Orphan drug biotech Retrophin saw its shares go up nearly 30 percent today, after news hit that not only was the company’s rare disease drug approved, but that it also received a priority review voucher from US health regulators.
Today, the US Food and Drug Administration (FDA) approved Cholbam (cholic acid) capsules for treatment of pediatric and adult patients with bile acid synthesis disorders due to single enzyme defects. The drug was also approved as an adjunct to standard of care for peroxisomal disorders, including Zellweger spectrum disorders. Patients with these rare, genetic, metabolic conditions exhibit manifestations of liver disease, steatorrhea and complications from decreased fat-soluble vitamin absorption.
As a result of the agency’s approval, Retrophin exercised its option to purchase Asklepion Pharmaceuticals and all of the rights to the drug for an upfront cash payment of $27 million and 661,278 shares of Retrophin common stock. Additionally, Asklepion is eligible to receive milestone payments of up to $37 million, as well as tiered royalties based on future net sales of Cholbam.
The FDA approved Cholbam as an oral treatment for children aged three weeks and older, and adults. The drug is the first to FDA approved drug to turn off a genetically-damaged bile synthesis pathway and prevent its toxic products from damaging the liver. The agency approved the drug based on results from two pivotal studies that showed improved liver function test values and restoration of growth assessment by weight gain in comparison to the natural history of untreated patients. According to Asklepion, some of the patients in these trials have been healthy on therapy, exhibiting normal liver function for more than 16 years.
“The FDA approval of Cholbam is of vital importance to patients and families who are dealing with bile acid deficiency diseases,” said Philip Rosenthal, MD, Director of Pediatric Hepatology at the University of California, San Francisco. “Previously, the patients who rely on this life-saving medicine were only able to receive it through research studies. Making this therapy more widely available is a significant accomplishment of science and collaboration in this rare disease space.”
In addition to receiving an approved drug through the deal, Retrophin also got a priority review voucher that the FDA awarded Asklepion. The agency provides these vouchers as an effort to encourage development of new drugs and biologics for the prevention and treatment of rare pediatric diseases. The vouchers speed up review of a drug of the company’s choice, guaranteeing its user a six-month review period, as opposed to the standard 10-month process. Retrophin also has the option to sell its voucher to the highest bidder. In November, Gilead Sciences bought a voucher from Knight Pharmaceuticals for $125 million.
Bile acid synthesis disorders are most commonly diagnosed in infants. In the US, there are at least 500 babies born with bile acid deficiencies each year. Children with bile acid deficiency diseases may present during the neonatal period or during early childhood. If left untreated, these deficiencies can cause the buildup of defective bile acids that lead to cholestasis, nutrient malabsorption, liver disease, neurologic disease, and eventually, liver failure and death. Due to the rarity of these diseases, many physicians are unfamiliar with them. It is believed that because of physicians’ unfamiliarity with these diseases, the majority of cases go undiagnosed and untreated.
“Cholbam complements Retrophin’s existine bile acid therapy, Chenodal (chenodeoxycholic acid), and will position us as the leading provider of treatments for patients with these bile acid synthesis and peroxisomal disorders,” said Retrophin’s Chief Executive Officer Stephen Aselage.
Since the agency granted Cholbam Orphan Drug Designation, it will have seven years of market exclusivity in the US.
Sources: US Food and Drug Administration; Retrophin, Inc.; Asklepion Pharmaceuticals, LLC.
Last updated: 3/18/15; 1:45pm EST