PROXIMAGEN NEUROSCIENCE PLC

("Proximagen" or "the Company")

Proximagen sublicenses rights to tonabersat in North America

London, UK, 12 April 2010 - Proximagen Neuroscience plc (AIM: PRX), the biotechnology company focused on diseases of the central nervous system, today announces that it has signed a development, license and sub-license agreement (the "Agreement") with Upsher-Smith Laboratories Inc. ("Upsher-Smith") in relation to tonabersat, a drug compound recently acquired by Proximagen through its acquisition of Minster Pharmaceuticals plc ("Minster").

Under the terms of the Agreement, Upsher-Smith will undertake the clinical development, regulatory filing and commercialisation of tonabersat for epilepsy in the USA, Canada and Mexico ("North America") and Proximagen will be entitled to royalty-free use of Upsher-Smith's arising clinical data when developing tonabersat for Europe, a market to which Proximagen is retaining full rights.  Upsher-Smith will also be making an upfront payment to Proximagen and any royalties and milestone receipts arising from sub-licensing tonabersat in territories excluding North America and Europe will be shared equally between Proximagen and Upsher-Smith.

The Agreement includes the grant of a sub-license of certain patents and know-how which were originally licensed to Minster by SmithKline Beecham plc (subsequently "GSK").  GSK has been made aware of the partnering discussions with Upsher-Smith and their support has enabled the Agreement with Upsher-Smith. The signing of the Agreement also follows the announcement by Proximagen on 11 March 2010 that tonabersat had achieved positive efficacy results in National Institute of Health non-clinical epilepsy studies.

Commenting on the Agreement, Kenneth Mulvany, Chief Executive Officer of Proximagen, said:  "We are delighted that Upsher-Smith share our confidence that tonabersat has the potential to become a leading therapy for the treatment of epilepsy and our experience of working with Upsher-Smith over the last two years on the PRX1 programme has convinced us that they have the expertise, resources and commitment to bring tonabersat to the market in North America.  We also believe that the retention by Proximagen of EU marketing rights, whose value would be enhanced by the successful development of tonabersat in North America, has the potential to deliver significant long-term value to our shareholders."  

Commenting on the Agreement, Mark Evenstad, President of Upsher-Smith said: "This agreement supports our strategic vision of building a leadership position in the central nervous system field.  Because of the excellent working relationship that was established during our collaboration on the PRX1 program we are very excited to broaden our partnership with Proximagen to include this exciting compound.  We are also very pleased to have demonstrated a commitment level to Proximagen that has provided them with the confidence to once again partner with Upsher-Smith."

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About Proximagen

Proximagen is a leading biotechnology company committed to developing novel drugs and innovative new treatments for disorders of the central nervous system, bringing new hope to patients and value to our shareholders. Founded in 2003 as a spin-out from King's College London, Proximagen joined the Alternative Investment Market of the London Stock Exchange in March 2005, raising £13.5 million via a placing. In June 2009, the Company raised an additional £50 million.

Proximagen's growth strategy is science-driven and seeks to balance financial and scientific risk as it develops a pipeline of pre-clinical and clinical stage compounds, using its expertise in neuroscience and drug development. The company takes a flexible approach to how far it develops programmes before partnering, being mindful of a number of factors including development risk, the progress of competitor programmes, its financial position and its belief that the retention of rights to certain territories is an important long-term value driver.

Proximagen's pipeline now comprises a broad portfolio of programmes from discovery through clinical development, addressing a number of therapeutic areas including Parkinson's disease, epilepsy, cognition and neuropathic pain.

The Company continues to expand its drug pipeline through acquisition, in-licensing and partnering, with the aim of becoming one of the world's leading companies developing therapeutics for patients suffering from diseases of the central nervous system.

For more information, please visit the company's website at www.proximagen.com

About Upsher-Smith

Upsher-Smith Laboratories, Inc., founded in 1919, is a rapidly growing, privately held pharmaceutical company that develops, manufactures, and markets branded and branded generic prescription and over-the-counter products.  Upsher-Smith's product portfolio focuses in the areas of women's health, dermatology, cardiology, and central nervous system diseases.  The company's growing CNS pipeline concentrates on diseases with significant unmet need, including epilepsy and Parkinson's disease.  To expand its CNS pipeline, Upsher-Smith seeks alliances and co-development programs, pursues licensing and acquisitions, and leverages the development of its core competency in formulation development. 

For more information, visit www.upsher-smith.com.