Kali Therapeutics licensed its lead trispecific T‑cell engager KT‑501 to Sanofi in a deal worth up to $1.2 billion, including substantial near‑term payments. Sanofi described the arrangement as a re‑entry into T‑cell engager programs and committed immediate funding to advance the phase 1 asset in autoimmune indications, notably rheumatoid arthritis. Kali retains early clinical momentum after initiating a Phase Ia study and will hand global development and commercialization rights to Sanofi. The transaction signals continued Big Pharma appetite for multispecific T‑cell engagement beyond oncology and underscores the sector’s ongoing partnering activity to accelerate clinic‑stage biologics.