Oyster Therapeutics, a London biotech developing pills that clear toxic proteins from the brain, has closed a $60M (£44.7M) Series A-2 round led by 4BIO Capital.
The company announced the financing on 10 November, alongside a new name. It was previously known as Kesmalea Therapeutics.
Eli Lilly and Company joined as a new investor, together with CE Ventures, Actium Group and TOHO Ventures, managed by Global Brain. Existing backers Syncona, Oxford Science Enterprises, Mission BioCapital and MGB Ventures also took part.
What does Oyster Therapeutics do?
Oyster works on targeted protein degradation, or TPD. The approach steers the cell's own waste-disposal system to break down proteins that cause disease.
Most degraders are large molecules. They struggle to cross into the brain and usually cannot be taken as a pill.
Oyster's SELFTAC platform gets around that. Its drugs are given as two small molecules that circulate separately and then assemble into the active degrader inside the body.
What is Oyster's lead drug?
The lead programme is an oral degrader that targets tau. Abnormal build-up of tau defines a group of diseases called tauopathies, the best known of which is Alzheimer's.
The drug is designed to enter the brain and remove harmful forms of tau while leaving healthy tau alone. A pill also allows room-temperature storage and cheaper manufacturing, which matters for diseases that affect millions of people.
Oyster has also signed a sponsored research deal with Massachusetts General Hospital. That work is led by Dr Catarina Silva, a tau researcher and assistant professor of neurology at Harvard Medical School.
What did the company and investors say?
Chief executive Rob Johnson said the financing speeds up Oyster's progress towards the clinic. He said it will help validate a new approach to TPD that fixes some of its biggest limits by using smaller molecules.
Owen Smith, partner at 4BIO Capital, said the firm backs teams like this with conviction before every question is answered.
CE Ventures, the Sharjah-based corporate venture arm of Crescent Enterprises, confirmed its investment on the same day.
Why is Lilly's involvement notable?
Lilly already sells Kisunla, an Alzheimer's drug that targets amyloid plaques rather than tau. Its stake gives Oyster a strategic backer with deep experience in the disease.
Tau has been a hard target. Several antibody-based tau drugs from large pharma companies have failed in trials, which is why a different mechanism has drawn attention.
What this means for UK founders
Oyster shows that London life sciences can still pull in global pharma money at Series A. It builds on earlier Bizztor coverage of Cytospire's £61M Series A, also led by 4BIO Capital.
The rebrand is worth noting too. Renaming at the point of a major raise is common in biotech, when a company moves from research platform to a drug candidate heading for patients.
You can track the wider sector in Bizztor's UK healthtech funding data and London startup funding data.