Emerging treatment options for metabolic dysfunction-associated steatotic liver disease and its related liver diseases

Abstract

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a leading and increasingly prevalent chronic liver disease, affecting approximately 1.2 billion people worldwide. It can be triggered by genetic susceptibility factors and dietary habits. MASLD is characterized by liver fat accumulation, inflammation, cell death, and varying degrees of liver fibrosis. Without appropriate treatment and management, the progressive form of MASLD, metabolic dysfunction-associated steatohepatitis (MASH), can lead to liver cirrhosis and hepatocellular carcinoma. Currently, there are two United States Food and Drug Administration approved drugs for the treatment of MASH with moderate to advanced liver fibrosis: resmetirom, an oral agonist of thyroid hormone receptor-β, and semaglutide, a glucagon-like peptide-1 (GLP-1) receptor agonist. Ongoing clinical trials indicate that many emerging therapies show promising efficacy and potential applications for MASLD and MASH treatment, including dual glucagon receptor and GLP-1 receptor agonists, fibroblast growth factor analogues, and pan-peroxisome proliferator-activated receptor agonists. In this review, we summarize the pathogenesis of MASLD and MASH and examine current clinical trials for their treatment, with a focus on pharmaceutical therapies, dietary modifications, and natural products. Additionally, repurposing currently approved drugs for metabolic diseases, as well as combination therapies, may provide effective treatment strategies for MASLD and MASH.

Key Words: Metabolic dysfunction-associated steatotic liver disease; Metabolic dysfunction-associated steatohepatitis; Clinical trials; Molecular mechanisms; Treatments; Therapeutic strategies

Core Tip: Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common type of chronic liver disease, affecting more than a quarter of the global population. MASLD is driven by many factors, including dietary and genetic factors. Without effective treatment, MASLD can lead to liver cirrhosis and cancer. Currently, treatment options for MASLD and metabolic dysfunction-associated steatohepatitis (MASH), an advanced form of MASLD, are limited. Ongoing clinical trials suggest that drug repurposing for metabolic disorders, dietary modifications, exercise, natural products, and combination therapies offer promising strategies for the management and treatment of MASLD and MASH.

INTRODUCTION

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a leading and increasingly prevalent chronic liver disease, affecting more than 1.2 billion people worldwide[1]. MASLD can be driven by several genetic susceptibility factors and dietary habits, which are characterized by major pathogenic features, including hepatic lipid accumulation, inflammation, cell death, and metabolic dysfunction[2]. Without appropriate treatment and management, metabolic dysfunction-associated steatohepatitis (MASH), a severe form of MASLD, may lead to liver cirrhosis and hepatocellular carcinoma. Resmetirom, an oral agonist of thyroid hormone receptor-β (THR-β), is the first approved drug by the United States Food and Drug Administration (FDA) for the treatment of adults with MASH and moderate to advanced liver fibrosis[3]. In 2025, semaglutide, the active ingredient in the Wegovy^® formulation, was approved for MASH treatment[4].

MASLD is commonly associated with other metabolic disorders, including dyslipidemia, obesity, and type 2 diabetes mellitus (T2DM)[5]. Furthermore, patients with MASLD and prediabetes or T2DM have a higher risk of developing advanced liver fibrosis compared to patients without diabetes[6]. In addition, individuals with both MASLD and T2DM tend to have a higher body mass index (BMI) and a lower level of high-density lipoprotein cholesterol compared to healthy people[6]. Therefore, the treatment of MASLD or MASH becomes more complex for patients with MASLD-associated metabolic disorders.

In this paper, we first summarize the pathogenesis of MASLD and MASH and review current clinical trials for their treatment, with a focus on pharmaceutical therapies, dietary modifications, and natural products. We then review emerging therapeutic strategies aiming to enhance treatment efficacy for MASLD and MASH. These approaches are discussed in the context of patients with MASLD alone as well as those with MASLD and associated metabolic disorders.

MASLD AND MASH PATHOGENESIS

The key pathogenic features of MASLD and MASH include hepatic inflammation, lipid accumulation, insulin resistance, fibrosis, and cell death. The pathogenesis and progression of MASLD and MASH are regulated by multiple factors, including diet as well as genetic and epigenetic influences.

Insulin resistance

Long-term obesity leads to lipid accumulation in multiple organs, organelle dysfunction, and obesity-associated insulin resistance. Under this condition, adipose tissue releases excessive free fatty acids (FFAs) and pro-inflammatory cytokines[7,8], contributing to MASLD progression. Insulin resistance enhances hepatic lipid accumulation, leading to endoplasmic reticulum (ER) stress, lipotoxicity, and oxidative stress, which further exacerbate insulin resistance. ER stress and subsequent activation of unfolded protein response induced by the accumulation of misfolded proteins increase the phosphorylation and activation of protein kinase R-like ER kinase, inositol-requiring enzyme 1, and activating transcription factor 6. Regulation of these molecular signaling pathways activates the c-Jun-N-terminal kinase/nuclear factor (NF)-κB signaling pathway, which in turn promotes the phosphorylation of insulin receptor substrate-1 to cause insulin resistance and MASH progression[9].

