Protalix BioTherapeutics reports positive results from PRX-105 Phase I clinical trial

Protalix BioTherapeutics, Inc. (NYSE-Amex: PLX) announced today the completion of its phase I clinical trial of PRX-105, a plant cell expressed pegylated recombinant human acetylcholinesterase in development for biodefense indications.  The trial established the pharmacokinetics of the protein and demonstrated that single dose, intravenous administration of PRX-105 is safe and well tolerated.

"We are very pleased with the favorable safety and pharmacokinetic results from our phase I clinical trial of PRX-105," said Dr. David Aviezer, Protalix's President and Chief Executive Officer.  "The positive results also provide further validation of the safety and breadth of our ProCellEx™ plant cell based expression system."

The Company plans to perform additional safety studies in healthy volunteers and animals in collaboration with civil and military agencies in the United States and Israel, for which discussions have been initiated.  Given the nature of the biodefense indications for which the Company is developing PRX-105, efficacy trials of PRX-105 in humans (phase II and phase III) are not required.

The phase I clinical trial of PRX-105 is a first in human, open label, non-randomized, single-dose study.  PRX-105 is administered intravenously by slow bolus injection to 10 healthy volunteers in the trial.  The trial is being conducted in collaboration with Professor Hermona Soreq, from the Hebrew University in Jerusalem, Israel, a world leader in the field of acetylcholinesterase research.  The production of PRX-105 is based on patents that were licensed to Protalix Ltd. by Yissum, the Technology Transfer Company of the Hebrew University, Jerusalem.

Pre-clinical studies have indicated that PRX-105 successfully protects animals exposed to organophosphate nerve gas agent analogs, in both the prophylactic and post-exposure settings.