Positive Data from taliglucerase alfa Switchover Trial

Protalix BioTherapeutics, Inc. announced positive preliminary data from the first 15 patients that completed the Company's nine month, worldwide, multi-center, open-label, switchover trial of taliglucerase alfa for the treatment of Gaucher disease under a protocol cleared by the U.S. Food and Drug Administration (FDA). The data indicate that patients can safely be switched to taliglucerase alfa from imiglucerase (Cerezyme(R)).

Patients enrolled in the trial were switched from imiglucerase (doses ranging from 10-60 U/kg every other week) to an equivalent dose using the same number of units of taliglucerase alfa. The data from the first 15 patients demonstrate that maintenance of efficacy was achieved over a nine month period with no increased safety concerns. Patients' hemoglobin and platelet counts remained stable demonstrating hematological stability. As measured by MRI, mean spleen volume and liver volume also remained stable. There was no evidence of increased safety concerns in patients switched from Cerezyme(R) to taliglucerase alfa and there were no drug related serious adverse events. Hypersensitivity reactions were not reported in this patient group. One patient developed non-neutralizing IgG antibodies to taliglucerase at the end of the study. Detailed data will be presented at an upcoming medical meeting.

The switchover trial was originally designed and cleared by FDA to enroll 15 patients, however, it was expanded to recruit a total of 30 patients as a result of the shortage of enzyme replacement therapy for Gaucher patients. Adult enrollment in the study has closed; pediatric enrollment remains open.

"We are pleased with the interim results of the switchover trial to taliglucerase alfa," said Dr. David Aviezer, the Company's President and Chief Executive Officer. "Through our Phase III pivotal and extension trial, pediatric study in naïve patients, switch-over trial, expanded access and named patient programs, ATU program in France and supply agreement in Brazil, we are generating a robust clinical database for taliglucerase alfa."

Taliglucerase alfa is under review by the U.S. Food and Drug Administration with a Prescription Drug User Fee Action (PDUFA) date scheduled for February 25, 2011.