Protalix Announces New Clinical Data on ELELYSO to be Presented at the WORLD Symposium 2013

Protalix Announces New Clinical Data on ELELYSO to

be Presented at the WORLD Symposium 2013

CARMIEL, Israel, February 13, 2013/GlobeNewswire/Protalix

BioTherapeutics, Inc. (NYSE MKT:PLX, TASE:PLX), announced today that new clinical data on ELELYSO (taliglucerase alfa) will

be presented at the 9th Annual Meeting of the Lysosomal Disease Network: WORLD Symposium 2013 being held February 13-15 in

Orlando, Florida. ELELYSO, the Company's first commercial product, is the first FDA-approved plant cell-based enzyme replacement

therapy for Gaucher disease.

"The data to be presented at

the conference further reinforce the use of ELELYSO as a treatment option for Gaucher patients, including na ve Gaucher patients,

and patients who were previously treated with imiglucerase (Cerezyme )," stated Professor Ari Zimran, M.D., Director

of the Gaucher Clinic in Shaare Zedek Medical Center, Jerusalem, Israel and lead clinical investigator. "With the approval

of ELELYSO in Israel, I am pleased to be able to provide a new treatment option to my patients."

Gregory Pastores, M.D., Professor of

Neurology and Pediatrics and Director of the Neurogenetics Laboratory at the New York University School of Medicine, is presenting

long-term data from the Company's multi-center, open-label switchover extension trial of ELELYSO for the treatment of Gaucher

disease. The Company's original switchover trial was a nine-month trial in which patients with stable disease were switched from

treatment via intravenous infusions of imiglucerase (Cerezyme ) to intravenous infusions of ELELYSO every two weeks at an equivalent

dose to the patient's previous imiglucerase dose. Patients who participated in the switchover trial were given the option to continue

treatment with ELELYSO in the Company's switchover extension trial.

Twenty-five adult patients completed

the switchover trial, of which 19 elected to continue treatment with ELELYSO through the long-term extension trial. Five of the

six patients who did not enroll in the extension trial continued nonetheless to receive ELELYSO through the Company's various compassionate

use programs. One patient was unable to comply with the study protocol and therefore was not eligible to participate in the extension

A 24 month interim analysis of the

switchover trial demonstrates that all patients remained stable with regard to all key disease parameters, spleen volume, liver

volume, platelet count and hemoglobin concentration, as well as the chitotriosidase activity biomarker after switching to ELELYSO

from imiglucerase. The safety analysis presented for the 24-month switchover treatment duration demonstrates that ELELYSO was well

tolerated, and no drug related serious adverse events were reported. One patient developed neutralizing IgG antibodies that were

determined to be positive in an in vitro assay, and were determined to be negative in a cell-based assay. Four of the 19 patients

enrolled in the extension trial discontinued treatment; one switched to the ELELYSO compassionate use program, one enrolled in

another clinical trial, one was unable to comply with the study protocol and one was not pleased with that individual's personal

results. In conclusion, the data demonstrates that ELELYSO has a well-established safety profile and is an effective alternative

treatment for adult Gaucher patients treated previously with Cerezyme.

These results will also be presented

during the poster sessions, which will take place on Wednesday, February 13 from 4:30-6:30 PM ET and on Thursday, February 14 from

Professor Ari Zimran is presenting

a poster describing long-term safety and efficacy data from the Company's double-blind, follow-on extension study of ELELYSO for

the treatment of Gaucher disease in adult na ve patients. Eligible patients who completed treatment in the Company's pivotal

nine-month phase III clinical trial were offered the opportunity to participate in the extension study and continue to receive

ELELYSO at the same dose they received in the pivotal trial for an additional 30 months in a blinded manner. Accordingly, the extension

trial included two treatment groups; one treated with a 60 U/kg dose and the other with a 30 U/kg dose. The primary endpoint of

the extension trial was the percent change from baseline in spleen volume. Major secondary endpoints included percentage change

from baseline in hemoglobin concentration, liver volume, platelet count and chitotriosidase activity. Twenty-six patients enrolled

in the extension trial which was performed in centers throughout Europe, Israel, North America, South America and South Africa.

