Merck Serono: FDA Grants Priority Review to Cladribine Tablets for the Treatment of Relapsing Forms of MS

GENEVA, Switzerland, July 28, 2010 - Merck Serono, a division of Merck KGaA, Darmstadt, Germany, announced
today that the U.S. Food and Drug Administration (FDA) has accepted for
filing the New Drug Application (NDA) for Cladribine Tablets as a therapy for
relapsing forms of multiple sclerosis (MS).

The application also has been granted a Priority Review
designation by the FDA, which means the review period for the NDA is reduced.
The goal for completing a Priority Review is six months instead of the
standard 10 months. Priority Review is applied to drugs that have the
potential to provide significant advances in treatment. A decision by the FDA
is expected in Q4 2010.

"This is a critical milestone on the path to potential
approval for short course therapy with Cladribine Tablets, moving us one step
closer to meeting an unmet need as an oral, disease-modifying drug available
for relapsing MS," said Fereydoun Firouz, President and CEO of EMD Serono,
Inc., the US affiliate of Merck KGaA, Darmstadt, Germany. "Our commitment to
people living with MS is to transform the way they approach their therapy
options, and Priority Review for short-course therapy with Cladribine Tablets
means we are moving closer to delivering on this promise. We look forward to
working with the FDA throughout the regulatory process."

The NDA is supported by results from the CLARITY 1 study, a
two-year, randomized, double-blind, placebo-controlled Phase III trial of
Cladribine Tablets in people with relapsing-remitting MS. The CLARITY study
results were published in The New England Journal of Medicine 2 in February
2010.

1 CLARITY: CLAdRIbine Tablets treating MS OrallY

2 Giovannoni G et al. A placebo-controlled trial of oral cladribine for
relapsing multiple sclerosis; N Engl J Med 362:416, February 4, 2010

About the CLARITY study design

The CLARITY study was a two-year (96-week), randomized,
double-blind, placebo-controlled, international trial. It randomized 1,326
patients with relapsing-remitting multiple sclerosis (MS) according to the
revised McDonald criteria. 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). Cladribine
Tablets were 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 took Cladribine Tablets for 8 to
20 days during the year. In the second year, two treatment courses were
administered to all patient groups, meaning that patients took Cladribine
Tablets for 8 to 10 days during the year.

The primary endpoint of the CLARITY study was the relapse rate
over 96 weeks. Secondary endpoints included MRI endpoints, proportion of
subjects relapse-free and disability progression at 96 weeks.

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. Merck Serono initiated global filings for
Cladribine Tablets in mid-2009 and, to date has submitted regulatory
applications for Cladribine Tablets covering about 40 countries. Cladribine
Tablets was granted its first marketing approval in July 2010, in Russia.

    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.

For more information, please visit www.merckserono.com or
www.merck.de

Merck Serono S.A., Geneva, 9 Chemin des Mines, 1202 Geneve, Suisse, Media relations, Tel: +41-22-414-36-00