Oyster Therapeutics Raises $60 Million for Tau Drug
The London biotech, formerly Kesmalea, will advance an oral tau-targeting Alzheimer's candidate after a first-round financing led by 4BIO Capital.
Updated on Nov. 10, 2026 in Biotech
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Oyster Therapeutics, formerly known as Kesmalea and based in London, raised $60 million in first-round Series A financing led by 4BIO Capital, with Eli Lilly participating as a new investor. The company also entered a sponsored research agreement with Massachusetts General Hospital to access tau biology expertise.
Why it matters
Tau-targeting approaches have a mixed record in Alzheimer's research, and several prominent tau programs have failed. Oyster's oral, brain-penetrant candidate is positioned as an alternative to bispecific degraders that require injection and struggle to reach the central nervous system.
Oyster's lead candidate is an oral, brain-penetrant tau degrader built on its SELFTAC platform, which uses two small molecules that self-assemble in the body into an active form. Its clinical performance and dosing data remain unreported.
The players
Oyster Therapeutics
A London-based biotech formerly known as Kesmalea, developing oral tau-targeting degraders for Alzheimer's disease built on its SELFTAC platform.
Eli Lilly
A major pharmaceutical company that participated as a new investor in Oyster's financing and has previously pursued tau-targeting programs that did not succeed.
Massachusetts General Hospital
A Boston teaching hospital and research institution with which Oyster entered a sponsored research agreement to access tau biology expertise.
The details
The financing was led by 4BIO Capital, with new investor Eli Lilly and existing backers including CE Ventures, Actium Group, TOHO Ventures, Syncona, Oxford Science Enterprises, Mission BioCapital, and MGB Ventures participating. The company's SELFTAC degraders are designed to remove tau and other target proteins using cells' innate protein-clearance machinery.
Timeline
- November 10, 2026: Oyster announced the $60 million financing and rebrand from Kesmalea.
The Tech Race
Several named tau-targeting programs from Johnson & Johnson and Eli Lilly have failed, leaving the tau approach with an uncertain record. Oyster's SELFTAC degraders differ from bispecific degraders by being small enough to dose orally and reach the central nervous system.
For people living with or caring for someone with Alzheimer's, an oral tau-targeting drug would be a far more accessible format than injected therapies, though no candidate has yet been shown to work clinically. Patients and families should not expect any new treatment from this financing in the near term.
The takeaway
Tau-directed drugs have a difficult record, so investment in new mechanisms is best read as a bet still awaiting clinical proof. Readers interested in Alzheimer's progress should watch for early human data before drawing conclusions.
Further reading
Explore more Biotech developments shaping drug discovery and neurodegenerative disease research.
Source note: This article includes information reported by Pharmaphorum.
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