Lilly and CSL Partner on Clazakizumab Antibody Development

CSL and Eli Lilly have struck a strategic licensing agreement regarding clazakizumab, an anti-interleukin-6 (IL-6) monoclonal antibody.¹ Under the agreement’s terms, CSL receives an upfront payment of $100 million and remains eligible for future clinical, regulatory, and commercial milestones, as well as royalties on global net sales. Lilly will be responsible for exploring development, global regulatory approval, and distribution of the treatment to patients with end-stage kidney disease (ESKD). This collaboration demonstrates an industry trend of targeted therapies being simultaneously advanced across disparate therapeutic areas to maximize life-cycle value.

How Does This Collaboration Influence the Development Trajectory of Clazakizumab?

The agreement effectively splits the development path of the monoclonal antibody based on specific therapeutic indications.¹ CSL is maintaining its focus on the primary indication through the ongoing POSIBIL6ESKD Phase III clinical trial, which is currently evaluating the safety and efficacy of the treatment in preventing cardiovascular events for patients with ESKD who are on dialysis. This targeted approach addresses a specific high-risk patient population. On the strength of this collaboration, Bill Mezzanotte, EVP and head of R&D, CSL, commented in a press release,¹ "This agreement marks a significant step forward in our mission to bring innovative therapies to patients worldwide. Clazakizumab is a promising therapeutic candidate with the potential to significantly impact the treatment landscape for various immuno-inflammatory and cardiovascular conditions. Lilly is another patient-focused organization, and we look forward to working with them to maximize the potential of this important medicine."

What Are the Clinical and Manufacturing Implications of Targeting the IL-6 Pathway?

Originally developed by Vitaeris Inc. and acquired by CSL in 2020, clazakizumab functions by preventing IL-6 from binding to its receptor, thereby mitigating the inflammatory cascade.¹ The molecule represents a sophisticated intervention in the pathogenesis of diseases in which the overproduction of IL-6, a mediator of immune regulation, hematopoiesis, and vascular inflammation, is a key driver. By addressing this cytokine, clazakizumab may provide therapeutic benefits across a range of immuno-inflammatory conditions beyond the initial focus on cardiovascular events in the ESKD population. The success of this molecule hinges on demonstrating consistent efficacy in managing these complex biological processes across the different indications now being explored by the two partner organizations.

How Else Is Eli-Lily Continuing to Build its Manufacturing Portfolio?

Eli-Lilly is building on the strategic partitioning of antibody rights.² The recent acquisition biotechnology firm, Orna Therapeutics, specializing in circular ribonucleic acid (oRNA) technology for up to $2.4 billion further illustrates a focus on scaling advanced immunology platforms. The move from traditional cell-based therapies to in vivo chimeric antigen receptor T-cell therapies represents a significant shift in production logistics. While ex vivo approaches are often hampered by high costs and complex supply chains, this oRNA platform allows for simplified production and improved formulation into lipid nanoparticles (LNPs).

By leveraging LNPs to deliver circular ribonucleic acid directly to the patient, the manufacturing process bypasses the need for individualized cell harvesting and re-infusion.² This approach allows the body to generate its own therapeutic proteins, offering potentially more durable expression than current cell therapy platforms. These programs target B cell-driven autoimmune diseases, aligning with the broader strategy of addressing immuno-inflammatory conditions through diverse therapeutic modalities.

What Role Does Diverse Modality Integration Play in Future Immunology Pipelines?

Integrating genetic medicine alongside monoclonal antibodies creates a comprehensive toolkit for resetting the immune system.² This integration provides long-term innovation potential in cell engineering, enabling the development of therapies for patients who have limited options. By combining these technologies, Eli-Lilly can pursue potential best-in-class programs that address the underlying mechanisms of complex diseases.

References

1. CSL Limited. CSL and Lilly enter licensing agreement for clazakizumab [news release]. Melbourne (Australia): CSL Limited; 2026 Feb 18.
2. ​Eli Lilly and Company. Lilly to acquire Orna Therapeutics to advance cell therapies [news release]. Indianapolis (IN): Eli Lilly and Company; [cited 2026 Feb 18]. Available from: https://investor.lilly.com/news-releases/news-release-details/lilly-acquire-orna-therapeutics-advance-cell-therapies