Grey Wolf Therapeutics is a UK- and Australian-based drug discovery and development biotechnology company spearheading a new therapeutic approach in immuno-oncology. The company’s first-of-its-kind immuno-oncology approach is centered on inhibiting the endoplasmic reticulum aminopeptidases (ERAP1 or ERAP2), which play a key role in the antigen presentation pathway. Inhibiting ERAP1 or ERAP2 generates novel cancer antigens and upregulates certain other neoantigens, resulting in the mobilisation of an entirely novel T cell response against the tumour that increases tumour visibility where current therapies are ineffective, and bypasses the challenge faced by current immunotherapy when once anti-tumourigenic T cells become irreversibly exhausted and hence ineffective. Based on this approach, the company is developing a portfolio of potentially first-in-class small molecules that inhibit ERAP1 or ERAP2. The company’s lead development candidate, GRWD5769, is a potent and selective ERAP1 inhibitor that elicits a powerful and differentiated immune response against the tumour and is entering the clinic in the first half of 2023. A second program, focused on ERAP2 inhibition, is advancing through the discovery process. The company is leveraging its leadership in neoantigen creation to unlock entirely novel cancer antigens that can be targeted with MHC Class I directed therapies, such as soluble T cell receptor (TCR) and TCR mimic bispecifics.