Press release
Sep 5, 2005

Arakis Commences Phase IIB Trial for Rheumatoid Arthritis Drug

Tokyo, Japan / Little Chesterford, UK – 5 September 2005: Sosei Co. Ltd. (“Sosei”), a leading Japanese biopharmaceutical company, today announces that its wholly-owned subsidiary Arakis Ltd (“Arakis”), has commenced a Phase IIb dose ranging study of AD 452, a novel, small molecule, disease modifying anti-rheumatic drug (DMARD), designed to reduce joint inflammation and destruction, pain, and preserve mobility.

The study is a randomised, multi-centre, double blind, placebo controlled 12 week trial designed to evaluate the efficacy and safety of AD 452 on a background of methotrexate in patients with active rheumatoid arthritis (RA). A total of at least 292 patients in four treatment groups will be enrolled at study centres in Europe and the USA. Efficacy will be assessed using ACR 20 and DAS 28 (see glossary). The trial is being undertaken under US and EU regulatory authorisations and will take approximately one year to complete.
Results from the earlier Phase IIa trial completed in April 2005 confirmed that AD 452 has an attractive pharmacokinetic profile following once-daily oral dosing and was well tolerated at the three dose levels tested.

RA is a type of chronic arthritis or inflammation of the lining of the joints with the potential to affect the entire body. Symptoms include joint pain, stiffness, warmth, redness and swelling. It may also include bone and cartilage breakdown, loss of joint shape, alignment and movement. Although the exact cause of RA is unknown, there appears to be a genetic component and an external trigger to the body’s immune system causing it to attack healthy joint tissue. The prevalence of RA is estimated at 1% of the population worldwide which equates to approximately six million people; 75% of whom are women. Significantly, after ten years of RA, fewer than 50% of patients can continue to work or function normally on a day to day basis. The market for RA drugs is currently worth some $5.5 billion and is forecast to almost double to $10.5 billion by 2008.

Shinichi Tamura, Chief Executive Officer of Sosei, said: “RA is a particularly debilitating disease, but the utility of the therapies presently available is often limited by efficacy, side effect or cost considerations. Rheumatologists still need more ways to treat RA due to its variable and long-term nature. We believe that a safe and effective small molecule cytokine modulator, such as AD 452 used in combination with methotrexate, could significantly enhance available treatment options and provide valuable patient benefits.”

Notes to Editors:


ACR scores: the widely accepted composite scale of improvement in RA, developed by the American College of Rheumatology (ACR). The number refers to the percentage improvement in swollen joint count, tender joint count and three or more of the following measures: patient’s own assessment of disease activity; physician assessment of disease activity; patient’s own assessment of RA pain; acute-phase reactant (ESR, CRP) and disability questionnaire.

DAS or Disease Activity Score: is a composite measure which is used to assess disease activity in patients with RA. DAS28 (CRP) incorporates the measurement of the number of tender and swollen joints, C-reactive protein and patient global assessment.

Current treatment regime for patients with RA
Small molecule Disease Modifying Anti-Rheumatic Drugs or DMARDs are typically used in the early treatment of RA to slow down the progression of the disease. Methotrexate is currently the most commonly prescribed DMARD. However, treatment is often discontinued for reasons of limited efficacy or side effects. For more severe or advanced conditions, the newer biological DMARDs may to be used, but only as a second or third line treatment due to their high cost, currently in excess of $10,000 per patient per year, and potential side effects. Side effects from DMARDs include increased susceptibility to infection, hair loss, the suppression of blood cell formation in bone marrow, kidney or liver damage.

About Sosei
Sosei Co. Ltd., founded in 1990 by Shinichi Tamura, the former CEO of Genentech Japan, is a leading Japanese biopharmaceutical company with significant expertise in drug development. It enriches its core product pipeline by in-licensing compounds from Western and Japanese companies, by its distinctive Drug Reprofiling Platform® (DRP®) and through new molecular entity (NME) research programmes in collaboration with biopharmaceutical companies and universities both in Japan and the West.

Sosei is also developing its own sales and marketing organization in Japan. The company is capitalising on its extensive global network established over the past 10 years in its successful technology transfer business.

About Arakis
Arakis is a UK based biopharmaceutical company that discovers, develops and commercialises innovative medicinal products based on established drugs and drug templates. Its main therapeutic areas are inflammatory disease and pain.

Arakis has four products in clinical development: AD 237 for chronic obstructive pulmonary disease (COPD) and AD 452 for rheumatoid arthritis (RA) which have completed Phase IIa trials and AD 337 for fibromyalgia syndrome and AD 923 for cancer breakthrough pain (CBP) which are in Phase I. In addition, there is a preclinical pipeline of other opportunities, two exploratory developments and a number of research projects.

Sosei acquired Arakis in August 2005.