European Union CHMP Recommends Approval of New Formulation of Multiple Sclerosis Treatment Rebif(R) (Interferon Beta-1a)

GENEVA, Switzerland, June 28 /PRNewswire/ --

- New Formulation of Rebif(R) Designed to Improve Tolerability and
Immunogenicity Profiles

Merck Serono S.A.  (NYSE:SRA) (virt-x: SEO) announced today that the
Committee for  Medicinal Products for Human Use (CHMP) of the European 
Medicines Agency (EMEA) has issued a positive opinion recommending 
marketing authorization of  a new formulation of Rebif(R) 
(interferon beta-1a) for the treatment of  relapsing multiple sclerosis  
(MS). The new formulation of Rebif(R) has been  developed to increase 
treatment benefit by improving injection tolerability  and reducing 
immunogenicity.

"The CHMP recommendation for the new formulation of Rebif(R)
is encouraging news for patients with multiple sclerosis in Europe", said
Anthony Coombs, Head of Global Therapeutic Area Neurology at Merck Serono.
"While Rebif(R) is well established in the treatment of multiple sclerosis,
this new formulation demonstrates our commitment to the further development
of products that enhance the convenience and tolerability of treatments for
patients with multiple sclerosis".

The CHMP reviews drug applications for all 27 countries in the
European Union(1) as well as Iceland and Norway. The CHMP recommendation will
now be considered by the European Commission, which will deliver its final
decision on the granting of the marketing authorization.

Rebif(R), which was originally approved in Europe in 1998, has been
proven effective on the following three key measures of treatment
effectiveness: MRI lesion area and activity, relapse rates, and disability
progression. The safety and efficacy of Rebif(R) are supported by a robust
long-term clinical development program including comparative studies and 13
years of patient experience from around the world.

"Merck Serono's efforts over the years to continuously provide
enhanced therapeutic solutions for patients with multiple sclerosis are
commendable," said Professor Per Soelberg Sørensen, from the Danish MS
Research Center, Copenhagen University Hospital, Rigshospitalet. "Clinical
trial data show that the new formulation of Rebif offers promising
improvements which could translate into additional benefits to the patient."

One-year (48-week) data from an ongoing two-year (96-week) Phase III
study of the new formulation of Rebif(R) were presented at the 17th Meeting
of the European Neurological Society (ENS), in Rhodes, Greece(2). The data
showed that the rate of injection-site reactions in patients with MS who
received the new formulation of Rebif(R) over one year was three times lower
when compared with historical data from previous trials. The data also showed
that 13.9% of patients treated with the new formulation of Rebif(R) had
neutralizing antibodies after one year treatment. The results at one year
showed that patients who tested positive for neutralizing antibodies at both
the 24 and 48-week timepoints represented 2.5% of the patients. The most
frequent side effect was flu-like syndrome, which is typical of interferon
therapy. Flu-like syndrome tends to be most prominent at the initiation of
therapy, is relatively easy to treat and decreases in frequency with
continued treatment.

The new formulation of Rebif(R) has been developed in the same strengths
and pharmaceutical forms as currently registered, i.e. 8.8, 22 and 44 mcg, as
a solution for injection in pre-filled syringes. This new formulation
originates from an innovative approach, using state-of-the-art technologies.
It is the latest of many product developments from Merck Serono to
continuously enhance the convenience and tolerability of Rebif(R). Other
enhancements have included the Rebiject II auto-injector to facilitate
injections; a 29 gauge-5 bevel needle pre-filled syringe, the thinnest needle
in a ready-to-use pre-filled syringe for the treatment of MS; and a titration
pack designed to make starting on Rebif(R) therapy easier and more
convenient.

About Rebif(R)

Rebif(R) (interferon beta-1a) is a disease-modifying drug used to treat
relapsing forms of multiple sclerosis (MS) and is similar to the interferon
beta protein produced by the human body. Interferon helps modulate the body's
immune system, fight disease and reduce inflammation.

