Pathios Therapeutics

Pathios Therapeutics, launched in 2017, is a clinical-stage drug discovery company headquartered in Oxford, UK. It was co-founded by a team including Tom McCarthy, Kirsty McCarthy, Alan Naylor, and Peter Joyce. Tom McCarthy, the Executive Chairperson, has over 25 years of experience in the field and previously led Spinifex Pharmaceuticals to a ~US$700 million acquisition by Novartis. The company operates within the M:M Bio (Molecule to Medicine) ecosystem, also created by Tom and Kirsty McCarthy, which incubates and supports biotech companies.

The company's core focus is on developing small molecule inhibitors that target GPR65, a pH-sensing G protein-coupled receptor (GPCR). This receptor is activated by the acidic tumor microenvironment (TME) found in most solid cancers, causing immune cells like tumor-associated macrophages (TAMs) to become immunosuppressive, which allows cancer to evade the immune system. By inhibiting GPR65, Pathios aims to reverse this immunosuppression and restore the anti-tumor activity of immune cells. This approach has been validated by human genetic data showing that natural loss-of-function variants in the GPR65 gene are associated with significantly improved survival rates across various solid tumors.

Pathios' lead candidate is PTT-4256, an orally bioavailable, highly potent, and selective GPR65 inhibitor. The company has advanced PTT-4256 into a Phase 1/2 clinical trial (RAISIC-1) in Australia for patients with advanced solid tumors, which began in late 2024. The business model centers on the discovery and clinical development of these first-in-class therapies. The company generates capital through venture funding and strategic partnerships. To date, Pathios has raised US$58 million from investors, including a Series B round that secured a $25 million first close in April 2024 with backing from Canaan, Brandon Capital Partners, and a strategic investment from Bristol Myers Squibb.

Keywords: GPR65 inhibitor, cancer immunotherapy, immuno-oncology, tumor microenvironment, PTT-4256, small molecule drugs, GPCR, clinical-stage biotech, Tom McCarthy, drug discovery, solid tumors, immunosuppression, tumor-associated macrophages, M:M Bio, cancer therapies, immunology, oncology, neuroinflammatory disorders, neurodegenerative disorders, G protein-coupled receptor, acidic TME