Hyperion Therapeutics enrolls first patient in HPN-100 phase III clinical trial for urea cycle disorders (News-Medical-Net) Hyperion Therapeutics today announced that the first patient has been enrolled in its pivotal phase III clinical trial of investigational compound HPN-100 (glycerol phenylbutyrate). The 4-week, multi-center, randomized, double-blind, cross-over study is designed to evaluate the non-inferiority of glycerol phenylbutyrate to BUPHENYL® (sodium phenylbutyrate) Tablets and Powder in adults with urea ... [News Source]