CSL has penned an exclusive collaboration deal with Swiss biotech, Alentis Therapeutics, which will see the pair join forces to progress a novel antifibrotic therapy designed to treat a range of kidney and liver diseases.
As per the agreement, CSL will hand over $355m upfront and up to $1.2bn in potential commercial milestone payments to join Alentis in its efforts to develop and commercialise the novel drug across multiple indications. In exchange, Alentis will provide CSL with 55% of the drug’s global profits, provided it makes it to market.
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At the core of this deal is lixudebart, Alentis’ Claudin-1-targeting anti-inflammatory and antifibrotic drug. With this collaboration now underway, both parties hope that lixudebart could become a first-in-class therapy for multiple rare diseases impacting the kidneys and liver. This includes ANCA-associated vasculitis with rapidly progressive glomerulonephritis (AAV-RPGN) and focal segmental glomerulosclerosis (FSGS), as well as chronic autoimmune liver disease, primary sclerosing cholangitis (PSC).
Alentis is currently evaluating lixudebart in AAV-RPGN in the Phase II RENAL trial (NCT06047171), which is pitting several doses of the drug against placebo in patients with the rare autoimmune disease. Following the signing of this agreement, CSL will fully fund the rest of the RENAL study, while setting cash aside for the planned Phase III trial, as well as other development activities for lixudebart in AAV-RPGN.
CSL has also committed to financially covering the Phase II trials and other applicable development activities around lixudebart in FSGS and PSC.
If the drug were to secure approval in AAV-RPGN, it would join Roche and Biogen’s Rituxan (rituximab), as well as Amgen’s Tavneos (avacopan) on the market – though the latter drug’s commercial future currently hangs in the balance as European and US regulators question its benefit-risk profile. CSL branch, CSL Vifor owns the commercialisation rights to Tavneos in Europe.
With Tavneos future market positioning unclear, CSL could potentially regain its legacy in the AAV-RPGN space through lixudebart, which CSL’s EVP and head of R&D, Bill Mezzanotte, says could hold the “potential to become an important new therapeutic option to help improve kidney function and prevent progression to end-stage kidney disease”.
Currently, renal diseases are one of CSL’s key areas of focus, with the company having played a key role in bringing Immunoglobulin A nephropathy (IgAN) therapy, Filspari (sparsentan), to market with the drug’s original creator, Travere Therapeutics. In Q2 2026, Filspari pulled in sales of $246m – marking a 93% uptick year-on-year and highlighting the drug’s burgeoning commercial potential. Analysts at GlobalData currently forecast that the drug will become a blockbuster seller in 2028, with sales expected to approach the $2bn mark at the end of the forecast period in 2032.
