ALG.APV-527 is a bispecific agonistic antibody for tumor-directed immunotherapy co-developed with Aptevo Therapeutics. It was generated by proprietary binding elements obtained from Alligator’s ALLIGATOR-GOLD® antibody library, which were produced as a bispecific compound using Aptevo’s bispecific technology platform. ALG.APV-527 is based on Alligator’s first generation bispecific antibody, ATOR-1016.

ALG.APV-527 targets 4-1BB (CD137), a member of the TNFR superfamily of co-stimulatory receptors found on activated T cells, and an undisclosed tumor-associated antigen (TAA) widely overexpressed in a number of different types of cancer. The co-stimulatory receptor 4-1BB is known to play an important role in modulating and augmenting the immune response to cancer by promoting the activation, expansion and enhanced effector function of tumor-specific T cells. It is, therefore, an especially promising target for new immunotherapeutic approaches for cancer treatment.

Combining the 4-1BB and TAA antibodies in the same molecule results in a compound whose effect is localized to the tumor-specific immune cells residing in the tumor environment. This enables effective tumor-directed immune activation without causing the adverse reactions otherwise associated with the systemic administration of immune activating drugs.

ALG.APV-527 is currently in late research phase and initiation of cell line development for subsequent clinical production is expected to begin shortly.