For BioMarin:                                       For Genzyme:
------------                                        -----------
Jeremy Price                                        Dan Quinn (media)
Manager, Investor Relations                         (617) 591-5849
BioMarin Pharmaceutical Inc.
(415) 884-6777

Fredda Malkoff                                      Elliott Hillback (investors)
Feinstein Kean Healthcare                           (617) 252-7842
(617) 577-8110

For Immediate Release:

                 BioMarin and Genzyme Announce Positive Findings
         from Phase 3 Trial and Extension Study of Aldurazyme for MPS I

Novato,  CA and  Cambridge,  MA,  June 24, 2002 - BioMarin  Pharmaceutical  Inc.
(Nasdaq and Swiss SWX New Market: BMRN) and Genzyme General (Nasdaq: GENZ) today
announced  detailed  results from the  six-month  double-blind  Phase 3 clinical
trial of Aldurazyme(TM) (laronidase) and preliminary six-month findings from the
trial's ongoing  open-label  extension study.  Aldurazyme is an  investigational
enzyme replacement  therapy for patients with  mucopolysaccharidosis  I (MPS I).
Data from the extension study indicate that patients who received Aldurazyme for
twelve months continued to improve upon the results seen in the first six months
of treatment.

Ed  Wraith,  M.D.,  of the  Willink  Biochemical  Genetics  Unit  at  the  Royal
Manchester Children's Hospital,  Manchester, UK, and one of the trial's clinical
investigators, presented findings from both the double-blind and extension study
portions  of the  Phase  3  trial  on  Saturday,  June  22 at the  International
Symposium on Mucopolysaccharide and Related Diseases in Paris, France.  BioMarin
and Genzyme will submit the six-month  interim  extension study data to the U.S.
Food and Drug  Administration  (FDA) in the  third  quarter  to  complete  their
"rolling" Biologics License Application (BLA).

"The data presented on Saturday indicate that this is a promising  treatment for
the complex array of symptoms experienced by MPS I patients,  who currently have
no specific  treatment  available to them," said Dr. Wraith.  "I am particularly
encouraged  by the results seen in patients who have now been on treatment for a
full year."

Extension Study Results

All  45  MPS  I  patients   from  the   six-month,   randomized,   double-blind,
placebo-controlled Phase 3 trial were enrolled in the open-label extension study
in order to further evaluate the safety and efficacy of Aldurazyme. Patients who
were previously on placebo were switched to Aldurazyme for the extension  study,
while those patients who received  Aldurazyme during the first six months of the
trial  continued to receive  Aldurazyme  via weekly  infusions in the  extension

The extension  study  includes  analysis of the same two primary  endpoints that
were  evaluated  in the  double-blind  portion  of the Phase 3 trial:  pulmonary
function, as measured by forced vital capacity (FVC), and endurance, as measured
by the  distance  covered in a  six-minute  walk  test.  Patients  who  received
Aldurazyme in the double-blind  portion of the trial and who continue to receive
treatment in the extension  study  maintained  improvement in FVC, moving from a
5.3 percentage point mean increase in percent of predicted normal FVC during the
first six months of treatment to a 5.9  percentage  point mean increase after an
additional  six months of treatment as part of the extension  study.  These same
patients  improved from a 19.7 meter mean increase in the  six-minute  walk test
over the first six months of treatment to a 42.9 meter mean  increase  after six
additional months of treatment as part of the extension study.

During  the  extension  study,  patients  who  were  switched  from  placebo  to
Aldurazyme  experienced a slight decline in FVC compared to baseline (-0.6%) but
began to improve during the second half of the six-month  extension  period.  In
the six-minute walk test,  patients who were switched from placebo to Aldurazyme
showed a mean improvement of 23.8 meters,  which is consistent with the increase
seen among patients who received six months of treatment with Aldurazyme  during
the double-blind portion of the trial.

Additional findings from the extension study have been generally consistent with
results seen in both the Phase 1 trial and the double-blind portion of the Phase
3 trial: statistically significant reductions in liver size and in the excretion
of  urinary   glycosaminoglycans   (GAGs),  the  carbohydrate   substances  that
accumulate in patients with MPS I. Patients who received  Aldurazyme in both the
double-blind and extension study periods maintained the reductions in liver size
and urinary GAG excretion that were seen in the first six months of treatment.

The  safety  profile  in  the  extension   study  has  been  comparable  to  the
double-blind period. The most commonly reported reactions were fever,  headache,
rhinitis, and rash. One patient in the extension study died of causes considered
by the principal investigator to be unrelated to treatment.

Double-Blind Phase 3 Results

In addition to the extension  study data, Dr. Wraith  presented a  comprehensive
review of data from the  double-blind  portion of the Phase 3 trial,  from which
preliminary results were announced last November. In the first six months of the
trial,  patients  treated with Aldurazyme  achieved a 5.3 percentage  point mean
increase in pulmonary  capacity as measured by FVC compared to patients  treated
with placebo (p=0.016). In November,  BioMarin and Genzyme reported a p-value of
0.028 for the FVC test, but subsequent analysis led to the revision to 0.016. In
addition,  patients  demonstrated a positive trend in endurance as measured by a
six-minute  walk test,  where they improved by a mean of 38.1 meters compared to
patients  treated  with  placebo  (p=0.066).  When  analyzed by a  prospectively
defined   parametric   statistical   analysis  that  accounts  for  pre-existing
differences in individual patients, the six-minute walk test reached statistical
significance (p=0.039).


Patients  in  the  Aldurazyme  group  achieved  statistically  significant  mean
reductions  in  liver  size  (p=0.001)  and  urinary  GAG  excretion  (p<0.001),
consistent with the findings in the Phase 1 trial.

