Addex Presents Data on ADX10059 at the Annual Meeting of the American Academy of Neurology

GENEVA, Apr 29 (MARKET WIRE) --
Allosteric modulation company Addex Pharmaceuticals (SWISS: ADXN)
announced today the presentation of Phase IIa data on ADX10059, an mGluR5
negative allosteric modulator, which shows efficacy in treating acute
migraine attacks and provides evidence that inhibition of this glutamate
receptor subtype could play a role in stopping migraine attacks before
they start. Data were presented at the 61st Annual Meeting of the
American Academy of Neurology (Seattle, USA).

"Medication is available to prevent migraine but these treatments are
often secondary uses of the drug and come with potentially limiting
side-effects," noted Dr. Peter Goadsby of the UCSF Headache Center and
investigator in the study. "New therapies specifically developed for
migraine prevention are urgently needed especially for the substantial
proportion of migraine sufferers who have frequent attacks and have
significant disability in their daily lives. Targeting mGluR5 signaling
with ADX10059 is an interesting approach that is showing significant
promise in early clinical evaluation."

Preclinical experiments and small scale studies in migraineurs with drugs
like ketamine, which acts on glutamate signaling through NMDA receptors
(functionally related to mGluR5) and the NMDA antagonist memantine,
suggest that mGluR5 could play a role in the "migraine circuit," a
positive feedback loop that generates the symptoms of a migraine attack.
The initial step to test this hypothesis was Addex' proof of concept
study in acute treatment of migraine attacks.

In the Phase IIa trial of 129 migraine patients presented at ANN,
significantly more patients taking ADX10059 than those taking placebo
(16.7% vs 4.7%, respectively p = 0.039) were pain-free two hours after
dosing. ADX10059 administration yielded better pain improvement than
placebo at all time points up to two hours after treatment of a migraine
attack. In addition, there were trends to superiority for ADX10059 over
placebo for migraine pain improvement (mild or no pain) at all time points
up to two hours post-dosing.

"The clinical trial data for ADX10059, presented here at AAN, proved the
concept that by terminating acute attacks in some patients, mGluR5
inhibition plays a role in migraine pathophysiology. Now we are looking
forward to the data from our ongoing Phase IIb migraine prevention study
in the first half of 2010," said Charlotte Keywood, chief medical officer.

In December 2008, Addex initiated a Phase IIb trial to study ADX10059 as a
prophylactic agent in migraine. The 12-week trial will compare ADX10059
(25mg, 50mg or 100mg) versus placebo in migraine patients who suffer three
or more attacks per month. Data from the migraine prevention trial are
expected in the first half of 2010.

AAN Abstract P06.006: "Investigation of the Role of mGluR5 Inhibition in
Migraine: A Proof of Concept Study of ADX10059 in Acute Treatment of
Migraine" will be presented by Peter Goadsby, Director of the UCSF
Headache Center, San Francisco, and Charlotte Keywood, Chief Medical
Officer, Addex Pharma, during Poster Session VI: Headache III in room 6E
on Wednesday, April 29, 2009 4:00 PM. The authors are available for
interviews prior to and during the conference.

Migraine is a condition distinguished by recurrent episodes of a
characteristic headache, which can be accompanied by a variety of other
symptoms such as nausea, and sensitivity to light and sound. The average
migraine patient suffers 12 attacks a year. The International Headache
Society estimates that about 25% of migraine patients have three or more
attacks per month and could benefit from migraine prevention treatment. A
migraine attack, which typically lasts about 24 hours but can range from
4-72 hours, has three distinct phases: the prodrome phase, when an array
of individual warning signs -- like blurred vision or tingling of the
skin -- may begin to appear; the headache phase; and the postdrome phase,
when many patients report fatigue or other "hangover-like" symptoms. As
migraine attacks are prolonged, many patients and especially those with
frequent attacks, lose a significant amount of work and family time to
suffering caused by the disease. Indeed, migraine is currently estimated
to cost employers $13 billion annually in lost productivity in the United
States. Prevalence of migraine is estimated at 12% in the United States,
where about 30 million people suffer from migraine. Given the role of
glutamate in the pathophysiology of migraine, the future of migraine
prophylaxis, may lie in modulating one of the receptors in the glutamate
system, mGluR5.

mGluR5 inhibition: Research has shown that glutamate is the major
neurotransmitter involved in the initiation and the propagation of the
migraine circuit, a positive feedback loop that leads to pain and
inflammation in the brain and hence migraine symptoms. mGluR5 is known to
be expressed in key brain regions involved in the migraine circuit. Addex
postulated that ADX10059 could interrupt the migraine circuit to abort an
active attack and potentially prevent an attack from being triggered.
ADX10059 has been shown by Addex to have a superior effect to placebo in
acute treatment of migraine headache in Phase IIa testing. Inhibition of
mGluR5 has therapeutic potential in multiple indications because mGluR5 is
involved in a variety of functions in the central and peripheral nervous
systems*. In addition to migraine, mGluR5 inhibitors have achieved
clinical proof of concept in separate studies in patients with
gastroesophageal reflux disease (GERD), Parkinson's disease levodopa
induced dyskinesia (PD-LID) and generalized anxiety disorder (GAD).
Inhibition of mGluR5 also has potential in Fragile X syndrome.

*mGluR5 antagonists: Discovery, characterization and drug development,
Current Opinion in Drug Discovery & Development 2008 11(5):655-665

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 patients better results than 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 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 to treat multiple
indications by large pharma competitors.

Our product pipeline and technology already have proven their value
through our relationships with four of the top 10 pharmaceutical
companies in the world. Specifically, in two separate license agreements
with Merck & Co., Inc., we are developing positive allosteric modulators
of mGluR4 and mGluR5 as drugs to treat Parkinson's disease and
schizophrenia, respectively. A third agreement, with Ortho McNeil
Pharmaceuticals Inc., a Johnson & Johnson company, is focused on
development of positive allosteric modulators of mGluR2 to treat anxiety
and schizophrenia. Separately, investment funds from Roche and
GlaxoSmithKline have extended their validation of our technology,
products and management by making significant investments in Addex.

Disclaimer: The foregoing release may contain 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, future economic performance
or prospects, and, by their very nature, involve inherent risks and
uncertainties, both general and specific, whether known or unknown,
and/or any other factor that may materially differ from the plans,
objectives, expectations, estimates and intentions expressed or implied
in such forward-looking statements. Such may in particular cause actual
results with allosteric modulators of mGluR2, mGluR4, mGluR5, mGluR7 or
other therapeutic targets 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
mGluR2, mGluR4, mGluR5, mGluR7 will be approved for sale in any market or
by any regulatory authority. Nor can there be any guarantee that
allosteric modulators of mGluR2, mGluR4, mGluR5, mGluR7 or other
therapeutic targets will achieve any particular levels of revenue (if
any) in the future. In particular, management's expectations regarding
allosteric modulators of mGluR2, mGluR4, mGluR5, mGluR7 or other
therapeutic targets 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 Ltd 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, except as may be required by
applicable laws.

English (PDF) http://hugin.info/138017/R/1309787/302655.pdf

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

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