Sanofi pays $180m for rights to Kali autoimmune drug
California biotech Kali Therapeutics has snagged its first major pharma partner, Sanofi, which is committing $180 million in near-term payments for rights to a T-cell engager (TCE) for autoimmune diseases.
The agreement gives the French pharma group exclusive worldwide rights to KT501, a trispecific antibody that simultaneously binds to CD3, CD19, and BCMA – three antigens found on the surface of B cells. The deal also includes up to $1.05 billion in development and commercial milestone payments, along with tiered royalties on product sales ranging from the high single digits to double digits if it reaches the market.
The trispecific has been developed using Kali's drug discovery and development platform, which generates TCEs that offer precise targeting of immune system targets with a masking technology that attempts to avoid off-target side effects, which can be a major problem with the class.
Earlier this month, Kali started dosing patients in a first-in-human phase 1a trial with a target enrolment of 24 adult subjects with rheumatoid arthritis. Patients will receive a single subcutaneous administration of the TCE in ascending doses, with safety, tolerability, pharmacokinetic, and pharmacodynamic results due in 2027.
Studies in non-human primates have shown that it can strongly deplete B cells, whilst also limiting some common side effects of TCEs, including minimising the release of cytokines that can cause potentially serious adverse reactions.
"Our platform leverages state-of-the-art protein engineering to solve complex therapeutic challenges," commented Kali's chief executive, Weihao Xu.
"This collaboration highlights the potential of our unique CD3 masking technology to decouple potency from toxicity, aiming to provide safer, more effective options for patients."
For Sanofi, the deal continues a run of licensing agreements in the immunology and inflammation (I&I) arena as it starts to contemplate the loss of market exclusivity in the early 2030s for Regeneron-partnered IL-4 and IL-13 inhibitor Dupixent (dupilumab), its $18 billion-plus blockbuster.
This month, the company also paid $135 million upfront for rights to Hong Kong-based Sino Biopharmaceutical's JAK/ROCK inhibitor rovadicitinib in a deal worth up to $1.53 billion, while in January it expanded an alliance with US biotech Earendil Labs covering multiple AI-derived drug candidates, including candidates for inflammatory bowel disease.
Last year, Sanofi also shored up its long-term I&I pipeline with deals involving Dren Bio and EVOQ Therapeutics.
