Emerging Therapies for MASLD

Abstract

Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly categorized under nonalcoholic fatty liver disease (NAFLD), has risen to prominence due to its increasing global prevalence and its complex association with metabolic syndrome. Despite advances in understanding its multifaceted pathophysiology, MASLD remains a therapeutic challenge, with no FDA-approved pharmacologic treatments to date. This review synthesizes current epidemiological data, elucidates disease mechanisms, highlights risk factors and clinical presentation, and critically examines diagnostic and therapeutic strategies, with a special focus on emerging therapies grounded in recent evidence and international guidelines. Consideration is given to mechanisms of action, clinical trial outcomes, and practical implications for healthcare professionals managing MASLD in contemporary practice.

Introduction

MASLD represents a spectrum of liver diseases characterized by hepatic steatosis in the context of metabolic dysfunction, encompassing simple steatosis to steatohepatitis, fibrosis, and cirrhosis. The increasing burden of MASLD mirrors the global rise in obesity, type 2 diabetes mellitus (T2DM), and other metabolic comorbidities. The redefinition of the disease emphasizes the metabolic underpinnings and aims to better stratify risk and guide management. Given the heterogeneity in disease progression and outcomes, understanding recent advances and emerging therapies is crucial for clinicians.

Epidemiology / Disease Burden

MASLD affects approximately 25-30% of the adult population worldwide, with significant geographic and ethnic variability. The prevalence is notably higher in individuals with obesity (up to 80%) and T2DM (over 60%). MASLD is now the leading cause of chronic liver disease and is projected to become the most common indication for liver transplantation in the coming decades. The disease imposes substantial healthcare costs and is associated with increased cardiovascular and liver-related morbidity and mortality, underscoring the urgent need for effective interventions.

Pathophysiology

The pathogenesis of MASLD is multifactorial, involving a complex interplay between insulin resistance, adipose tissue dysfunction, genetic predisposition, gut microbiota alterations, and chronic inflammation. The accumulation of hepatic triglycerides results from increased lipolysis, de novo lipogenesis, and impaired beta-oxidation. Subsequent oxidative stress, mitochondrial dysfunction, and inflammatory signaling drive progression from simple steatosis to steatohepatitis and fibrosis. Recent research has identified key molecular targets, including peroxisome proliferator-activated receptors (PPARs), farnesoid X receptor (FXR), and fibroblast growth factor 21 (FGF21), paving the way for targeted therapies.

Risk Factors

Major risk factors for MASLD include obesity (especially central adiposity), T2DM, dyslipidemia, metabolic syndrome, polycystic ovarian syndrome, and sedentary lifestyle. Genetic variants such as PNPLA3, TM6SF2, and MBOAT7 further modulate individual susceptibility and disease severity. Ethnic disparities exist, with higher prevalence and advanced disease seen in Hispanic populations, while African Americans tend to have lower rates of hepatic steatosis despite similar metabolic profiles.

Clinical Features

MASLD is often asymptomatic in early stages, with many patients presenting incidentally with elevated liver enzymes or steatosis on imaging. Symptoms, when present, are nonspecific, including fatigue and right upper quadrant discomfort. Progressive disease may manifest as hepatomegaly, advanced fibrosis, cirrhosis, or complications such as portal hypertension and hepatocellular carcinoma. Extrahepatic manifestations include increased risk of cardiovascular disease, chronic kidney disease, and certain malignancies.

Diagnosis

Diagnosis of MASLD requires evidence of hepatic steatosis (by imaging or histology) and exclusion of secondary causes of steatosis, such as significant alcohol intake, viral hepatitis, or medications. Noninvasive tools, including ultrasound, MRI-proton density fat fraction (MRI-PDFF), transient elastography, and serum biomarkers (e.g., FIB-4, NAFLD fibrosis score), are increasingly used to assess steatosis and fibrosis. Liver biopsy remains the gold standard for staging, particularly in cases of diagnostic uncertainty or suspected advanced fibrosis.

Treatment & Management

Lifestyle modification remains the cornerstone of MASLD management, emphasizing weight loss through caloric restriction, increased physical activity, and dietary interventions such as the Mediterranean diet. A sustained weight loss of 7-10% is associated with histologic improvement in steatosis and inflammation, and regression of fibrosis. Management of comorbidities, including glycemic and lipid control, is essential. Pharmacotherapy for MASLD is currently limited, with off-label options such as pioglitazone and vitamin E reserved for select cases. Bariatric surgery may be considered for eligible patients with morbid obesity and advanced disease.

Recent Advances / Emerging Therapies

Recent years have witnessed significant progress in the development of novel agents targeting key pathways implicated in MASLD pathogenesis. Several promising therapies are under investigation:

FXR Agonists: Obeticholic acid, a selective FXR agonist, has demonstrated improvement in fibrosis and steatohepatitis in phase 3 trials, though concerns remain regarding pruritus and dyslipidemia. Other FXR modulators are in various stages of development.

PPAR Agonists: Lanifibranor (a pan-PPAR agonist) and elafibranor (a dual PPAR-α/δ agonist) have shown histologic benefits in MASLD/NASH, with ongoing trials evaluating their long-term safety and efficacy.

GLP-1 Receptor Agonists: Semaglutide and liraglutide initially developed for T2DM have exhibited significant reductions in hepatic steatosis and inflammation, with semaglutide showing promise in resolving NASH without worsening fibrosis.

FGF21 Analogues: Pegbelfermin and efruxifermin, analogues of FGF21, have demonstrated reductions in liver fat and markers of fibrosis, suggesting a potential role in future MASLD treatment paradigms.

SGLT2 Inhibitors & Combination Therapies: Sodium-glucose cotransporter 2 inhibitors, used primarily for diabetes, show benefit in reducing hepatic fat and improving metabolic parameters. Combination therapies targeting multiple pathways are under active investigation to address the multifactorial nature of MASLD.

The translation of these agents into clinical practice awaits ongoing phase 3 trial results, regulatory approvals, and long-term safety data.

Guideline Recommendations

Current international guidelines from organizations such as AASLD, EASL, and APASL emphasize lifestyle modification and management of metabolic comorbidities as first-line interventions. Pharmacologic therapy is recommended for patients with biopsy-proven steatohepatitis and fibrosis, particularly when lifestyle interventions fail. Vitamin E and pioglitazone may be considered in non-diabetic, biopsy-proven NASH. Emerging agents should be prescribed within clinical trials until robust evidence and regulatory guidance become available. Regular monitoring for disease progression and associated metabolic and cardiovascular risks is advised.

Conclusion

MASLD represents a growing global health challenge due to its rising prevalence and significant clinical consequences. Recent advances in understanding disease mechanisms have catalyzed the development of novel targeted therapies, many of which are demonstrating promising outcomes in clinical trials. While lifestyle modification remains foundational, the future of MASLD management will likely involve combination approaches integrating emerging pharmacologic agents with comprehensive metabolic risk reduction. Ongoing research, multidisciplinary collaboration, and updated guidelines will be pivotal in optimizing care for patients with MASLD.