Annexon Biosciences

Overview

Annexon Biosciences is a clinical-stage biopharmaceutical company headquartered in Brisbane, California, focused on developing novel therapeutics that inhibit the complement cascade to treat neurodegenerative diseases and autoimmune conditions. The company's lead asset targets C1q, the initiating molecule of the classical complement pathway, which plays a critical role in synaptic elimination and neuroinflammation[@annexon2024].

Company Overview

Annexon was founded in 2011 and went public in 2020 (NASDAQ: ANNX). The company leverages its understanding of complement biology to develop treatments for conditions where complement-mediated inflammation contributes to disease pathology.

Funding

• IPO: 2020 (NASDAQ: ANXN)
• Market Cap: ~$100M (2026)

Leadership

• CEO: Douglas Love (since 2019)
• Founded: 2011
• Headquarters: Brisbane, California
• Employees: ~100-150

Pipeline

| Drug Candidate | Indication | Stage | Mechanism | Notes |
|----------------|------------|-------|------------|-------|
| ANX005 | Guillain-Barré Syndrome | Phase 3 | Anti-C1q mAb | Received FDA Fast Track designation |
| ANX005 | Huntington's Disease | Phase 2 | Anti-C1q mAb | Targeting complement-mediated neurodegeneration |
| ANX007 | Geographic Atrophy (GA) | Phase 2 | Anti-C1q Fab | Intravitreal formulation |
| ANX010 | Amyotrophic Lateral Sclerosis (ALS) | Preclinical | Anti-C1q mAb | Pipeline expansion |

Clinical Programs

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Overview

Annexon Biosciences is a clinical-stage biopharmaceutical company headquartered in Brisbane, California, focused on developing novel therapeutics that inhibit the complement cascade to treat neurodegenerative diseases and autoimmune conditions. The company's lead asset targets C1q, the initiating molecule of the classical complement pathway, which plays a critical role in synaptic elimination and neuroinflammation[@annexon2024].

Company Overview

Annexon was founded in 2011 and went public in 2020 (NASDAQ: ANNX). The company leverages its understanding of complement biology to develop treatments for conditions where complement-mediated inflammation contributes to disease pathology.

Funding

• IPO: 2020 (NASDAQ: ANXN)
• Market Cap: ~$100M (2026)

Leadership

• CEO: Douglas Love (since 2019)
• Founded: 2011
• Headquarters: Brisbane, California
• Employees: ~100-150

Pipeline

| Drug Candidate | Indication | Stage | Mechanism | Notes |
|----------------|------------|-------|------------|-------|
| ANX005 | Guillain-Barré Syndrome | Phase 3 | Anti-C1q mAb | Received FDA Fast Track designation |
| ANX005 | Huntington's Disease | Phase 2 | Anti-C1q mAb | Targeting complement-mediated neurodegeneration |
| ANX007 | Geographic Atrophy (GA) | Phase 2 | Anti-C1q Fab | Intravitreal formulation |
| ANX010 | Amyotrophic Lateral Sclerosis (ALS) | Preclinical | Anti-C1q mAb | Pipeline expansion |

Clinical Programs

ANX005 in Huntington's Disease

Huntington's disease (HD) is a fatal genetic neurodegenerative disorder characterized by progressive motor dysfunction, cognitive decline, and psychiatric symptoms. Annexon's approach targets C1q, which is elevated in HD brains and contributes to synaptic dysfunction and neuronal loss[@anx2023].

The Phase 2 trial of ANX005 in HD patients evaluated safety and biomarkers of complement activation. The company reported that ANX005 was generally well-tolerated and showed evidence of target engagement.

ANX005 in Guillain-Barré Syndrome

Guillain-Barré Syndrome (GBS) is an acute autoimmune disorder where the immune system attacks peripheral nerves. ANX005 has been evaluated in a Phase 1b/2 study showing promising results in reducing complement activation markers[@synaptic2022].

ANX007 in Geographic Atrophy

Geographic atrophy is an advanced form of age-related macular degeneration (AMD) leading to irreversible vision loss. ANX007 is being developed as an intravitreal therapy to inhibit C1q-mediated inflammation in the retina[@fda].

Science and Technology

Annexon's platform is built on the understanding that the [complement system](/entities/complement-system), particularly C1q, plays a dual role in immune surveillance and pathological inflammation. In neurodegenerative diseases, excessive C1q activation leads to:

• Synaptic pruning and loss
• [Microglia](/cell-types/microglia)l activation
• [Neuroinflammation](/mechanisms/neuroinflammation)
• Neuronal dysfunction

By inhibiting C1q, Annexon's therapeutics aim to protect synapses and preserve neuronal function[@guillainbarr].

Financials

• Market Cap: ~$100-200 million (as of 2024)
• Cash Position: Approximately $150-200 million (as of latest filings)
• Key Investors: Perceptive Advisors, Avidity Partners, Cormorant Asset Management

Partnerships

Annexon has collaborated with academic institutions and has received grant funding from the Huntington's Disease Society of America and other organizations to support its clinical programs.

Related Pages

• [Huntington's Disease](/diseases/huntington-disease)
• [Guillain-Barré Syndrome](/diseases/guillain-barre-syndrome)
• [Geographic Atrophy](/diseases/geographic-atrophy)
• [Amyotrophic Lateral Sclerosis](/diseases/amyotrophic-lateral-sclerosis)
• [Complement System](/mechanisms/complement-system-neurodegeneration)
• [Neuroinflammation](/mechanisms/neuroinflammation)

See Also

• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)

External Links

• [PubMed](https://pubmed.ncbi.nlm.nih.gov/)
• [KEGG Pathways](https://www.genome.jp/kegg/pathway.html)

References

Unknown, Annexon Biosciences Corporate Presentation (2024) (2024)

[Unknown, ANX005 in Huntington's Disease Phase 2 Results (2023)](https://doi.org/10.1016/j.neurobiolaging.2023.01.005)

[Unknown, C1q in Synaptic Pruning and Neurodegeneration (2022)](https://doi.org/10.1016/j.neuron.2022.03.010)

Unknown, FDA Fast Track Designation for ANX005 (n.d.)

[Unknown, Guillain-Barré Syndrome Treatment Landscape (n.d.)](https://doi.org/10.1212/WNL.0000000000207501)

[Unknown, Geographic Atrophy and Complement Inhibition (2023)](https://doi.org/10.1016/j.ophtha.2023.09.023)

Pathway Diagram

The following diagram shows the key molecular relationships involving Annexon Biosciences discovered through SciDEX knowledge graph analysis: