Mirum Pharmaceuticals’ Ctexli (chenodiol) has gained US Food and Drug Administration (FDA) approval for treating adults with cerebrotendinous xanthomatosis (CTX), a rare lipid storage disease.
It is the first drug approved by the US regulator for the condition.
In June 2024, the company submitted a new drug application (NDA) for chenodiol to the US regulator to treat patients with CTX.
Ctexli's efficacy was assessed in a 24-week, placebo-controlled, randomised, double-blind crossover withdrawal trial.
Subjects treated with Ctexli, at a dose of 250 mg three times per day, showed a significant decrease in plasma cholestanol as well as urine 23S-pentol.
The drug replaces deficiencies in bile acids, minimising abnormal cholesterol metabolite deposits.
FDA Center for Drug Evaluation and Research, Office of Rare Diseases, Pediatrics, Urologic and Reproductive Medicine director Janet Maynard stated: “The FDA is dedicated to supporting new drug development for rare diseases including very rare metabolic diseases like cerebrotendinous xanthomatosis.
“CTX is a progressive multisystemic disorder that significantly impacts patients and previously lacked approved treatments. Today’s approval provides a safe and effective treatment option for CTX.”
A liver toxicity warning for individuals with pre-existing liver conditions or bile duct abnormalities who are at an increased liver damage risk is included in the drug’s prescribing information.
Liver blood tests are recommended before commencing the treatment then annually thereafter, and as clinically indicated.
Symptoms such as stomach pain, nausea and yellowing of the skin should prompt patients to discontinue the drug and consult their doctor.
Common side effects of the drug include diarrhoea, abdominal pain and upper respiratory tract infections.
Caused by a mutation in the cytochrome P450 family 27 subfamily A member 1 (CYP27A1) gene, CTX leads to a deficiency of an enzyme that is crucial for fat breakdown.
This results in abnormal cholesterol metabolite deposition in several body parts, causing organ and tissue damage.
In July 2023, the company expanded its bile acid product portfolio through a $445m acquisition deal with Travere Therapeutics.
