BioMarin Pharmaceutical Inc. has licensed from Daiichi Suntory Pharma Co., Ltd. the exclusive worldwide rights (excluding Japan) for the use of tetrahydrobiopterin (6R-BH4) to treat the endothelial dysfunction that causes vascular complications in diabetes, cardiovascular and other diseases. These rights are covered by US, European and other foreign patents and patent applications. The newly acquired rights expand BioMarin's market opportunity for 6R-BH4 well beyond phenylketonuria (PKU).

In November 2004, BioMarin announced two separate agreements with Daiichi Suntory Pharma relating to 6R-BH4 for genetic diseases including PKU: a license to intellectual property, preclinical and clinical data, and a manufacturing and supply agreement. 6R-BH4 is the active pharmaceutical ingredient in Phenoptin (sapropterin hydrochloride), BioMarin's investigational Phase 3 product candidate for the treatment of PKU. The new license extends BioMarin's exclusive rights to Daiichi Suntory Pharma's patents and data related to 6R-BH4 for all indications, a company release stated.

Emil Kakkis, senior vice president of Business Operations at BioMarin, commented, "Vascular endothelial dysfunction is an important underlying cause of morbidity and mortality in diabetes, cardiovascular and other diseases. 6R-BH4 is an essential cofactor required for the production of nitric oxide, which regulates vascular endothelial function. Researchers have established that a deficiency of 6R-BH4 contributes to endothelial dysfunction, and in limited academic studies, have demonstrated that 6R-BH4 administration improves vascular endothelial function in animal models and patients with diabetes and other cardiovascular diseases."

In exchange for the exclusive rights to the intellectual property and data for all indications, in all territories outside of Japan, BioMarin will pay Daiichi Suntory Pharma an upfront payment, an undisclosed royalty on sales of 6R-BH4, and developmental milestones for up to two indications, the release concluded.