Mirum Pharmaceuticals, Inc. announced positive data from the Phase 3 RESTORE study evaluating Chenodal(R) (chenodiol) tablets in 13 adult patients with cerebrotendinous xanthomatosis, or CTX. The study objective was to evaluate the safety and efficacy of Chenodal by measurement of urine bile alcohols and other secondary measures. The primary endpoint of reduction in bile alcohols (urine 23S-pentol) was highly statistically significant (p<0.0001).

In CTX, a deficiency of the bile acid CDCA leads to a buildup of bile alcohols which precedes a toxic accumulation of cholestanol. Cholestanol is the key driver of symptomatic burden and disease progression, including irreversible neurological dysfunction. Results from the RESTORE study demonstrated that treatment with Chenodal not only improved urine bile alcohols but also serum cholestanol.

Additionally, a greater proportion of patients receiving placebo required blinded rescue therapy, demonstrating the robustness of the effect. Data from the RESTORE study will be presented at an upcoming scientific congress, including forthcoming results from the open-label pediatric group of patients. In addition, Mirum will be submitting a new drug application to the U.S. FDA in the first half of 2024.

The Phase 3 RESTORE study is a randomized withdrawal, placebo-controlled clinical trial which evaluated the safety and efficacy of ChenODal in patients with cerebrotend Circular cholestanol. Chenodal is administered at 250 mg three times daily in tablet format. CDCA is a naturally occurring bile acid that was originally approved for the treatment of people with radiolucent stones in the gallbladder.

More recently, the US Food and Drug Administration (FDA) granted Chenodal orphan drug designation for cerebrotendinous xthomatosis (CTX). CTX is a rare progressive disorder that can affect the brain, spinal cord, tendons, eyes and arteries. Chenodal is not indicated for the treatment of CTX but has received a medical necessity determination in the U.S. by the FDA.

Full data from the Phase 3 RESTore clinical trial are expected to be presented at an upcoming medical congress.