Protagonist Therapeutics, Inc

Protagonist Therapeutics, Inc. (NASDAQ: PTGX) is an integrated discovery and development company focused on creating medicines for inflammatory and immunology disorders, hematologic conditions, and metabolic diseases. The company operates through a proprietary technology platform built around constrained peptides, which are smaller than antibody-based drugs yet large enough to bind difficult therapeutic targets while enabling oral delivery.

The company's lead program, Icotyde (icotrokinra), is a first-in-class oral peptide IL-23 receptor antagonist licensed to Johnson & Johnson's Janssen Biotech division. Icotyde targets moderate-to-severe plaque psoriasis and other IL-23-mediated diseases, with regulatory submissions filed to the FDA and European Medicines Agency in 2025. Protagonist retains eligibility for up to $630 million in future development and sales milestones plus royalties ranging from six to ten percent on net worldwide sales.

Rusfertide, a first-in-class injectable hepcidin mimetic, addresses polycythemia vera, a rare blood disorder characterized by overproduction of red blood cells. Protagonist partnered with Takeda Pharmaceuticals in January 2024, receiving a $300 million upfront payment and remaining eligible for up to $975 million in additional milestone payments. The companies submitted an NDA to the FDA in December 2025, with Takeda expecting a 2026 launch.

The company's wholly-owned pipeline includes PN-881, an oral IL-17 antagonist in Phase 1 development for immune-mediated skin diseases; PN-477, a triple GLP-1/GIP/glucagon receptor agonist peptide for obesity with both oral and subcutaneous formulations; PN-458, a dual GLP-1/GIP receptor agonist also in development for obesity; and PN-8047, an oral hepcidin functional mimetic for polycythemia vera. As of fiscal year-end 2025, the company maintained cash, cash equivalents, and marketable securities of approximately $646 million, positioning it to advance its clinical development programs while awaiting potential regulatory approvals and commercial launches of its partnered products.