Sotio has struck a deal to fuse bispecifics with its antibody-drug conjugate (ADC) capabilities, agreeing to pay Biocytogen up to $325.5 million in upfront and milestone fees for rights to targeting molecules.
China’s Biocytogen uses transgenic mice to generate bispecific antibodies. Bispecifics made their name as a standalone drug modality but they can also be conjugated to cytotoxic payloads to create ADCs with a twist. Using antibodies that hit two targets could enable the creation of resistance-busting molecules, as well as candidates with reduced off-target toxicity and greater cancer-killing power.
Sotio has built out its ADC capabilities over the past eight years through deals with NBE-Therapeutics, LigaChem Biosciences and Synaffix. The deals gave the Czech biotech access to conjugation technology, payloads and ADC candidates.
Bispecific targeting molecules are the next piece of the puzzle. Sotio has turned to Biocytogen to fill that gap. The collaboration gives Sotio the option to license multiple fully human bispecific antibodies found using Biocytogen’s RenLite mice. Sotio also has an option to use Biocytogen’s ADC platform. The biotechs will work together during the research phase, after which Sotio will take over for development.
Sotio has already selected the first targets for a bispecific program. Assets that emerge from the deal will slot into a pipeline that now skews heavily toward ADCs. Sotio lists five ADCs in its pipeline but only one has a disclosed target, Claudin18.2, and is in the clinic.
The biotech was focused on cytokines when it put itself on the map with a 280 million euros ($305 million) round in 2018. However, the failure of an IL-15 superagonist set back Sotio’s work on cytokines. The biotech is still looking for combination opportunities for the IL-15 candidate—and developing a next-generation asset that fuses a superagonist to an anti-PD-1 antibody— but ADCs are the star turn.