(Avacta) Pharmacokinetic and Biodistribution of Formatted Affimer® Biotherapeutics Targeting PD-L1

Introduction

Programmed Cell Death-Ligand 1 (PD-L1) is part of the immune checkpoint system involved in preventing autoimmunity. PD-L1 is upregulated on tumour cells and binds to its receptor, PD-1, expressed by immune cells in the tumour microenvironment. AntiPD-L1 immunotherapies have shown to be effective treatments both as monotherapies and in combinations with chemotherapies and radiotherapies, providing long term responses in a subset of patients. We have developed a PD-L1 Affimer® antagonist (AVA04) that could differentiate itself from the current clinically approved mAbs due to its smaller size, improved tissue penetration and alternative routes of delivery such as a subcutaneous injection. It also opens the possibility of generating additional PD-L1 antagonist based therapeutics such as targeted radiopharmaceuticals, drug conjugates, bispecifics and cytokine fusions.