Resmetirom

Resmetirom is the world's first innovative drug approved by the United States FDA for the treatment of nonalcoholic steatohepatitis.

It improves liver fat accumulation and fibrosis by activating the thyroid hormone receptor-β.

Resmetirom has shown positive results in improving liver biochemical markers, histological features and reducing hepatic steatosis.

1. Main ingredient

 Resmetirom

2. Applicable people

 Adult patients with nonalcoholic steatohepatitis with cirrhosis.

3. Use in Specific Populations

 3.1 Pregnancy  

There are no available data on Resmetirom use in pregnant women to evaluate for a drugassociated risk of major birth defects, miscarriage, or other adverse maternal or fetal outcomes.  There are risks to the mother and fetus related to underlying NASH with liver fibrosis (see Clinical  Considerations). In animal reproduction studies, adverse effects on embryo-fetal development  occurred in pregnant rabbits treated with resmetirom at 3.5 times the maximum recommended dose  during organogenesis. These effects were associated with maternal toxicity, whereas no embryo-fetal  effects were observed at lower dose levels with better tolerance in pregnant rabbits. No embryo-fetal  developmental effects occurred in pregnant rats treated with resmetirom or the metabolite MGL-3623.  A pre- and postnatal development study in rats with maternal dosing of resmetirom during  organogenesis through lactation showed a decrease in birthweight and increased incidence of  stillbirths and mortality (postnatal days 1-4) at 37 times the maximum recommended dose (see Data).  These effects were associated with marked suppression of maternal T4, T3, and TSH levels.

The background risk of major birth defects and miscarriage for the indicated population is unknown.  All pregnancies have a background risk of birth defect, loss, and other adverse outcomes. In the U.S.  general population, the estimated background risk of major birth defects and miscarriage in clinically  recognized pregnancies is 2 to 4% and 15 to 20%, respectively.

3.2 Lactation  

There is no information regarding the presence of Resmetirom in human or animal milk, the effects  on the breast-fed infant, or the effects on milk production. The developmental and health benefits of  breastfeeding should be considered along with the mother's clinical need for Resmetirom and any  potential adverse effects on the breastfed infant from Resmetirom or from the underlying maternal  condition.

3.3 Pediatric Use  

The safety and effectiveness of Resmetirom have not been established in pediatric patients.  

3.4 Geriatric Use  

In Trial 1, of the 594 patients with NASH who received at least one dose of Resmetirom, 149 (25%)  were 65 years of age and older and 13 (2%) were 75 years of age and older.  No overall differences in effectiveness but numerically higher incidence of adverse reactions have been  observed in patients 65 years of age and older compared to younger adult patients.

3.5 Renal Impairment  

The recommended dosage in patients with mild or moderate renal impairment is the same as in patients  with normal kidney function. Resmetirom has not been studied in patients with severe renal impairment.

3.6 Hepatic Impairment  

Avoid use of Resmetirom in patients with decompensated cirrhosis (consistent with moderate to  severe hepatic impairment). Moderate or severe hepatic impairment (Child-Pugh Class B or C)  increases resmetirom Cmax and AUC, which may increase the risk  of adverse reactions.

4. Storage

 Store at 20 °C to 25°C (68 °F to 77°F); excursions permitted to 15 °C to 30°C (59° F to 86°F)

5.  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.

FDA，2024.03