FDA Approves Mirum Drug for Rare Genetic Disease

The Food and Drug Administration (FDA) has recently approved a new drug developed by Mirum Pharmaceuticals to tackle a rare genetic disorder known as cerebrotendinous xanthomatosis (CTX). This condition is characterized by harmful fat deposits in various organs due to a genetic mutation that hinders the production of an essential enzyme responsible for breaking down cholesterol. The drug, named Ctexli, is specifically designed for adult patients suffering from CTX.

Mirum Pharmaceuticals acquired Ctexli as part of a strategic 2023 acquisition from Travere Therapeutics, in which Mirum secured Travere's bile acid portfolio for a transaction valued at $210 million. Ctexli, a synthetic variant of chenodeoxycholic acid, had previously received approval for the treatment of non-calcified gallstones in the gallbladder.

The FDA's decision to approve Ctexli was heavily influenced by compelling data from a Phase 3 clinical trial involving adult CTX patients. During the 24-week study period, participants received a 250-milligram dose of Ctexli three times per day. Results from the trial indicated a significant reduction in toxic cholesterol metabolites, namely plasma cholestanol and bile alcohols, in comparison to a placebo.

Despite its promising efficacy, the drug does come with a cautionary warning regarding potential liver toxicity. Consequently, patients are required to undergo liver function tests both before beginning and during the course of treatment with Ctexli. Additional side effects reported include headache, constipation, diarrhea, high blood pressure, muscle weakness, and upper respiratory tract infections.

This FDA approval grants Mirum Pharmaceuticals a form of regulatory exclusivity, allowing them to market Ctexli for the treatment of CTX. Chris Peetz, CEO of Mirum, expressed his enthusiasm for the approval, stating that it opens a pathway to better identify and treat adult CTX patients across the United States. Peetz also emphasized the hope that earlier diagnoses could help patients avoid some of the debilitating and irreversible symptoms associated with the disorder.

Ctexli will be accessible through Mirum Pharmaceuticals' patient support platform. The company has indicated that the pricing for Ctexli will align with the cost of the previous formulation used for gallstone treatment. Furthermore, Mirum has committed to ensuring affordability, with the majority of patients expected to pay no more than $10 for access to the treatment.

In summary, the introduction of Ctexli represents a significant advancement in the treatment of cerebrotendinous xanthomatosis, offering new hope for patients afflicted by this rare genetic disorder. With robust clinical trial data supporting its effectiveness and safety, Ctexli is poised to make a meaningful impact on the lives of those living with CTX, provided that careful monitoring and management of potential side effects are maintained. The drug's availability through a dedicated patient support platform further underscores Mirum Pharmaceuticals' commitment to ensuring that this innovative treatment reaches those who need it most, without imposing undue financial burden.