The sleep  study,  as measured by the  apnea-hypopnea  index,  showed a positive
trend (p=0.145) in the overall patient population.  One post-hoc subset analysis
of the 21 patients judged by the  investigators  to have clinically  significant
sleep apnea at baseline  demonstrated a  statistically  significant  improvement
(p=0.037).   Two  additional  secondary  endpoints  did  not  reach  statistical
significance: a health assessment questionnaire and shoulder range of motion.

The  safety  profile  in the  double-blind  portion  of the  Phase 3  trial  was
comparable   between  the  treatment  group  and  the  placebo  group,  with  no
Aldurazyme-related  serious adverse events. The most commonly reported reactions
were fever (14 patients on the placebo and 10 in the treatment group);  headache
(16 on placebo and 11 in the treatment group);  rhinitis (10 on placebo and 8 in
the treatment group); and rash (5 on placebo and 8 in the treatment group).

On  Friday,  June 21,  Joseph  Muenzer,  M.D.,  Ph.D.,  Associate  Professor  of
Pediatrics at the University of North Carolina, Chapel Hill, and also one of the
clinical  trial's  investigators,  presented new  perspectives  on the burden of
illness among MPS I patients,  which were derived from baseline  evaluations  of
the 45  patients  enrolled  in the Phase 3 trial of  Aldurazyme.  Dr.  Muenzer's
analysis  highlights the  heterogeneity  of the clinical effects of MPS I, which
include  organ  damage,  particularly  to  the  liver  and  spleen,  respiratory
problems,   musculoskeletal   disorders,   a  high  rate  of   infections,   and
gastrointestinal problems.

About MPS I

MPS  I  (also  known  as  Hurler,  Hurler-Scheie,  and  Scheie  syndromes)  is a
life-threatening   genetic   disease  caused  by  a  deficiency  of  the  enzyme
alpha-L-iduronidase.  This  deficiency  leads  to the  accumulation  of  complex
carbohydrates  (GAGs) in the  lysosomes  of cells,  leading  to the  progressive
dysfunction  of  cellular,  tissue and organ  systems.  Resulting  symptoms  can
include impaired cardiac and pulmonary function,  delayed physical  development,
skeletal and joint deformities,  reduced endurance,  and in some cases,  delayed
mental function.  A majority of patients die before adulthood from complications
of the disease.


BioMarin and Genzyme formed a joint venture in 1998 to develop and commercialize
Aldurazyme  worldwide.  Under the terms of the joint  venture,  if approved  for
commercial  sale,  BioMarin will  manufacture  Aldurazyme  and Genzyme will have
responsibility  for the  commercialization  of the product.  The companies  have
obtained Orphan Drug  designation and Fast Track status for Aldurazyme for MPS I
from the FDA and orphan medicinal  product  designation from the European Agency
for the Evaluation of Medicinal Products (EMEA).

Genzyme  General  develops  and  markets  therapeutic  products  and  diagnostic
products and  services.  Genzyme  General has five  therapeutic  products on the
market and a strong pipeline of therapeutic  products in development  focused on
the treatment of genetic diseases and other chronic debilitating  disorders with
well-defined patient populations. Genzyme General is a division of Genzyme Corp.

BioMarin Pharmaceutical  specializes in the development and commercialization of
therapeutic  enzyme  products to treat  serious,  life-threatening  diseases and

This  press  release  contains  forward-looking  statements,  including  without
limitation statements about: the results from the six-month findings of the open
label extension study (which may differ from the preliminary results reported in
this press  release),  the expected  timing of  completion of the BLA filing for
Aldurazyme,  and the potential regulatory approval for the  commercialization of
Aldurazyme and  commercialization  plans.  These statements are subject to risks
and  uncertainties  that could cause actual  results to differ  materially  from
those   projected  in  these   forward-looking   statements.   These  risks  and
uncertainties  include,  among  others:  the results and timing of the  on-going
Phase 3 trial;  the actual  timing and content of the  completed  BLA filing for
Aldurazyme;  the  content and timing of  decisions  made by the FDA and the EMEA
regarding  Aldurazyme;  the  ability to  manufacture  sufficient  quantities  of
product  for  development  and  commercialization  activities  and to do so in a
timely manner;  enrollment rates for clinical trials;  the continued  funding of
the joint venture between Genzyme and BioMarin; decisions made by physicians and
third party payers regarding the use of and  reimbursement  for Aldurazyme;  our
ability to obtain and  maintain  adequate  patent and other  proprietary  rights
protection for Aldurazyme; the scope, validity and enforceability of patents and
other  proprietary  rights held by third parties  related to therapies for MPS I
and the  actual  impact of such  patents  and other  rights  on our  ability  to
commercialize  Aldurazyme;  the competitive environment for therapies for MPS I;
and the risks and  uncertainties  described  in  reports  filed by  Genzyme  and
BioMarin  with the  Securities  and  Exchange  Commission  under the  Securities
Exchange  Act of 1934,  as amended,  including  without  limitation  the factors
contained under the caption  "Factors  Affecting  Future  Operating  Results" in
Exhibit 99.2 to Genzyme  Corporation's  2001 Annual Report on Form 10-K. Genzyme
General   Division  common  stock  is  a  series  of  common  stock  of  Genzyme
Corporation.  Therefore,  holders of Genzyme  General  Division common stock are
subject to all of the risks and  uncertainties  described in the those  reports.
Genyzme  and  BioMarin  caution  investors  not to place  undue  reliance on the
forward-looking  statements  contained in this press release.  These  statements
speak  only as of the date of this  press  release,  and  Genzyme  and  BioMarin
undertake no obligation to update or revise the statements.

Genzyme(R) is a registered trademark of Genzyme  Corporation.  AldurazymeTM is a
trademark of BioMarin/Genzyme LLC.
                                    # # #

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