Protalix BioTherapeutics has announced the receipt of approval from the Israeli Ministry of Health to initiate a Phase I clinical trial of PRX-112 (Oral GCD), which is the company's orally administered product candidate for treating Gaucher disease. A plant cell-expressed form of the glucocerebrosidase enzyme (GCD), Oral GCD is naturally encapsulated within carrot cells and administered orally. Protalix BioTherapeutics expects to initiate the Phase I trial in two Israeli medical centers within the coming month.
"The majority of currently diagnosed patients with Gaucher disease are treated with biweekly intravenous infusions of enzyme replacement therapy," said Protalix BioTherapeutics President and CEO Dr. David Aviezer. "Having a safe and effective orally available enzyme agent would potentially improve patients' quality of life without compromising on the benefits of enzyme therapy. Our clinical trial programs for IV administered plant cell-expressed GCD have already demonstrated that the enzyme is safe and effective in treating Gaucher disease. Now, in evaluating Oral GCD, our main goal is to achieve therapeutic levels of the enzyme in the bloodstream after oral consumption by patients."
An open label safety and pharmacokinetic study, the Phase I clinical trial is designed to assess the delivery of prGCD after oral administration of Oral GCD in 12 Gaucher patients. The subjects will be given 250mL of re-suspended carrot cells in a single oral administration during the trial's first cohort and three consecutive daily administrations during the trial's second cohort. Protalix BioTherapeutics expects to complete the Phase I trial during the second quarter of 2013.
Oral GCD preclinical studies have demonstrated the stability of the enzyme in the carrot cell as well as the capacity of the cell's cellulose wall to protect the enzyme against degradation in the digestive tract in an in-vitro model of the stomach and intestines. Both rats and pigs that have been fed with PRX 112 (lyophilized carrot cells expressing GCD) have demonstrated enzyme levels in the plasma and accumulation of the active enzyme in target organs like the spleen and liver.
"Our animal studies have already demonstrated the capacity of plant cells to serve as a vehicle for oral administration of other therapeutic proteins," said Dr. Yoseph Shaaltiel, Protalix BioTherapeutics' executive vice president, research & development. "These proteins include, for example, our plant cell-expressed antiTNF fusion protein, a plant cell version of etanercept (Enbrel). Given the results of our preclinical studies, we believe our Oral GCD clinical study will support our belief that we have developed a wider platform for oral protein delivery."
For more information, visit www.protalix.com
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