CARMIEL, Israel—The small Israeli biotech company Protalix Biotherapeutics, Inc. has already produced a biosimilar that may cut into Genzyme's market for Cerezyme treatment for Gaucher's Disease and is now going after Amgen Wyeth's Enbrel™ (etanercept). Protalix has just reported promising data on a recombinant anti-TNF treatment that might compete with etanercept for rheumatoid arthritis, psoriasis, and related conditions.

Unlike its larger competitors, Protalix uses a plant cell culture system to produce these therapeutic recombinant proteins. The company recently 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.

According to the company, 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.

"We are very encouraged by the preclinical data generated from our pr-antiTNF thus far," said Dr. Yoseph Shaaltiel, Executive Vice President, R&D of Protalix. "These data further validate our ProCellEx™ technology and its ability to produce a wide range of complex therapeutic proteins in plant cells. Given our highly efficient and cost effective manufacturing process, we feel the company is well positioned to be an active participant in the biosimilar market."