Spero Therapeutics licensed global rights outside Greater China to Innovent’s anti-CD40L antibody IBI355 in a deal worth up to $1.1 billion. Phase 2 trials are planned in IgG4-related disease in 2027, while Innovent will advance Sjögren’s disease development in China.
Written By: Rishabh Sonawane, BPharm
Reviewed By: Pharmacally Editorial Team
Spero Therapeutics has licensed global rights outside Greater China to Innovent Biologics’ investigational anti-CD40L antibody IBI355 (SP001) under a deal worth up to $1.1 billion. The agreement positions Spero to expand into autoimmune diseases, with a Phase 2 trial in IgG4-related disease (IgG4-RD) planned for the second quarter of 2027, while Innovent will continue development in Greater China and expects to launch a Phase 2 study in Sjögren’s disease (SjD) by early 2027.
Under the agreement, Spero gains exclusive rights to develop, manufacture, research, and commercialize IBI355 worldwide except Mainland China, Hong Kong, Macau, and Taiwan. Innovent will receive an upfront payment and remains eligible for development, regulatory, and commercial milestone payments totaling approximately $1.1 billion, in addition to tiered royalties on future net sales in Spero’s territories.
Anti-CD40L therapy targets upstream immune signaling
IBI355 (SP001) is a third-generation, humanized Fc-silent IgG1 monoclonal antibody that blocks CD40 ligand (CD40L), a key immune signaling protein involved in T-cell and B-cell activation. Because CD40L regulates multiple immune pathways upstream of inflammation, inhibiting this target may offer therapeutic benefit across a range of autoimmune disorders.
Unlike earlier anti-CD40L antibodies that raised concerns about platelet activation and thromboembolic events, IBI355 incorporates an Fc-silent design intended to minimize platelet-related safety risks while maintaining a prolonged IgG-like half-life through preserved FcRn interaction.
Innovent has evaluated IBI355 in two Phase 1 healthy volunteer studies, including single ascending dose (SAD) and multiple ascending dose (MAD) trials, as well as a Phase 1b MAD study in patients with Sjögren’s disease. Findings from the SjD study were presented at the EULAR 2026 Congress, supporting continued clinical development.
Development plans focus on autoimmune diseases with limited treatment options
Spero’s first clinical priority will be IgG4-related disease, a chronic fibroinflammatory disorder that can affect multiple organs, including the pancreas, kidneys, lungs, salivary glands, and lacrimal glands. Patients often experience recurrent inflammation, progressive fibrosis, organ damage, and prolonged dependence on corticosteroids or B-cell-depleting therapies.
Commenting on the program, Dr. Arezou Khosroshahi, Professor of Medicine at Emory University School of Medicine, noted that CD40L is an important regulator of immune activation involved in IgG4-RD progression. He said interrupting CD40L signaling without depleting B cells represents a promising strategy for patients who require additional treatment options to control chronic inflammation and disease relapse.
Meanwhile, Innovent will continue advancing IBI355 in Sjögren’s disease, a systemic autoimmune disorder characterized by chronic inflammation, autoantibody production, and lymphocytic infiltration of exocrine glands. Despite affecting millions of patients, particularly women, no approved therapy currently addresses the underlying systemic disease.
Partnership expands Spero’s pipeline beyond infectious diseases
Spero President and Chief Executive Officer Esther Rajavelu said the licensing agreement establishes the company’s immunology pipeline following its experience developing therapies for serious infectious diseases. She highlighted CD40L inhibition as a clinically validated pathway with potential applications across multiple autoimmune and inflammatory disorders beyond IgG4-related disease.
Innovent’s Chief R&D Officer for General Biomedicine, Dr. Lei Qian, said the collaboration combines both companies’ expertise in immunology and supports efforts to accelerate development of new therapies for patients with chronic autoimmune diseases.
The partnership provides Spero with its lead immunology asset while allowing Innovent to retain commercialization rights in Greater China and participate in the program’s long-term success through milestone payments and royalty revenue. Initial Phase 2 studies in both IgG4-related disease and Sjögren’s disease are expected to begin in 2027, marking the next stage of clinical development for the anti-CD40L antibody.
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About the Writer
Rishabha Sonawane, B.Pharm (LinkedIn) is healthcare writer with a strong interest in medical writing, regulatory affairs, clinical research, and AI-driven drug discovery. He has completed specialized training from the NIH and ICMR in clinical pharmacology, clinical research, and scientific writing. Passionate about evidence-based healthcare communication, he focuses on translating complex scientific research into clear, accurate, and engaging medical content.