BioMarin Pharmaceutical Inc. (Nasdaq and SWX: BMRN) today announced that the first patient has initiated treatment in the Phase 2 clinical study of 6R-BH4 for the treatment of poorly controlled hypertension. The company expects to announce data from this study in early 2007.

"6R-BH4, commonly known as tetrahydrobiopterin, is an essential enzyme cofactor that plays a key role in the production of nitric oxide, a molecule that regulates vascular tone. A secondary deficiency of 6R-BH4 disrupts NO production, resulting in loss of vasodilation control and increased blood pressure," stated Emil Kakkis, M.D., Ph.D., Chief Medical Officer of BioMarin. "Our goal is to confirm results seen earlier in pilot clinical studies that demonstrated that oral administration of 6R-BH4 can reduce blood pressure in individuals who remain hypertensive despite treatment with other medications."

The Phase 2, multicenter, double-blind, placebo-controlled, parallel group study is designed to evaluate the safety and efficacy of 6R-BH4 on blood pressure in patients with poorly controlled systemic hypertension. The study will be conducted at up to 25 sites in the United States and will enroll approximately 84 patients, with the intention that approximately half of the patients will have type 2 diabetes. Among other eligibility criteria, to participate in the study, patients must have elevated blood pressure while on at least two different medications for hypertension. Study patients will receive oral doses of 5 mg/kg of 6R-BH4 or a placebo twice daily for an eight-week period. The primary endpoint variable of the study is the change in systolic blood pressure (SBP) from baseline to Week 8. The primary endpoint analysis will compare the mean change in SBP between the 6R-BH4 and placebo groups. A secondary endpoint analysis will compare the mean change in diastolic blood pressure (DBP) between the 6R-BH4 and placebo groups.

About 6R-BH4

6R-BH4, commonly known as BH4 or tetrahydrobiopterin, is a naturally occurring enzyme cofactor that is required for numerous biochemical and physiologic processes, including the synthesis of nitric oxide (NO). NO has been shown to play a key protective role throughout the cardiovascular system and produces multiple positive effects, such as relaxing smooth muscle, reducing blood pressure, controlling inflammation and reducing platelet aggregation. Researchers have demonstrated that a deficiency of BH4 can disrupt NO synthesis, resulting in a loss of normal endothelial NO production. This loss of endothelial NO production, commonly referred to as endothelial dysfunction, has been associated with many cardiovascular diseases, including hypertension, diabetic vascular disease, peripheral arterial disease, coronary arterial disease and pulmonary hypertension, and has been shown to be a strong predictor of cardiovascular adverse events in a number of clinical studies.

6R-BH4 is the same enzyme cofactor currently being evaluated in BioMarin's Phenoptin(TM) (sapropterin dihydrochloride) for phenylketonuria (PKU). In March 2006, BioMarin and Serono, BioMarin's corporate partner for the Phenoptin and 6R-BH4 programs, announced positive results from the Phase 3 clinical study of Phenoptin for PKU. All primary and secondary endpoints of the study were met. The type and incidence of adverse events was similar in the Phenoptin and placebo groups. Phenoptin was well tolerated and investigators reported that no serious adverse event occurred.

About BioMarin

BioMarin develops and commercializes innovative biopharmaceuticals for serious diseases and medical conditions. The company's product portfolio is comprised of two approved products and multiple clinical and preclinical product candidates. Approved products include Naglazyme(TM) (galsulfase) for mucopolysaccharidosis VI (MPS VI), a product wholly developed and commercialized by BioMarin, and Aldurazyme(R) (laronidase) for mucopolysaccharidosis I (MPS I), a product which BioMarin developed through a 50/50 joint venture with Genzyme Corporation. Investigational product candidates include Phenoptin(TM) (sapropterin dihydrochloride), a Phase 3 product candidate for the treatment of phenylketonuria (PKU), and 6R-BH4 for cardiovascular indications, which is currently in Phase 2 clinical development for the treatment of poorly controlled hypertension. For additional information, please visit www.BMRN.com. Information on BioMarin's website is not incorporated by reference into this press release.

Forward-Looking Statement

This press release contains forward-looking statements about the business prospects of BioMarin Pharmaceutical Inc., including, without limitation, statements about: the development of its product candidate 6R-BH4, both in Phenoptin for the treatment of PKU and for other indications, including hypertension; the expect effects of 6R-BH4 in poorly controlled hypertension and other indications; the final results of the data from the Phase 3 trial of Phenoptin; and expectations regarding filings with regulatory agencies. These forward-looking statements are predictions and involve risks and uncertainties such that actual results may differ materially from these statements. These risks and uncertainties include, among others: the results of preclinical and clinical trials related to 6R-BH4; results and timing of current and planned clinical trials of Phenoptin for the treatment of PKU and 6R-BH4 for other indications, including poorly controlled hypertension; the content and timing of decisions by the U.S. Food and Drug Administration, the European Medicines Agency and other regulatory authorities concerning 6R-BH4 and the Phenoptin formulation; the conclusion of the final data analysis of the Phase 3 trial of Phenoptin; and those factors detailed in BioMarin's filings with the Securities and Exchange Commission, including, without limitation, the factors contained under the caption "Risk Factors" in BioMarin's 2005 Annual Report on Form 10-K and the factors contained in BioMarin's reports on Forms 10-Q and 8-K. Stockholders are urged not to place undue reliance on forward-looking statements, which speak only as of the date hereof. BioMarin is under no obligation, and expressly disclaims any obligation, to update or alter any forward-looking statements.

  NOTE:  Aldurazyme(R) is a registered trademark of BioMarin/Genzyme LLC.

   Contacts:

   Investors                               Media
   Joshua A. Grass                         Susan Ferris
   Director, Business                      Senior Manager, Corporate
    Development & Finance                   Communications
   BioMarin Pharmaceutical Inc.            BioMarin Pharmaceutical Inc.
   415-506-6777                            415-506-6701

SOURCE: BioMarin Pharmaceutical Inc.