Strong efficacy and favorable safety profile of MabCampath(r) (alemtuzumab)
for previously untreated patients with B-CLL indicated by interim Phase III
results

Initial data from a Phase III comparative study suggest efficacy and safety
with MabCampath(r), even in poor-prognosis patients

Berlin and Cambridge, MA - June 3, 2006 - Schering AG, Germany (FSE: SCH,
NYSE: SHR) and Genzyme Corporation (Nasdaq: GENZ) today announced interim
results from CAM307, an international and confirmatory Phase III clinical
trial comparing MabCampath(r) (alemtuzumab) with chlorambucil in previously
untreated patients with progressive B-cell chronic lymphocytic leukemia (B-
CLL). Preliminary results of the secondary endpoint from this study showed
that patients who received the monoclonal antibody MabCampath exhibited
significantly higher overall and complete response rates, with a manageable
safety profile, compared with those patients who were treated with
chlorambucil. The data were presented at the 42nd Annual Meeting of the
American Society of Clinical Oncology (ASCO) in Atlanta.

The open-label, randomized trial with 297 patients compared the efficacy
and safety of MabCampath to chlorambucil, which is considered by many to
offer the most tolerable safety profile for previously untreated patients.
The study examined a primary endpoint of progression- free survival and
secondary endpoints that included safety, response rate and overall
survival.

"We are pleased with the initial results of the CAM307 study showing
conclusive data that MabCampath might be a safe and effective treatment in
first-line therapy for patients with B-CLL," stated Peter Zundorf, Head of
Schering Group's Oncology Global Business Unit. "This is very encouraging
news, and we are committed to supporting further research of MabCampath in
first-line therapy, to bring forth a safe and most effective early-line
treatment option for patients with B-CLL."

As reported at ASCO, a pre-specified and independent interim review of the
secondary endpoint data showed a nearly 30 percent greater (83% vs. 56%)
overall response rate (ORR) among patients treated with MabCampath vs.
chlorambucil (p< 0.0001), and a 12-fold increase (24% vs. 2%) of complete
response rates (CRR) in patients achieving MabCampath therapy (p< 0.0001).

In the comparison of safety parameters of MabCampath vs. chlorambucil,
rates of grade 3-4 thrombocytopenia, anemia, and serious infections, other
than CMV, were found to be comparable between treatment arms. Although the
rates of CMV, neutropenia and leukopenia were higher in the MabCampath arm,
the difference in the incidence of febrile neutropenia was found to be
insignificant.

A correlation between the cytogenetic profile of the patients participating
in the CAM307 trial  suggest a statistically significant ORR and CRR were
observed in patients with certain cytogenetic abnormalities. Statistically
significant higher response rates to MabCampath were observed in patients
with a 13q deletion, a common genetic event observed in patients with B-
CLL, and in the ORR of patients with 11q deletions, a cytogenetic
abnormality typically associated with poor prognosis. In patients with a
17p deletion, another marker of poor prognosis, ORR was 3 times higher
among patients receiving MabCampath vs. those receiving chlorambucil (64%
vs. 20%, respectively); however, due to the small number of patients in
this group (10 patients in the MabCampath arm and 11 patients in the
chlorambucil arm), this trend did not reach statistical significance.

Lead investigator Peter Hillmen, MB, ChB, of the Leeds General Infirmary,
Leeds, United Kingdom, stated, "In addition to the excellent overall safety
and efficacy findings we are observing thus far in CAM307, we also observed
impressive responses in patients with poor prognostic cytogenetic
abnormalities when treated with MabCampath. This group of poor risk
patients have very low response rates and a short survival when treated
with conventional chemotherapy. The good results seen with MabCampath
promise a novel, more effective therapeutic option for these patients with
poor risk CLL. We therefore look forward to receiving the final study
results of MabCampath in relation to responses and survival in these
difficult-to- treat populations."

MabCampath received accelerated approval in 2001 and is currently indicated
for the treatment of B-CLL in patients who have been treated with
alkylating agents and who have failed fludarabine therapy. Determination of
the effectiveness of MabCampath is based on overall response rates.
Comparative, randomized trials demonstrating increased survival or clinical
benefit such as improvement in disease-related symptoms have not yet been
conducted. Schering AG, Germany, holds exclusive worldwide marketing and
distribution rights to the product, which is marketed in the U.S. as
Campath(r) by Berlex Oncology, a business unit of Berlex Laboratories, a U.S.
affiliate of Schering AG, Germany. Schering AG, Germany and Genzyme are co-
developing MabCampath in oncology and other indications.

