Oyster Therapeutics Raises $60 Million to Develop Alzheimer’s Drugs

Oyster Therapeutics, formerly known as Kesmalea Therapeutics, has raised $60 million in Series A financing to advance its next-generation targeted protein degradation programmes for Alzheimer’s disease and other neurodegenerative conditions. The company has also announced its rebranding as it prepares to move its lead drug candidate towards clinical development.

Announced on November 10, 2026, the funding round was led by London-based investment firm 4BIO Capital, with participation from new and existing investors. New investors include Eli Lilly and Company, CE Ventures, Actium Group and TOHO Ventures, managed by Global Brain. Existing investors Syncona, Oxford Science Enterprises, Mission BioCapital and MGB Ventures also participated.

The funding will primarily support the development of Oyster’s lead programme, an oral drug candidate designed to target the tau protein. The company aims to advance this candidate into clinical development as a potential treatment for Alzheimer’s disease and other tau-related conditions.

Developing a New Approach to Alzheimer’s Treatment

Tau is a protein that plays an important role in maintaining the structure of nerve cells. However, abnormal changes in tau can cause it to build up in the brain, disrupting communication between nerve cells and contributing to neurodegenerative diseases such as Alzheimer’s.

Oyster’s lead drug candidate is designed to selectively remove harmful forms of tau while preserving the healthy forms of the protein. The company is developing it as an oral treatment that can cross the blood-brain barrier and reach the central nervous system.

The ability to reach the brain is a major challenge in developing targeted protein degradation treatments for neurological diseases. Many conventional protein degraders are relatively large molecules, making it difficult for them to cross the blood-brain barrier.

To address this challenge, Oyster is developing its proprietary SELFTAC® platform, which is designed to create smaller targeted protein degraders with improved drug-like properties.

The technology allows smaller components of a degrader to cross biological membranes before coming together to form a functional molecule that directs disease-causing proteins towards the cell’s natural disposal system.

The company believes this approach could improve brain penetration and oral availability, opening new possibilities for treating neurological conditions.

Research Collaboration with Massachusetts General Hospital

Alongside the financing, Oyster has entered into a sponsored research agreement with Massachusetts General Hospital (MGH) to strengthen its research into tau-related diseases.

The collaboration will provide access to specialised tau research capabilities, including patient-derived neuronal cell lines and techniques to study oligomeric tau, a form of the protein considered particularly harmful to nerve cells.

The research will be conducted under the supervision of Dr. Catarina Silva, an investigator at the Mass General Brigham Neuroscience Institute and Assistant Professor of Neurology at Harvard Medical School.

Strengthening the Targeted Protein Degradation Pipeline

Rob Johnson, CEO of Oyster Therapeutics, said the new funding would help the company move its lead programme towards clinical development while continuing to advance its SELFTAC platform.

He highlighted the need for new treatment approaches that can address the underlying causes of diseases such as Alzheimer’s, rather than only managing their symptoms.

Owen Smith, Partner at 4BIO Capital, said Oyster’s approach could help overcome important technical challenges in targeted protein degradation, particularly the difficulty of delivering these treatments to the brain.

With the $60 million financing, Oyster plans to advance its lead tau degrader and expand its wider research platform. The company’s work reflects growing interest in targeted protein degradation as a potential treatment strategy for neurodegenerative diseases, an area where new therapeutic approaches are still urgently needed.