FDA Approves New Therapy for Urea Cycle Disorders

The FDA has approved Olpruva (sodium phenylbutyrate) to treat certain patients living with urea cycle disorders (UCDs), a genetic condition that causes ammonia to build up in the blood. This ca can lead to brain damage and neurocognitive impairments. Developed by Acer Therapeutics and Relief Therapeutics, Olpruva is a new formulation of sodium phenylbutyrate packaged as a premeasured, single dose packet. It is indicated for patients who have deficiencies of the specific enzymes that are responsible for removing ammonia from the blood, including carbamylphosphate synthetase, ornithine transcarbamylase, or argininosuccinic acid synthetase.

“The FDA’s approval of Olpruva, an innovative formulation of sodium phenylbutyrate packaged for the first time in single-dose envelopes, marks the culmination of our ongoing dedication to develop new and differentiated treatment options for those affected by rare diseases,” Chris Schelling, chief executive officer and founder of Acer, said in a press release. “Patients who are living with UCDs now have an alternative treatment option with Olpruva, to address some of the challenges they may have with existing therapy.”

The approval was made under the 505(b)(2) section of the Food, Drug and Cosmetic Act, which allows for companies to use third-party data for approval. In its application, Acer cited preclinical and clinical safety and efficacy data from the reference listed drug, Buphenyl powder, which is approved as adjunctive therapy in the chronic management of patients with urea cycle disorders. In its NDA, Acer provided additional data including studies that evaluated the bioavailability and bioequivalence of Olpruva compared with Buphenyl powder.

Acer Therapeutics has not released a list price for Olpruva, but indicated in an investor presentation that it is likely to be priced significantly lower than Ravicti, another medication currently available for urea cycle disorders. Ravicti has an annual average wholesale average cost of $950,000. Buphrenyl has an annual average wholesale average cost of $300,000. Both Ravicti and Buphrenyl are packaged as bulk containers and both were developed by Horizon Therapeutics.

Acer indicated it intends to offer patient support services designed to facilitate access to therapy. Navigator by Acer Therapeutics is designed to assist UCD patients with support, access, education, and adherence.