Addex Achieves Second Milestone in Parkinson's Disease Collaboration With Merck & Co., Inc.

GENEVA, SWITZERLAND, Jul 10 (MARKET WIRE) --
Allosteric modulation company Addex Pharmaceuticals (SWISS: ADXN)
announced today that the second preclinical milestone has been achieved
in an exclusive collaboration and license agreement with Merck & Co.,
Inc. (through its affiliate Merck Sharp & Dohme Research Ltd). The
collaboration is focused on developing an emerging type of drugs, called
allosteric modulators, for treatment of Parkinson's disease and other
undisclosed indications. Allosteric modulators have broad potential to
address important therapeutic targets; this collaboration with Merck is
focused on developing drugs that specifically activate the metabotropic
glutamate receptor 4 (mGluR4). The preclinical study showed the desired
non-dopaminergic activity profile after oral administration of mGluR4
positive allosteric modulator (PAM) in an animal model of Parkinson's
disease.

"We are pleased that these preclinical data show such promise in the
animal model used," said Emmanuel Le Poul, head of the CNS Business Unit
at Addex. "This work is a further validation of the target and the
strength of our collaboration, as both teams have contributed to this
achievement."

"Innovative non-dopaminergic therapies represent a significant opportunity
to address an important unmet medical need in Parkinson's disease
patients," said Vincent Mutel, CEO of Addex. "We are proud that our
allosteric modulation drug discovery and development platform has
generated highly innovative products in Parkinson's disease in addition
to other important indications with unmet medical need including:
gastroesophageal reflux disease, migraine, schizophrenia and anxiety."

Addex will discuss the mGluR4 PAM collaboration and its clinical and
preclinical stage allosteric modulator pipeline and discovery platform
during its R&D Day on July 16, 2009. A webcast and recording of the Addex
R&D Day will be made available at www.addexpharma.com.

Addex will receive $500,000 for achieving the second preclinical
milestone. Addex received $250,000 after achieving the first preclinical
milestone during the first quarter of 2008. Under the terms of the
agreement, first announced in December 2007, Addex received $3 million
upfront and is eligible for up to $106.5 million in research, development
and regulatory milestones for the first product developed for multiple
indications. Additional milestones of up to $61 million would be payable
if a second and third product is developed. Addex is eligible to receive
undisclosed royalties on sales of any products resulting from this
collaboration. Merck is responsible for clinical development.

mGluR4 may play an important role in Parkinson's disease, which is a
debilitating movement disorder. Current treatments focus on
dopamine-replacement strategies, however most patients reach a stage where
dopaminergic treatments are no longer effective. There can also be
debilitating side effects with dopaminergic treatments and many patients
limit doses so their side effects will be less cumbersome. The recent
success of surgical approaches suggests that bypassing the dopamine system
may provide a more effective treatment strategy. It is believed that
selective activation of mGluR4 is one way to do this and could correct the
circuitry that modulates motor excitability. This has the potential to
provide significant benefit in Parkinson's disease.

Published research* shows that mGluR4 activators, like those in
development at Addex, could work via two distinct mechanisms to alleviate
symptoms of Parkinson's disease and, potentially, even slow the
progression of the disease: 1) mGluR4 activation triggers a compensatory
mechanism that may spare or potentiate the use of dopamine receptor
activators; 2) mGluR4 activation may have a neuroprotective effect that
helps to preserve the brain's dopaminergic neurons.

*Nature Reviews Neuroscience, Vol 6, Oct. 2005, pp 787-798

Glutamate, like dopamine and serotonin, is a key neurotransmitter in the
human brain, an important signaling molecule involved in control of
multiple brain functions ranging from motor control to mood. Although
marketed drugs modulate specific receptors involved in both the
dopaminergic and serotinergic systems, it has been difficult to develop
drugs that can selectively target specific receptors of glutamate, which
has many different receptors, some of which can cause serious side effects
if improperly modulated.

Merck has been a pioneer in research on mGlu receptors and the
metabotropic glutamatergic system for multiple indications. For example,
research by Merck scientists provided the first evidence that mGluR4
activation has potential for treatment of Parkinson's disease. However, a
remaining challenge has been to make drug-like molecules that activate
mGluR4 in a specific fashion. Addex is a pioneer in developing allosteric
modulators, truly selective small molecule drug candidates, for human
health.

