PAT-SC1 Overview

In October 2009, Patrys acquired the rights to PAT-SC1 from Debiovision Inc., a member of the global drug development Debiopharm Group.

PAT-SC1 was the first of the Patrys’ IgM antibodies to be used in a clinical trial conducted at the University of Würzburg Medical Centre in Germany. Between 1997 and 2001, 51 patients with CD55-positive gastric cancer were treated with a single intravenous low dose of PAT-SC1 48 hours prior to surgery. Of those 51 patients treated, 35 of them had no evidence of metastatic disease at operation and were classified as having R0 stage disease. Patients did not receive any additional treatment (radiotherapy or chemotherapy).

Survival of these patients has been followed over time and compared to a historic control group of patients with R0 stage gastric cancer who did not receive PAT-SC1 before surgery. Ten year follow-up data is now available on 30 of the PAT-SC1 treated patients. Fifty-five per cent of these patients are still alive whilst only 30% of the control group have survived, indicating that the treatment of gastric cancer patients with PAT-SC1 confers a significant survival benefit.  There are no broadly effective treatments for gastric cancer, as evidenced by the fact that 80% of patients die within five years of diagnosis.

PAT-SC1's target/antigen, CD55^PAT-SC1, is an isoform of the membrane-bound CD55 (DAF-B) ("wild-type CD55").  CD55^PAT-SC1 has been shown to be significantly over-expressed on the membrane of gastric cancer tissues (74%), while no expression has been detected on healthy cells and tissues.

While Patrys is the only company to identify a cancer-specific form of CD55, extensive third party literature has reported wild-type CD55 to play a role in cancer differentiation, migration and tissue invasiveness.  Patients with CD55+ expressing tumours are more likely to have a poor prognosis.

The Company expects that it will take approximately 12 months to reach large scale production levels of PAT-SC1 in the PER.C6® cell line, at which time Patrys intends to either advance the product into Phase II clinical trials for the treatment of gastric cancer patients (subject to financing) or partner the product.

Recent PAT-SC1 Milestones

• Completion of acquisition of PAT-SC1 from Debiopharm
• Adaptation to Patrys’ proprietary manufacturing platform
• Confirmation of U.S Orphan Drug Designation for PAT-SC1

Upcoming PAT-SC1 Events

• Completion of manufacturing to support clinical trial
• Commencement of Phase II clinical trial as either internal or partnered product