BioMarin Announces Results for Phase 1 Clinical Study of BMN 195
for Duchenne Muscular Dystrophy

BMN 195 Program Discontinued due to Pharmaceutical and Pharmacokinetic Challenges
Novato, Calif, August 2, 2010 – BioMarin Pharmaceutical Inc. (Nasdaq: BMRN) announced today that it
has completed the Phase 1 clinical study of BMN 195, a small molecule utrophin up-regulator, for the
treatment of Duchenne muscular dystrophy (DMD). The Phase 1 clinical trial was a single-center, doubleblind, placebo-controlled, single-dose escalation study followed by a multiple-dose escalation study in healthy volunteers.

The administration of up to 400 mg/kg did not achieve plasma concentrations believed to be required to
increase utrophin expression. Moreover, plasma concentrations of BMN 195 were even lower on repeat
administration. Based on these results, BioMarin has concluded that the likelihood of achieving a
therapeutic effect in DMD patients is highly unlikely and has discontinued development of BMN 195.
“Duchenne muscular dystrophy remains a serious unmet medical need affecting approximately 40,000
patients in the developed world, and BioMarin remains committed to this disease area,” said Jean-
Jacques Bienaimé, Chief Executive Officer of BioMarin. “Given the limitations of BMN 195, we believe
that other approaches to up-regulation of utrophin may be more possible, and we continue to believe that
utrophin upregulation is a viable approach for the treatment of DMD. We are currently working on
additional candidates to take forward into early human studies, and the new compound we are working on
appears to overcome the limitations of BMN 195.”

About Duchenne Muscular Dystrophy
Duchenne muscular dystrophy is a fatal neuromuscular disorder that affects 1 in 3,500 boys with an
estimated patient population of over 40,000 in the developed world.
DMD is caused by a genetic defect that results in DMD patients lacking an important protein called
dystrophin, which is crucial to maintaining muscle integrity and function. The absence of dystrophin
results in extensive muscle wasting in all voluntary muscles as well as the heart and breathing muscles
and causes severe restriction in the mobility of DMD patients by their early teens and is ultimately fatal,
generally in their twenties. Currently there is no cure for DMD. Corticosteroid treatment is the only
frontline therapy and acts to only delay the progression of the disease.

About BioMarin
BioMarin develops and commercializes innovative biopharmaceuticals for serious diseases and medical
conditions. The company’s product portfolio comprises four approved products and multiple clinical and
pre-clinical product candidates. Approved products include Naglazyme® (galsulfase) for
mucopolysaccharidosis VI (MPS VI), a product wholly developed and commercialized by BioMarin;
Aldurazyme® (laronidase) for mucopolysaccharidosis I (MPS I), a product which BioMarin developed
through a 50/50 joint venture with Genzyme Corporation; Kuvan® (sapropterin dihydrochloride) Tablets,
for phenylketonuria (PKU), developed in partnership with Merck Serono, a division of Merck KGaA of
Darmstadt, Germany; and Firdapse™ (amifampridine phosphate), which has been approved by the
European Commission for the treatment of Lambert Eaton Myasthenic Syndrome (LEMS). Other product
candidates include GALNS (N-acetylgalactosamine 6-sulfatase), which is currently in clinical development
for the treatment of MPS IVA and PEG-PAL (PEGylated recombinant phenylalanine ammonia lyase),
which is currently in Phase II clinical development for the treatment of PKU. 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 BMN 195, and expectations related to further development of product candidates for DMD.
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 current and planned pre-clinical research of various compounds; the content and timing of
decisions by the U.S. Food and Drug Administration and other regulatory agencies, 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 2009 Annual Report on Form 10-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 statement, whether as a result of new information, future events or otherwise.
BioMarin®, Naglazyme® and Kuvan® are registered trademarks of BioMarin Pharmaceutical Inc.
Firdapse™ is a trademark of BioMarin Huxley Ltd.

Aldurazyme® is a registered trademark of BioMarin/Genzyme LLC.
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BioMarin Initiates Phase 1 Clinical Study of BMN 195 for Duchenne Muscular Dystrophy

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