Rebif(R), which was approved in Europe in 1998 and in the US
in 2002, is registered in more than 80 countries worldwide. In the United
States, Rebif(R) is co-marketed by EMD Serono, Inc. (the US affiliate of
Merck Serono) and Pfizer Inc. Rebif(R) has been proven to delay the
progression of disability, reduce the frequency of relapses and reduce MRI
lesion activity and area(3). Rebif(R) is not approved for treatment of
chronic progressive MS. Rebif(R) is available in a 22 mcg and 44 mcg
ready-to-use pre-filled syringe and a titration pack, and can be stored at
room temperature for up to 30 days if a refrigerator is not available.

Most commonly reported side effects are injection site disorders,
flu-like symptoms, elevation of liver enzymes and blood cell abnormalities.
Patients, especially those with depression, seizure disorders, or liver
problems, should discuss treatment with Rebif(R) with their doctors.

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. In addition to Rebif(R), the Company also offers a second therapy
within its US portfolio of MS therapies: Novantrone(R) (mitoxantrone for
injection concentrate) for worsening forms of MS. Full prescribing
information for these products can be obtained by contacting the Company or
visiting its website. Additional therapeutic options are currently under
development at Merck Serono, including oral cladribine, currently in Phase
III and potentially the first oral therapy for MS, as well as several
products in early stage development including: osteopontin, an MMP-12
inhibitor, a JNK inhibitor and interferon beta:Fc. Merck Serono also is
taking a leading role in developing an understanding of the role of genetics
in MS, with a whole genome scan currently underway.

About multiple sclerosis

Multiple sclerosis (MS) is a chronic, inflammatory condition
of the nervous system and is the most common, non-traumatic, neurological
disease in young adults. The World Health Organization estimates that up to
2.5 million people suffer from 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.

Forward-looking statements

Some of the statements in this press release are forward
looking. Such statements are inherently subject to known and unknown risks,
uncertainties and other factors that may cause actual results, performance or
achievements of Merck Serono S.A. and affiliates to be materially different
from those expected or anticipated in the forward-looking statements.
Forward-looking statements are based on Merck Serono's current expectations
and assumptions, which may be affected by a number of factors, including
those discussed in this press release and more fully described in Serono's
Annual Report on Form 20-F filed with the U.S. Securities and Exchange
Commission on February 28, 2006. These factors include any failure or delay
in Merck Serono's ability to develop new products, any failure to receive
anticipated regulatory approvals, any problems in commercializing current
products as a result of competition or other factors, our ability to obtain
reimbursement coverage for our products, the outcome of any government
investigations and litigation. Merck Serono is providing this information as
of the date of this press release, and has no responsibility to update the
forward-looking statements contained in this press release to reflect events
or circumstances occurring after the date of this press release.

About Merck Serono S.A.

Merck Serono S.A. is a global biotechnology leader, with sales
in over 90 countries. The Company is the world leader in reproductive health,
with Gonal-f(R) (follitropin alfa for injection), Luveris(R) (lutropin alfa
for injection) and Ovidrel(R)/Ovitrelle(R) (choriogonadotropin alfa
injection). It has strong market positions in neurology, with Rebif(R)
(interferon beta-1a), as well as in metabolism and growth, with Saizen(R)
[somatropin (rDNA origin) for injection], Serostim(R) [somatropin (rDNA
origin) for injection] and Zorbtive(TM) [somatropin (rDNA origin) for
injection]. The Company has recently entered the psoriasis area with
Raptiva(R) (efalizumab). Merck Serono's research programs are focused on
growing these businesses and on establishing new therapeutic areas, including
oncology and autoimmune diseases.

Bearer shares of Merck Serono S.A., the holding company, are
traded on the virt-x (SEO).

About Merck

Merck is a global pharmaceutical and chemical company with sales of EUR
6.3 billion in 2006, a history that began in 1668, and a future shaped by
35,091 employees in 62 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.

(1) Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Poland, Portugal, Romania, Slovakia,
Slovenia, Spain, Sweden, United Kingdom

(2) Rebif(R) New Formulation (RNF; interferon beta-1a): 1-year results of 
a phase IIIb study in patients with relapsing forms of multiple sclerosis -
P.Sørensen, O. Barbarash, F. Casset-Semanaz, G. Giovannoni, J. King, L. Metz,
G. Pardo, J. Simsarian, B. Stubinski on behalf of the RNF Study Group

(3) The exact correlation between MRI findings and the current or future
clinical status of patients, including disability progression, is unknown.