Resmetirom

1 INDICATIONS AND USAGE REZDIFFRA is indicated in conjunction with diet and exercise for the treatment of adults with noncirrhotic nonalcoholic steatohepatitis (NASH) with moderate to advanced liver fibrosis (consistent with stages F2 to F3 fibrosis). This indication is approved under accelerated approval based on improvement of NASH and fibrosis [see Clinical Studies (14) ] . Continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory trials. Limitations of Use Avoid use of REZDIFFRA in patients with decompensated cirrhosis [see Use in Specific Populations (8.7) , Clinical Pharmacology (12.3) ] . REZDIFFRA is a thyroid hormone receptor-beta (THR-beta) agonist indicated in conjunction with diet and exercise for the treatment of adults with noncirrhotic nonalcoholic steatohepatitis (NASH) with moderate to advanced liver fibrosis (consistent with stages F2 to F3 fibrosis). This indication is approved under accelerated approval based on improvement of NASH and fibrosis. Continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory trials. (1) Limitations of Use Avoid use of REZDIFFRA in patients with decompensated cirrhosis. (1)

12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Resmetirom is a partial agonist of the thyroid hormone receptor-beta (THR-β). Resmetirom produced 83.8% of the maximum response compared to triiodothyronine (T3), with an EC 50 of 0.21 µM in an in vitro functional assay for THR-β activation. The same functional assay for thyroid hormone receptor-alpha (THR-α) agonism showed 48.6% efficacy for resmetirom relative to T3, with an EC 50 of 3.74 µM. THR-β is the major form of THR in the liver, and stimulation of THR-β in the liver reduces intrahepatic triglycerides, whereas actions of thyroid hormone outside the liver, including in heart and bone, are largely mediated through THR-α. 12.2 Pharmacodynamics Liver Fat Content Resmetirom decreases liver fat content as measured by magnetic resonance imaging-protein density fat fraction (MRI-PDFF) or FibroScan controlled attenuation parameter (CAP). Reductions in liver fat content by MRI-PDFF were observed at 16 (the first assessment) and 52 weeks of treatment. Reductions in liver fat content by CAP were observed at 52 weeks of treatment. Prohormone FT4 Resmetirom decreased concentrations of prohormone FT4 were observed at the first assessment at 4 weeks of treatment. Similar decreases in FT4 were observed during the treatment [see Adverse Reactions (6.1) ]. Sex Hormone Binding Globulin (SHBG) Resmetirom increased concentrations of sex hormone binding globulin (SHBG) were observed at the first assessment at 4 weeks of treatment, and at longer durations of treatment. The clinical significance of this change is unknown. Cardiac Electrophysiology At a dose two times the maximum recommended dose, resmetirom does not prolong the QT interval to any clinically relevant extent. 12.3 Pharmacokinetics Following once daily doses, steady state is typically reached within 3 to 6 days of dosing. Resmetirom steady state exposure increases in a dose proportional manner between doses of 40 mg (0.5 times the lowest approved recommended dose) and 100 mg. Resmetirom exposure increases in a greater than dose proportional manner between doses of 100 mg and 200 mg (2 times the highest approved recommended dose) by about 5.6-fold. Resmetirom exposure increased 1.5- to 3-fold following once daily dosing; however, the MGL-3623 metabolite does not accumulate. The estimated resmetirom systemic exposure at steady state in NASH patients is summarized in Table 5 . Resmetirom exposure is similar between NASH patients with F2 stage fibrosis and F3 stage fibrosis. Table 5: Resmetirom Estimated Systemic Exposure at Steady State in Patients with NASH with Fibrosis (F2 and F3) Abbreviations: AUC t au,ss = area under the concentration-versus-time curve over one dosing interval at steady state; C max,ss = maximum concentration at steady state; CV = arithmetic coefficient of variation Parameter Resmetirom 80 mg Once Daily Mean (CV%) Resmetirom 100 mg Once Daily Mean (CV%) C max,ss (ng/mL) a 778 (41.5) 971 (40.9) AUC tau,ss (ng*h/mL) a 5850 (60.5) 7

