Alligator Bioscience and Aptevo Therapeutics Announce that FDA has Issued a “May Proceed” Notification for the ALG.APV-527 IND

Drug Candidate progressing to the clinic for evaluation in the treatment of 5T4-expressing tumor antigens in multiple solid tumor types.

Lund, Sweden, and Seattle Washington, September 19, 2022 – Alligator Bioscience AB (“Alligator”) and Aptevo Therapeutics (“Aptevo”) today announced that the US Food and Drug Administration (FDA) has issued a “may proceed” notification for the ALG.APV-527 investigational new drug application (IND), allowing the companies to initiate clinical trials evaluating the compound for the treatment of 5T4-expressing tumor antigens in multiple solid tumor types. The companies are moving rapidly to initiate a multi-center Phase 1 trial in the US.

“We are very happy to see ALG.APV-527 make significant progress towards the clinic this year, an important milestone achievement for the Alligator and Aptevo teams. It’s exciting to know that this compound will soon join APVO436, currently in a phase 1b clinical trial for the treatment of AML, in clinical studies here in the US. I would like to thank our partners at Alligator for their close collaboration and expertise. Advancing ALG.APV-527 has been a true team effort and we value our partnership,” said Marvin White, President, and CEO of Aptevo. “ALG.APV-527 is specifically designed to trigger 4-1BB-mediated antitumor activity in 5T4-expressing tumor indications, meaning it has potential across a range of solid tumors with high unmet medical need. The addition of a new clinical candidate in active development serves as further validation of Aptevo’s proprietary ADAPTIRÒ platform.”
“This IND clearance marks an important step in the development of ALG.APV-527 and is a testament to the strength of our partnership with Aptevo. This new IND also demonstrates our ability to bring innovative antibodies to the clinic” said Søren Bregenholt, PhD, CEO of Alligator Bioscience. “This compound will now become Alligator’s third asset in clinical development. We are looking forward to initiating this Phase 1 first in human study in multiple solid tumors and further investigating the indications where it is most effective.”

ALG.APV-527 is an antibody with dual function: tumor-binding and 4-1BB immunomodulatory agonist effects. This has the potential to be clinically important because 4-1BB has the ability to stimulate the immune cells (antitumor-specific T cells) involved in tumor control, making immune cell stimulation through 4-1BB a particularly compelling target for cancer immunotherapy.  Preclinical results, presented at the Society of Immunotherapy Cancer’s 2021 Annual Meeting, highlighted the differentiated design of the molecule that minimizes systemic immune activation, allowing for highly efficacious tumor-specific responses as demonstrated by potent activity in in vitro models.

The tumor-binding function of ALG.APV-527 targets the 5T4 tumor-associated antigen. 5T4 is a protein expression in multiple solid tumor types and limited expression in normal tissues, making 5T4 a compelling target molecule for cancer therapy.

Updated 2022-09-19