The Company has tested the efficacy of PAN-811 in a standard animal model of stroke in which the middle cerebral artery of a rat is surgically occluded for a period of 2 hours (MCAo).  Following arterial occlusion, an area of cell death (necrosis) develops as a result of the sudden arrest of circulation. After this period the artery is opened up and the neural tissue is reperfused. In order to measure the resultant neural damage, animals are sacrificed 24 hours after MCAo and brain slices are stained with a dye that stains live cells.  Neurons that do not stain or show a reduced level of staining make up the core and penumbra of the infarct. Using computer assisted image reconstruction the total infarct volume can be determined.

Initial experiments involved the treatment of rats 10 minutes prior to MCAo with a 1 mg/kg I.V. injection of PAN-811; this pre-treatment resulted in a 23% reduction in total infarct volume. A subsequent experiment investigated treatment with the same dose of drug but delivered one hour after initiation of arterial occlusion.  In this case the neuroprotection, due to treatment with PAN-811, was on the order of 35%. A third experiment investigated dose escalation of PAN-811 via i.c.v. delivery and demonstrated even greater efficacy (59% at 10µg/rat) with even higher doses expected to be even more efficacious.

Currently further preclinical experiments are being performed and the Company expects to be ready to initiate clinical studies with this drug in the near future.