Antengene UCB ATG-201: Global License Agreement for CD19/CD3 Bispecific T-Cell Engager in Autoimmune Diseases

Hong Kong-headquartered Antengene Corporation Limited and Brussels-based UCB (Euronext Brussels) have entered into a global license agreement granting UCB worldwide exclusive rights to develop, manufacture, and commercialize ATG-201, a CD19/CD3 bispecific T-cell engager antibody targeting B cell-related autoimmune diseases. Under the deal, UCB also gains access to associated manufacturing technology. Antengene will complete first-in-human Phase 1 studies in China and Australia before transferring further clinical development to UCB.

Antengene will receive USD 60 million upfront and USD 20 million in near-term milestone payments, totaling USD 80 million in upfront and near-term consideration. The company is eligible for over USD 1.1 billion in success-based development, regulatory, and sales milestones, along with tiered royalties on future net sales. Specific royalty rates, milestone breakdowns by category, and termination provisions were not disclosed. No equity component was referenced. The deal is structured as a full global out-license, with Antengene retaining no long-term territorial commercialization rights.

Deal context

ATG-201 is a bispecific antibody built on Antengene's proprietary AnTenGager platform, which uses a "2+1" format — two CD19 binding arms and one CD3 binding arm — combined with steric hindrance masking technology and a proprietary fast-on-fast-off CD3 binder. The molecule is designed to redirect T cells to eliminate CD19-expressing B cells while reducing the risk of cytokine release syndrome. Antengene plans to submit clinical trial applications for ATG-201 in China and Australia in Q1 2026. The asset is pre-Phase 1, with no clinical trial registry entries publicly available at the time of announcement.

For UCB, the deal adds a B cell autoimmune therapy modality to an immunology pipeline historically built on monoclonal antibodies and other biologics. UCB previously pursued CD22-targeted B cell depletion through an epratuzumab collaboration with Immunomedics, structured in 2009 with approximately USD 38 million upfront and later restructured in 2011; that program was ultimately discontinued. The ATG-201 agreement represents a return to B cell-targeting strategies, this time via a T-cell engager format. No prior deals between Antengene and UCB were identified; this is the first transaction between the two companies.

For Antengene, the transaction represents a shift from its historical pattern of in-licensing Western assets for Asia-Pacific development — such as its selinexor license from Karyopharm Therapeutics — to out-licensing a proprietary, platform-derived candidate to a global pharma company. Nine additional disclosed products remain in the AnTenGager pipeline.

The Antengene licensing deal is one of several large transactions centered on CD19 in autoimmune diseases over the past 18 months. In January 2025, Merck acquired global ex-China rights to Curon Biopharmaceutical's CD19 CAR-T candidates for autoimmune diseases in a deal worth up to USD 2 billion with USD 200 million upfront. In December 2024, AstraZeneca acquired Candid Therapeutics for approximately USD 2.4 billion, gaining access to a CD19-targeted T-cell engager program for autoimmunity. Bristol Myers Squibb also licensed CD19 CAR-T assets for autoimmune applications in 2024 in a deal reported at up to USD 1.1 billion.

Other CD19-targeting molecules in active clinical development for autoimmune or B cell-mediated diseases include:

• Blinatumomab (Amgen) — approved CD19/CD3 BiTE for B-ALL; under investigation in autoimmune indications including systemic sclerosis case studies
• KYV-101 (Kyverna Therapeutics) — CD19 CAR-T in Phase 2 for lupus nephritis
• Curon Biopharmaceutical CD19 CAR-T candidates — Phase 1 for autoimmune diseases (licensed to Merck)
• Candid Therapeutics CD19 TCE — preclinical/early clinical (acquired by AstraZeneca)

The UCB license agreement positions the company within this competitive set, though ATG-201's differentiated platform design — incorporating conditional T-cell activation via steric masking — may address tolerability concerns that have limited earlier CD19/CD3 bispecific T-cell engager approaches. ATG-201 remains at an early development stage, and clinical data will be required to confirm whether the platform's design translates into a differentiated safety and efficacy profile relative to both CAR-T and other TCE modalities targeting ATG-201 autoimmune diseases indications.

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