At thirty-six months of treatment, both the primary and major

secondary efficacy endpoints were achieved. Mean spleen volume decreased 62% and 47% in each of the 60 U/kg dose and 30 U/kg dose

groups, respectively; mean hemoglobin concentration increased by 3 g/dL, from 11.0 g/dL to 14.0 g/dL, in the 60 U/kg dose group

and by 1.9 g/dL, from 12.4 g/dL to 14.3 g/dL, in the 30 U/kg dose group; mean liver volume decreased 19% and 21% in each of the

60 U/kg dose and 30 U/kg dose groups, respectively; mean platelet counts increased by 62,972 /mm3, from 73,055 to 136,027

/mm3, in the 60 U/kg dose group and by 29,783 /mm3, from 64,900 to 94,683/mm3, in the 30 U/kg

dose group; and mean chitotriosidase activity decreased 83.0% and 73.5% for each of the 60 U/kg dose and 30 U/kg dose groups, respectively.

The safety analysis presented for both

treatment groups demonstrates that ELELYSO was well tolerated, and no drug related serious adverse events were reported. Two participants

developed neutralizing IgG antibodies that were determined to be positive in an in vitro assay, and were determined to

be negative in a cell-based assay. In addition, one patient in the 60 U/kg dose group experienced a hypersensitivity reaction during

month 10 of treatment. Treatment of this patient with ELELYSO has been continued with premedication for an additional 44 months

without any treatment related adverse events reported. Three of the 26 participants enrolled in the extension trial discontinued

treatment; one switched into the ELELYSO compassionate use program, one was unable to comply with study protocol and one had a

skin reaction during month 15.

The long-term safety and efficacy results

from the na ve adult patient extension study demonstrate that ELELYSO has a well-established safety profile and is an effective

long-term treatment for Gaucher disease.

Professor Zimran will also present

a poster entitled "A Multicenter, Double-Blind, Randomized Safety and Efficacy Study of Two Dose Levels of Taliglucerase

Alfa in Pediatric Patients with Gaucher Disease." These data were first announced by the Company at the 10th Annual European

Working Group on Gaucher Disease Meeting in June 2012.

of the posters are being posted on the investor relations page of the Company's website, www.protalix.com. The content of

the Company's website is not intended to be incorporated by reference into this press release or in any report or document we file.

Safety Information for ELELYSO

As with any intravenous protein product,

allergic reactions, some severe, were reported in the taliglucerase alfa clinical trials. A definition of anaphylaxis (as defined

by Sampson et al 2006) was retrospectively applied to some of these reports. In patients who have experienced anaphylaxis during

infusion with ELELYSO or with other ERT, caution should be exercised upon retreatment; appropriate medical support should be readily

Infusion reactions (including allergic

reactions), defined as a reaction occurring within 24 hours of the infusion, were the most commonly observed reactions in patients

treated with ELELYSO in clinical studies. The most commonly observed symptoms of infusion reactions were headache, chest pain or

discomfort, asthenia, fatigue, urticaria, erythema, increased blood pressure, back pain and arthralgia, and flushing. Most of these

reactions were mild and did not require treatment intervention.

About Protalix BioTherapeutics, Inc.

Protalix is a biopharmaceutical company focused on the development

and commercialization of recombinant therapeutic proteins expressed through its proprietary plant cell based expression system,

ProCellEx . Protalix's unique expression system presents a proprietary method for developing recombinant proteins in a cost-effective,

industrial-scale manner. Protalix's first approved product manufactured by ProCellEx, ELELYSO (taliglucerase alfa), an enzyme

replacement therapy for the treatment of Gaucher disease, was approved for marketing by the U.S. Food and Drug Administration (FDA)

in May 2012, and by Israel's Ministry of Health in September 2012. Additional marketing applications for taliglucerase alfa have

been filed in other countries. Protalix is partnered with Pfizer Inc. for worldwide development and commercialization, excluding

Israel, where Protalix retains full rights. Protalix's development pipeline also includes the following product candidates: PRX-102,

a modified version of the recombinant human alpha-GAL-A protein for the treatment of Fabry disease; PRX-105, a pegylated recombinant

human acetylcholinesterase in development for several therapeutic and prophylactic indications, a biodefense program and an organophosphate-based

pesticide treatment program; an orally-delivered glucocerebrosidase enzyme that is naturally encased in carrot cells, also for

the treatment of Gaucher disease; pr-antiTNF, a similar plant cell version of etanercept (Enbrel ) for the treatment of certain

immune diseases such as rheumatoid arthritis, juvenile idiopathic arthritis, ankylosing spondylitis, psoriatic arthritis and plaque

psoriasis; and others.

Forward Looking Statements

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. The terms "anticipate," "believe," "estimate," "expect"

and "intend" and other words or phrases of similar import are intended to identify forward-looking statements. 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