Accession Therapeutics secures £5.7m to advance targeted cancer immunotherapies

Oxford-based biopharmaceutical company Accession Therapeutics Limited has raised £5.7m in a new funding round, achieving a post-money valuation of £75.6m. The allotment was finalised on 18 March 2026, with filings confirmed today.

Incorporated in December 2020, Accession Therapeutics is a clinical-stage company focused on developing targeted cancer immunotherapies. The firm, which currently employs 48 people, aims to solve one of the most persistent challenges in oncology: treating advanced solid tumours that have become resistant to conventional therapies, while minimising systemic toxicity.

To achieve this, the company has developed its proprietary TROCEPT platform. The technology utilises genetically modified adenoviruses designed to exclusively target and infect cancer cells. Once inside the tumour, the virus delivers a transgene that codes for therapeutic proteins, effectively turning the cancer cells into factories for anti-tumour drugs. Because the virus bypasses healthy cells, the treatment can be administered intravenously with a significantly reduced risk of off-target side effects.

The company's lead candidate, TROCEPT-01, is currently undergoing Phase 1 clinical development in the ATTEST trial. The therapy is designed to selectively generate a clinically validated checkpoint inhibitor directly within advanced solid tumours. A second candidate, TROCEPT-02, is also progressing toward clinical stages. As a clinical-stage biotech firm, Accession Therapeutics is currently pre-revenue, with future income dependent on clinical milestones, upfront payments, and potential commercial royalties.

This £5.7m injection adds to a strong history of financial backing for the Oxford firm. Accession Therapeutics previously raised an £11m seed round in 2021, followed by a £16.6m Series A in late 2022. More recently, the company secured a £30.5m financing round in December 2025 to push its TROCEPT platform further into clinical trials. Existing backers of the company include Singapore-based iGlobe Partners, Primavera Capital Group, and Birk Venture.

The latest funding for Accession Therapeutics arrives amid a period of cautious optimism for the UK biotechnology sector. According to the BioIndustry Association, 2025 was a highly selective year for life sciences investment. Total venture capital investment in UK biotech fell by 13.2 percent year-on-year to £1.79bn across 58 deals.

Despite this contraction, the UK firmly retained its position as Europe's leading national biotech market, accounting for 30 percent of all European venture financing. The market also saw a sharp rebound in the final quarter of 2025, which recorded 22 completed deals, the highest quarterly count of the year. This late surge has signalled renewed investor confidence heading into 2026, particularly for clinical-stage companies demonstrating clear progress. The average deal size in the sector also rose to £30.8m in 2025, driven by a concentration of capital into high-conviction assets.

Accession Therapeutics will use its continued financial backing to generate full clinical data from its ongoing Phase 1 study of TROCEPT-01 and to advance its broader pipeline of first-in-class immunotherapies.