Annexon Announces Initiation of Phase 2/3 Trial of ANX005 in Patients with Guillain-Barré Syndrome

SOUTH SAN FRANCISCO, CA, USA I December 21, 2020 I Today, Annexon, Inc. (“Annexon”) (Nasdaq: ANNX), a clinical stage biopharmaceutical company developing novel therapies for patients with classical complement-mediated disorders of the brain, body, and eye, announced that patient dosing has started in a Phase 2/3 clinical study of full-length monoclonal antibody, ANX005, to treat Guillain-Barré Syndrome (GBS). GBS is a rare, acute, antibody-mediated autoimmune disease that impacts the peripheral nervous system and can lead to acute paralysis and/or permanent disability from nerve loss.

“We are pleased to advance our GBS program into later-stage clinical development, bringing us closer to potentially delivering a much-needed treatment option to patients combatting this debilitating disease,” said Douglas Love, president and chief executive officer of Annexon. “The advancement of ANX005 also continues to inform our ongoing clinical development across a host of additional complement-mediated autoimmune and neurodegenerative diseases.”

Currently there are no approved therapies in the United States for GBS.  ANX005 has received both Fast Track and Orphan Drug designations for the treatment of GBS.

“There is strong scientific rationale that blocking initiation of the classical complement cascade through specific inhibition of C1q has potential as a therapeutic intervention for GBS,” said Hugh Willison, M.D., Professor of Neurology, Head of Neuroinflammation, Glasgow Biomedical Research Centre. “This anti-C1q approach is designed to act early in the disease course to prevent nerve damage and irreversible neurological disability in GBS patients.” 

About the Clinical Trial and ANX005

The randomized, placebo-controlled Phase 2/3 trial is designed to evaluate the efficacy of ANX005 in improving disability in GBS patients. In addition to this study, Annexon has fully enrolled a global GBS drug-drug interaction (DDI) trial assessing safety and potential pharmacokinetic effect of ANX005 co-administered with IVIg in GBS patients. Data are anticipated from the GBS DDI trial in early 2021. Annexon completed a Phase 1b trial of ANX005 in patients with GBS that demonstrated full target engagement of C1q in serum and the cerebrospinal fluid (CSF), as well as a significant reduction in neurofilament light chain (NfL), a well-accepted biomarker shown to be elevated in patients with GBS and correlated with disease severity and clinical outcomes.

ANX005 is an IV formulated monoclonal antibody designed to inhibit C1q and the entire classical complement pathway. ANX005 is intended to treat patients with antibody-mediated autoimmune and complement-mediated neurodegenerative disorders. Annexon has completed a Phase 1b monotherapy clinical trial of ANX005 in GBS and has received Fast Track and Orphan Drug designations from the U.S. Food and Drug Administration for the treatment of GBS.

More information can be found at

About Annexon, Inc.

Annexon is a clinical-stage biopharmaceutical company developing a pipeline of novel therapies for patients with classical complement-mediated disorders of the brain, body and eye. The company’s pipeline is based on its platform technology addressing well-researched classical complement-mediated autoimmune and neurodegenerative disease processes, both of which are triggered by aberrant activation of C1q, the initiating molecule of the classical complement pathway. Annexon is deploying a disciplined, biomarker-driven development strategy designed to identify patients, and to measure target engagement and response to treatment. For more information, visit

SOURCE: Annexon

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