Recent MASLD Breakthroughs: Essential MRCP PACES Update

Introduction

If you are preparing for the MRCP PACES, the landscape of fatty liver disease has shifted dramatically over the past two years. The nomenclature has changed, the diagnostic algorithms have been refined, and—most importantly—the first pharmacological therapy for metabolic dysfunction-associated steatohepatitis (MASH) has received FDA approval. Exiners are well aware of these developments, and candidates who demonstrate current knowledge will immediately stand out at the bedside and in consultation stations.

This article synthesises the key advances you need to know for MRCP PACES, drawing on the latest NICE guidance, EASL–EASD–EASO clinical practice guidelines, and pivotal trial data.

1. Nomenclature: Why It Changed and Why It Matters

From NAFLD to MASLD

In 2023, a multinational consensus panel renamed non-alcoholic fatty liver disease (NAFLD) to metabolic dysfunction-associated steatotic liver disease (MASLD). The older term was considered stigmatising, inaccurate (many patients do drink modestly), and did not reflect the metabolic aetiology.

Similarly, NASH (non-alcoholic steatohepatitis) became MASH (metabolic dysfunction-associated steatohepatitis).

PACES Pearl: At the bedside, if you mention "NAFLD," you will not be penalised, but switching to MASLD signals awareness of current consensus. Examiners notice.

Definition of MASLD

MASLD is defined as hepatic steatosis (on imaging, biopsy, or blood-based scores) in the presence of at least one cardiometabolic risk factor:

• Overweight or obesity (BMI ≥ 25 kg/m², or ≥ 23 in Asian populations)

• Type 2 diabetes mellitus or prediabetes

• Hypertension

• Dyslipidaemia (elevated triglycerides, low HDL)

• Acanthosis nigricans or polycystic ovarian syndrome

A small subset of patients with steatosis but no cardiometabolic risk factors are now classified as having metabolic ALD (MetALD) or cryptogenic steatotic liver disease.

2. Burden and Why Examiners Care

MASLD is now the most common cause of chronic liver disease worldwide, affecting approximately 30% of the global adult population. In the UK, it has overtaken alcohol-related liver disease and chronic viral hepatitis as the leading indication for liver transplantation in some registries.

Key statistics candidates should know:

In a PACES Station 1 or 5 scenario, you may encounter a patient with hepatomegaly, acanthosis nigricans, and features of metabolic syndrome. Recognising this constellation rapidly allows you to frame a focused differential and management plan.

3. Non-Invasive Testing: The New Diagnostic Algorithm

Steatosis Assessment

• FIB-4 index (age × AST × platelet count / √ALT) is the first-line tool recommended by NICE and EASL for identifying patients at risk of advanced fibrosis.

• FIB-4 < 1.3 (or < 2.0 in those over 65): low risk; reassure and recheck in 2–3 years.

• FIB-4 > 1.3: proceed to secondary assessment.

Secondary Fibrosis Assessment

If FIB-4 is elevated, the following are recommended:

1. Enhanced Liver Fibrosis (ELF) score — a serum panel (hyaluronic acid, PIIINP, TIMP-1) that predicts advanced fibrosis. NICE recommends this as the preferred second-line test in primary and secondary care.

2. Transient elastography (FibroScan) — measures liver stiffness in kilopascals (kPa). Values > 8–10 kPa suggest significant fibrosis (≥F2); > 15 kPa strongly suggests cirrhosis.

3. Agile 3+ and Agile 4 scores — newer composite scores combining FibroScan, AST/ALT ratio, platelets, diabetes status, sex, and age to predict advanced fibrosis or cirrhosis with greater accuracy.

When Is Liver Biopsy Still Needed?

Biopsy remains necessary when:

• Non-invasive tests are discordant

• There is clinical suspicion of an alternative or overlapping diagnosis (e.g., autoimmune hepatitis, drug-induced liver injury)

• Confirmation of MASH is required before initiating pharmacotherapy

PACES Consultation Tip: When discussing a new diagnosis of MASLD in Station 2 or 5, frame your investigation plan around FIB-4 → ELF/FibroScan → biopsy if needed. This demonstrates a structured, guideline-concordant approach.

4. The Landmark MAESTRO-NASH Trial and Resmetirom

Background

For decades, management of MASH relied on lifestyle modification (7–10% body weight loss) and treatment of comorbidities. There were no approved pharmacotherapies specifically for MASH.

The Trial

MAESTRO-NASH (published in The Lancet, 2024) was a phase 3, double-blind, randomised controlled trial investigating resmetirom, a thyroid hormone receptor-β (THR-β) agonist that preferentially acts on hepatic tissues.

Key design features:

• 966 patients with biopsy-confirmed F2–F3 (bridging fibrosis) MASH

• Randomised to resmetirom 80 mg daily, 100 mg daily, or placebo for 52 weeks

• Dual primary endpoints: ≥ 1 stage improvement in MASH without worsening of fibrosis, and ≥ 1 stage improvement in fibrosis without worsening of MASH

Results

Resmetirom was generally well tolerated. Mild diarrhoea and nausea were the most common adverse events, typically transient.

Regulatory Outcome

In March 2024, the FDA approved resmetirom (brand name Rezdiffra) for the treatment of non-cirrhotic MASH with moderate to advanced fibrosis (F2–F3). This was the first-ever approved pharmacotherapy for MASH. NICE appraisal is underway, with guidance expected in late 2025.

