Protalix BioTherapeutics Treatment for Ulcerative Colitis Shows Positive Data

Israel-based Protalix Biotherapeutics, Inc. believes it’s on the right track in developing an oral medicine for ulcerative colitis that could potentially replace current TNF-inhibitor therapies that are administered via injection or infusion.

This morning the company announced positive results from its Phase II clinical trial testing its plant cell therapy OPRX-106. The Protalix drug candidate is a plant cell-expressed recombinant human tumor necrosis factor receptor II fused to an IgG1 Fc domain (TNFRII-Fc). The medication is designed to be delivered orally. When it is passing through the digestive tract the company said the plant cells in OPRX-106 function as a natural delivery vehicle. The investigational treatment is biologically active in the gut without triggering the formation of anti-drug antibodies, which is an issue with current TNF-inhibitors.

Yaron Ilan, a gastroenterologist at The Hadassah Hebrew University Medical Center in Jerusalem, said the data from the trial suggests that OPRX-106 could address a large unmet need in the treatment of ulcerative colitis.

"OPRX-106 has the potential to address the partial loss of response seen in anti-TNF alpha treatment, which is driven by the high presence of neutralizing antibodies," Ilan said in a statement. "In addition, by being delivered orally, OPRX-106 could potentially avoid certain side effects, such as malignancies and opportunistic infections, which currently appear in the black box warning of the prescribing information for commercially-available anti-TNF alpha biologics."

Although the Phase II trial was small, Protalix said the results were quite promising. The trial included a total of 24 patients with active mild to moderate ulcerative colitis. Only 18 of those patients actually completed the study.

Patients were randomized to receive either 2mg or 8 mg doses of OPRX-106 daily for eight weeks. The company said 67 percent of patients experienced a clinical response with 28 percent seeing a clinical remission. Additionally, the company said 72 percent of patients showed improvements in stool functions, including a reduction in rectal bleeding and inflammation. A total of 61 percent of the patients showed improvements in their Geboes score, which is an assessment of disease activity in ulcerative colitis. Protalix said it intends to release full results of the Phase II trial later this year.

Protalix said OPRX-106 was safe and well tolerated. Headaches were the most common adverse event. Most importantly no anti-drug antibodies were detected, the company said.

Protalix Chief Executive Officer Moshe Manor expressed his excitement for the Phase II results.

"They demonstrate efficacy and a lack of immunogenicity together with a favorable safety profile, which could potentially overcome one of the most challenging drawbacks of current ulcerative colitis therapies administered via injection and infusion," Manor said in a statement.

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