Clinically significant liver injury, including acute liver failure requiring transplant, has occurred in patients treated with ZEPOSIA in the postmarketing setting. Signs of liver injury, including elevated serum hepatic enzymes and elevated total bilirubin, have occurred as early as ten days after the first dose.

In MS Study 1 and Study 2, elevations of ALT to 5-fold the upper limit of normal (ULN) or greater occurred in 1.6% of patients treated with ZEPOSIA 0.92 mg and 1.3% of patients who received IFN beta-1a. Elevations of 3-fold the ULN or greater occurred in 5.5% of patients treated with ZEPOSIA and 3.1% of patients who received IFN beta-1a. The median time to an elevation of 3-fold the ULN was 6 months. The majority (79%) of patients continued treatment with ZEPOSIA with values returning to less than 3-fold the ULN within approximately 2-4 weeks. ZEPOSIA was discontinued for a confirmed elevation greater than 5-fold the ULN. Overall, the discontinuation rate because of elevations in hepatic enzymes was 1.1% of patients with MS treated with ZEPOSIA 0.92 mg and 0.8% of patients who received IFN beta-1a.

In UC Study 1, elevations of ALT to 5-fold the ULN or greater occurred in 0.9% of patients treated with ZEPOSIA 0.92 mg and 0.5% of patients who received placebo, and in UC Study 2 elevations occurred in 0.9% of patients and no patients, respectively. In UC Study 1, elevations of ALT to 3-fold the ULN or greater occurred in 2.6% of UC patients treated with ZEPOSIA 0.92 mg and 0.5% of patients who received placebo, and in UC Study 2 elevations occurred in 2.3% of patients and no patients, respectively. In controlled and uncontrolled UC studies, the majority (96%) of patients with ALT greater than 3-fold the ULN continued treatment with ZEPOSIA with values returning to less than 3-fold the ULN within approximately 2 to 4 weeks. Overall, the discontinuation rate because of elevations in hepatic enzymes was 0.4% in patients treated with ZEPOSIA 0.92 mg, and none in patients who received placebo in the controlled UC studies.

Individuals with an AST or ALT greater than 1.5-fold ULN were excluded from MS Study 1 and Study 2 and greater than 2 times the ULN for UC Study 1 and Study 3. There are no data to establish that patients with preexisting liver disease are at increased risk to develop elevated liver function test values when taking ZEPOSIA. Dosage adjustment in patients with mild or moderate hepatic impairment (Child-Pugh class A or B) is required [see Dosage and Administration (2.3)], and use of ZEPOSIA in patients with severe hepatic impairment (Child-Pugh class C) is not recommended [see Use in Specific Populations (8.6)].

Obtain transaminase and bilirubin levels, if not recently available (i.e., within 6 months), before initiation of ZEPOSIA. Obtain transaminase levels and total bilirubin levels periodically during treatment and until two months after ZEPOSIA discontinuation.

Patients should be monitored for signs and symptoms of any hepatic injury. Patients who develop symptoms suggestive of hepatic dysfunction, such as unexplained nausea, vomiting, abdominal pain, fatigue, anorexia, or jaundice and/or dark urine, should have hepatic enzymes promptly checked, and ZEPOSIA should be interrupted. Treatment should not be resumed if a plausible alternative etiology for the signs and symptoms cannot be established, because these patients are at risk for severe drug-induced liver injury.