Re Agreement

ARK THERAPEUTICS GROUP PLC

Ark Therapeutics and PsiOxus Therapeutics enter manufacturing partnership

London, UK - 12 September 2011, Ark Therapeutics Group plc ("Ark") is pleased to announce that it has signed a manufacturing partnership agreement with PsiOxus Therapeutics Ltd ("PsiOxus") under which Ark will provide full manufacturing and related services to support the development of PsiOxus' ColoAd1 programme for the treatment of colorectal cancer. Ark will work with PsiOxus in providing oncolytic adenoviral material for IV administration in toxicological and Phase I/II clinical studies, utilising Ark's suspension based single use system (ATOSUS). Financial details of the agreement were not disclosed.

Martyn Williams, CEO of Ark commented: "We are delighted to announce the partnership with PsiOxus for their highly promising ColoAd1 programme. As well as providing leading edge manufacturing capabilities, PsiOxus will benefit from Ark's experience in the regulatory CMC aspects of developing a gene-based medicine. We look forward to a long and successful partnership."

John Beadle, CEO of PsiOxus, stated: "Of critical importance to us was to choose a manufacturing partner who had not only the relevant manufacturing know-how but also the manufacturing development capability and specific regulatory knowledge to ensure we hit our development timelines through the timely provision of material for final pre-clinical toxicology and clinical phases. We believe Ark has the necessary expertise and experience to do this."

For further information please contact:

Ark Therapeutics Group plc

Ark Therapeutics Group plc is a specialist healthcare group (the "Group") addressing high value areas of unmet medical need within vascular disease and cancer. These are large and growing markets, where opportunities exist for effective new products to generate significant revenues.

Ark has an early stage pipeline emanating from collaborations with University College, London and the AI Virtanen Institute in Kuopio, Finland, the development of which it intends to progress in collaboration with pharmaceutical and biotech partners.

In addition Ark has the ability to off-set a proportion of its R&D costs and to generate sustainable revenues through the exploitation of its proprietary technology platform, process development, scale-up and manufacturing capabilities on behalf of third parties.

Ark has its origins in businesses established in the mid-1990s by Professor John Martin of University College London and Professor Seppo Ylä-Herttuala of the AI Virtanen Institute at the University of Kuopio, Finland, both of whom remain consultants on the Company's research and development programmes.

Ark's shares were first listed on the London Stock Exchange in March 2004 (AKT.L).

PsiOxusTherapeutics, Ltd.

PsiOxus Therapeutics is an Oxford, UK based development stage biotechnology company using non-traditional approaches to develop novel therapeutics that address cancer and other clinically unmet diseases. The Company's lead candidate is MT-102, a dual action Anabolic Catabolic Transforming Agent (ACTA) in phase II clinical development for the treatment of cachexia and sarcopenia. ColoAd1, an oncolytic virus for the systemic treatment of metastatic cancer, has demonstrated optimal anti-cancer properties in late pre-clinical development against a wide range of solid tumours and will enter phase I/II clinical development in 2012. The Company is also developing treatments based upon the research phase vaccine platform PolySTAR, which combines recombinant viral vectors with polymers to shield them from the immune system, and the research phase adjuvant and immunotherapeutic platform PolyMAP, which combines polymers with synthetic adjuvants to significantly enhance the effectiveness of vaccines. www.PsiOxus.com

This announcement includes "forward-looking statements" which include all statements other than statements of historical facts, including, without limitation, those regarding the Group's financial position, business strategy, plans and objectives of management for future operations (including development plans and objectives relating to the Group's products and services), and any statements preceded by, followed by or that include forward-looking terminology such as the words "targets", "believes", "estimates", "expects", "aims", "intends", "will", "can", "may", "anticipates", "would", "should", "could" or similar expressions or the negative thereof. Such forward-looking statements involve known and unknown risks, uncertainties and other important factors beyond the Group's control that could cause the actual results, performance or achievements of the Group to be materially different from future results, performance or achievements expressed or implied by such forward-looking statements. Such forward-looking statements are based on numerous assumptions regarding the Group's present and future business strategies and the environment in which the Group will operate in the future. Among the important factors that could cause the Group's actual results, performance or achievements to differ materially from those in forward-looking statements include those relating to Ark's funding requirements, regulatory approvals, clinical trials, reliance on third parties, intellectual property, key personnel and other factors. These forward-looking statements speak only as at the date of this announcement. The Group expressly disclaims any obligation or undertaking to disseminate any updates or revisions to any forward-looking statements contained in this announcement to reflect any change in the Group's expectations with regard thereto or any change in events, conditions or circumstances on which any such statements are based. As a result of these factors, readers are cautioned not to rely on any forward-looking statement.