Addex Extends Parkinson’s Disease Collaboration with Merck & Co., Inc.

Geneva, Switzerland, - Allosteric modulation company Addex Pharmaceuticals (SIX:ADXN) announced today the extension of its research collaboration with Merck & Co., Inc., through an affiliate, for an additional year. The collaboration is focused on developing positive allosteric modulators (PAM) of the metabotropic glutamate receptor 4 (mGluR4) for the treatment of Parkinson’s disease and other undisclosed indications.

Addex will receive research funding from Merck in addition to the original financial terms, which include milestones and royalties.

Earlier this year Addex disclosed that a preclinical study had shown that the collaboration had yielded orally available mGluR4 PAM with efficacy in an animal model of Parkinson’s disease.

“We are delighted that Merck values the contribution of our allosteric modulator discovery platform and wishes to include us in building further upon the excellent progress this program has made to date,” said Emmanuel Le Poul, head of the CNS Business Unit at Addex.

“Developing innovative non-dopaminergic drugs for Parkinson’s disease is an increasingly important part of our work at Addex,” said Vincent Mutel, CEO of Addex. “We are proud to be advancing mGluR4 PAMs with our collaborators at Merck.”

Under the terms of the exclusive collaboration and license agreement, first announced in December 2007, Addex received $3 million upfront and has received two preclinical milestones of $250,000 and $500,000, to date. Addex is eligible to receive 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. Extension of the research collaboration allows Addex to recognize $1.8 million in research funding over 12 months beginning on December 1, 2009.

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. In Parkinson’s disease, the death of dopamine producing neurons leads to excess glutamate signaling.

Parkinson’s disease is a degenerative disease of the brain that often impairs motor skills, speech, and other functions. It is estimated that 60,000 new cases are diagnosed each year in the U.S., where more than 1.5 million people currently have PD. While the condition usually develops after the age of 65, 15% of those diagnosed are under 50. PD affects both men and women in almost equal numbers.

mGluR4 may play an important role in Parkinson’s disease. 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, especially levodopa induced dyskinesia, and many patients are encouraged to limit doses so their side effects will appear later and 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 via a non-dopaminergic mechanism.

Published research* shows that mGluR4 activators, like those in development by Addex and Merck, 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. Thus, this approach has the potential to provide significant benefit in Parkinson’s disease.

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

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, an mGluR5 NAM, has achieved clinical proof of concept and is in Phase IIb testing for the treatment of GERD and, separately, migraine prevention. ADX48621, an mGluR5 NAM, has completed Phase I testing and will enter Phase II for PD-LID in 2010. Addex partner Ortho-McNeil-Janssen Pharmaceuticals, a Johnson & Johnson company, is performing Phase I testing of ADX71149, an mGluR2 PAM, which has potential for anxiety and schizophrenia.

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.