ALG.APV-527: A tumor-binding and immunomodulatory antibody in the same molecule

4-1BB has the ability to stimulate the immune cells (antitumor-specific T cells) involved in tumor control, making 4-1BB a particularly compelling target for cancer immunotherapy. The tumor-binding function of ALG.APV-527 targets the 5T4 tumor-associated antigen. 5T4 is a protein expression in multiple tumor types, as well as certain types of aggressive tumor cells (tumor-initiating cells), but at low levels or not at all in normal tissue, making 5T4 a compelling target molecule for cancer therapy.

1. ALG.APV-527 is seeking the tumor area and binds to the target molecule 5T4 on the surface of tumor cells.
2. In the tumor area, ALG.APV-527 simultaneously binds to 4-1BB on the surface of T cells.
3. The beneficial T cells are activated to kill tumor cells.


Preclinical data for ALG.APV-527 has been presented at several scientific conferences. Data shows that ALG.APV-527 has the potential to selectively stimulate and strengthen the T cell response in the tumor without stimulating the immune system in the rest of the body. Data shows that ALG.APV-527 is localized to 5T4 positive tumors and selectively stimulates and enhances the tumor-directed immune responses of the T cells and NK cells. Additionally, data shows that the 5T4 antigen is expressed by a wide range of tumor types. The findings support its overall potential to evoke an effective tumor-targeting immune response with fewer adverse events.

Alligator and Aptevo have made a joint decision to postpone submission of a CTA (Clinical Trial Authorization), previously planned before year-end. The companies are initiating discussions with potential partners for the upcoming clinical development of ALG.APV-527.

In July 2017, Aptevo Therapeutics and Alligator Bioscience signed an agreement regarding the co-development of ALG.APV-527. The antibody is based on Alligator’s original bispecific drug candidate ATOR-1016. Under the agreement, the companies will equally own and finance the development of the drug candidate through Phase II clinical trials.