CTEXLI

Clinical summary

Indications and usage 1 INDICATIONS AND USAGE CTEXLI is indicated for the treatment of cerebrotendinous xanthomatosis (CTX) in adults. CTEXLI is a bile acid indicated for treatment of cerebrotendinous xanthomatosis (CTX) in adults. ( 1 ) Dosage and administration 2 DOSAGE AND ADMINISTRATION • Before initiating CTEXLI, obtain baseline liver transaminase (alanine aminotransferase [ALT] and aspartate aminotransferase [AST]) and total bilirubin levels in all patients. ( 2.1 ) • The recommended dosage is 250 mg orally three times daily. ( 2.2 ) 2.1 Important Recommendation Prior to CTEXLI Treatment Initiation Before initiating CTEXLI, obtain baseline liver transaminase (alanine aminotransferase [ALT] and aspartate aminotransferase [AST]) and total bilirubin levels in all patients [see Warnings and Precautions ( 5.1 )] . 2.2 Recommended Dosage The recommended dosage of CTEXLI is 250 mg administered orally three times daily. Administer CTEXLI with or without food. Swallow tablets whole. Missed Dose If a dose of CTEXLI is missed, advise the patient to skip the missed dose and to resume taking the prescribed dose at the next scheduled time. Patients should not take a double dose. 2.3 Administration Modification and Monitoring If liver transaminase (ALT, AST) levels are elevated > 3 times the upper limit of normal (ULN) or total bilirubin level is >2 times ULN, interrupt treatment with CTEXLI until the levels have returned to baseline values. Monitor liver transaminase and total bilirubin levels yearly and as clinically indicated [see Warnings and Precautions ( 5.1 )]. Warnings and cautions 5 WARNINGS AND PRECAUTIONS Hepatotoxicity : Obtain baseline liver transaminase and total bilirubin levels in all patients and monitor yearly and as clinically indicated. Interrupt treatment until the levels have returned to baseline values. For persistent or recurrent liver test abnormalities, consider discontinuing CTEXLI. ( 5.1 ) 5.1 Hepatotoxicity Chenodiol, including CTEXLI, has been associated with hepatotoxicity [see Adverse Reactions ( 6 )] . In Trial 1, one CTEXLI-treated patient (7%) had increased ALT levels > 3 times ULN, which led to treatment interruption. Patients with pre-existing liver disease or bile duct abnormalities may be at higher risk for hepatotoxicity during treatment with CTEXLI. Published reports suggest patients who are poor sulfators of lithocholic acid are more likely to develop chenodiol-induced serum aminotransferase elevations [see Clinical Pharmacology ( 12.3 )] . Obtain baseline liver transaminase (ALT, AST) and total bilirubin levels in all patients prior to treatment initiation with CTEXLI. If liver transaminase levels are elevated > 3 times ULN or total bilirubin level is >2 times ULN, interrupt treatment with CTEXLI until the levels have returned to baseline values. Monitor liver transaminase and total bilirubin levels yearly and as clinically indicated. For persistent or recurrent liver test abnormalities, consider discontinuing CTEXLI. Inform the patient of the symptoms of hepatotoxicity (e.g., abdominal pain, bruising, dark-colored urine, fatigue, bleeding, jaundice, nausea, and pruritus). If clinical signs and symptoms consistent with hepatotoxicity occur, have the patient discontinue CTEXLI immediately. Drug interactions 7 DRUG INTERACTIONS • Bile acid sequestering agents and aluminum-based antacids: Avoid concomitant use with CTEXLI. ( 7.1 ) • Coumarin and its derivatives: Monitor prothrombin time and adjust dosage accordingly. ( 7.2 ) 7.1 Effect of Other Drugs on CTEXLI Co-administration of bile acid sequestering agents, such as cholestyramine and colestipol, or aluminum-based antacids may decrease absorption of CTEXLI in the intestine and may result in decreased efficacy of CTEXLI. Avoid concomitant use of bile acid sequestering agents or aluminum-based antacids with CTEXLI. 7.2 Effect of CTEXLI on Other Drugs Due to potential hepatotoxicity, CTEXLI may affect the pharmacodynamics of coumarin and its derivatives, causing unexpected prolongation of the prothrombin time and hemorrhage. If concomitant use of CTEXLI with coumarin or its derivatives is unavoidable, monitor prothrombin time. Adjust the dosage of coumarin or its derivatives in accordance with its approved product labeling. Pregnancy 8.1 Pregnancy Risk Summary Available data from published case reports over decades of use with chenodiol during pregnancy have not identified an increased risk of major birth defects, miscarriage, or other adverse maternal or fetal outcomes. Serious hepatic, renal and adrenal lesions occurred in fetuses of female Rhesus monkeys treated at doses 1 to 2 times the recommended human dose based on body surface area (mg/m 2 ). Hepatic lesions also occurred at doses comparable to the human dose based on body surface area in neonatal baboons born to mothers administered chenodiol during pregnancy ( see Data ). The animal study findings have not been demonstrated with human use. The background risk of