Parkinson's disease is a brain disorder characterized by movement
disorders and other symptoms. It occurs when certain nerve cells
(neurons) in a part of the brain called the substantia nigra die or
become impaired. Normally, these cells produce a vital chemical known as
dopamine. Dopamine allows smooth, coordinated function of the body's
muscles and movement. When approximately 80% of the dopamine-producing
cells are damaged, the symptoms of Parkinson's disease appear.

About 1.5 million Americans currently have Parkinson's disease, and about
60,000 new cases are diagnosed each year. Parkinson's is one of the
fastest growing diseases, driven by the ageing population. Parkinson's
disease drugs had global sales of around $2.5 billion in 2005, which
analysts believe could grow to $3.8 billion by 2010.

Although no marketed products slow the disease progression, there are a
number of medicines that effectively ease the symptoms. The medicines most
commonly prescribed attempt to either replace or mimic dopamine. They can
improve the tremor, rigidity and slowness associated with Parkinson's
disease but they also can cause side effects like dyskinesia (involuntary
movements) and eventually stop working, as the dopaminergic neurons
continue to die.

Addex Pharmaceuticals (www.addexpharma.com) discovers and develops
allosteric modulators for human health. Allosteric modulators are a
different kind of orally available small molecule therapeutic agent, which
we believe will offer a competitive advantage over classical drugs. Our
lead allosteric modulator product, ADX10059, has achieved clinical proof
of concept and is in Phase IIb testing for the treatment of GERD and,
separately, migraine headache. Both are important diseases for which
existing products with limited efficacy have established multi-billion
dollar markets despite sub-optimal efficacy. ADX10059 is a first-in-class
mGluR5 inhibitor, a therapeutic strategy that also is being pursued in
multiple indications by large pharma competitors.

Our products and technology already have proven their value through our
partnerships with four of the top 10 pharmaceutical companies in the
world. Specifically, two separate agreements with Merck & Co., Inc., are
focused on developing allosteric modulators as drugs to treat Parkinson's
disease and schizophrenia, respectively. A third agreement with
Ortho-McNeil-Janssen Inc. is focused on development of allosteric
modulators to treat anxiety and schizophrenia. In addition,
GlaxoSmithKline and Roche have made equity investments in Addex.

Disclaimer: The foregoing release contains forward-looking statements that
can be identified by terminology such as "not approvable", "continue",
"believes", "believe", "will", "remained open to exploring", "would",
"could", or similar expressions, or by express or implied discussions
regarding Addex Pharmaceuticals Ltd, its business, the potential approval
of its products by regulatory authorities, or regarding potential future
revenues from such products. Such forward-looking statements reflect the
current views of Addex Pharmaceuticals Ltd regarding future events, and
involve known and unknown risks, uncertainties and other factors that may
cause actual results with allosteric modulators of mGluR4, mGluR2 or
mGluR5 to be materially different from any future results, performance or
achievements expressed or implied by such statements. There can be no
guarantee that allosteric modulators of mGluR4, mGluR2 or mGluR5 will be
approved for sale in any market or by any regulatory authority. Nor can
there be any guarantee that allosteric modulators of mGluR4, mGluR2 or
mGluR5 will achieve any particular levels of revenue (if any) in the
future. In particular, management's expectations regarding allosteric
modulators of mGluR4, mGluR2 or mGluR5 could be affected by, among other
things, unexpected actions by our partners, unexpected regulatory actions
or delays or government regulation generally; unexpected clinical trial
results, including unexpected new clinical data and unexpected additional
analysis of existing clinical data; competition in general; government,
industry and general public pricing pressures; the company's ability to
obtain or maintain patent or other proprietary intellectual property
protection. Should one or more of these risks or uncertainties
materialize, or should underlying assumptions prove incorrect, actual
results may vary materially from those anticipated, believed, estimated
or expected. Addex Pharmaceuticals is providing the information in this
press release as of this date and does not undertake any obligation to
update any forward-looking statements contained in this press release as
a result of new information, future events or otherwise.

German (PDF): http://hugin.info/138017/R/1327976/313045.pdf

French (PDF): http://hugin.info/138017/R/1327976/313044.pdf

English (PDF): http://hugin.info/138017/R/1327976/312982.pdf

Chris Maggos
Head of IR & Communications
Addex Pharmaceuticals
+41 22 884 15 11
chris.maggos@addexpharma.com

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