
Annexon, Inc.
Unlocking the next generation of complement therapies
South San Francisco, United States · Founded 2016
- Headquarters
- South San Francisco, California
- Employees
- 1–10
- Founded
- 2016
- Business Model
- B2B
- Website
- annexonbio.com
- Last Round
- Series ENov 2025
- Rounds
- 6
About
Annexon Biosciences (Nasdaq: ANNX) is a clinical-stage biopharmaceutical company developing a new class of complement medicines targeting the classical complement pathway via C1q inhibition. Its pipeline addresses autoimmune, neurodegenerative, and ophthalmic disorders, with candidates including ANX005, ANX007, and ANX009 in clinical development. The company was founded in 2011 by Arnon Rosenthal and Ben Barres.
Summary
Annexon, Inc. is a Biopharmaceutical company based in South San Francisco, United States, founded in 2016. Its most recent funding was a Series E round in Nov 2025. Investors include GV, Alta Partners and Bain Capital Life Sciences.
Tech & App Stack
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Funding History
Nov 2025
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Full funding history, per-round amounts, and investor participation.
Investors
GV
1 round
Alta Partners
1 round
Bain Capital Life Sciences
1 round

Goldman Sachs
1 round
Wells Fargo
1 round
Omega Funds
1 round
Cowen Healthcare Investments
1 round
BlackRock
1 round
Deerfield Management
1 round
Eventide Asset Management
1 round
Farallon Capital
1 round
Janus Fund
1 round
Surveyor Capital
1 round
Adage Capital
1 round
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