Protagonist Therapeutics, Inc., a biopharmaceutical company, discovers and develops peptide-based therapeutic drugs to address hematology and blood disorders, and inflammatory and immunomodulatory diseases.

It is developing rusfertide (PTG-300), an injectable hepcidin mimetic that is in Phase II clinical trials for the treatment of patients with polycythemia vera and hereditary hemochromatosis, as well as for the treatment of other blood disorders; PN-943, an oral, alpha-4-beta-7 integrin- specific antagonist peptide that is in Phase II clinical trials for treating inflammatory bowel disease (IBD); and PN-235, an orally delivered interleukin-23 receptor specific antagonist for the treatment of IBD and non-IBD indications.

The company has a license and collaboration agreement with Janssen Biotech, Inc.

Protagonist Therapeutics, Inc. was incorporated in 2006 and is headquartered in Newark, California.