Grey Wolf Therapeutics Closes Oversubscribed $49 Million Series B Financing to Advance First-of-its-Kind Neoantigen Creation Approaches.

Premier Syndicate of Life Science Industry Investors led by Pfizer Ventures and Earlybird Venture Capital and including Canaan, Andera Partners, Oxford Science Enterprises and British Patient Capital

Proceeds to Support Advancement of Lead Candidate, ERAP1 Inhibitor GRWD5769, into the Clinic in 1H 2023; Continued R&D for Follow-On ERAP Inhibition Strategies

Oxford, UK – January 26, 2023

Grey Wolf Therapeutics, a biotechnology company focused on generating entirely novel anti-tumour immune responses through targeted cancer neoantigen creation, today announced the closing of an oversubscribed $49 million Series B financing. The financing was co-led by Pfizer Ventures and Earlybird Venture Capital, and also included investment from new investors Oxford Science Enterprises and British Patient Capital and existing investors Canaan and Andera Partners. Proceeds will support the continued development of the company’s first-of-its-kind immuno-oncology approaches designed to overcome key resistance mechanisms through the creation of novel cancer antigens. This includes the anticipated advancement of the company’s lead asset, GRWD5769, into a Phase 1/2 clinical trial in the first half of 2023.

Grey Wolf Therapeutics’ unique therapeutic strategy is centered on generating entirely novel immune responses against tumours thereby overcoming key resistance mechanisms to current immuno-oncology therapy such as poor tumour recognition by T cells and T cell exhaustion. This is achieved through targeted inhibition of the endoplasmic reticulum aminopeptidases (ERAP1 or ERAP2), which drives the generation and presentation of novel and potent cancer antigens to the surface of tumour cells, in turn eliciting a de novo T cell response against tumours.

The ground-breaking research and development activities conducted by the Grey Wolf team have generated a pipeline of novel ERAP inhibition programs, led by GRWD5769, a potentially first-in-class ERAP1 inhibitor. During the first half of 2023, the company intends to initiate an adaptive Phase 1/2 clinical trial evaluating the safety, tolerability, and efficacy of GRWD5769, including a planned combination with the PD-1 inhibitor Libtayo® (cemiplimab), in a range of solid tumour types. Additionally, the company will direct a portion of the Series B proceeds to follow-on programs including efforts focused on ERAP2 inhibition and the identification of 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.

“This syndicate of leading life science industry investors brings a wealth of relevant expertise and resources to Grey Wolf at a critical time in our evolution as we prepare to enter the clinic,” said Peter Joyce, Ph.D., Chief Executive Officer of Grey Wolf Therapeutics. “The funding these groups have committed to Grey Wolf will not only support our efforts to demonstrate clinical proof-of-concept for ERAP inhibition with our lead program, but it will also drive our continued scientific exploration in this area as we aim to further advance and broaden our pipeline of first-of-their-kind therapeutics.”

“The scientific ground being pursued by the Grey Wolf team is fertile with potential solutions for overcoming two of the most significant resistance mechanisms limiting current immune-oncology therapies – poor tumour visibility and T cell exhaustion,” said Marie-Claire Peakman, Ph.D., principal with Pfizer Ventures.  “We look forward to supporting the company as it enters the clinical setting and works to develop an actionable and completely novel therapeutic approach.”

“We believe Grey Wolf is establishing the next essential pillar in oncology treatment, with the potential to overcome treatment resistance and change the game for attacking cancer,” said Rabab Nasrallah, Ph.D., principal, Earlybird Venture Capital. “Importantly, preclinical research suggests that the company’s elegant treatment approach holds great promise as a monotherapy, as well as the potential to synergistically improve outcomes when used in rational combination with other anti-cancer agents including immune checkpoint inhibitors. This flexibility further amplifies the potential breadth of impact these investigational therapeutics may have in treating patients.”

In conjunction with the financing, Grey Wolf Therapeutics has announced several new appointees to its board of directors including:

  • Sally Dewhurst, senior associate, Oxford Science Enterprises
  • Emma Johnson, investment manager, British Patient Capital
  • Rabab Nasrallah, principal, Earlybird Venture Capital
  • Marie-Claire Peakman, principal, Pfizer Ventures

About Grey Wolf Therapeutics

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.


Grey Wolf Therapeutics
Peter Joyce
Chief Executive Officer
+44 (0) 01865 292 038

Vida Strategic Partners
Tim Brons (Media)