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Protalix BioTherapeutics Presents Data on the Company's Fabry Program and Oral Enzyme Gaucher Program With Experts in the Field of Lysosomal Disorders

CARMIEL, Israel, Protalix BioTherapeutics, Inc. announced today that management presented data on the Company's preclinical Fabry program and oral enzyme Gaucher program with experts in the field of lysosomal disorders at a Company-sponsored medical meeting which was recently held in New York City.

The primary objective of the meeting was to discuss taliglucerase alfa, the Company's proprietary intravenously administered plant cell expressed form of glucocerebrosidase (GCD) for the treatment of Gaucher disease. Taliglucerase alfa is currently under review in the United States, the European Union, Brazil and other territories. The Company also presented data on the Company's preclinical programs including PRX-102, a modified alpha-Galactosidase-A (alpha-GAL-A) for the treatment of Fabry disease and oral GCD, a naturally encapsulated plant cell expressed form of GCD for the treatment of Gaucher disease.

PRX-102 for the treatment of Fabry Disease

PRX-102 is the Company's proprietary plant cell expressed modified version of the recombinant human alpha-GAL-A protein under development for the treatment of Fabry disease. Fabry disease is a rare hereditary, genetic lysosomal storage disorder caused by an X-linked deficiency of the enzyme alpha-GAL-A. The disease causes harmful accumulations of lipids in the kidneys, autonomic nervous system and cardiovascular system that may lead to kidney failure, increase the risk of heart attack and stroke and can be life-threatening.

In pre-clinical studies, PRX-102 demonstrated preliminary efficacy in a Fabry animal model. Chemical modifications made to the enzyme improved the enzyme activity and stability, resulting in prolonged activity profiles and enhanced bioavailability in animals. The modifications also have the potential to decrease the immunogenicity of the enzyme, which is a major drawback of currently approved therapies for Fabry disease.

The Company recently held a pre-Investigational New Drug (IND) meeting with the U.S. Food and Drug Administration (FDA) regarding PRX-102. The Company plans to submit an IND application this year, and pending approval of the IND, commence clinical studies.

"We believe our proprietary Fabry product has the potential to be a 'best-in-class' enzyme resulting from the unique modifications made to the protein," said Dr. Yoseph Shaaltiel, Protalix's Executive Vice President, Research and Development. "Following the anticipated IND approval, we intend to conduct a phase I/II clinical trial in Fabry disease patients."

Orally-delivered glucocerebrosidase enzyme (GCD) for the treatment of Gaucher disease

Gaucher disease is an inherited, genetic lysosomal storage disorder caused by mutations or a deficiency of the enzyme GCD. The disease causes harmful accumulations of lipids in the spleen, liver, lungs and brain, and affects patients' bones and bone marrow. Oral GCD for the treatment of Gaucher disease is a plant cell expressed form of GCD that is naturally encapsulated within carrot cells genetically engineered to express the GCD enzyme.

Pre-clinical studies of oral GCD demonstrate the stability of the enzyme in the cell and the capacity of the cellulose wall to protect the enzyme against degradation in the digestive tract in an in-vitro model of the stomach and intestines. Additionally, rats fed with lyophilized carrot cells expressing GCD have accumulated the active enzyme in the target organs, the spleen and liver.

The Company's development of an oral delivery of encapsulated GCD has the advantage of leveraging the well-characterized mechanism of action for taliglucerase alfa (an intravenously-delivered plant cell expressed GCD), which has completed phase III clinical trials and has a PDUFA date set by the FDA of February 25, 2011. Furthermore, delivering GCD orally may dramatically change the treatment paradigm for Gaucher patients, as currently approved enzyme replacement therapies are only delivered intravenously.

"Using the plant-cell expression system for oral delivery of GCD is revolutionary because it targets the disease-specific organs without the need for lifetime dependence on repeated intravenous infusions. Moreover, it is unlike substrate reduction therapy which is oral, but may have unpredictable long term untoward effects due to the inhibition of other non-disease-specific compounds. Finally, oral administration of the enzyme for patients with Gaucher disease will increase compliance and facilitate management," said Professor Ari Zimran, Director of the Gaucher Clinic in Shaare Zedek Medical Center, Jerusalem, Israel and lead investigator of the phase III clinical trial of taliglucerase alfa.

The Company intends to initiate phase I clinical trials of oral GCD in healthy individuals who are carriers of Gaucher disease and show reduced enzymatic activity at baseline. The Company expects to present additional data on this program at an upcoming medical meeting.