Merck Serono: Enrollment Completed for ORACLE MS Study of Cladribine Tablets in Patients at Risk of Developing MS

GENEVA, November 17, 2010 - Merck Serono, a division of Merck KGaA, Darmstadt, Germany,
announced today the completion of patient enrollment in the ORACLE MS 1
clinical study. This randomized, double blind, placebo-controlled,
international Phase III trial is designed to evaluate the therapeutic effects
of Cladribine Tablets on the time to conversion to multiple sclerosis (MS) in
people with a first clinical event suggestive of the disease. A total of 617
patients considered at high risk of developing MS due to a recently
experienced isolated demyelinating event and having magnetic resonance
imaging (MRI) brain scans consistent with early signs of MS were randomized
in the study.

"The clinical development program of Cladribine Tablets is designed to
characterize the potential therapeutic effects of Cladribine Tablets therapy
at the various stages of multiple sclerosis," said Dr. Bruno Musch, Merck
Serono's Head of Global Clinical Development Neurodegenerative Diseases. "The
completion of patient enrollment in the ORACLE MS study is a significant
milestone as this study will provide insight on the impact of Cladribine
Tablets therapy on the course of multiple sclerosis when administered early
in the disease process."

Besides the ORACLE MS study, the Phase III program of
Cladribine Tablets includes the completed CLARITY 2 study and the ongoing
CLARITY EXTENSION study in patients with relapsing-remitting MS. Cladribine
Tablets were recently approved in Australia and Russia as a treatment of
relapsing-remitting MS, under the brand name Movectro(R), and are under
regulatory review in other countries. Registration applications for
Cladribine Tablets as a treatment for relapsing-remitting MS are supported by
the results from the CLARITY study.

1 ORACLE MS: ORAl CLadribine in Early MS

2 CLARITY: CLAdRIbine Tablets treating MS orallY

ORACLE MS study design

The ORACLE MS study is a two-year (96-week), randomized,
double-blind, placebo-controlled, international trial. It randomized 617
patients considered at risk of developing MS due to a recently experienced
isolated demyelinating event (e.g. optic neuritis, myelopathy or brainstem
syndrome) and having MRI brain scans consistent with early signs of MS. Study
participants were randomized to one of three different treatment groups
consisting of two different dose regimens of Cladribine Tablets or matching
placebo tablets (1:1:1 ratio).

Patients will be treated for a period of two years (96 weeks), or up to
the time when they experience a second attack leading to a diagnosis of
clinically definite MS, in which case they would be offered open-label
treatment with Rebif(R) 44 mcg three times a week for a 96-week maintenance
treatment period. Patients who do not convert to clinically definite MS
within the initial 96-week period of the study will be eligible to enroll in
a 96-week long-term follow-up treatment period. These maintenance and
long-term follow-up periods of the study are intended to assess the effect of
early treatment with Cladribine Tablets on relapses and subsequent treatment
response to disease-modifying therapy for relapsing-remitting MS and to
evaluate the sustained effect of Cladribine Tablets in delaying the
development of definite MS.

In the study, Cladribine Tablets are given in two (3.5 mg/kg
total dose) or four (5.25 mg/kg total dose) treatment courses in the first
year, with each course consisting of once daily administration for four to
five consecutive days (depending on patient weight), which means study
patients take Cladribine Tablets for only 8 to 20 days during the first year.
In the second year, two treatment cycles are administered to both patient
groups receiving Cladribine Tablets, meaning that patients take Cladribine
Tablets for 8 to 10 days during the second year.

The primary endpoint of the ORACLE MS study is time to conversion to
clinically definite MS, according to the Poser criteria, defined by either a
second attack, or a sustained increase in EDSS. Other endpoints include time
to conversion to MS according to the McDonald criteria (the main secondary
endpoint), assessments of MRI brain scans, and disability progression.

