SAN MATEO, Calif., March 23, 2026 /PRNewswire/ -- Kali Therapeutics, a biotechnology company focused on the discovery and development of next-generation biologics, today announced that they have entered into a license agreement with Sanofi for a tri-specific T-cell engager, which has the potential to treat a broad range of B cell-mediated autoimmune diseases.

Under the agreement, Sanofi will obtain exclusive worldwide rights to KT501, a novel tri-specific antibody utilizing Kali Therapeutics' proprietary discovery and research platform. KT501 is being evaluated in a first-in-human study to investigate the safety, tolerability, pharmacokinetics and pharmacodynamics in participants with Rheumatoid Arthritis. Kali Therapeutics will receive upfront and near-term payments totaling $180 million. Kali Therapeutics is also eligible to receive up to a total of $1.05 billion in development and commercial milestone payments and tiered royalties on product sales ranging from the high-single to double digits.

"We are thrilled to collaborate with Sanofi, a global leader in immunology, to advance the development of KT501, our lead tri-specific program," said Weihao Xu, CEO of Kali Therapeutics. "Our platform leverages state-of-the-art protein engineering to solve complex therapeutic challenges. 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."

Weihao Xu, CEO of Kali Therapeutics, added: "Autoimmune diseases require treatments that are not only highly potent but also exhibit a superior safety profile. KT501 represents a significant leap forward in this regard. By depleting a broad range of B cell populations effectively while minimizing cytokine release, we believe KT501 can address significant unmet needs of autoimmune patients. We are confident that Sanofi's extensive expertise will accelerate the development of this promising therapy."

About Kali Therapeutics

Kali Therapeutics is a clinical-stage biotech company redefining biopharmaceutical innovation. By combining advanced protein engineering and high-throughput experimental techniques, Kali Therapeutics streamlines the drug discovery and research process. The company's proprietary immune cell engager platform enables precise optimization of functionality, manufacturability, and developability of biologics with first-in-class or best-in-class potential. Kali Therapeutics leverages T-cell engagers with precise targeting and controlled cytotoxicity to enable a transformative immune system reset and regeneration.

About KT501

KT501 is a novel IgG-like tri-specific T-cell engager designed to bind CD3, CD19, and BCMA with high affinity, thereby targeting a broad range of B cell populations. Utilizing an innovative molecular design aimed at maximizing potency while minimizing cytokine release via a unique CD3 masking platform, KT501 has demonstrated potent B cell depletion in peripheral and tissues and significantly reduced cytokine production in non-human primate (NHP) studies. These attributes position KT501 as a promising therapy with the potential to treat a broad range of B cell-mediated autoimmune diseases.

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SOURCE Kali Therapeutics