Protagonist Therapeutics, Inc Stock: price and directors' dealings · United States · SEC (Form 4)

About Protagonist Therapeutics, Inc

Protagonist Therapeutics, Inc. is a U.S.-listed biopharmaceutical company traded on the NASDAQ (NYSE/NASDAQ universe), headquartered in Newark, California, in Silicon Valley, United States. The company was built around a peptide-based discovery platform aimed at engineering structurally constrained therapeutic peptides that can preserve some of the selectivity and potency associated with biologics while offering a development profile that may be more practical than traditional antibody programs in certain settings. For equity investors, Protagonist is best viewed as a development-stage biotech: its valuation is driven primarily by clinical, regulatory, and partnering milestones rather than mature product revenue. ([sec.gov](https://www.sec.gov/Archives/edgar/data/1377121/000110465926019696/ptgx-20251231x10k.htm?utm_source=openai)) Historically, Protagonist has focused on transforming its proprietary science into drug candidates against biologically validated targets. Its strategy combines internal R&D with selective partnerships, allowing the company to advance high-value assets while preserving optionality through licensing economics. The company also describes itself as having a global footprint, with operations in Newark and Brisbane, Australia, reflecting an execution model that is not purely domestic even though its corporate headquarters and stock market listing are in the United States. ([protagonist-inc.com](https://www.protagonist-inc.com/locations?utm_source=openai)) The core business lines are centered on immunology, inflammation, and selected hematology/metabolic opportunities. The most advanced program is rusfertide, a hepcidin functional mimetic being developed for polycythemia vera (PV). According to recent SEC filings and company updates, a New Drug Application was submitted in 2025 and the program was under priority review in 2026. Protagonist has also expanded its preclinical pipeline with PN-8047, an oral hepcidin mimetic, plus obesity assets such as PN-477 and PN-458, and an oral IL-4R alpha antagonist for atopic dermatitis and moderate-to-severe asthma. ([sec.gov](https://www.sec.gov/Archives/edgar/data/1377121/000110465926055661/ptgx-20260331x10q.htm?utm_source=openai)) In competitive terms, Protagonist is not a large-scale commercial pharma company; rather, its competitive position depends on scientific differentiation, the novelty of its peptide platform, and the ability to convert pipeline progress into partnering value. That is why collaborations matter so much to the investment case. The company’s arrangements with Takeda and Johnson & Johnson provide access to potential milestones, royalties, and commercial economics while reducing some development risk. In 2026, the company disclosed a $50 million milestone related to FDA approval of icotytde, and it also exercised its right to opt out of the U.S. profit-and-loss sharing structure with Takeda for rusfertide, reshaping the future economics of that asset toward a royalty-based model. ([sec.gov](https://www.sec.gov/Archives/edgar/data/1377121/000110465926055661/ptgx-20260331x10q.htm?utm_source=openai)) Recent news underscores a catalyst-rich profile. Protagonist reported full-year 2025 results in February 2026, followed by a first-quarter 2026 update in May 2026. Those releases highlighted continued investment in discovery and development, a larger preclinical pipeline, and ongoing regulatory progress on rusfertide. For investors in France, Belgium, and Switzerland, the key takeaway is that PTGX remains a classic NASDAQ biotech story: high scientific optionality, meaningful partnering validation, and substantial upside or downside tied to clinical readouts and FDA decisions in the United States. ([sec.gov](https://www.sec.gov/Archives/edgar/data/0001377121/000110465926055629/tm2613550d1_ex99-1.htm?utm_source=openai))