Protagonist Therapeutics announced the initiation of dosing in a Phase I healthy volunteer study of PTG-200, a potential first-in-class, gastrointestinal-restricted, oral peptide interleukin (IL)-23 receptor antagonist. PTG-200 works by blocking the IL-23 pathway, a mechanism that has been targeted by currently marketed injectable antibody treatments for inflammatory bowel disease (IBD) and other autoimmune conditions.

"We are very pleased to initiate this first-in-human trial of PTG-200," said Richard S. Shames, M.D., Protagonist Therapeutics Chief Medical Officer. "There remains a significant need for novel improved therapies in inflammatory bowel disease. An oral treatment could offer significant advantages, including improved patient convenience and compliance, and the potential for improved safety and tolerability."

The Phase 1 study, which is being conducted in Australia, is a randomized, double-blind, placebo-controlled, single and multiple dose-escalation trial in approximately eighty healthy volunteers. The study will be conducted in three parts: single-ascending doses of PTG-200; multiple ascending doses; and a single dose cross-over, comparing tablet to capsule formulations of PTG-200. Primary endpoints for the study are safety and tolerability of PTG-200. Secondary endpoints include the identification of the maximally tolerated dose and evaluation of pharmacokinetic and pharmacodynamic parameters.

Protagonist is developing PTG-200 in collaboration with Janssen Biotech, which has licensed the worldwide rights to PTG-200 for all indications including IBD.