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Encouraging Preliminary Safety and Efficacy Trends in Phase 2 Clinical Study of PEG-PAL in PKU
Conference Call and Webcast to Be Held Today at 5:00 p.m. ET
Aug 2, 2010
NOVATO, Calif.

BioMarin Pharmaceutical Inc. announced today an update in the Phase 2 clinical study of PEG-PAL (PEGylated recombinant phenylalanine ammonia lyase) for the treatment of phenylketonuria (PKU). Data reported in this announcement reflect preliminary results as of July 23, 2010. Complete top-line results are expected in the fourth quarter of 2010.

  Key highlights of the study:
  --  23 adult patients have been enrolled in the study, and patients have
      been followed for a median of 111 days.  The first enrolled patients
      have been in the study for over 300 days.
  --  Seven patients have received at least 1 mg/kg/week for at least four
      weeks in several different dosing frequencies (up to three times per
      week).  Of these, six have had Phe levels below 600 umol/L for at
      least three weeks and in some cases, up to three months.  Their
      baseline Phe levels were reduced from a median of 1,293 umol/L to a
      median of 527 umol/L, representing an approximate 60% reduction in
      blood Phe. Two patients have had blood Phe levels documented below 5
      umol/L, and their physicians have substantially liberalized their
  --  An additional 16 patients have been treated with lower doses at
      shorter periods of time and are continuing to have their doses
      escalated according to the protocol.  Importantly, several patients
      escalating to higher doses are also beginning to have their Phe levels
      trend down.
  --  Three patients have chosen not to continue in the ongoing program for
      personal reasons, though one patient also had generalized skin
      reaction at the time of discontinuation.
  --  Injection site reaction is the most common treatment emergent adverse
      event, occurring in 43% of patients.  Injection site reactions are
      generally mild to moderate, self-limited and unaccompanied by other
      sequelae.  Other less common adverse events are also mild to moderate,
      self limited and do not interfere with continuation in the study.
  --  Three other patients have had generalized skin reaction during the
      study, all self-limited and managed with medical therapy and transient
      dose reduction.  All patients have experienced Phe levels lower than
      pre-treatment baseline levels after the rashes resolved.
  --  Antibody and PK analyses are underway.
  --  Dose and schedule optimization, as well as enrollment of additional
      cohorts of patients, are ongoing.  Additionally, liberalization of
      diet will be further studied.

"Based on my positive experiences to date, I am optimistic that PEG-PAL can improve phenylalanine levels in patients with PKU with an acceptable safety profile," stated Dr. Nicola Longo, Professor of Pediatrics and Adjunct Professor of Pathology at the University of Utah and Clinical Investigator in the PEG-PAL Phase 2 trial. "There remains an unmet need in PKU for patients who are unable to control their phenylalanine levels with diet or Kuvan and hopefully, PEG-PAL can offer another treatment option to these patients."

"We are very encouraged by these preliminary findings, especially given the safety concerns as we entered the Phase 2 trial," said Hank Fuchs, M.D., Chief Medical Officer of BioMarin. "Assuming the continuation of positive safety and efficacy trends in this ongoing study, we believe these data could support advancement to a Phase 3 trial at the end of 2011 with blood Phe level reductions as a primary endpoint for product registration. Getting to this stage has involved a tremendous amount of work by both the BioMarin team and our various collaborators. As with any program, we developed and tested many candidates before settling on PEG-PAL. Among the collaborators that helped us in this process we would like to particularly thank the Stevens laboratory at The Scripps Research Institute, Scriver laboratory at McGill University, and the local and national PKU communities."

The Phase 2 clinical trial is an open-label, multi-center study to be conducted in a series of dose-escalating cohorts from 0.001 mg/kg. The primary treatment period of eight once weekly injections at a fixed dose will be followed by dose and frequency optimization and an extension period where doses can be increased up to 2.0 mg/kg/week.

The primary objective is to evaluate the effect of PEG-PAL on blood Phe concentrations in subjects with PKU. The secondary objectives are to evaluate the safety and tolerability, immune response and steady state pharmacokinetics of subcutaneous injections of multiple dose levels of PEG-PAL.

Conference Call Details

BioMarin will host a conference call and webcast today, Monday, August 2, at 5:00 p.m. ET. This event can be accessed on the investor section of the BioMarin website at www.BMRN.com.

  Date: August 2, 2010
  Time: 5:00 p.m. ET
  U.S. / Canada Dial-in Number:  800.573.4840
  International Dial-in Number:  617.224.4326
  Participant Code: 78258415
  Replay Dial-in Number: 888.286.8010
  Replay International Dial-in Number: 617.801.6888
  Replay Code: 76507562

  About PEG-PAL

PEG-PAL (PEGylated recombinant phenylalanine ammonia lyase) is an investigational enzyme substitution therapy for the treatment of PKU. Pharmacology studies conducted in the PKU mouse model demonstrated that weekly subcutaneous administrations of PEG-PAL resulted in a significant and stable decrease of plasma phenylalanine. BioMarin estimates that PEG-PAL could be a potential treatment option for a significant portion of the PKU population.

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(TM) (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 PEG-PAL, and expectations related to clinical trials of PEG-PAL. 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 clinical trials related to PEG-PAL; the content and timing of decisions by the U.S. Food and Drug Administration and other regulatory agencies, particularly with respect to PEG-PAL, 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(TM) is a trademark of BioMarin Huxley Ltd.

  Aldurazyme® is a registered trademark of BioMarin/Genzyme LLC.


  Investors                              Media
  Eugenia Shen                           Susan Berg
  BioMarin Pharmaceutical Inc.           BioMarin Pharmaceutical Inc.
  (415) 506-6570                         (415) 506-6594

First Call Analyst:
FCMN Contact: eshen@bmrn.com

SOURCE: BioMarin Pharmaceutical Inc.

CONTACT: Investors, Eugenia Shen, +1-415-506-6570, or Media, Susan Berg,
+1-415-506-6594, both of BioMarin Pharmaceutical Inc.