Examiner Alert: If asked about pharmacological management of MASH in PACES, mentioning resmetirom by name and mechanism demonstrates cutting-edge knowledge. Frame it as: "Resmetirom is a THR-β agonist recently approved by the FDA for F2–F3 MASH; NICE appraisal is pending in the UK."

5. Other Emerging Therapies to Know

While resmetirom is the only currently approved agent, several drugs are in late-phase development:

GLP-1 Receptor Agonists (Semaglutide, Tirzepatide)

Semaglutide showed improvement in MASH resolution but did not significantly improve fibrosis in its phase 2 trial. Phase 3 trials are ongoing. Tirzepatide (dual GLP-1/GIP agonist) showed promising results in early-phase studies.

These agents are primarily beneficial through weight loss (≥ 10% reduction is associated with fibrosis regression), but they also appear to have direct hepatic anti-inflammatory effects.

FGF21 Analogues (Pegozafermin, Efruxifermin)

Fibroblast growth factor 21 analogues reduce hepatic fat and improve fibrosis biomarkers. Phase 3 trials are ongoing.

PPAR Agonists (Lanifibranor)

A pan-PPAR agonist currently in phase 3 development (NATIVE trial showed improvement in MASH activity and fibrosis).

6. Cardiovascular Risk: The Hidden Killer

Cardiovascular disease is the leading cause of mortality in patients with MASLD, not liver disease. This is a critical point that examiners emphasise.

Management Principles

Every patient with MASLD should undergo:

1. Comprehensive cardiovascular risk assessment (QRISK3 score)

2. Aggressive management of dyslipidaemia — statins are safe in MASLD, including in compensated cirrhosis, and should not be withheld

3. Optimisation of glycaemic control — metformin is safe but does not specifically treat MASH; pioglitazone has shown MASH benefit in T2DM patients

4. Blood pressure optimisation

5. Smoking cessation advice

PACES Station 5 Scenario: A 58-year-old man with T2DM, BMI 32, and newly diagnosed MASLD with F2 fibrosis. The consultation should cover: lifestyle intervention (weight loss target, Mediterranean diet, exercise), cardiometabolic optimisation (statin, glycaemic control, antihypertensives), liver-specific surveillance (variceal screening if F4, HCC surveillance if cirrhosis), and emerging therapies (resmetirom eligibility).

7. Cirrhosis and HCC Surveillance in MASLD

Patients who progress to F4 (cirrhosis) require:

• 6-monthly abdominal ultrasound ± AFP for hepatocellular carcinoma (HCC) surveillance — MASLD is now a major driver of HCC incidence, even in non-cirrhotic patients in some studies

• Variceal screening via OGD per Baveno VII criteria (if LSM > 15 kPa or platelets < 150 × 10⁹/L)

• Nutritional assessment — sarcopenia is common and associated with worse outcomes

Baveno VII also introduced the concept of "rule of 5": liver stiffness measurement (LSM) > 5 kPa suggests steatosis or early fibrosis, while LSM > 15 kPa strongly suggests clinically significant portal hypertension.

8. Practical PACES Scenarios

Scenario A: Station 1 (Respiratory/Abdominal Examination)

A 52-year-old woman with T2DM and BMI 33 is found to have hepatomegaly on abdominal examination. Your spot diagnosis may be MASLD. On presentation:

• Present findings: hepatomegaly (smooth, non-tender), acanthosis nigricans, central obesity

• Differential: MASLD with likely steatohepatitis, haemochromatosis (check for skin pigmentation, DM, arthropathy), autoimmune hepatitis

• Investigations: LFTs (AST/ALT ratio, GGT), FIB-4, lipid profile, HbA1c, ferritin, viral serologies, autoimmune screen, FibroScan

Scenario B: Station 5 (Integrated Assessment)

A 45-year-old man with recently diagnosed MASLD, FIB-4 of 2.8, is anxious about "needing a liver transplant." Discuss:

• Reassure that FIB-4 elevation warrants further assessment, not immediate alarm

• Explain secondary testing (ELF score or FibroScan)

• Discuss that only a minority progress to cirrhosis

• Address cardiovascular risk as the primary mortality driver

• Discuss lifestyle measures: 7–10% weight loss target, Mediterranean diet, 150 minutes/week moderate exercise, alcohol minimisation

• Mention resmetirom as a newly approved option if fibrosis is confirmed at F2–F3

• Offer hepatology referral

9. High-Yield Summary Table for PACES

10. Key Take-Home Messages

1. MASLD is the new NAFLD. Use the term in PACES to demonstrate currency.

2. FIB-4 first, then ELF or FibroScan. A structured approach to fibrosis staging is essential.

3. Resmetirom (Rezdiffra) is the first FDA-approved drug for F2–F3 MASH. Know the trial name (MAESTRO-NASH), mechanism (THR-β agonist), and that NICE appraisal is pending.

4. Cardiovascular risk management is paramount. Every MASLD patient needs statin, BP, and glycaemic optimisation.

5. Weight loss of ≥ 10% can regress fibrosis. Lifestyle intervention remains the foundation of therapy.

6. Progressors need surveillance. Cirrhosis screening, HCC surveillance, and variceal screening are guideline-mandated.

Conclusion

The MASLD field has transformed dramatically, with new nomenclature, structured non-invasive testing pathways, and the dawn of pharmacotherapy. For MRCP PACES candidates, integrating these advances into your clinical reasoning will signal a consultant-level understanding of modern hepatology. Whether you encounter a fatty liver patient in Station 1, discuss management in Station 5, or navigate a consultation about disease progression, being fluent in MASLD will strengthen your performance across the board.

Good luck with your preparation — stay current, stay structured, and let your knowledge shine.