Protalix is a publicly traded biotechnology company (NYSE Amex: PLX), that is producing recombinant therapeutic proteins through the ProCellEx™ plant cell system.
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taliglucerase alfa :

Our Lead Product Candidate, taliglucerase alfa (prGCD)

taliglucerase alfa (previous scientific name prGCD), our lead proprietary product candidate, is a plant cell expressed recombinant Glucocerebrosidase enzyme (GCD) for the treatment of Gaucher disease. We have successfully completed our pivotal phase III trial in September 2009. The Phase III clinical trial for taliglucerase alfa was a nine month, randomized, double-blind, parallel group, dose-ranging safety and efficacy study in patients with Gaucher disease. The trial met its primary endpoint, mean reduction in spleen volume after nine months compared with baselines, in both 60 U/kg dose and in the lower 30 U/kg dose treatment groups (P<0.0001). The primary endpoint was stipulated in the Special Protocol Assessment (SPA) agreed on by the Company and the U.S Food and Drug Administration (the "FDA") prior to the commencement of the trial. Additionally, the primary endpoint was observed already after six months of treatment in both treatment groups. Statistically significant improvements compared with baselines were also observed in the secondary endpoints, including increase in hemoglobin level, decrease in liver size and increase in platelet count at the 60 U/kg dose. Statistically significant improvements compared with baselines were observed in hemoglobin level and liver size and significant nominal reduction in platelet count in the lower dose of 30 U/kg. The safety analysis for both doses showed that taliglucerase alfa was well tolerated and no serious adverse events were reported. Only 6% of patients in the trial developed antibodies to taliglucerase alfa during the study. None of the patients in the trial developed neutralizing antibodies to taliglucerase alfa . Only 6% of the patients in the trial experienced hypersensitivity. Most adverse events were mild in intensity and not drug related and were transient in nature. The trial was developed under a Special Protocol Assessment (SPA).. The Company’s new drug application (NDA) for taliglucerase alfa has been accepted by the FDA and granted a Prescription Drug User Fee Act (PDUFA) action date of February 25, 2011. In addition, we are conducting a Switch Over study to assess the safety and efficacy of taliglucerase alfa (previous scientific name prGCD). The trial was originally designed to include 15 patients with Gaucher disease that are currently undergoing enzyme replacement therapy with imiglucerase (Cerezyme®), Such trial was amended to include additional patients. Patients with stable disease will be switched from intravenous imiglucerase treatment every two weeks to intravenous infusions of taliglucerase alfa every two weeks for a nine-month period. The taliglucerase alfa 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.In November 2010 we announced positive preliminary data from the first 15 patients that completed the switchover trial. 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® 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. At the end of the nine-month treatment period, all eligible patients from both trials will be offered the opportunity to enroll in the Company's on-going extension study. In addition, the Company is currently making taliglucerase alfa available to Gaucher disease patients in the U.S. and other countries under an Expanded Access Program approved by the FDA In previous clinical trials in healthy subjects and in vivo primate studies, taliglucerase alfa has demonstrated an increased half-life and prolonged presence of the enzyme in the blood serum of the subjects as compared to Cerezyme, the only enzyme replacement therapy currently marketed to treat Gaucher disease. We believe that taliglucerase alfa (previous scientific name prGCD), if approved, has the potential to offer patients and healthcare payers a more effective and cost efficient treatment of Gaucher.

Increased Glycan Efficacy and Consistency

We believe that our ProCellEx™ protein expression system produces recombinant proteins that exhibit consistent enzymatic activity from batch to batch. This results in a highly active product that may achieve a desired therapeutic effect more effectively than the activity demonstrated in proteins produced through mammalian cell-based expression systems due to its greater glycan efficacy and consistency. This quality increases the effective consistency in potency and further increases the cost advantages from using our plant cell-based expression technology compared to competing protein expression methodologies.

Longer Half-Life

The data generated in preclinical and human clinical trials relating to the half-life of prGCD in the subjects' blood serum after infusion showed that the half-life of prGCD is significantly longer than that of Cerezyme when measured and compared to publicly available data on Cerezyme.

Cost-Effective

prGCD is potentially less expensive to produce as the manufacturing process does not require the large initial set-up investments involved in mammalian cell-based protein production, the extensive ongoing costs associated with growth media and monitoring throughout the production process nor any of the post-expression modification costs in order to modify the glycosilation of the proteins produced through the mammalian cell-based methodologies.

As such, we believe that prGCD's potential advantages may lead prGCD to become a highly efficacious and cost-effective treatment alternative for Gaucher disease patients.


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