). We limited the analysis to PNPLA3 due to the low frequency of variants in other genes associated with MASLD/MASH (Supplemental Table S1, http://links.lww.com/HEP/K487). Baseline clinical characteristics of the trial populations by PNPLA3 rs738409 genotype are shown in Supplemental Table S2, http://links.lww.com/HEP/K487.

Efruxifermin demonstrated consistent efficacy across PNPLA3 genotype groups. The interaction between genotype and treatment on fibrosis improvement at week 96 was not statistically significant for either dose of efruxifermin (data not shown) or for the combined efruxifermin doses in either trial (interaction: p=0.57 in HARMONY and p=0.72 in SYMMETRY). At week 96, the proportion of participants with fibrosis improvement was comparable for the ancestral (CC) and high-risk (CG or GG) PNPLA3 genotype groups across the trial populations (Figure 1). PNPLA3 genotype also did not impact the change in noninvasive tests of fibrosis, for example, liver stiffness measured by transient elastography (LSM), enhanced liver fibrosis (ELF) test score, and pro-C3 (Supplemental Table S3, http://links.lww.com/HEP/K487). Similar changes in adiponectin, lipids, and measures of insulin resistance were observed with efruxifermin versus placebo across PNPLA3 genotype groups. PNPLA3 genotype did not affect the incidence or severity of adverse events (data not shown).

FIGURE 1.

Percentage of participants in phase 2b trials of efruxifermin with fibrosis improvement at week 96 by PNPLA3 rs738409 genotype. (A) Participants with F2/F3 MASH in HARMONY. (B) Participants with F4c MASH in SYMMETRY. Participants with available baseline and week 96 histology data as well as genotype data at the time of data cutoff were included in the analysis. Fibrosis improvement was defined as ≥1-stage fibrosis decrease without MASH worsening (defined as an increase from baseline in any of the NAS subscores of ballooning, inflammation, and steatosis). Treatment by genotype interaction was evaluated for combined efruxifermin dose groups. *p<0.05 versus placebo within genotype group. The analysis of the proportion of participants with fibrosis improvement for efruxifermin versus placebo was based on the Cochran–Mantel–Haenszel test, after adjustment for stratification factors. Point estimates were calculated using the Miettinen and Nurminen method. Abbreviations: F2/F3, stage 2 or 3 fibrosis; F4c, compensated cirrhosis; MASH, metabolic dysfunction–associated steatohepatitis; NAS, nonalcoholic fatty liver disease activity score; PNPLA3, patatin-like phospholipase domain-containing 3 gene.

Consistent with enrichment of the high-risk PNPLA3 G-allele in individuals with MASH relative to the general population, the majority (74% or 189/257) of participants in phase 2b trials of efruxifermin carried at least one PNPLA3 G-allele. In both trials, there was no effect of genotype on efruxifermin-related improvements in fibrosis evaluated by histology or noninvasive measures, markers of liver injury (ALT, AST), insulin sensitivity, or lipids. Increased levels of adiponectin, a marker of fibroblast growth factor receptor 1c (FGFR1c) activation in adipocytes,¹ indicate that the pharmacodynamic response to efruxifermin was preserved across genotypes. A limitation of this analysis is the small sample size of the genotype subgroups. Additional studies are needed to confirm these results and rule out other potential interactions, such as other genetic variants or changes in diet or lifestyle.⁷

Due to the role of PNPLA3 genetic variants in MASH, PNPLA3 genotype-treatment interactions have been evaluated for other MASH treatments. Histological response to resmetirom was not modified by PNPLA3 genotype in a large phase 3 trial in people with F2/F3 MASH.⁸ However, a lower rate of MASH resolution by histology was observed among individuals with the PNPLA3 G-allele in a phase 2b study of tirzepatide in MASH.⁹ The relationship between PNPLA3 genotype and histological response to semaglutide in MASH clinical trials has not been published, although a retrospective study of patients treated with semaglutide indicated that ALT decreases were greater in individuals with the PNPLA3 G-allele.¹⁰ Results of larger trials of efruxifermin, semaglutide, tirzepatide, and other MASH treatments in development are needed to evaluate the potential impact of PNPLA3 genotype (and other common genetic variants) on treatment response in MASH and the role of routine PNPLA3 genotyping for therapeutic decision-making in clinical practice.

In conclusion, the antifibrotic and metabolic benefits of efruxifermin were preserved across PNPLA3 genotypes in this analysis of individuals with MASH and F2/F3 fibrosis or compensated cirrhosis, for whom there is a high unmet medical need.

Supplementary Material

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