ADEL, a biopharmaceutical company developing therapies for neurodegenerative diseases, announced an exclusive worldwide license agreement with Sanofi on December 15th, 2025. The agreement will see Sanofi acquire the rights to ADEL-Y01, a potential first-in-class antibody therapy for Alzheimer’s disease, in a deal valued at up to $1.04 billion.

According to a company press release, ADEL-Y01 is a humanized monoclonal antibody designed to selectively target tau protein acetylated at Lysine-280. Differing from therapies that target total tau, this treatment intends to specifically inhibit the aggregation and propagation of toxic tau species without interrupting the function of normal microtubule-associated tau. ADEL-Y01 is currently being investigated in a Phase I clinical trial.

Sanofi will pay ADEL an upfront fee of $80 million for the exclusive worldwide rights to ADEL-Y01, with additional compensation tied to completion of various development and commercial milestones. ADEL will also be eligible for up to double-digit tiered royalties on net sales of any commercial product resulting from the collaboration.

“This strategic partnership with Sanofi, a global leader in healthcare, underscores ADEL’s technological strength and highlights the therapeutic promise of ADEL-Y01,” said Seung-Yong Yoon, CEO, ADEL, in the release. “By combining our scientific expertise with the proven development and commercialization capabilities of Sanofi, we hope to accelerate the delivery of this disease-modifying therapy to people living with Alzheimer’s around the world.”

“ADEL’s innovative approach to targeting tau acetylation offers a promising and differentiated mechanism for addressing the underlying causes of Alzheimer’s disease,” said Erik Wallstroem, Global Head of Multiple Sclerosis, Neurology and Gene Therapy Development, Sanofi, in the release. “We look forward to advancing ADEL-Y01 through clinical development to provide new hope for patients living with this devastating condition.”