Protalix Says New Clinical Data on ELELYSO Will Be Presented at WORLD Symposium

Protalix BioTherapeutics, Inc.

, 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 naïve 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 trial. 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 4:30-6:00 PM ET. 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 naïve 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 /mm^3, from 73,055 to 136,027 /mm^3, in the 60 U/kg dose group and by 29,783 /mm^3, from 64,900 to 94,683/mm^3, 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 naïve 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. Copies 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.