Aptevo Therapeutics, Emergent Biosolution’s planned biosciences business spin-off company, and Alligator Bioscience, a biotechnology company developing antibody-based pharmaceuticals for tumor-directed immunotherapy, have agreed to co-develop an immunotherapy bispecific antibody candidate, ALG.APV-527, based on Alligator’s bispecific antibody, ATOR-1016.

The new bispecific candidate was developed using Aptevo’s bispecific technology platform and includes proprietary binding elements generated by Alligator’s antibody library.  Initiation of cell-line development for the manufacturing of clinical material is expected to begin shortly.

Working under a previously executed material transfer agreement, the companies have engineered and selected ALG.APV-527 as a lead bispecific antibody candidate, featuring a mechanism of action targeting 4-1BB, a member of the TNFR superfamily of co-stimulatory receptors found on activated T cells, and an undisclosed tumor antigen overexpressed in a number of different types of cancer, according to Alligator Bioscience.

Under the agreement, the parties will jointly own and share equally in the development costs associated with advancing this candidate through to the end of Phase II clinical development. At that time, the parties may opt to out-license the candidate or continue further development separately or in partnership.  In addition, the agreement provides an option for the companies to develop a second bispecific antibody candidate based on this mechanism of action, which would also be jointly owned and funded by Aptevo and Alligator.

Source: Alligator Bioscience