GENEVA, SWITZERLAND–(EMWNews – August 5, 2008) – Addex Pharmaceuticals (SWISS: ADXN)

announced today that on July 31, 2008, The Swiss Helvetia Fund,

Inc.

1270 Avenue of the Americas, Suite 400, New York, NY 10020,

U.S.A.,

has informed of exceeding the threshold of 5% in the shareholding

of

Addex Pharmaceuticals Ltd., holding a total of 314,860 registered

shares, corresponding to 5.37% of the voting rights.

About Addex

Addex Pharmaceuticals discovers and develops allosteric

modulators

for human health. Allosteric modulators are an emerging class

of

orally available small molecule therapeutic agents that we

believe

will offer patients better results than classical drugs.

Most

marketed drugs bind receptors where the body’s own natural

molecular

activators (i.e. endogenous ligands) bind, specifically to a key

part

of each receptor’s anatomy called the “active site”. In short,

most

drugs must out-compete endogenous ligands for the active site.

By

contrast, allosteric modulators are non-competitive because they

bind

receptors and modify their function even if the endogenous

ligand

also is binding it. In addition, because of this,

allosteric

modulators aren’t limited to simply turning a receptor on or off,

the

way most drugs are. Instead, they act more like a dimmer

switch,

offering control over the degree of activation or deactivation,

while

offering the body the ability to maintain control over

initiating

receptor activation. Furthermore, the allosteric approach

generally

affords freedom to operate – even on well-known, clinically

validated

targets – because the intellectual property surrounding

allosteric

chemistry and the allosteric sites on receptors is most

often

un-exploited.

ADX10059, our most advanced product, is an mGluR5 NAM

(metabotropic

glutamate receptor 5 negative allosteric modulator). It

has

demonstrated clinically and statistically significant efficacy

in

separate Phase IIa clinical trials in gastroesophageal reflux

disease

(GERD) patients and migraine headache patients and has potential

in

additional indications.

The Addex allosteric modulation discovery and development

platform

have been additionally validated through three seperatate

product

license or collaboration agreements with Merck & Co., Inc.

and

Johnson & Johnson as well as investments by Roche Ventures and

SR

One, the venture investment arm of GlaxoSmithKline.

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, mGluR5 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

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, mGluR5 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 mGluR4, mGluR2, mGluR5 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 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.

Copyright © Hugin AS 2008. All rights reserved.

Contact: Chris Maggos Head of IR & Communications Addex Pharmaceuticals +41 22 884 15 11