Sanofi and Kali Therapeutics signed an exclusive global license agreement for KT501, a novel trispecific antibody for the treatment of B cell-mediated autoimmune diseases.[1] Sanofi will acquire exclusive worldwide rights to KT501, which uses Kali Therapeutics' proprietary research platform.[1] KT501 is an IgG-like trispecific T-cell engager that binds to CD3, CD19 and BCMA with high affinity and targets a broad spectrum of B cells.[1] The antibody has an innovative molecular design that maximizes efficacy and minimizes cytokine release thanks to a unique CD3 masking platform.[1] In non-human primate studies, KT501 has shown robust clearance of B cells in the periphery and tissues with significantly reduced cytokine production.[1] KT501 is currently being evaluated in a first-in-human study investigating safety, tolerability, pharmacokinetics and pharmacodynamics in patients with rheumatoid arthritis.[1] Kali Therapeutics will receive upfront and short-term payments totaling $180 million, up to $1.05 billion in development and commercialization milestones, and tiered sales royalties in the high single digits to high hundreds.[1]