PROTALIX BIOTHERAPEUTICS, INC. (PLX)

[genisi]

About 15% of the patients develop antibodies to the current commercially available recombinant human glucocerebrosidase, expressed in CHO cells. There were worries that prGCD being a plant-derived glycoproteins (since higher number of mannose residues may result in increased immunogenicity due to the presentation of nonmammalian glycans), might be associated with excessive immunogenicity effects or excessive neutralizing antibody formation, beyond that the standard rate seen for recombinant therapeutic proteins. But that was not the case with PLX's glucocerebrosidase. Also the antibodies found in the switchover trial were not neutralizing antibodies.