# Oyster Therapeutics (formerly Kesmalea Therapeutics)

> London preclinical biotech developing small oral, brain-penetrant targeted protein degraders for tau-linked neurodegenerative diseases.

## Why it is interesting

November 10, 2026 company statement confirms a $60M Series A-2, led by 4BIO Capital, and a rebrand from Kesmalea. The separately issued lead-investor release shortens the stage to 'Series A'; these refer to the same financing. SELFTAC and the tau degrader remain preclinical; no human efficacy is established.

## Profile

- **Latest funding:** Series A-2 — $60M (November 10, 2026)
- **Latest known valuation:** Undisclosed (November 10, 2026)
- **Total disclosed equity funding:** $60M
- **Stage:** series-a
- **Status:** private
- **Industries:** N/A
- **Coverage:** full
- **Last updated:** 2026-11-11
- **Latest funding investors:** 4BIO Capital, Eli Lilly and Company, CE Ventures, Actium Group, TOHO Ventures, Syncona, Oxford Science Enterprises, Mission BioCapital, MGB Ventures

## Key facts

- $60M Series A-2 announced Nov 10, 2026; do not relabel as a new Series B or a separate Series A.
- Rebranded from Kesmalea, the same legal company lineage; avoid creating two startups.
- Lead oral tau degrader at preclinical stage; no human efficacy or confirmed clinical start.
- Massachusetts General Hospital sponsored research collaboration disclosed, not clinical trial.
- Historical 2022 financing and 2023 extension exist and are distinct from this A-2; FX conversion required before public numeric backfill.

## Funding history

- Series A-2 · $60M · November 10, 2026
  Source: https://www.businesswire.com/news/home/20261109552229/en/

**By:** [Venture Capital Tracker](https://venturecapitaltracker.com/editorial-policy)
**Last updated:** November 11, 2026

**Editorial note:** AI tools assisted with research, structure, or drafting. Venture Capital Tracker retains human editorial responsibility for factual accuracy, relevance, and source quality before publication.

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Source: https://venturecapitaltracker.com/startup/oyster-therapeutics