About Cladribine Tablets

Merck Serono's oral formulation of cladribine (Cladribine
Tablets) is an investigational treatment for patients with relapsing forms of
multiple sclerosis (MS). Cladribine is a small molecule that may interfere
with the behavior and the proliferation of certain white blood cells,
particularly lymphocytes, which are thought to be involved in the
pathological process of MS. Cladribine Tablets were approved in Russia in
July 2010 and in Australia in September 2010 as a treatment of
relapsing-remitting MS and are under regulatory review in other countries.

The clinical development program for Cladribine Tablets
includes:

    - The CLARITY (CLAdRIbine Tablets treating MS orallY) study and its
    extension: a two-year Phase III placebo-controlled trial designed to
    evaluate the efficacy and safety of Cladribine Tablets as a monotherapy
    in patients with relapsing-remitting MS and the CLARITY EXTENSION
    two-year Phase III study designed to provide data on the long-term
    safety and efficacy of extended administration of Cladribine Tablets for
    up to four years.

    - The ORACLE MS (ORAl CLadribine in Early MS) study: a two-year Phase
    III placebo-controlled trial designed to evaluate the efficacy
    and safety of Cladribine Tablets as a monotherapy in patients at risk of
    developing MS (patients who have experienced a first clinical event
    suggestive of MS). This trial was announced in September 2008.

    - The ONWARD (Oral Cladribine added oN to interferon beta-1a in patients
    With Active Relapsing Disease) study: a Phase II placebo-controlled
    trial designed primarily to evaluate the safety and tolerability of
    adding Cladribine Tablets treatment to patients with relapsing forms of
    MS, who have experienced breakthrough disease while on established
    interferon-beta therapy. This trial was announced in January 2007.

    - The PREMIERE (PRospective observational long-term safEty registry of
    Multiple sclerosis patIEnts who have participated in CladRibinE clinical
    trials) registry: an eight-year observational safety registry of patients
    who have participated in Cladribine Tablets clinical trials, designed to
    support the evaluation of the long-term safety of Cladribine Tablets in
    MS.

About multiple sclerosis

Multiple sclerosis (MS) is a chronic, inflammatory condition
of the central nervous system and is the most common, non-traumatic,
disabling neurological disease in young adults. It is estimated that
approximately two million people have MS worldwide. While symptoms can vary,
the most common symptoms of MS include blurred vision, numbness or tingling
in the limbs and problems with strength and coordination. The relapsing forms
of MS are the most common.

About Merck Serono

Merck Serono is the division for innovative prescription
pharmaceuticals of Merck KGaA, Darmstadt, Germany, a global pharmaceutical
and chemical company. Headquartered in Geneva, Switzerland, Merck Serono
discovers, develops, manufactures and markets innovative small molecules and
biopharmaceuticals to help patients with unmet medical needs. In the United
States and Canada, EMD Serono operates through separately incorporated
affiliates.

Merck Serono has leading brands serving patients with cancer (Erbitux(R),
cetuximab), multiple sclerosis (Rebif(R), interferon beta-1a), infertility
(Gonal-f(R), follitropin alfa), endocrine and metabolic disorders (Saizen(R)
and Serostim(R), somatropin), (Kuvan(R), sapropterin dihydrochloride) as well
as cardiometabolic diseases (Glucophage(R), metformin), (Concor(R),
bisoprolol), (Euthyrox(R), levothyroxine). Not all products are available in
all markets.

With an annual R&D expenditure of more than EUR 1 billion,
Merck Serono is committed to growing its business in specialist-focused
therapeutic areas including neurodegenerative diseases, oncology, fertility
and endocrinology, as well as new areas potentially arising out of research
and development in autoimmune and inflammatory diseases.

About Merck

Merck is a global pharmaceutical and chemical company with
total revenues of EUR 7.7 billion in 2009, a history that began in 1668, and
a future shaped by approximately 40,000 (including Merck Millipore) employees
in 64 countries. Its success is characterized by innovations from
entrepreneurial employees. Merck's operating activities come under the
umbrella of Merck KGaA, in which the Merck family holds an approximately 70%
interest and free shareholders own the remaining approximately 30%. In 1917
the U.S. subsidiary Merck & Co. was expropriated and has been an independent
company ever since.

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