2 DOSAGE AND ADMINISTRATION The recommended dosage of REZDIFFRA is based on actual body weight. For patients weighing: o <100 kg, the recommended dosage is 80 mg orally once daily. o ≥100 kg, the recommended dosage is 100 mg orally once daily. Administer REZDIFFRA with or without food. Swallow REZDIFFRA tablets whole; do not split, crush, or chew tablets ( 2.1 ) See full prescribing information for REZDIFFRA dosage modifications with concomitant use of moderate CYP2C8 inhibitors. ( 2.2 ) 2.1 Recommended Dosage and Administration The recommended dosage of REZDIFFRA is based on actual body weight. For patients weighing: <100 kg, the recommended dosage is 80 mg orally once daily. ≥100 kg, the recommended dosage is 100 mg orally once daily. Administer REZDIFFRA with or without food [see Clinical Pharmacology (12.3) ] . Swallow REZDIFFRA tablets whole; do not split, crush, or chew tablets. Advise patients that if a dose is missed, do not take the missed dose and resume with the next scheduled dose. 2.2 Dosage Modifications for CYP2C8 Inhibitors Concomitant use of REZDIFFRA with strong CYP2C8 inhibitors (e.g., gemfibrozil) is not recommended [see Drug Interactions (7.1) ] . If REZDIFFRA is used concomitantly with a moderate CYP2C8 inhibitor (e.g., clopidogrel) [see Drug Interactions (7.1) ] , reduce the dosage of REZDIFFRA: <100 kg, reduce the dosage of REZDIFFRA to 60 mg once daily. ≥100 kg, reduce the dosage of REZDIFFRA to 80 mg once daily.

6 ADVERSE REACTIONS The following clinically significant adverse reactions are described elsewhere in labeling: Hepatotoxicity [see Warnings and Precautions (5.1) ] Gallbladder-Related Adverse Reactions [see Warnings and Precautions (5.2) ] The most common adverse reactions with REZDIFFRA (reported in at least 5% of patients and higher compared to placebo) are: diarrhea, nausea, pruritus, vomiting, constipation, abdominal pain, and dizziness. (6.1) To report SUSPECTED ADVERSE REACTIONS, contact Madrigal Pharmaceuticals, Inc. at 1-800-905-0324 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in clinical trials of another drug and may not reflect the rates observed in clinical practice. The safety of REZDIFFRA was evaluated in two randomized, double-blind, placebo-controlled trials that enrolled a total of 2019 patients. Trial 1 Trial 1 included patients who had noncirrhotic NASH with stages F2 and F3 fibrosis at eligibility (n=888) [see Clinical Studies (14) ] . Adverse Reactions Leading to Discontinuations The exposure-adjusted incidence rates (EAIRs) per 100 person-years (PY) for treatment discontinuation due to any adverse reaction were higher in the REZDIFFRA dosage arms: 4 per 100 PY, 5 per 100 PY, and 8 per 100 PY in placebo, REZDIFFRA 80 mg once daily, and REZDIFFRA 100 mg once daily arms, respectively. Diarrhea and nausea were the most common causes of treatment discontinuation. Common Adverse Reactions Table 1 displays EAIRs per 100 PY for the common adverse reactions that occurred in at least 5% of patients with F2 or F3 fibrosis treated in either drug arm with REZDIFFRA and were greater than that reported for placebo. Table 1: Exposure-Adjusted Incidence Rates (EAIR) of Common Adverse Reactions Reported with REZDIFFRA in Adult Patients with Noncirrhotic NASH (Trial 1) a, b, c a Population includes adult patients with noncirrhotic NASH with liver fibrosis (stages F2 and F3 at eligibility). b Median exposure duration was 68 weeks for placebo, 74 weeks for REZDIFFRA 80 mg once daily, and 66 weeks for REZDIFFRA 100 mg once daily. c EAIRs are per 100 person-years (PY) where total PYs were 435, 435, and 407 for placebo, 80 mg once daily, and 100 mg once daily arms, respectively. d The EAIR per 100 PY can be interpreted as an estimated number of first occurrences of the adverse reaction of interest if 100 patients are treated for one year. Abbreviations: EAIR, exposure-adjusted incidence rate; PY, person-years; NASH, nonalcoholic steatohepatitis Adverse Reaction Placebo N=294 n (EAIR d ) REZDIFFRA 80 mg Once Daily N=298 n (EAIR d ) REZDIFFRA 100 mg Once Daily N=296 n (EAIR d ) Diarrhea 52 (14) 78 (23) 98 (33) Nausea 36 (9) 65 (18) 51 (15) Pruritus 18 (4) 24 (6) 36 (10) Vomiting 15 (4) 27 (7) 30 (8) Constipation 18 (4) 20 (5) 28 (8) Abdominal pain 18 (4) 22 (5) 27 (7) Dizziness 6 (1) 17 (4) 17 (4) Gastrointestinal Adverse Reactions The incidence of gastrointestinal adverse reactions was higher for the REZDIFFRA drug arms compared to placebo. The EAIRs for gastrointestinal adverse reactions were 57 per 100 PY, 73 per 100 PY, and 89 per 100 PY in the placebo, REZDIFFRA 80 mg once daily, REZDIFFRA 100 mg once daily arms, respectively. Diarrhea typically began early in treatment initiation and was mild to moderate in severity. The median time (Q1 to Q3) to a diarrheal event was 39 (2 to 195) days, 17 (3 to 70) days, and 6 (2 to 54) days in the placebo, REZDIFFRA 80 mg once daily, and REZDIFFRA 100 mg once daily arms, respectively. Median duration of diarrhea was 9 days for placebo compared to 20 days for both REZDIFFRA 80 mg once daily and REZDIFFRA 100 mg once daily dosage arms. Nausea also began early in treatment and was mild to moderate in severity. Among patients with nausea, the median time (Q1 to Q3) to a nausea event

