BioMarin reports positive Phase III Kuvan results

According to the company, Kuvan, an investigational oral small molecule, resulted in significant reductions in blood Phe levels in some phenylketonuria (PKU) patients.

The Phase III clinical study enrolled 89 patients with elevated blood Phe levels aged eight years and above at 29 sites in the US, Europe and Canada. All patients enrolled had demonstrated a reduction in blood Phe levels following treatment with Kuvan in a Phase II screening study.

The patients were randomly assigned to receive placebo or 10mg/kg of Kuvan daily for six weeks. Patients were evaluated every two weeks for changes in blood Phe levels and adverse events. The primary objective was to assess the efficacy of Kuvan compared with placebo for reduction of blood phenylalanine in patients with PKU. The secondary objective was to assess the safety of Kuvan compared with placebo. A total of 87 patients completed six weeks of treatment.

Patients treated with Kuvan for six weeks had a mean decrease in blood Phe level of 236uM/L (29%) compared to a mean increase of 3 uM/L (3%) in the placebo group. Prior to treatment, patients in the Kuvan group and placebo group had mean blood Phe levels of 843uM/L and 888 uM/L, respectively.

After six weeks of treatment, 54% of patients treated with Kuvan and 23% of patients in the placebo group had a blood phenylalanine concentration below the recommended 600uM/L level. Blood phenylalanine concentrations fell by about 200uM/L after one week in the Kuvan group, and this reduction persisted for the remaining five weeks of the study.

“We recently received priority review from the FDA and hope to receive FDA approval by late November. In the interim, we are pleased to be able to provide Kuvan to PKU patients prior to commercial availability through our expanded access program,” said Emil Kakkis, chief medical officer of BioMarin.

Kuvan is being developed in partnership with Merck Serono, a division of Merck KGaA.