Lipid accumulation

Excessive hepatic lipid accumulation is another key feature of MASLD or MASH. Hepatic lipid accumulation is induced by activation of de novo lipogenesis (DNL) and increased transport of FFAs into the liver[10]. FFAs are derived from enhanced adipose tissue lipolysis and dietary intake of fatty acids and sugars[10,11], such as glucose and fructose. Uptake of circulating FFAs by the liver is regulated by proteins, such as caveolins, FATPs (fatty acid transport proteins), and CD36 (cluster of differentiation 36), located on the hepatocyte plasma membrane. Upregulation of sterol regulatory element binding protein 1c mediated DNL in MASLD significantly contributes to hepatic accumulation of triglyceride and promotes the expression of lipogenic genes[12]. Additionally, the conversion of amino acids into lipids via DNL can further increase liver fat accumulation by contributing to acetyl-CoA production[11].

In addition, mitochondrial dysfunction can impair fatty acid β-oxidation, thereby reducing lipid utilization and inducing oxidative stress in MASLD[13]. High-fat diet (HFD) feeding promotes lipid accumulation, impairs fatty acid oxidation, and upregulates lipogenesis genes[14], such as acetyl-CoA carboxylase, fatty acid synthase (FASN), and stearoyl-CoA desaturase 1.

Cellular death

Lipotoxicity and oxidative stress induce hepatocyte death during the progression of MASLD[15]. Several forms of cell death are implicated in MASLD[16], including pyroptosis[17,18], apoptosis[19], ferroptosis[20,21], and necroptosis[22]. Recent review papers have summarized the critical roles of cell death mechanisms in MASLD pathogenesis[23,24]. In addition, these forms of cell death play key roles in the progression of liver fibrosis[25]. In brief, apoptosis is a programmed cell death in MASLD and MASH that can contribute to liver inflammation and fibrosis. It is associated with the increased activation and expression of pro-apoptotic factors, such as cleaved caspases-3 and -7, and decreased activation and expression of anti-apoptotic factors, such as B-cell lymphoma-extra large[26]. Necroptosis, distinct from apoptosis and necrosis, is a regulated form of cell death and is associated with the overexpression of necroptotic factors, including phosphorylated mixed lineage kinase domain-like protein, receptor-interacting kinase 1 (RIPK1), and RIPK3[27]. Pyroptosis is an inflammatory form of cell death, which is commonly associated with the activation of nucleotide-binding domain leucine-rich repeat-receptor, pyrin domain-containing-3 (NLRP3) inflammasome[25,28]. Ferroptosis is also a form of regulated cell death induced by the accumulation of iron-dependent lipid peroxides, with overexpression of markers such as arachidonate 15-lipoxygenase and Acyl-CoA synthetase long chain family member 4[29]. For example, hepatocyte-specific transforming growth factor-beta-activated kinase 1 deficiency increased hepatocellular ferroptosis and oxidative stress, promoting liver injury[30]. Hepatocyte death promotes hepatic inflammation and fibrosis through activation of NF-κB/JNK, FasL/MyD88, TGF-β/Smad, and NLRP3 inflammasome signaling pathways[31].

Inflammation

Inflammation accompanies most acute and chronic liver diseases[32], including MASLD and MASH. Consumption of a high-fat, high-sugar diet can promote the progression of MASLD to MASH by increasing inflammatory cytokines [e.g., interleukin-1β (IL-1β) and tumor necrosis factor alpha or TNF-α] in innate immune cells (e.g., macrophages and neutrophils). These cytokines mediate cellular communication during MASH progression. For example, IL-1β secreted by liver macrophages activates liver sinusoidal endothelial cells via IL1 receptor, increasing chemokine expression and promoting the infiltration of additional inflammatory immune cells[33]. TNF-α secretion by infiltrating monocyte-derived macrophages plays a key role in MASH progression[34], which can be regulated by cyclooxygenase 2, a key enzyme controlling prostanoid synthesis. In contrast, Sdc4-deficiency in monocytes upregulates interleukin-10 expression, which inhibits TNF-α production in hepatocytes induced by palmitic acid in vitro[35]. In MASH, TNF, IL-1β, and transforming growth factor beta 1 (TGF-β1) derived from activated Kupffer cells or monocyte-derived macrophages contribute to macrophage-mediated activation of hepatic stellate cells (HSCs) and liver fibrosis development[36]. Increased expression levels of IL-1β, interleukin 6 (IL-6), and TNF-α have been observed in patients and are associated with MASH and liver fibrosis[37]. Furthermore, patients with MASLD show elevated populations of circulating monocytes and NK cells[38], which correlate with higher levels of proinflammatory cytokines (e.g., IL-6).

