Aptevo, Alligator in Bispecific Antibody Development Pact

Aptevo Therapeutics Inc. and Alligator Bioscience have entered into an agreement to co-develop an immunotherapy bispecific antibody candidate, ALG.APV-527, based on Alligator’s first generation bispecific antibody, ATOR-1016.  The new candidate was developed using Aptevo’s bispecific technology platform and includes binding elements generated by Alligator’s ALLIGATOR-GOLDantibody library. The companies plan to initiate cell line development for the manufacture of clinical material soon.

Working under a previous material transfer agreement, the companies have engineered ALG.APV-527 as a lead bispecific antibody candidate featuring a novel 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 widely overexpressed in several types of cancer.

The companies will jointly own and share development costs through Phase II development, at which point, the parties may opt to out-license the candidate or continue further development separately or in partnership. The agreement also provides an option for the companies to develop a second bispecific antibody candidate based on this novel mechanism of action.

"Our collaboration with Alligator Bioscience has unlocked tremendous synergies, enabling us to capitalize on our companies’ respective expertise in therapeutic antibody engineering," said Marvin L. White, president and chief executive officer of Aptevo. "The addition of a 4-1BB bispecific candidate expands and diversifies Aptevo’s portfolio while demonstrating the flexibility of our ADAPTIR platform in addressing novel mechanisms of action, in addition to redirected T-cell cytotoxicity.  Also, importantly, it allows us to pursue an exciting new therapeutic opportunity with broad potential application in the treatment of non-hematological cancers. If proven successful, this new approach would be a significant advance in cancer immunotherapy."

"With five immuno-oncology programs currently in development, each with first- or best-in-class potential, this partnership with Aptevo allows us to further build on the promise of bispecific therapeutics for tumor-directed immunotherapy," said Per Norlén, chief executive officer of Alligator Bioscience. "Our technology platform enables the generation of highly functional antibodies with optimal stability and manufacturing properties, merged into an exceptional bispecific antibody using Aptevo´s ADAPTIR platform.  We look forward to advancing our collaboration with Aptevo on this promising new therapeutic approach."