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Annexon Biosciences Inc. has raised over $75M investment to build classical complement pathway treatments

Annexon Biosciences Inc. (San Francisco, California, USA) has raised $75 million investment to fund development of its lead complement inhibitors through several clinical stages, according to the company. The investment of venture funds was led by Bain Capital Life Sciences, Surveyor Capital and Adage Capital Partners, which also include NEA, Blackstone Life Sciences, Novartis Venture Fund and Satter Investment Management.


The complement cascade is an innate part of the immune defence system, consisting of over 30 serum proteins. In general, substances on the surface of microbes or other infectious agents can trigger the complement cascade, which then activates a series of biochemical steps leading to the lysis (or bursting) of invading cells. However, certain complement proteins may also help trigger inflammation. Several components of the complement cascade have been found in drusen deposits which led to the hypothesis that AMD may result from dysfunctional inflammation which incorporates inappropriate complement activation. A series of seminal papers over 12+ years ago established an association between variants in complement genes and increased risk of AMD, findings which attracted significant attention in the search for a clinical target. The complement pathway contains three arms – classical, alternative and lectin – all of which converge on C3, potentially making the molecule a key therapeutic target. Lead drug candidates, ANX005 and ANX007, are potent inhibitory antibodies against C1q, the initiating molecule of the classical complement cascade. They block activation of the entire classical pathway, including downstream C3 and C5, while leaving the protective functions of other complement pathways (lectin and alternative pathways) intact. ANX007 has the same C1q inhibition properties as ANX005 and is designed for treatment of ophthalmic diseases such as glaucoma and geographic atrophy. Local administration enables target engagement within the eye while leaving the complement pathway to function elsewhere in the body. ANX007 IVT is designed by an antigen binding fragment (Fab) for use in ophthalmic settings including the company of a Phase 1b proof-of-principle study, expected to read potential results in some time to the completion in FY2019.


According to Doug Love, Esq., Chief Executive Officer and President of Annexon, the company states that, “[t]he classical complement pathway plays a central role in immunity. Malfunction or disruption of this pathway is at the core of many diseases and represents an attractive target for therapeutic intervention. We have made great strides in building a portfolio of product candidates across multiple indications over the past two years. Proceeds from this financing will fund our lead programs in antibody-mediated autoimmune, ophthalmic and neurodegenerative indications through several clinical stages, including completion of proof-of-concept trials. Further, these funds will also support the rapid advancement of our next generation drug candidates in autoimmune and neurodegenerative settings.”