Sterile inflammation refers to non-infectious immune cell activation, which is triggered by damage-associated molecular patterns (DAMPs) released from injured and dying cells. In this process, DAMPs are recognized by pattern recognition receptors and signaling pathways, such as toll-like receptors, NOD-like receptors, and cyclic GMP-AMP synthase-stimulator of interferon genes signaling pathway, which detects both pathogen DNA and host-derived DNA. Activation of these pathways stimulates inflammation and cytokine secretion, thereby contributing to MASH progression[39].

Furthermore, feeding a HFD can increase gut barrier permeability by regulating inflammatory cytokine secretion[40]. Gut microbiota-derived metabolites and components can then translocate into the liver via the portal vein, activating immune cells and promoting liver inflammation[41].

Fibrosis

The severity of liver fibrosis has a significant impact on the long-term prognosis for patients with MASLD[42], which has been shown to be the most accurate predictor of mortality in this population[43]. Therefore, targeting fibrosis is critical for the treatment of MASLD. TGF-β is a master regulator of liver fibrosis. The TGF-β/Smad signaling pathway is activated to cause fibrosis in various chronic liver diseases[44], including MASLD. TGF-β1 can activate HSCs to increase extracellular matrix (ECM) production, leading to liver fibrosis[45]. Mechanistically, TGF-β1 binds to TGF-β receptor complexes to initiate and activate intracellular signaling by promoting SMAD2/3 phosphorylation. The phosphorylated SMAD2/3 then form an oligomeric complex with SMAD4 and translocate into the nucleus to regulate target gene expression, including genes encoding ECM proteins, such as type I collagen and alpha-smooth muscle actin[44]. Additionally, metabolic reprogramming from oxidative phosphorylation to glycolysis, along with hepatic metabolic dysfunction, can induce senescence-associated factors that contribute to liver fibrosis progression[46].

Genetic mutations and epigenetic factors

The protein patatin-like phospholipase domain-containing protein 3 (PNPLA3) I148M variant (C>G, rs738409) is associated with liver inflammation and fibrosis. Lee et al[47] reported that the PNPLA3 I148M variant significantly increased the numbers of CD3⁺ T cells and CD68⁺ macrophages in the periportal region compared with controls and was associated with immune cell activation. Circulating activin A (a member of the TGF-β family) expression was elevated in patients carrying the I148M variant, which was associated with the progression of liver fibrosis[48]. In addition, the PNPLA3 148M variant enhances macrophage necroptosis and inflammation in MASLD[22].

Overall, multiple pathogenic processes contribute to MASLD progression to MASH and advanced chronic liver diseases (Figure 1). In the following section, we review the current clinical trials in the management and treatment of MASLD and MASH by targeting these pathways.

Figure 1 Factors contributing to metabolic dysfunction-associated steatotic liver disease progression. These factors include liver inflammation, lipotoxicity, cell death, liver fibrosis, and genetic variants. MASLD: Metabolic dysfunction-associated steatotic liver disease; MASH: Metabolic dysfunction-associated steatohepatitis; HCC: Hepatocellular carcinoma.

THERAPEUTIC TARGETS FOR MASLD AND MASH

Targeting the key pathogenic features described above provides strategies for MASLD and MASH therapy. In this section, we summarize several key molecular targets and their functions in the pathogenesis of MASLD and MASH.

Fatty acid synthase

Dysregulation of extrahepatic and intrahepatic lipid metabolism promotes fat accumulation, which triggers lipotoxicity and cellular stress, thereby accelerating liver inflammation and fibrosis progression[49]. FASN is a key rate-limiting enzyme that controls hepatic DNL. One study showed that hepatocyte-specific overexpression of sorting nexin 8 in vivo can significantly inhibit a high-cholesterol and high-fat diet-induced hepatic steatosis by suppressing FASN expression[50].

Fibroblast growth factors

Fibroblast growth factors (FGFs) have been shown to play protective roles in MASLD by inhibiting hepatic steatosis and lipotoxicity, ameliorating insulin resistance, and reducing oxidative stress, ER stress, and inflammation[51]. For example, FGF21 can act on the central nervous system to enhance sympathetic nerve activity, thereby suppressing hepatic DNL[52]. Treatment with a long-acting analogue of FGF21 inhibits liver fibrosis in mouse MASH models by regulating macrophage phenotypic changes and the crosstalk between macrophages and HSCs[53]. In addition, FGF19 is a key metabolic regulator. Treatment with liver-targeted lipid nanoparticles carrying a non-mitogenic FGF19 mRNA can suppress diet-induced hepatic steatosis and improve metabolic dysregulation by modulating bile acid levels and composition[54].

GLP-1 and its receptor

GLP-1 is an incretin hormone secreted by intestinal epithelial endocrine L cells[55]. It plays an essential role in regulating blood glucose levels and lipid metabolism[56]. GLP-1 receptor agonists mimicking GLP-1 can be used to treat various metabolic diseases[56], including MASLD. These agonists can decrease blood glucose levels and enhance glucose-dependent secretion of insulin[57].

