Sanofi has returned to T-cell engager (TCE) territory via an agreement to pay $180 million in the near term for a phase 1-stage trispecific antibody from Kali Therapeutics.
The California biotech took the TCE, dubbed KT501, into a first-in-human study of patients with rheumatoid arthritis earlier this month, according to the federal trials database. Sanofi is hoping that the candidate, which is designed to bind CD3, CD19 and BCMA, will be of use against a wide range of B-cell-mediated autoimmune diseases.
In return for the worldwide rights, Kali will receive $180 million in upfront and near-term payments, with up to $1.05 billion in development and commercial milestone payments to potentially follow as well as tiered royalties on product sales.
KT501 was designed with Kali’s protein engineering platform with the aim of providing high affinity to bind to its three targets while minimizing cytokine release syndrome—a potentially serious side effect of immunotherapies that redirect T cells.
The therapy has already demonstrated “potent” B cell depletion in peripheral cells and tissues and significantly reduced cytokine production in preclinical studies, Kali explained in the March 23 release.
“Autoimmune diseases require treatments that are not only highly potent but also exhibit a superior safety profile,” Kali CEO Weihao Xu said in a statement. “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,” Xu added.
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Sanofi is no stranger to TCEs, which remain a hot ticket for pharma dealmaking this year. The French drugmaker bought TCE-focused Amunix for $1 billion back in 2021 but sold off a trio of clinical-stage TCEs to Vir Biotechnology three years later.
Still, Sanofi has continued to name-check TCEs as a modality it’s interested in, even though the company doesn’t list any of these drugs in its pipeline.
Despite a bold ambition to become an “immunoscience powerhouse,” Sanofi’s portfolio was beset by a string of clinical setbacks last year that ultimately led to the recent ousting of CEO Paul Hudson.
Meanwhile, Kali, which is named after the Hindu goddess of death and destruction, has two other TCEs in its pipeline. They include another trispecific candidate as well as the CD19-directed KT502, which the biotech hopes to take into the clinic in the first half of the year.