The results presented at ASCO represent interim safety and efficacy data to
be released from CAM307, a comparative, confirmatory trial being conducted
to satisfy post-approval commitments to U.S. and European health
authorities (FDA and EMEA). Once the final data from the study's primary
endpoint of progression-free survival are available, Genzyme and Schering
AG expect to file an application seeking to expand the product's current
label to include previously untreated B-CLL patients who require therapy.

"Based on these preliminary results, MabCampath may have significantly
better efficacy with manageable safety against chlorambucil as first-line
therapy in B-CLL," stated Mark Enyedy, senior vice-president and general
manager of Genzyme's oncology business unit. "We look forward to advancing
MabCampath further in its clinical development and to working with the
health authorities regarding a supplement to the product label to treat
patients earlier in the course of their disease. We are also very pleased
to have conducted this post-approval commitment study in the timeframe we
committed to the health authorities."

Additional information

About Study Design
The trial randomized 297 previously untreated patients with progressive
disease requiring treatment at 44 medical centers in Europe and the United
States. Patients were treated with either 30 mg of MabCampath IV three
times per week for a maximum of 12 weeks, inclusive of dose escalation
periods, or 40 mg/m2 of chlorambucil PO once every 28 days to a maximum of
12 cycles.

About Safety
Interim efficacy and safety data suggest that previously untreated B-CLL
patients who received MabCampath as a single agent have an excellent
response rate with a manageable toxicity profile. As expected, the most
common drug administration-related events noted to date were pyrexia,
rigors, nausea, hypotension, and vomiting. Overall, nausea and vomiting
were more frequent in the chlorambucil arm. In the interim results of this
trial, serious adverse events related to treatment occurred in 25 percent
of MabCampath and 6 percent of patients on chlorambucil.

The difference in SAE frequency observed may be explained by CMV
viremia/infection that was treated in hospitals in some countries,
therefore classified as grade 3-4 SAEs, and which all seem to have been
managed successfully.

The incidence of grade 3-4 thrombocytopenia and anemia appear to be
comparable in both treatment arms.  Grade 3-4 neutropenia and leukopenia as
well as serious infections (due largely to the incidence of CMV infections)
appear to be more frequent in the MabCampath arm. However, the difference
in the incidence of febrile neutropenia was found to be insignificant. One
likely treatment-related death occurred in the chlorambucil arm.

About Chronic Lymphocytic Leukemia (CLL)
CLL is the most prevalent form of adult leukemia, affecting approximately
120,000 people in Europe and the United States. The disease is most
commonly diagnosed among people age 50 or older. CLL is characterized by
the accumulation of functionally immature white blood cells (lymphocytes)
in the bone marrow, blood, lymph tissue, and other organs. Two types of
lymphocytes are present in the blood, B cells and T cells. About 95 percent
of CLL cases involve cancerous B cells.  Because these B cells have a
longer than normal life span, they begin to build up and "crowd out" the
normal, healthy blood cells. The accumulation of functionally immature
cells in the bone marrow excludes the generation of healthy cells and can
become fatal. Symptoms include fatigue, bone pain, night sweats, fevers and
decreased appetite and weight loss. Bone marrow involvement also leads to
weakening of the immune system, exposing the patient to a higher risk of
infection.

About MabCampath
MabCampath is the first and only humanized monoclonal antibody approved for
B-CLL therapy and the first product with proven efficacy in CLL patients
who have failed both alkylating agents and Fludara(r) (fludarabine phosphate)
treatment. No other therapy has shown comparable efficacy in this group of
patients. MabCampath has a completely different mode of action compared
with conventional chemotherapy.  By selectively targeting the CD52 antigen,
expressed at higher concentration on malignant lymphocytes, MabCampath
activates cellular processes that lead to the lysis of malignant cell
types.  These processes also result in removal of malignant lymphocytes
from the bone marrow, blood, and other affected organs, which in turn can
lead to an increase in life expectancy.