Peroxisome proliferator-activated receptors

Peroxisome proliferator-activated receptors (PPARs) have three subtypes, including PPARα, PPARβ/δ, and PPARγ. PPARα agonists can significantly lower triglyceride levels and increase the levels of high-density lipoprotein (HDL) cholesterol; therefore, they are approved for the treatment of hypertriglyceridemia and lipid abnormalities in patients with cardiovascular disease or diabetes[58]. PPARγ agonists improve glycemic control and have been used to treat hyperglycemia and T2DM[59]. Currently, pan-PPAR agonists such as lanifibranor can improve hepatic steatosis and insulin resistance in patients with MASLD and T2DM, demonstrating therapeutic functions for the treatment of metabolic disorders[60].

THR-β

Resmetirom, a selective THR-β agonist, is the first treatment approved by the United States FDA for MASLD. THR-β agonist can regulate hepatic lipid and glucose metabolism[61]. The gene expression of THR-β is negatively associated with serum triglyceride levels and hemoglobin A1c and is also inversely correlated with MASH scores in patients[62]. THR-β exhibits a distinct function in lipid regulation compared to thyroid hormone receptor-α[63]. In addition, thyroid hormone therapy can reduce liver triglyceride accumulation by enhancing fatty acid disposal through lipophagy and β-oxidation[64]. Currently, several clinical studies are ongoing to evaluate the therapeutic efficacy of THR-β.

CLINICAL TRIALS

Currently, different phases of clinical trials are performed to evaluate the treatments of MASLD or MASH that target the abovementioned molecular pathways.

Phase 1

Subcutaneous administration of pemvidutide, a GLP-1/glucagon dual receptor agonist, once weekly at doses of 1.2 mg, 1.8 mg, or 2.4 mg significantly decreased liver fat content than the placebo in patients with MASLD. The relative reductions in hepatic fat content from baseline were 46.6%, 68.5%, and 57.1% for three doses, respectively, vs 4.4% for the placebo group. At the dose of 1.8 mg, pemvidutide significantly induced body weight loss and reduced alanine aminotransferase (ALT) levels and liver corrected T1 [a non-invasive, magnetic resonance imaging (MRI)-based biomarker], indicating amelioration of liver inflammation and fibrosis[65].

Treatment with an oral THR-β agonist ALG-055009 once daily at doses from 0.3 mg to 1.0 mg reduced the levels of apolipoprotein B and low-density lipoprotein (LDL) cholesterol and increased sex hormone-binding globulin in a dose-dependent manner in healthy individuals. Mean maximum reductions for all doses vs placebo were 27.6% vs 9.3% and 26.8% vs 7.7% from baseline for apolipoprotein B and LDL-cholesterol, respectively. The treatment did not cause significant adverse events and induced a transient decrease in thyroid hormone levels[66].

ATP-citrate lyase (ACLY) converts cytosolic citrate generated from the tricarboxylic acid cycle to acetyl-CoA and represents a promising therapeutic target for hypercholesterolemia treatment[67]. Treatment with oral ACLY inhibitor 326E markedly decreased hepatic fat accumulation by reducing DNL and increasing fatty acid oxidation. A randomized phase 1b/2a clinical trial displayed that 326E reduced the levels of circulating gamma-glutamyl transferase (GGT) and was well tolerated in patients with MASH[68]. Another phase 1/2 clinical trial found that treatment with GSK4532990 (ARO-HSD), an RNA interference therapeutic targeting hydroxysteroid 17-beta dehydrogenase 13 (HSD17β13) in hepatocytes, decreased HSD17β13 mRNA and protein expression levels and reduced liver injury enzyme alanine aminotransferase from baseline at doses of 200 mg or less[69].

Phase 2

Treatment with pemvidutide improved MASH resolution in patients with F2-F3 fibrosis at doses of 1.2 mg and 1.8 mg over 24 weeks, without worsening liver fibrosis[70]. Tirzepatide, a dual GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) receptor agonist, is used for the treatment of T2DM, obesity, and MASH[71]. A phase 2 clinical trial revealed that responders to tirzepatide had obvious reductions in body weight, hemoglobin A1c (HbA1c) levels, as well as improvement in liver fibrosis, compared with non-responders among patients with MASH[72]. This study also revealed that normalization of hepatic fat was an important parameter for the resolution of both MASH and liver fibrosis. Treatment with a dual agonist of the glucagon receptor and GLP-1 receptor (survodutide) improved MASH resolution without worsening of fibrosis in adults with MASH and F1-F3 fibrosis[73]. A phase 2 clinical trial demonstrated that once-weekly subcutaneous administration of retatrutide, a novel triple agonist of the GIP, GLP-1, and glucagon receptors, reduced liver fat compared with baseline after 24 weeks. This effect was dose-dependent, with average changes in hepatic fat from baseline of -42.9% at 1 mg, -57.0% at 4 mg, -81.4% at 8 mg, -82.4% at 12 mg, and +0.3% for the placebo[74]. In addition, mazdutide (IBI362), a dual agonist of the glucagon receptor and GLP-1 receptor, has been approved for the treatment of T2DM in China[75], and it is currently under phase 2 clinical evaluation for MASH (NCT06937749).

