Press release
Jan 6, 2010

Update on Phase I Clinical Study of RS(+) Mefloquine for Malaria

Tokyo, Japan – 6 January 2010: Sosei Group Corporation (“Sosei”; TSE Mothers Index: 4565), the biopharmaceutical company, today announced that Treague Limited, a Cambridge, UK based pharma company and Medicines for Malaria Venture (MMV), a Geneva-based not-for-profit organisation, have reported the results of their comparative Phase I study of the single enantiomer, RS(+) mefloquine for the treatment of malaria.

Although the two active study drugs had different side effect profiles, the trial was not able to achieve its clinical objective of demonstrating a substantially superior safety profile for the single enantiomer compared with racemic mefloquine. Accordingly, Treague and MMV have decided to terminate the project.

Sosei licensed its Intellectual Property and Know How relating to the RS(+) isomer of mefloquine to Treague in November 2008 having previously investigated the compound as a treatment for rheumatoid arthritis.