Protalix BioTherapeutics Announces First Patient Enrolled in Open-Label, Switchover Trial of prGCD for the Treatment of Gaucher Disease

PRESS RELEASE:

Protalix BioTherapeutics, Inc. (Amex: PLX), announced today enrollment of the first patient in a worldwide, multi-center, open-label, switchover trial to assess the safety and efficacy of prGCD. prGCD is the Company's proprietary plant cell expressed recombinant form of human glucocerebrosidase (GCD) that is in development for the treatment of Gaucher disease, a rare and serious lysosomal storage disorder in humans. The trial is designed to include 15 patients with Gaucher disease that are currently undergoing enzyme replacement therapy with imiglucerase (Cerezyme®).

Patients that are eligible for the switchover trial will be evaluated to establish the stability of their disease. In the trial, patients with stable disease will be switched from intravenous imiglucerase treatment every two weeks to intravenous infusions of prGCD every two weeks for a nine-month period. The prGCD dose administered to each patient will be equal to the patient's previous imiglucerase dose and the infusions will be administered at selected investigational sites. At the end of the nine-month treatment period, all eligible patients will be offered the opportunity to enroll in the Company's on-going extension study.

"We are pleased to announce the initiation of our switchover trial," said Dr. Einat Brill-Almon, Vice President of Product Development at Protalix BioTherapeutics. "While this trial is not required by the FDA for the approval of prGCD, we believe the results of the trial will demonstrate the safe and efficacious transition of Gaucher patients, who are currently undergoing other treatments, to our novel drug. Data from this trial should provide additional confidence to physicians regarding our treatment for Gaucher disease and provide support for the widespread use of prGCD."

prGCD is also currently being evaluated in a pivotal phase III, multi-center, randomized, double-blind, parallel group, dose-ranging trial to assess the safety and efficacy of prGCD in naive patients suffering from Gaucher disease. The Company has completed patient enrollment in the phase III clinical trial and plans to announce top-line results in the second half of 2009. The Company expects to file a New Drug Application with the United States Food and Drug Administration in the fourth quarter of 2009.