Oral treatment with berberine ursodeoxycholate (HTD1801 tablets, 1000 mg twice daily), an ionic salt of berberine and ursodeoxycholic acid (UDCA), significantly improved glycemic control, decreased body weight, and reduced liver fat content and serum ALT and GGT levels[76]. The mean absolute reduction in liver fat content was -4.8% vs -2.0% compared to placebo.

Subcutaneous treatment of pegbelfermin (BMS-986036), a PEGylated human FGF21 analogue, significantly decreased hepatic lipid fraction in patients with MASH compared with placebo at doses of 10 mg daily (-6.8% vs -1.3%) and 20 mg (-5.2%vs -1.3%) weekly for 16 weeks[77]. A phase 2b trial further showed that pegozafermin treatment significantly improved hepatic fibrosis without worsening of MASH[78].

Subcutaneous treatment with aldafermin, an engineered human FGF19 analogue, significantly inhibited the progression of liver fibrosis compared with placebo at a dose of 3 mg once daily for 48 weeks[79]. The least-squares mean difference in the change in enhanced liver fibrosis was -0.5 (95%CI: -0.7 to -0.2; P = 0.0003) between the 3 mg group and the placebo group[79].

Lanifibranor, a PPAR agonist, has been shown in phase 2 clinical trials to decrease liver fat accumulation, inflammation, and fibrosis in patients with MASH with or without T2DM[80].

Denifanstat is an oral FASN inhibitor and suppresses DNL. Oral administration of denifanstat at 50 mg once per day for 52 weeks significantly improved the MASLD activity score, achieved MASH resolution, and did not worsen fibrosis in patients with MASH and F2 or F3 fibrosis[81].

Phase 3

UDCA inhibits hepatic inflammation and fat accumulation in mice with HFD-induced MASLD by activating PPARα and cytochrome P450 family 4 subfamily A member 14 mediated β-fatty acid oxidation in the liver[82]. Patients with MASLD who received 24-norursodeoxycholic acid (norUDCA) tablets, a synthetic UDCA homologue, had a significant reduction in ALT levels compared with the placebo group at a dose of 1500 mg for 12 weeks. At both weeks 18 and weeks 24, norUDCA also induced significant improvement in liver fibrosis at 57% of the norUDCA-treated group vs 40% in the placebo group, as well as liver stiffness[83].

Dapagliflozin, an oral inhibitor of sodium-glucose co-transporter 2 (SGLT2), reduces the reabsorption of glucose and sodium, thereby increasing their urinary excretion[84]. Patients with MASH who received dapagliflozin significantly increased the proportion of MASH resolution without worsening of liver fibrosis or had better fibrosis improvement without worsening of MASH compared with placebo[85].

Phase 4

Berberine, a natural bioactive isoquinoline alkaloid found in plants such as Berberis vulgaris and Berberis aquifolium, has multiple effects, including reducing hepatic steatosis and inhibiting glucogenesis[86,87]. A phase 4 clinical trial showed that berberine decreased levels of LDL cholesterol, apolipoprotein B, and high-sensitivity C-reactive protein (hs-CRP) in patients with obesity and MASLD and without causing significant adverse events compared with placebo[88]. The largest reductions in LDL cholesterol, apolipoprotein B, and hs-CRP compared to placebo were -7.72 (95%CI: -13.13 to -1.93) mg/dL, -3.42 (95%CI: -6.33 to -0.51) mg/dL, and -0.072 (95%CI: -0.140 to -0.004) mg/dL, respectively.

Overall, the treatments are summarized in a table (Table 1) to show their effects in clinical trials.

Table 1 Treatment of metabolic dysfunction-associated steatotic liver disease and metabolic dysfunction-associated steatohepatitis in clinical trials.