In its indicated patients population, MabCampath demonstrates a side effect
profile that can be safely managed with appropriate prophylaxis and
monitoring for opportunistic infections. These side effects are
predictable, manageable and reversible. Furthermore, since MabCampath does
not eliminate stem cells in the bone marrow, patients can repopulate their
hematopoietic system with their own healthy blood cells. MabCampath is not
currently indicated as a first-line treatment in CLL.

Schering AG, Germany is a research-based pharmaceutical company.  Its
activities are focused on four business areas: Gynecology & Andrology,
Oncology, Diagnostic Imaging as well as Specialized Therapeutics for
disabling diseases. As a global player with innovative products Schering AG
aims for leading positions in specialized markets worldwide. With in-house
R&D and supported by an excellent global network of external partners,
Schering AG is securing a promising product pipeline. In Oncology, Schering
AG maintains a prominent leadership position by offering a range of
hematological and solid tumor treatments. Schering AG is strongly invested
in bringing to market an innovative and broad oncology R&D portfolio of
systemic and targeted therapies, potentially offering novel therapeutic
options for people with cancer. Using new ideas, Schering AG aims to make a
recognized contribution to medical progress and strives to improve the
quality of life: making medicine work.

One of the world's leading biotechnology companies, Genzyme is dedicated to
making a major positive impact on the lives of people with serious
diseases.  This year marks the 25th anniversary of Genzyme's founding.
Since 1981, the company has grown from a small start-up to a diversified
enterprise with more than 8,000 employees in locations spanning the globe
and 2005 revenues of $2.7 billion. Genzyme has been selected by FORTUNE as
one of the "100 Best Companies to Work for" in the United States. With many
established products and services helping patients in more than 80
countries, Genzyme is a leader in the effort to develop and apply the most
advanced technologies in the life sciences. The company's products and
services are focused on rare inherited disorders, kidney disease,
orthopaedics, cancer, transplant and immune diseases, and diagnostic
testing. Genzyme's commitment to innovation continues today with a
substantial development program focused on these fields, as well as heart
disease and other areas of unmet medical need.

This press release has been published by Corporate Communication of
Schering AG, Berlin, Germany.

Your contacts at Corporate Communication:
Media Relations: Verena von Bassewitz, T: +49-30-468 19 22 06,
verena.vonbassewitz@schering.de
Investor Relations: Peter Vogt, T: +49-30-468 128 38,
peter.vogt@schering.de
Pharma Communication: Frank Richtersmeier, T: +49-30-468 176 61;
frank.richtersmeier@schering.de
Pharma Communication: Astrid Kranz, T: +49-30-468 120 57,
astrid.kranz@schering.de


Your contacts in the U.S.:
Media Relations: Kimberley Jordan, T:+1-973-305 5340,
kimberley_jordan@berlex.com
Investor Relations: Joanne Marion, T: +1-973-487 2164,
joanne_marion@berlex.com

Your contacts at Genzyme Corporation:
Media Relations: Maria Cantor, T: +1-617-768-6690
Investor Relations: Kristen Galfetti: T: +1-617-768-6563


Find additional information at: www.schering.de/eng

Certain statements in this press release that are neither reported
financial results nor other historical information are forward-looking
statements, including but not limited to, statements that are predictions
of or indicate future events, trends, plans or objectives. Undue reliance
should not be placed on such statements because, by their nature, they are
subject to known and unknown risks and uncertainties and can be affected by
other factors that could cause actual results and Schering AG's plans and
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update publicly or revise any of these forward-looking statements, whether
to reflect new information or future events or circumstances or otherwise.

This press release contains forward-looking statements, including
statements about the results of the CAM307 trial, and regulatory plans and
expected timelines for the expansion of the product label for Campath into
earlier-line CLL.  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: that final results of the CAM307 trial demonstrate safety and
efficacy comparable to the preliminary data that have been released to
date, the actual timing and content of submissions to and decisions made
by the U.S. Food and Drug Administration and other regulatory
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filed by Genzyme with the Securities and Exchange Commission. Please see
the disclosure under the heading "Factors Affecting Future Operating
Results" in the Management's Discussion and Analysis of Financial Condition
and Results of Operations section of Genzyme's Quarterly Report on Form 10-
Q for the quarter ended March 31, 2006 for a more complete discussion of
these and other risks. Genzyme cautions investors not to place substantial
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 undertakes no obligation to update or revise the statements.