The collaboration will build on ALX Oncology's expertise in developing therapies that block the CD47 checkpoint pathway and Tallac's pipeline of next-generation immunotherapies derived from its toll-like receptor agonist antibody conjugate (TRAAC) platform. The firms will advance an anti-signal regulatory protein α (SIRPα) antibody conjugated to a toll-like receptor 9 (TLR9) agonist for targeted activation of both the innate and adaptive immune systems.

Systemic administration of TLR9 has been unsuccessful, but with TRAAC that now becomes possible, the companies said. They have "promising" preclinical data with multiple TRAAC molecules. The partnership will further advance SIRPα TRAAC, a systemically delivered TLR9 agonist targeting dendritic cells via SIRPα receptors to elicit an adaptive antitumor immune response.

Each company will share equally in the cost of research and development as well as any profits or losses incurred.