Boehringer bets up to $500m on Sitryx immunology programme

Germany's Boehringer Ingelheim could sink up to $500 million into a partnership with UK startup Sitryx focused on a family of small-molecule drugs for autoimmune and inflammatory diseases.

The deal includes upfront and milestone payments, as well as royalties, and gives Boehringer global rights to an undisclosed programme, with a novel mechanism of action, that the company reckons could deliver a disease-modifying drug with potential across multiple indications.

The privately-held German drugmaker gains a license to "multiple candidates and associated intellectual property within this small molecule inhibitor programme" and said it has full responsibility for "research, clinical development and commercialisation."

Oxford-based Sitryx, which also has operations in Boston in the US, was founded in 2018 with seed funding from SV Health Investors and raised $30 million in Series A funding, topped up with another $39 million in 2023, which took the total funding for the company north of $75 million.

Since then, the company has transitioned to a clinical-stage company, starting a phase 1a trial of its lead in-house programme, first-in-class oral PKM2 modulator SYX-5219, in atopic dermatitis last year. A phase 1b study started patient dosing earlier this year.

Boehringer is its second major partnership, coming after Sitryx joined forces with Eli Lilly in 2020 in a deal that spans up to four programmes for autoimmune diseases. The lead asset in the Lilly agreement – which included an upfront payment of $50 million and up to $820 million in development milestones – is a mimetic of the natural anti-inflammatory metabolite itaconate, codenamed SYX-1042, and completed a phase 1 trial in 2025.

Lilly has opted not to pursue that programme, returning rights to Sitryx, which has said it is looking at starting a development programme in psoriasis this year. Following after that, it has two preclinical-stage programmes, namely oral MTHFD2 and GLS-1 inhibitors.

The company has nominated a lead candidate in the MTHFD2 programme and is exploring development for psoriatic arthritis, with a lead GLS-1 inhibitor – with potential in disease characterised by inflammation and tissue remodelling – expected to be selected this year.

"Autoimmune and inflammatory diseases remain areas where innovation is urgently needed," said Carine Boustany, head of immunology and respiratory diseases research at Boehringer.

"Sitryx's small molecule inhibitor programme brings forward a promising new mechanism that aligns with our focus on advancing first-in-class approaches," she added.