The US Food and Drug Administration (FDA) has approved Mirum Pharmaceuticals’ Ctexli (chenodiol) to treat adults with cerebrotendinous xanthomatosis (CTX).
The oral drug is now the first treatment to be approved by the regulator for the rare lipid storage disease.
Affecting up to 2,000 people in the US, CTX is a progressive genetic disorder caused by a deficiency of an enzyme that allows the body to break down fats. This results in the deposition of atypical cholesterol metabolites in the brain and other areas of the body.
Symptoms vary, but can include chronic diarrhoea, frequent bone fractures, cataracts, dementia, seizures and difficulty with speech.
Ctexli is designed to replace deficient levels of one of the bile acids, reducing the abnormal deposits of cholesterol metabolites thought to be responsible for clinical abnormalities in CTX.
The FDA’s decision on the drug was supported by positive results from the 24-week phase 3 RESTORE study, which demonstrated that treatment with Ctexli at a dose of 250mg three times a day resulted in significant reduction in plasma cholestanol and urine 23S-pentol, cholesterol metabolites that are markedly increased in CTX patients, compared to placebo.
The prescribing information for Ctexli does, however, include a warning for liver toxicity and patients should have liver blood tests before starting treatment, and then once a year while receiving the drug.
Mirum’s chief executive officer, Chris Peetz, said: “The FDA’s approval of Ctexli is tremendous as it unlocks an opportunity to better identify and treat adult patients with CTX in the US.
“Our hope is that patients are diagnosed sooner and have a chance to avoid some of the debilitating and lasting symptoms associated with CTX.”
Also commenting on the authorisation, Janet Maynard, director of the office of rare diseases, paediatrics, urologic and reproductive medicine, in the FDA’s centre for drug evaluation and research, said: “The FDA is dedicated to supporting new drug development for rare diseases including very rare metabolic diseases like CTX.
“CTX is a progressive multi-systemic disorder that significantly impacts patients and previously lacked approved treatments. [This] approval provides a safe and effective treatment option for CTX.”
