Kuvan: Phase III data

The double-blind, North American Phase III PKU-016 ASCEND trial in 206 patients showed that 20 mg/kg/day oral Kuvan missed the primary endpoint of reducing ADHD-RS score from baseline to week 13 vs. placebo (9.5 vs. 5.4 points, p=0.085). BioMarin said ADHD-RS scores are commonly used to evaluate symptoms of inattentiveness and hyperactivity. Kuvan did significantly reduce the inattentiveness component of the ADHD-RS score from baseline to week 13 vs. placebo (6 vs. 2.6 points, p=0.036). The company said that PKU patients have a lower degree of hyperactivity compared to ADHD patients, which "likely resulted in less prominent benefits" on the domain.

The trial included a 2-week screening period, a 13-week double-blind, placebo-controlled treatment period and a 13-week open-label treatment period in which all patients received 20 mg/kg/day Kuvan. Of the 206 patients enrolled, 118 responded to Kuvan as determined by a reduction in blood Phe levels. Of the 118 responders, 38 patients had symptoms of ADHD and were thus included in the primary efficacy analysis. BioMarin said the data will be submitted for presentation at the Inborn Errors of Metabolism meeting in Barcelona in September and the American Society of Human Genetics meeting in Boston in October. ...