Rare Daily Staff

The U.S. Food and Drug Administration granted Fast Track and Rare Pediatric Disease designations to its experimental therapy UX007 for the treatment of long-chain fatty acid oxidation disorders, a group of genetic disorders in which the body is unable to convert long-chain fatty acids into energy.

Long-chain fatty acid oxidation disorders (LC-FAOD) can lead to severe depletion of glucose in the body, and serious liver, muscle, and heart disease, which can lead to hospitalizations or early death. Patients with LC-FAOD are currently treated with the avoidance of fasting, low-fat/high carbohydrate diets, carnitine, and medium-chain triglyceride oil (a medical food product). Despite current management, many patients have significant metabolic events including hospitalizations and mortality due to LC-FAOD.

UX007 is a highly purified, pharmaceutical-grade, synthetic, seven-carbon fatty acid triglyceride. It is intended to provide patients with medium-length, odd-chain fatty acids that can be metabolized to increase intermediate substrates in the Krebs cycle, a key energy-generating process. Unlike typical even-chain fatty acids, UX007 can be converted to new glucose through the Krebs cycle, potentially providing an important added therapeutic effect, particularly when glucose levels are too low.

“These designations for UX007 underscore FDA’s belief that new treatments are needed for patients with LC-FAOD, a severe and potentially life-threatening disease,” said Camille Bedrosian, chief medical officer of Ultragenyx. “In addition, they offer the potential to speed up our ability to bring UX007 to patients.”

Ultragenyx said it is on track to submit an application for approval of UX007 in mid-2019. The submission will include data from a company-sponsored phase 2 study of UX007 in 29 patients, data from a long-term safety and efficacy extension study in 75 patients, a retrospective medical record review of 20 original compassionate use patients, data from 70 patients treated through expanded access, and a randomized controlled investigator-sponsored study of 32 patients showing an effect of UX007 on cardiac function.

The FDA’s Fast Track designation is a process designed to facilitate the development and expedite the review of drugs to treat serious conditions and fill an unmet medical need. Fast Track designation allows for early and frequent communication with the FDA throughout the entire drug development and review process and allows for a rolling review of a company’s new drug application.

The FDA grants Rare Pediatric Disease designation for serious or life-threatening diseases with manifestations in individuals aged from birth to 18 years, including access to the FDA’s expedited review and approval process. The designation makes UX007 eligible for a Rare Pediatric Disease Priority Review voucher upon approval of the therapy by the FDA. 

The vouchers can be used to reduce the time of an FDA new drug approval review to six months from ten months. The vouchers are potentially lucrative because they are transferable. Most recently, GW Pharmaceuticals sold a Priority Review voucher for $105 million.

Photo: Camille Bedrosian, chief medical officer of Ultragenyx

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