5 WARNINGS AND PRECAUTIONS Hepatotoxicity : Monitor patients during treatment with REZDIFFRA for elevations in liver tests and for the development of liver-related adverse reactions. Discontinue REZDIFFRA and continue to monitor the patient if hepatotoxicity is suspected. (5.1) Gallbladder-Related Adverse Reactions : Cholelithiasis and cholecystitis were observed more often in REZDIFFRA-treated patients. If cholelithiasis is suspected, gallbladder diagnostic studies and appropriate clinical follow-up are indicated. If an acute gallbladder event such as acute cholecystitis is suspected, interrupt REZDIFFRA treatment until the event is resolved. (5.2) 5.1 Hepatotoxicity Hepatotoxicity has been observed with use of REZDIFFRA. One patient had normal alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin (TB) levels at baseline, who received REZDIFFRA 80 mg daily, developed substantial elevations of liver biochemistries that resolved when treatment was interrupted. After reinitiating REZDIFFRA, the patient had elevations of ALT, AST, and TB. Peak values observed were 58 x upper limit of normal (ULN) for ALT, 66 x ULN for AST, 15 x ULN for TB, with no elevation of alkaline phosphatase (ALP). Elevations in liver enzymes were accompanied by elevations in immunoglobulin G levels, suggesting drug-induced autoimmune-like hepatitis (DI-ALH). The liver tests returned to baseline following hospitalization and discontinuation of REZDIFFRA without any therapeutic intervention. Monitor patients during treatment with REZDIFFRA for elevations in liver tests and for the development of liver-related adverse reactions. Monitor for symptoms and signs of hepatotoxicity (e.g., fatigue, nausea, vomiting, right upper quadrant pain or tenderness, jaundice, fever, rash, and/or eosinophilia [>5%]). If hepatotoxicity is suspected, discontinue REZDIFFRA and continue to monitor the patient. If laboratory values return to baseline, weigh the potential risks against the benefits of restarting REZDIFFRA. If laboratory values do not return to baseline, consider DI-ALH or autoimmune liver disease in the evaluation of elevations in liver tests. 5.2 Gallbladder-Related Adverse Reactions In clinical trials, cholelithiasis, acute cholecystitis, and obstructive pancreatitis (gallstone) were observed more often in REZDIFFRA-treated patients than in placebo-treated patients. If cholelithiasis is suspected, gallbladder diagnostic studies and appropriate clinical follow-up are indicated. If an acute gallbladder event is suspected, interrupt REZDIFFRA treatment until the event is resolved [see Adverse Reactions (6.1) ] . 5.3 Drug Interaction with Certain Statins An increase in exposure of atorvastatin, pravastatin, rosuvastatin and simvastatin was observed when concomitantly administered with REZDIFFRA [see Clinical Pharmacology (12.3) ], which may increase the risk of adverse reactions related to these drugs. Dosage adjustment for certain statins is recommended [see Drug Interactions (7.2) ] . Monitor for statin-related adverse reactions including but not limited to elevation of liver tests, myopathy, and rhabdomyolysis .

4 CONTRAINDICATIONS None. None.