BioMarin Pharmaceutical Inc. and Serono have formed a strategic alliance for the further development and commercialization of two BioMarin product candidates, Phenoptin (sapropterin hydrochloride) and Phenylase (phenylalanine ammonia lyase).

Both products have shown potential in the treatment of phenylketonuria (PKU), and there is preliminary clinical evidence that suggests that the active ingredient in Phenoptin, a synthetic form of the naturally occurring enzyme cofactor 6R-BH4, may also be useful in the treatment of other serious diseases, including diabetes and cardiovascular diseases, the release said.

By the terms of their agreement, Serono acquires exclusive rights to market the products in all territories outside the United States and Japan. BioMarin retains exclusive rights to market the products in the United States. Serono will make an upfront payment of $25 million to BioMarin, and will make additional milestone payments of up to $232 million based on the successful development and registration of both products in multiple indications, of which $45 million are associated specifically with Phenoptin in PKU. Serono will also pay BioMarin undisclosed royalties on its net sales of the products. The companies will share equally all development costs following successful completion of Phase 2 trials for each product candidate in each indication.

BioMarin is currently investigating Phenoptin, an orally administered product, in a Phase 3 clinical trial for the treatment of PKU. PKU is an inherited metabolic disease caused by a deficiency of the enzyme phenylalanine hydroxylase, resulting in elevated levels of phenylalanine in the blood, which can result in serious neurological damage. There is currently no approved drug to treat PKU, which affects at least 50,000 diagnosed patients under the age of 40 worldwide. Phenylase, an enzyme substitution therapy for the treatment of severe forms of PKU, is currently in preclinical development, the release added.