BioMarin Initiates Phase III Clinical Trial of Phenoptin for PKU

BioMarin Pharmaceutical has announced that it has randomized the first patient in its Phase III clinical trial of Phenoptin, an investigational oral, small molecule therapeutic for the treatment of the genetic disease phenylketonuria (PKU). The company expects to announce data from this trial in the second half of 2005.

The Phase III, double-blind, placebo-controlled, multi-center trial is designed to evaluate the safety and efficacy of Phenoptin (sapropterin hydrochloride) for the treatment of individuals with PKU. The trial will enroll approximately 100 PKU patients and be conducted at approximately 30 sites worldwide. To qualify, patients must be over 8 years of age, have demonstrated a reduction in blood Phe levels while in the Phase II trial and have blood Phe levels greater than 600 umol/L at baseline.

Patients enrolled in the Phase III trial will be randomized on a one-to-one basis into a Phenoptin treatment group (10 mg/kg daily) or a placebo group and will be evaluated every two weeks for changes in blood Phe levels and for adverse events. The primary endpoint of the trial will be reduction in blood Phe levels compared to baseline levels, relative to placebo, after six weeks of treatment. Patients enrolled in the Phase III trial may be eligible to participate in a 22-week Phase III extension study designed primarily to evaluate long-term safety and to corroborate dose optimization and pharmacokinetics of Phenoptin.