Merck Serono: New Phase III Data for Cladribine Tablets to be Presented at the American Academy of Neurology 61st Annual Meeting in April 2009

GENEVA, Switzerland - CLARITY (CLAdRIbine tablets Treating MS OrallY) Study Data to be
Presented as Late-Breaking Oral Presentation

GENEVA, Switzerland, March 30 /PRNewswire/ –

Merck Serono, a division of Merck KGaA, Darmstadt, Germany,
announced today that the American Academy of Neurology (AAN) has accepted a
late-breaking abstract regarding cladribine tablets, its oral investigational
treatment of multiple sclerosis, for an oral presentation at the AAN 61st
Annual Meeting in Seattle.

The abstract is entitled “Results from the CLARITY study: a
Phase III, randomized, double-blind study to evaluate the safety and efficacy
of oral cladribine in relapsing-remitting multiple sclerosis”. The data is
currently scheduled to be presented as a late-breaking oral presentation on
April 29, 2009 by the study’s principal investigator, Dr Gavin Giovannoni,
Institute of Cell and Molecular Science, Barts and The London School of
Medicine and Dentistry, London, United Kingdom.

The CLARITY data is embargoed until the late-breaking
presentation. The late-breaker time is subject to the schedule of the AAN.
Information on the timing of the late-breaker can be found on the AAN website
at www.aan.com/go/am/science/latebreaking.

About Merck Serono and multiple sclerosis

Merck Serono is a leader in multiple sclerosis (MS) with
Rebif(R) (interferon beta-1a), a disease-modifying drug used to treat
relapsing forms of MS, which is registered in more than 80 countries
worldwide. Full prescribing information for this product can be obtained by
contacting the Company or visiting its website. Additional therapeutic
options are under development at Merck Serono, including cladribine tablets,
currently in Phase III and potentially the first oral therapy for MS, as well
as several products in early stage development. Merck Serono also is taking a
leading role in developing an understanding of the role of genetics 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 more
than 2 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, a global pharmaceutical and chemical group.
Headquartered in Geneva, Switzerland, Merck Serono discovers, develops,
manufactures and markets innovative small molecules and biopharmaceuticals to
help patients with unmet medical needs. Its North American business operates
in the United States and Canada as EMD Serono.

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 cardiometabolic
disorders (Glucophage(R), metformin); (Concor(R), bisoprolol); (Euthyrox(R),
levothyroxine); (Saizen(R) and Serostim(R), somatropin). Not all products are
available in all markets.

With an annual R&D expenditure of around EUR 1bn, 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 7.6 billion in 2008, a history that began in 1668, and a future shaped
by 32,800 employees in 59 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

www.merckserono.com

Source: Merck Serono

Merck Serono, 9 Chemin des Mines, 1202 Geneva, Switzerland. Media Relations, Tel.: +41-22-414-36-00.