Clinical trials	Phase	Treatments	Effects	Ref.
NCT05006885	1	Pemvidutide (also known as ALT-801), a GLP-1/glucagon dual receptor agonist	Reduction in body weight Reduction in ALT levels Decrease in liver corrected T1	[65]
NCT05090111	1	ALG-055009, an oral THR-β agonist	Decrease in atherogenic lipids in a dose-dependent manner. Increase in sex hormone-binding globulin	[66]
NCT06491576	1/2	BGT-002, an ATP-citrate lyase inhibitor	Reduction in circulating GGT levels	[68]
NCT04202354	1/2	GSK4532990 (ARO-HSD), an RNA interference targeting HSD17β13 mRNA in hepatocytes	Reduction in hepatic HSD17β13 mRNA and protein expression, as well as alanine aminotransferase	[69]
NCT05989711	2	Pemvidutide	Improvement in MASH resolution, without worsening liver fibrosis	[70]
NCT04166773	2	Tirzepatide, a dual GLP-1 and GIP receptor agonist	Reduction in body weight, HbA1c, with improvement of liver fibrosis	[72]
NCT04771273	2	Survodutide, a dual agonist of glucagon receptor and GLP-1 receptor	Improvement in MASH resolution without worsening of fibrosis	[73]
NCT04881760	2	Retatrutide, a novel triple agonist of the GIP, GLP-1, and glucagon receptors	A reduction in liver fat compared to placebo in a dose-dependent manner	[74]
NCT03656744	2	Berberine ursodeoxycholate (HTD1801), an ionic salt of berberine and ursodeoxycholic acid	Improved glycemic control and reduced body weight, liver fat content, and serum ALT and GGT levels	[76]
NCT02413372 NCT04929483	2	Pegbelfermin (BMS-986036), a PEGylated human FGF21 analogue	Decrease in hepatic fat fraction Improvement in liver fibrosis	[77,78]
NCT04210245	2	Aldafermin, an engineered human hormone FGF19 analogue	Reduction in liver fibrosis	[79]
NCT03459079	2	Lanifibranor, a pan-peroxisome proliferator-activated receptor agonist	Improvement in liver inflammation and fibrosis. Decrease hepatic fat accumulation	[80]
NCT04906421	2	Denifanstat, an oral fatty acid synthase inhibitor	Improvement in MASLD activity score without worsening fibrosis. Improvement in MASH resolution	[81]
CTRI/2023/08/0559821	3	24-norursodeoxycholic acid	Reduction in ALT levels. Improvement in liver fibrosis and stiffness	[83]
NCT03723252	3	Dapagliflozin, a SGLT inhibitor	Improvement in fibrosis and MASH resolution	[85]
NCT05647915	4	Berberine plus lifestyle intervention	Decrease in LDL cholesterol, apolipoprotein B, and hs-CRP levels	[88]

¹Clinical Trials Registry-India.

ALT: Alanine aminotransferase; FGF: Fibroblast growth factor; GGT: Gamma-glutamyl transferase; GGT: Gamma-glutamyl transferase; GIP: Glucose-dependent insulinotropic polypeptide; GLP-1: Glucagon-like peptide-1; hs-CRP: High-sensitivity C-reactive protein; HSD17β13: Hydroxysteroid 17-beta dehydrogenase 13; LDL: Low-density lipoprotein; SGLT2: Sodium-glucose co-transporter 2; THR-β: Thyroid hormone receptor beta; MASLD: Metabolic dysfunction-associated steatotic liver disease; MASH: Metabolic dysfunction-associated steatohepatitis.

POTENTIAL THERAPIES

Many other potential therapies for MASLD or MASH are currently in early-phase or small-scale studies.

Probiotics and fecal microbiota transplantation

Administration of three probiotics, including Lactobacillus delbrueckii subsp. Lactis (LL001), Lactobacillus helveticus (LH001), and Pediococcus pentosaceus KID7 (PPKID7), significantly decreased ALT and aspartate transaminase (AST) levels, body weight, and cholesterol levels in adult patients with MASLD. The effects of probiotics were mediated through the modulation of gut microbial profiles[89].

Diet modulation

Consumption of a low-carbohydrate polyunsaturated fatty acid diet or a low-fat healthy Nordic diet (HND) decreased hepatic fat and LDL cholesterol in patients with prediabetes and T2DM compared with usual care. In addition, HND intervention further decreased body weight, ALT, AST, triglycerides, CRP, and HbA1c[90].

Dietary interventions with a hypocaloric Mediterranean diet and a low-fat diet for 12 weeks had similar efficacy in reducing body weight, hepatic steatosis, and fibrosis, as evaluated by controlled attenuation parameter and liver stiffness measurement[91].

A 12-week diet intervention with a low-carb high-fat diet or a 5:2 diet (the intermittent fasting diet) in patients with MASLD significantly decreased body mass index and improved hepatic steatosis and liver stiffness compared with baseline[92].

A recent study showed that a telemedicine-based remote care program combining carbohydrate-reduced nutrition therapy, health coaching, and protocol-guided medication management, known as Virta individualized nutrition therapy, significantly reduced body weight and improved metabolic disorders in adults with overweight or obesity, prediabetes, and T2DM. This nutrition-focused telemedicine approach also significantly decreased the incidence and risk of developing MASLD or MASH, as well as advanced liver disease. In addition, participants who achieved at least 15% body weight loss demonstrated a greater reduction in the risk of new liver disease onset[93].

Polyphenols

Phenolic acids are a major class of dietary polyphenols produced in fruits, vegetables, and grains. They possess antioxidative and anti-inflammatory properties and therapeutic effects in various metabolic diseases[94,95]. A randomized, double-blind, placebo-controlled trial demonstrated that oral administration of the phenolic acid fraction of Anisopus mannii (10 mg/kg and 20 mg/kg body weight) for six months significantly improved imaging-based steatosis scores and reduced fasting triglycerides, non-HDL cholesterol, and ALT and AST levels compared with placebo[96].

