The US Food and Drug Administration has approved Hyperion Therapeutics' Ravicti to treat urea cycle disorders.
UCDs are genetic disorders that involve deficiencies of specific enzymes involved in the urea cycle that are normally required to remove ammonia from the blood. In people with UCDs, nitrogen accumulates and remains in the body as ammonia, which can cause brain damage, coma or death.
Ravicti (glycerol phenylbutyrate), a liquid taken three times a day with meals, helps dispose of ammonia in the body. It must be used with a protein-restricted diet and, in some cases, dietary supplements.
The major study supporting Ravicti’s safety and effectiveness involved 44 adults who had been using Buphenyl (sodium phenylbutyrate), the current standard treatment for UCDs marketed by Valeant Pharmaceuticals International. Blood testing showed Ravicti was as effective as Buphenyl in controlling ammonia levels, however the latter has an unpleasant smell and taste and UCD patients on Buphenyl must take 40 tablets per day, so compliance is a major issue.
The timing of the approval surprised some observers seeing as just over a fortnight ago, the FDA advised the company not to expect a final action by the Prescription Drug User Fee Act (PDUFA) date of January 23. The agency had said it was continuing to work on label and post-marketing requirements.