CSL has entered an exclusive global collaboration with Swiss biotech Alentis Therapeutics to co-develop and co-promote lixudebart, a potential first-in-class antibody for rare kidney and liver diseases. CSL will make an initial payment of US$355 million, with up to US$1.2 billion in commercial milestones, and total development spending could reach A$2.2 billion. Once commercialized, global profits would be shared 55% to CSL and 45% to Alentis.
Clinical Promise in Rare Kidney and Liver Diseases
Lixudebart is currently being evaluated in the ongoing Phase 2 RENAL trial for ANCA-associated vasculitis with rapidly progressive glomerulonephritis, a rare and potentially life-threatening autoimmune kidney condition. Interim data from 26 patients showed promising improvements in kidney function as measured by eGFR and proteinuria at 24 weeks. The investigational monoclonal antibody previously demonstrated improved liver function at six weeks in a Phase 1b study of patients with advanced liver fibrosis.
The therapy exerts anti-inflammatory and anti-fibrotic effects by selectively targeting exposed claudin-1, a driver of inflammatory and fibrotic signaling across several organs. Beyond the current AAV-RPGN program, CSL and Alentis plan to advance lixudebart for focal segmental glomerulosclerosis and primary sclerosing cholangitis. The drug has also received Orphan Drug designation from the US Food and Drug Administration for idiopathic pulmonary fibrosis.
Structure of the Collaboration
Under the agreement, CSL will make an initial payment of US$355 million to Alentis, with the Swiss biotech eligible for up to US$1.2 billion in commercial milestone payments. CSL will fully fund the completion of the Phase 2 RENAL trial and a planned Phase 3 trial in AAV-RPGN, as well as Phase 2 studies in focal segmental glomerulosclerosis and primary sclerosing cholangitis. Once commercialized, global profits will be shared 55% to CSL and 45% to Alentis.
The announcement marks CSL’s first major partnership since the company recorded a US$2.6 billion loss in August following write-downs related to its Vifor kidney treatment business. CSL executives described the transaction as a measured investment in a therapeutic area where the company already has clinical and commercial expertise. They also noted the deal is consistent with CSL’s strategy of balancing internal research with high-value external partnerships.
Strategic Importance for Both Companies
For Alentis, the collaboration provides substantial funding and the global nephrology capabilities needed to accelerate lixudebart across multiple indications in parallel. Dr Mark Pruzanski, Chief Executive Officer of Alentis Therapeutics, said the partnership validates claudin-1 as a novel therapeutic target and supports the company’s broader pipeline of antibody-drug conjugates. For CSL, the molecule offers several potential disease opportunities within a single program, which could help strengthen its global nephrology franchise.
Dr Bill Mezzanotte, Executive Vice President and Head of Research and Development at CSL, said the early clinical data are encouraging and the transaction is appropriately priced relative to industry benchmarks. He added that patients with AAV-RPGN face rapid kidney function decline and remain at risk of irreversible damage even with current treatments. CSL believes lixudebart could become an important option to improve kidney function and prevent progression to end-stage kidney disease.
CSL and Alentis are positioning lixudebart as a potential foundational therapy across rare kidney and liver conditions linked to fibrosis and inflammation. The partnership combines Alentis’ claudin-1 biology expertise with CSL’s clinical development, regulatory, and commercial infrastructure. With clinical data continuing to mature, the collaboration gives both companies a path to address significant unmet needs while sharing both development responsibilities and commercial rewards.