What is the recommended dosing and monitoring plan for resmetirom in an adult with biopsy‑proven F3 fibrosis (moderate‑to‑advanced fibrosis) due to metabolic dysfunction‑associated steatohepatitis who is non‑cirrhotic and already following diet and exercise?

Resmetirom Dosing and Monitoring for F3 Fibrosis in MASH

For an adult with biopsy-proven F3 fibrosis from MASH who is non-cirrhotic, initiate resmetirom at 80 mg once daily if body weight is <100 kg, or 100 mg once daily if ≥100 kg, administered with or without food. 1, 2

Dosing Algorithm

Weight-Based Dosing

• <100 kg body weight: 80 mg orally once daily
• ≥100 kg body weight: 100 mg orally once daily
• Can be taken with or without food 1, 2

Dose Modifications for Drug Interactions

• Strong CYP2C8 inhibitors (e.g., gemfibrozil): Avoid concomitant use 2
• Moderate CYP2C8 inhibitors (e.g., clopidogrel):
  • If <100 kg: reduce to 60 mg once daily
  • If ≥100 kg: reduce to 80 mg once daily 2
• OATP1B1/1B3 inhibitors (e.g., cyclosporine): Avoid concomitant use 2

Pre-Treatment Requirements

Before initiating resmetirom, exclude:

• Cirrhosis (resmetirom is contraindicated in decompensated cirrhosis) 2
• Autoimmune liver disease (check ANA, anti-smooth muscle antibody; if elevated, obtain quantitative immunoglobulins and consider liver biopsy) 1
• Alcohol-associated liver disease (assess alcohol intake history; consider phosphatidylethanol if uncertain) 1
• Viral hepatitis (HBV, HCV screening)
• Iron overload (ferritin, transferrin saturation)
• Untreated thyroid disorders 3

Monitoring Plan

Hepatic Safety Monitoring

Critical: Monitor for drug-induced autoimmune-like hepatitis (DI-ALH), which occurred in the MAESTRO-NASH trial with peak elevations of ALT 58× ULN, AST 66× ULN, and total bilirubin 15× ULN 2.

Monitor liver tests regularly for:

• Elevations in ALT, AST, total bilirubin, alkaline phosphatase
• Symptoms of hepatotoxicity: fatigue, nausea, vomiting, right upper quadrant pain, jaundice, fever, rash
• Eosinophilia (>5%) 2

If hepatotoxicity suspected:

• Discontinue resmetirom immediately
• Continue monitoring until laboratory values return to baseline
• If values normalize, weigh risks vs. benefits of restarting
• If values do not normalize, evaluate for DI-ALH or autoimmune liver disease 2

Gallbladder Monitoring

Cholelithiasis and cholecystitis occurred more frequently with resmetirom 2:

• If cholelithiasis suspected: obtain gallbladder imaging and clinical follow-up
• If acute cholecystitis suspected: interrupt treatment until resolved 2

Treatment Response Assessment

At 6-12 months, assess response using non-invasive tests (NITs) 1:

Liver stiffness measurement:

• Vibration-controlled transient elastography (VCTE)
• Magnetic resonance elastography (MRE)

Biochemical markers:

• ALT reduction (expect improvement) 3
• Enhanced liver fibrosis (ELF) score
• FIB-4 score

Hepatic fat assessment:

• MRI-proton density fat fraction (MRI-PDFF)
• Controlled attenuation parameter (CAP) on VCTE

Lipid Monitoring

Resmetirom significantly reduces LDL cholesterol:

• At week 24: expect 11.7-16.3% reduction in LDL-C 4, 5
• Monitor lipid panel at baseline and periodically

Thyroid Function

In selected patients (those with pre-existing thyroid conditions or symptoms), monitor thyroid function 3

Statin Dose Adjustments

If patient is on statins, limit daily dosage as follows 2:

• Atorvastatin
• Pravastatin
• Rosuvastatin
• Simvastatin

Common Pitfalls to Avoid

1. Do not use in cirrhotic patients: The FDA label explicitly excludes cirrhosis; avoid in decompensated cirrhosis 2

2. Do not miss autoimmune liver disease: Several MASH trials inadvertently included autoimmune cases, leading to elevated liver enzymes. Screen thoroughly before initiating 1

3. Do not ignore drug interactions: Strong CYP2C8 inhibitors are contraindicated; moderate inhibitors require dose reduction 2

4. Do not delay discontinuation if hepatotoxicity occurs: The DI-ALH case in trials showed dramatic enzyme elevations; early recognition and discontinuation are critical 2

5. Do not use liver biopsy for monitoring: The FDA label does not require biopsy for treatment initiation or monitoring; NITs are sufficient 1

Expected Outcomes

Based on the MAESTRO-NASH trial in F2-F3 patients 4, 5:

• MASH resolution (without fibrosis worsening): 25.9-29.9% vs. 9.5% placebo
• Fibrosis improvement by ≥1 stage (without NAS worsening): 26.5-28.9% vs. 17.3% placebo
• LDL-C reduction: 11.7-13.7% at 24 weeks

Concomitant GLP-1 Receptor Agonist Use

Real-world data show frequent concomitant use of GLP-1 receptor agonists with resmetirom, with treatment response appearing independent of weight-loss therapy 3. This combination is acceptable and may provide complementary benefits.