A little less than two years after San Francisco’s Mirum Pharmaceuticals ponied up $210 million to acquire Travere Therapeutics’ bile acid portfolio, the deal has paid off with a fresh FDA approval.
The FDA on Friday gave the green light to Mirum’s Ctexli, also known as chenodiol, for the treatment of adults with cerebrotendinous xanthomatosis (CTX).
The approval makes chenodiol—already cleared for decades to treat radiolucent gallstones under the brand name Chenodal—the first drug specifically indicated to treat CTX in the U.S., the FDA said in a press release.
CTX is a genetic metabolic disorder stemming from a gene mutation that causes a deficiency of the enzyme the body uses to break down fats.
Because the livers of patients with CTX don’t produce enough bile acid, people with the disorder can’t break down cholesterol normally. This leads to buildups of atypical cholesterol metabolites that ultimately damage parts of the body such as the brain, liver, skin and tendons.
Ctexli works by replacing low levels of one of the bile acids, helping clear out toxic cholesterol metabolite deposits, the FDA explained in its approval notice.
The medicine was approved based on phase 3 data showing three daily doses of 250 mg Ctexli significantly reduced levels of two cholesterol metabolites that are increased in CTX patients compared to placebo.
The drug bears a warning for liver toxicity in all patients with increased risk for liver damage and in patients with preexisting liver disease or bile duct abnormalities, the FDA noted. The regulator recommends patients get liver blood tests before starting Ctexli and then once a year while on treatment to help monitor potential risks.
While the formal approval is no doubt a win for Mirum—and further validation of the company’s Travere deal—CTX patients have been able to access chenodiol off-label for years. The medication won an orphan drug designation for CTX in 2010 and was classified as a “medical necessity” by the FDA.
The 2023 transaction saw Mirum hand Travere $210 million upfront and pledge up to $235 million in potential milestones to pick up Chenodal (chenodiol) and Cholbam, the latter of which was approved in 2015 for patients with rare bile acid synthesis disorders.
By snagging a full approval, Mirum will be able to actively promote the drug in CTX and could potentially be more proactive in screening those with the disease, the company’s CEO, Chris Peetz, told Fierce Pharma at the time of the deal.
“We think that we’ll be able to diagnose more undiagnosed patients,” the CEO said at the time. “And by treating this disease earlier, you can prevent some of the accumulation of irreversible defects.”
Mirum has yet to reveal pricing information or launch plans regarding Ctexi, though JMP Securities analyst Jonathan Wolleben figures the drug could tack on an additional $150 million to $200 million to Mirum’s revenue, Reuters reported Friday.
The green light also equips the drug with seven more years of protection against potential generics, the analyst said.
Prior to Mirum’s bile acid portfolio purchase from Travere, the company sported a single commercial product in the form of rare liver disease drug Livmarli.