Organization and Description of Business	6 Months Ended
Jun. 30, 2025
Organization and Description of Business
Organization and Description of Business	Note 1.Organization and Description of Business Protagonist Therapeutics, Inc. (the “Company”) is a discovery through late-stage development biopharmaceutical company focused on peptide therapeutics. The Company’s clinical programs fall into two broad categories of diseases: (i) inflammatory and immunomodulatory (“I&I”) diseases and (ii) hematology and blood disorders. Two novel peptides derived from the Company’s proprietary discovery technology platform, icotrokinra and rusfertide, are currently in advanced Phase 3 clinical development. Icotrokinra is a first-in-class investigational targeted oral peptide that selectively blocks the Interleukin-23 receptor (“IL-23R”) and is licensed to J&J Innovative Medicines (“JNJ”), formerly Janssen Biotech, Inc. Following icotrokinra’s joint discovery by the Company and JNJ scientists pursuant to their IL-23R collaboration, the Company was primarily responsible for the development of icotrokinra through Phase 1, with JNJ assuming responsibility for development in Phase 2 and beyond. In July 2025, a New Drug Application (“NDA”) was submitted to the U.S. Food and Drug Administration (“FDA”) by JNJ seeking the first approval of icotrokinra for the treatment of adults and pediatric patients 12 years of age or older with moderate-to-severe plaque psoriasis. Rusfertide, a first-in-class investigational injectable mimetic of the natural hormone hepcidin, is currently in development for treatment of the rare blood disorder polycythemia vera (“PV”). Rusfertide is being co-developed and will be co-commercialized with Takeda Pharmaceuticals, Inc. (“Takeda”), with the Company remaining primarily responsible for clinical development through a potential NDA filing. The Company also has a number of pre-clinical stage drug discovery programs addressing biologically and commercially validated targets, including IL-17 oral peptide antagonist PN-881, obesity triple agonist peptide PN-477, and oral hepcidin. The Company is headquartered in Newark, California and has one wholly owned subsidiary, Protagonist Pty Limited (“Protagonist Australia”), located in Brisbane, Queensland, Australia. Operating Segments Operating segments are components of an enterprise for which separate financial information is available and is evaluated regularly by the Chief Executive Officer, the Company’s chief operating decision maker (“CODM”), in deciding how to allocate resources and assessing performance. The Company operates and manages its business as one operating segment. The Company’s Chief Executive Officer reviews financial information on an aggregate basis for the purpose of allocating and evaluating financial performance. See Note 10 to these condensed consolidated financial statements for the Company’s interim disclosures related to the adoption of ASU 2023-07 Segment Reporting (Topic 280) Improvements to Reporting Segment Disclosures for interim periods beginning on January 1, 2025. Liquidity As of June 30, 2025, the Company had cash, cash equivalents and marketable securities of $673.0 million. The Company has incurred an accumulated deficit from inception through June 30, 2025 of $386.9 million. The Company’s ultimate success depends upon the outcome of its research and development and collaboration activities. The Company may incur additional losses in the future as it continues rusfertide Phase 3 development activities through a potential NDA filing and invests in its pre-clinical discovery programs and may need to raise additional capital to continue to execute its long-range business plan. Since the Company’s initial public offering in August 2016, it has financed its operations primarily through proceeds from offerings of common stock and payments received under license and collaboration agreements.

Organization and Description of Business

6 Months Ended

Jun. 30, 2025

Organization and Description of Business

Organization and Description of Business

Note 1.Organization and Description of Business

Protagonist Therapeutics, Inc. (the “Company”) is a discovery through late-stage development biopharmaceutical company focused on peptide therapeutics. The Company’s clinical programs fall into two broad categories of diseases: (i) inflammatory and immunomodulatory (“I&I”) diseases and (ii) hematology and blood disorders. Two novel peptides derived from the Company’s proprietary discovery technology platform, icotrokinra and rusfertide, are currently in advanced Phase 3 clinical development.

Icotrokinra is a first-in-class investigational targeted oral peptide that selectively blocks the Interleukin-23 receptor (“IL-23R”) and is licensed to J&J Innovative Medicines (“JNJ”), formerly Janssen Biotech, Inc. Following icotrokinra’s joint discovery by the Company and JNJ scientists pursuant to their IL-23R collaboration, the Company was primarily responsible for the development of icotrokinra through Phase 1, with JNJ assuming responsibility for development in Phase 2 and beyond. In July 2025, a New Drug Application (“NDA”) was submitted to the U.S. Food and Drug Administration (“FDA”) by JNJ seeking the first approval of icotrokinra for the treatment of adults and pediatric patients 12 years of age or older with moderate-to-severe plaque psoriasis.

Rusfertide, a first-in-class investigational injectable mimetic of the natural hormone hepcidin, is currently in development for treatment of the rare blood disorder polycythemia vera (“PV”). Rusfertide is being co-developed and will be co-commercialized with Takeda Pharmaceuticals, Inc. (“Takeda”), with the Company remaining primarily responsible for clinical development through a potential NDA filing.

The Company also has a number of pre-clinical stage drug discovery programs addressing biologically and commercially validated targets, including IL-17 oral peptide antagonist PN-881, obesity triple agonist peptide PN-477, and oral hepcidin.

The Company is headquartered in Newark, California and has one wholly owned subsidiary, Protagonist Pty Limited (“Protagonist Australia”), located in Brisbane, Queensland, Australia.

Operating Segments

Operating segments are components of an enterprise for which separate financial information is available and is evaluated regularly by the Chief Executive Officer, the Company’s chief operating decision maker (“CODM”), in deciding how to allocate resources and assessing performance. The Company operates and manages its business as one operating segment. The Company’s Chief Executive Officer reviews financial information on an aggregate basis for the purpose of allocating and evaluating financial performance. See Note 10 to these condensed consolidated financial statements for the Company’s interim disclosures related to the adoption of ASU 2023-07 Segment Reporting (Topic 280) Improvements to Reporting Segment Disclosures for interim periods beginning on January 1, 2025.

Liquidity

As of June 30, 2025, the Company had cash, cash equivalents and marketable securities of $673.0 million. The Company has incurred an accumulated deficit from inception through June 30, 2025 of $386.9 million. The Company’s ultimate success depends upon the outcome of its research and development and collaboration activities. The Company may incur additional losses in the future as it continues rusfertide Phase 3 development activities through a potential NDA filing and invests in its pre-clinical discovery programs and may need to raise additional capital to continue to execute its long-range business plan. Since the Company’s initial public offering in August 2016, it has financed its operations primarily through proceeds from offerings of common stock and payments received under license and collaboration agreements.