Protalix BioTherapeutics Completes Phase I Clinical Trial for PRX-105

Protalix BioTherapeutics Completes Phase I Clinical Trial for PRX-105

CARMIEL, Israel, June 8, 2010 /PRNewswire-FirstCall/ 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

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.

Protalix is a biopharmaceutical company focused on the development and commercialization of

proprietary recombinant therapeutic proteins expressed through its proprietary plant cell based

expression system. Protalix s ProCellEx presents a proprietary method for the expression of

recombinant proteins that Protalix believes will allow for the cost-effective, industrial-scale

production of recombinant therapeutic proteins in an environment free of mammalian components and

viruses. Protalix is also advancing additional recombinant biopharmaceutical drug development

programs. Taliglucerase alfa is an enzyme replacement therapy in development under a Special

Protocol Assessment with the FDA for Gaucher disease.

In August 2009, the FDA granted orphan drug status and fast track designation to taliglucerase alfa

for the treatment of Gaucher disease and Protalix filed a rolling NDA submission with the FDA in

December 2009. In November 2009, Protalix granted Pfizer Inc. exclusive, worldwide rights to

develop and commercialize taliglucerase alfa for the treatment of Gaucher disease, except in

Israel. Protalix retained the right to commercialize taliglucerase alfa in Israel.

Safe Harbor Statement

To the extent that statements in this press release are not strictly historical, all such

statements are forward-looking, and are made pursuant to the safe-harbor provisions of the Private

Securities Litigation Reform Act of 1995. These forward-looking statements are subject to known

and unknown risks and uncertainties that may cause actual future experience and results to differ

materially from the statements made. These statements are based on our current beliefs and

expectations as to such future outcomes. Drug discovery and development involve a high degree of

risk. Factors that might cause material differences include, among others, risks relating to: the

successful completion of our clinical trials; the review process of the FDA, the EMEA, other

foreign regulatory bodies and other governmental regulatory bodies, including the FDA s and the

EMEA s review of any filings we make in connection with the treatment protocol for taliglucerase

alfa; delays in the FDA s, the EMEA s or other health regulatory authorities approval of any

applications we file or refusals to approve such filings, including the NDA we filed with the FDA

or taliglucerase alfa for the treatment of Gaucher disease; refusals by such regulatory authorities

to approve the marketing and sale of a drug product even after acceptance of an application we file

for any such drug product; and other factors described in our filings with the Securities and

Exchange Commission. Companies in the pharmaceutical and biotechnology industries have suffered

significant setbacks in advanced or late-stage clinical trials, even after obtaining promising

earlier trial results or in preliminary findings for such clinical trials. Further, even if

favorable testing data is generated by clinical trials of drug products, the FDA, EMEA or any other

foreign regulatory authority may not accept or approve an NDA filed by a pharmaceutical or

biotechnology company for such drug product. Failure to obtain approval from the FDA, EMEA or any

other foreign regulatory authority of any of our drug candidates in a timely manner, if at all,

will severely undermine our business and results of operation by reducing our potential marketable

products and our ability to generate corresponding product revenues. The statements in this

release are valid only as of the date hereof and we disclaim any obligation to update this

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