Protalix Biotherapeutics reported preclinical data on pr-antiTNF, a biosimilar version of etanercept (Enbrel). Produced using the company's proprietary ProCellEx technology, pr-antiTNF is a plant cell–expressed recombinant fusion protein made from the soluble form of the human TNF receptor (TNFR), fused to the Fc component of a human antibody IgG1 domain. Pr-antiTNF has an identical amino acid sequence to Enbrel. In vitro and preclinical animal studies have demonstrated that pr-antiTNF exhibits similar activity to Enbrel. Specifically, pr-antiTNF binds TNF-alpha thereby inhibiting it from binding to cellular surface TNF receptors and protects L929 cells from TNF-induced apoptosis in a dose-dependent manner. In a proof-of-concept in vivo study using an established arthritis animal model, pr-antiTNF administered intraperitoneally significantly improved the clinical arthritis parameters associated with this accepted arthritis mouse model, including joint inflammation, swelling and tissue degradation. Data from the collagen-induced arthritis animal model studies are expected to be presented at an upcoming scientific conference.