Celltrion licenses next-generation autoimmune drug candidate from US biotech Kaigen for up to $580.5m

Celltrion is accelerating its push to become a global drug developer by licensing a next-generation autoimmune disease drug candidate from a US biotech.

The move is designed to broaden Celltrion's business beyond its biosimilar-centered model while leveraging its established overseas distribution network to expand its footprint in the global autoimmune disease market.

Celltrion announced Thursday that it had signed a global license-in agreement with Kaigen, a biotech based in Maryland, for KG013, a drug candidate targeting autoimmune diseases.

Under the deal, Celltrion secured exclusive worldwide rights to develop and commercialize KG013. The total contract value — including an upfront payment and milestone payments tied to development, regulatory approval and commercialization — reaches up to $580.5 million (769.5 billion won).

After commercialization, Celltrion will pay royalties based on net sales. Kaigen retains the right to participate in co-promotion in South Korea.

Kaigen is a biotech specializing in the development of multi-specific antibody drugs based on its proprietary PDEG platform technology, which breaks down pathogenic autoantibodies.

KG013 is a next-generation antibody drug candidate that targets APRIL (A Proliferation-Inducing Ligand), a signaling protein involved in the survival and function of antibody-producing B cells. Its primary indication is IgA nephropathy (IgAN), a chronic disease requiring long-term treatment and sustained safety management.

Unlike conventional approaches that broadly suppress immune cells or lower blood pressure, KG013 selectively inhibits the production of pathogenic IgA — the root cause of the disease. It is engineered to deliver significantly improved potency and durability compared with first-generation treatments, allowing disease control at lower doses and with longer dosing intervals. Celltrion aims to develop it as a best-in-class therapy.

With this agreement, Celltrion has completed a three-asset autoimmune drug lineup, adding the anti-APRIL antibody to the two candidates — including a fetal Fc receptor (FcRn) inhibitor — it licensed from Kaigen last year.

KG006, which breaks down immunoglobulin G (IgG), and KG013, which suppresses the production of IgA and IgM, are designed to complement each other and significantly broaden the range of treatable conditions.

Celltrion plans to combine the sales infrastructure and commercialization capabilities built around its globally established biosimilar portfolio — including tumor necrosis factor-alpha (TNF-α) and interleukin (IL) inhibitors — with its new drug lineup.

The company has designated anticancer drugs, obesity and metabolic diseases, and autoimmune diseases as its three pillars of drug development, and is accelerating a two-track strategy of in-house development and open innovation.

"Following last year's in-licensing of the FcRn inhibitor, securing rights to this anti-APRIL antibody has further strengthened our open innovation pipeline," a Celltrion official said. "We will maximize synergies with our existing core product portfolio to maintain a commanding lead in the global autoimmune disease market."