Protalix is developing an orally delivered glucocerebrosidase (GCD) enzyme for the potential treatment of Gaucher disease. Oral GCD is a plant cell-expressed form of GCD that is naturally encapsulated within carrot cells that are genetically engineered to express the GCD enzyme. Plant cells have the unique attribute of a cellulose cell wall which makes them resistant to enzyme degradation when passing through the digestive tract. The plant cell itself serves as a delivery vehicle to get the enzyme in active form to the bloodstream.
Oral Glucocerebrosidase Clinical Status:
Protalix has initiated a Phase I clinical trial of oral GCD in Israel. It is an open label safety and pharmacokinetic study designed to assess the delivery of plant recombinant human glucocerebrosidase (prGCD) after oral administration of Oral GCD in 12 Gaucher patients. Patients will receive re-suspended carrot cells in a single oral administration during the first cohort of the trial and three consecutive daily administrations during the second cohort of the trial. Protalix expects the trial to be completed during the third quarter of 2013. More details of the trial can be viewed on clinicaltrials.gov.
Preclinical studies of oral GCD demonstrate the stability of the enzyme in the carrot cell and 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. In vivo models have demonstrated enzyme levels in the plasma and accumulation of the active enzyme in target organs such as the spleen and liver.
Presentation: Using Plant Cells for Oral Delivery of Therapeutic Proteins ( View a PDF )