Supplementation of ellagic acid (200 mg once daily), an antioxidant and anti-inflammatory polyphenol, alongside a hypocaloric diet for eight weeks, significantly reduced ALT, AST, fasting blood sugar, triglycerides, and LDL cholesterol levels and decreased liver fibrosis[97].

Balance of electrolytes

A 12-month intake of mineral water (Fonte Essenziale^®), rich in bicarbonate, sulfate, calcium, and magnesium, significantly reduced biochemical parameters including AST, ALT, GGT, LDL, hs-CRP, and insulin levels. It also reduced liver steatosis severity, intestinal permeability markers, and systemic inflammatory markers, evidenced by decreased serum levels of lipopolysaccharide, TNF-α, IL-1β, and IL-6. Additionally, it inhibited systemic oxidative stress by decreasing the ratio of derivatives of reactive oxygen metabolites/biological antioxidant potential[98].

Targeting genetic mutation

The PNPLA3 I148M (rs738409 C>G) variant is a genetic risk factor for MASLD or MASH, contributing to hepatic steatosis[99] and fibrosis[100]. Treatment with AZD2693, a liver-targeted antisense oligonucleotide against PNPLA3 mRNA, improved hepatic steatosis compared to placebo. AZD2693 also reduced inflammation by lowering hs-CRP and IL-6 levels and increased polyunsaturated fatty acids in serum triglycerides in a dose-dependent manner[101].

Chemokine inhibitors

C-C motif chemokine ligand 24 (CCL24) expression is increased in many metabolic disorders, including MASLD and MASH[102]. Phase I clinical trials demonstrated that treatment with CM-101, a humanized anti-CCL24 monoclonal antibody, improved MASH resolution by decreasing serum levels of inflammatory and fibrotic biomarkers[103].

The above treatments are potent strategies for MASLD and MASH management. However, most of them were evaluated in small or early-phase clinical trials (Table 2). Larger confirmatory or late-phase clinical trials are required to further evaluate their effectiveness in MASLD or MASH therapy.

Table 2 Next-generation therapies for metabolic dysfunction-associated steatotic liver disease.

Clinical trials	Phase	Treatments	Effects	Ref.
NCT04555434	N/A	Probiotics	Decrease in ALT and AST levels, body weight, and cholesterol levels by regulating gut microbial components	[89]
NCT04527965	N/A	A low-carbohydrate PUFA diet or a low-fat HND	Decrease in liver fat accumulation and LDL cholesterol levels in both diets. HND intervention further decreases body weight, ALT, AST, triglycerides, CRP, and HbA1c levels	[90]
NCT06220695	N/A	Isocaloric Mediterranean diet and low-fat diet	Decrease in body weight, hepatic steatosis, and fibrosis	[91]
NCT03118310	2	5:2 diet low-carb high-fat	Decrease in body mass index, hepatic steatosis, and liver stiffness	[92]
PACTR2022065315457291	2	Phenolic acid fraction	Improvement in hepatic steatosis. Decrease in fasting triglycerides, non-HDL cholesterol, ALT, and AST levels	[96]
IRCT20180103038199N162	N/A	Ellagic acid, a polyphenol	Improvement in liver stiffness. Decrease in levels of ALT, AST, fasting blood sugar, triglycerides, and LDL cholesterols	[97]
NCT07211113	N/A	Fonte Essenziale®, a mineral water	Decrease in serum markers of liver injury, hepatic steatosis, systemic inflammation. Improvement in intestinal permeability	[98]
NCT04142424; NCT04483947	1	AZD2693, a liver-targeted antisense oligonucleotide against PNPLA3 mRNA	Improvement in hepatic steatosis. Decrease in hs-CRP and IL-6	[101]
NCT06025851; NCT06037577; NCT06044467	1	Anti-human CCL24 monoclonal antibody (CM-101)	Decrease in serum levels of inflammatory and fibrotic biomarkers	[102]

¹Pan African Clinical Trials Registry.

²Iranian Registration of Clinical Trials.

ALT: Alanine aminotransferase; AST: Aspartate aminotransferase; LDL: Low-density lipoprotein; HbA1c: Hemoglobin A1c; HDL: High-density lipoprotein; hs-CRP: High-sensitivity C-reactive protein; IL: Interleukin; mRNA: Messenger ribonucleic acid; N/A: Not applicable; PNPLA3: Patatin-like phospholipase domain-containing protein 3; PUFA: Polyunsaturated fatty acids; HND: Healthy Nordic diet.

STRATEGIES TO IMPROVE TREATMENT EFFICACY

Diagnostic biomarkers

Circulating microRNAs are potential non-invasive diagnostic biomarkers for MASLD[104,105]. After 12 months of nutritional intervention, a multivariate logistic regression model with parameters of miR29b-3p, miR122-5p, miR151a-3p, and BMI had a significant diagnostic accuracy for MASLD with an area under the receiver operating characteristic curve (AUROC) of 0.858[106]. Similarly, at 24 months post-nutritional intervention, logistic regression analysis using parameters of miR21-5p, miR151a-3p, and BMI yielded an AUROC of 0.8519[106].

