Press release
May 22, 2007

Sosei Announces Successful Completion of AD 923 Pharmacokinetic Study in the USA


Tokyo, Japan – 22 May 2007: Sosei Group Corporation (“Sosei”; TSE Mothers Index: 4565), a biopharmaceutical company, today announces the successful completion of a study of its fentanyl sublingual spray (AD 923), an opioid analgesic for the treatment of cancer breakthrough pain.

This was a pharmacokinetic Phase I single centre, open-label, single dose, crossover, randomised study of AD 923 versus Actiq® (oral transmucosal fentanyl citrate lozenge) and versus fentanyl citrate injection. The study was conducted in healthy human volunteers, under an IND in the United States. All of the primary and secondary objectives of the study were achieved.

The more rapid absorption of fentanyl from AD 923 compared with Actiq® was statistically significant, with substantial plasma exposure seen within 10 minutes. The median Tmax (time to maximum plasma concentration) for AD 923 was 40 minutes compared with 120 minutes for Actiq®. In addition, the higher absolute bioavailability of AD 923 compared with Actiq® was also statistically significant. Both formulations were well tolerated with no significant safety issues identified.

Sosei has reached agreement with EU regulatory authorities to move AD 923 directly into Phase III trials and plan to file a CTA (clinical trial application) in the second half of 2007. Following the outcome of this pharmacokinetic study the company will continue its discussions with the FDA regarding the detailed requirements for the Phase III programme in the USA.

Mr Shinichi Tamura, President & CEO of Sosei, said: "These data demonstrate that AD 923 has the potential to provide significantly faster onset of analgesia compared with existing therapy. Additionally, the higher absolute bioavailability indicates more predictable pain relief across the patient population. These factors together with the ease of administration will provide an optimised product with a rapid onset of action, which is generally recognised as being the most important attribute in the treatment of cancer breakthrough pain. We now look forward to moving this product into Phase III studies.”


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