argenx Eyes 'Oral Drugs'... Hanall, Celltrion Face FcRn Differentiation Challenge

argenx Acquires All Remaining Shares in UNP
FcRn Competition May Shift Toward Ease of Administration
Hanall Biopharma and Celltrion Still Face the Challenge of Differentiation

argenx, which pioneered the Fc receptor (FcRn) market with Vyvgart, a treatment for autoimmune diseases, is expanding its reach by acquiring a U.S. peptide drug discovery company. The move is seen as an effort to broaden its portfolio beyond injectable drugs to include oral and long-acting medicines. As competition in the FcRn market is increasingly likely to shift from efficacy to ease of administration, the calculations of Korean companies entering the market have also become more complex.

According to industry sources on Nov. 12, argenx said it signed a definitive agreement on Nov. 9 (local time) to acquire all remaining shares in U.S.-based Unnatural Products (UNP). The total transaction is valued at up to $1.15 billion (approximately KRW 1.67 trillion). The deal is structured to include an upfront payment of $550 million (approximately KRW 800 billion) from argenx's cash reserves, with up to an additional $595 million (approximately KRW 860 billion) payable upon the achievement of development and regulatory milestones. The boards of both companies have approved the deal, which is expected to close by the end of this year.

Industry analysts say the deal signals that argenx, a leading player in the FcRn inhibitor market, is preparing to expand in earnest into treatments focused on ease of administration. UNP is a U.S. biotech company that discovers oral macrocyclic peptides. It has been working with argenx under a joint research agreement since last year, 2025. Macrocyclic peptides are drugs made by forming amino acid chains into rings. Their strength lies in their ability to precisely target molecules like antibodies while also being formulated as oral medicines like small-molecule compounds.

As competition among FcRn inhibitors is increasingly likely to shift toward formulation, Korean companies are also expected to face growing challenges. If oral drugs or medicines with longer dosing intervals enter the market, later entrants will need to demonstrate differentiation not only in efficacy and safety but also in ease of administration to remain competitive. Hanall Biopharma and Celltrion are among the leading Korean companies developing FcRn inhibitors. FcRn is a receptor that extends the lifespan of immunoglobulin G (IgG) antibodies in the body. Blocking it can reduce disease-causing autoantibodies and alleviate symptoms.

IMVT-1402, which Hanall Biopharma licensed to U.S.-based Immunovant, is preparing to enter the market after achieving clinical development milestones. In a recently disclosed clinical trial for treatment-resistant rheumatoid arthritis, the 600 mg dose group met the primary endpoint. The company plans to report results from registration trials for Graves' disease and myasthenia gravis in 2027. Developing argenx's peptide platform into specific drug candidates and clinical results will take considerable time, making it a priority to demonstrate competitiveness in ongoing clinical trials.

Celltrion is developing a next-generation FcRn inhibitor that prioritizes lasting efficacy and ease of administration. A leading example is KG006, which it acquired from U.S. biotech company Kaijin in November 2025. Kaijin has described the drug as a next-generation FcRn inhibitor that uses a novel antibody structure to extend the duration of its efficacy and offers the convenience of subcutaneous injection. While argenx's move to secure oral drug development capabilities does not immediately put Celltrion at a competitive disadvantage, Celltrion will also need to provide concrete data showing how effectively its drug extends dosing intervals and sustains its effects compared with existing treatments.

An industry official said, "It has yet to be proven whether oral peptides can actually target FcRn and deliver efficacy comparable to antibody therapies." The official added, "As argenx expands its research and development beyond antibodies, Korean developers will also need to establish differentiation strategies involving long-term dosing approaches and duration of effect, alongside achieving clinical success."

This content was produced with the assistance of AI translation services.