Serum biomarkers were developed to evaluated the treatment efficacy of lanifibranor in MASH patients, including biomarkers of delta of matrix metalloproteinase 9, transferrin, and baseline adiponectin and ferritin for evaluating MASH resolution and fibrosis improvement; biomarkers of delta of hyaluronic acid, fructosamine, ALT, and baseline cytokeratin 18 fragment M65, for testing MASH resolution without worsening of fibrosis, and biomarkers of baseline cytokeratin 18 fragment M65, GGT, and delta of AST, insulin, and urea for evaluating liver fibrosis improvement without worsening of MASH. These biomarkers assess metabolic dysfunction, apoptosis, and fibrosis progression, providing a noninvasive, accurate strategy to monitor treatment response to lanifibranor, with an average AUC above 0.8 for all three scores[107].

Lifestyle change

A 10-month program combining energy restriction and exercise intervention significantly reduced body weight, fat mass, energy intake, HbA1c, liver fat accumulation, and insulin resistance[108]. A clinical study (CHRONO-NAFLD Project) showed that a hypocaloric Mediterranean-type diet with a 10-hour eating window from 8 AM to 6 PM further improved insulin resistance and significantly decreased HbA1c at 12 weeks compared with the Mediterranean diet alone[109].

Treatment of obesity and diabetes

Treatment with artichoke leaf extract significantly reduced hepatic fat accumulation and the liver size in patients with obesity and MASLD before bariatric surgery, as assessed by FibroScan and ultrasound[110]. Patients with MASH and obesity who underwent endoscopic sleeve gastroplasty experienced significant weight loss, with improvement in liver stiffness and steatosis[111]. A recent meta-analysis study demonstrated that treatment with GLP-1 receptor agonists and sodium-glucose cotransporter-2 inhibitors was associated with a significant decrease in the risk of hepatocellular carcinoma (HCC) and other liver-related events in T2DM patients, demonstrating hepatoprotective effects[112].

Drug repurposing and combinational therapy

Thiazolidinedione is a PPARγ agonist for the treatment of T2DM. SGLT2 inhibitors are applied to lower blood glucose levels in patients with T2DM. A randomized and controlled clinical trial demonstrated that there was a synergistic benefit of combining thiazolidinedione with a SGLT2 inhibitor in patients with T2DM[113]. These strategies are summarized in a table (Table 3).

Table 3 Strategies to improve metabolic dysfunction-associated steatotic liver disease treatment.

Clinical trials	Phase	Treatments	Effects	Ref.
NCT03183193	N/A	Dietary intervention	Modulation of circulating miRNAs	[105]
NCT03008070	2	Serum biomarkers	Providing a non-invasive test for evaluating the treatment response to lanifibranor	[107]
NCT03151798	N/A	Lifestyle change: Energy restriction and exercise	Decrease in body weight, fat mass, liver fat accumulation, and insulin resistance	[108]
NCT05866744	N/A	Time-restricted feeding	Improvement in insulin resistance. Decrease in HbA1c	[109]
DRKS000247061	N/A	Artichoke leaf extract	Decrease in hepatic fat accumulation and liver size	[110]
NCT03426111	N/A	Endoscopic sleeve gastroplasty	Decrease in body weight, liver stiffness, and hepatic steatosis	[111]
NCT03646292	4	Pioglitazone and empagliflozin	Reduction in hepatic fat, liver stiffness, and visceral fat	[113]

¹German Clinical Trials Register.

HbA1c: Hemoglobin A1c; N/A: Not applicable.

CONCLUSION

MASLD is a broad spectrum of liver disease, ranging from simple hepatic steatosis to MASH with progression of liver inflammation, hepatocyte death, and various degrees of liver fibrosis, which can result in liver cirrhosis and HCC[114,115]. Early stages of MASLD or MASH can be reversed with treatments such as the strategies mentioned above. In contrast, liver cirrhosis and HCC are not reversible, with very limited curative strategies[116,117]. Therefore, it is critically important to manage and treat MASLD and MASH at an early stage.

Various blood-based biomarkers (e.g., fibrosis-4 score calculated with age, AST, ALT, platelet count) and imaging scans (e.g., vibration-controlled transient elastography and magnetic resonance imaging) have been employed for the diagnosis and prognosis of MASLD, as well as for disease staging and evaluation of treatment efficacy[118]. For the treatment of MASLD and MASH or associated advanced liver disease, repurposing drugs originally approved for T2DM, obesity, or other metabolic disorders is a promising strategy to accelerate drug development[119,120]. In the near future, artificial intelligence and machine learning algorithms will accelerate the development of precision medicines for the treatment of MASLD and MASH[121,122].