Annexon (NASDAQ:ANNX) used its Investor Day presentation to outline the scientific rationale and clinical progress for vonoprument (ANX007), an intravitreal therapy being developed for geographic atrophy (GA) secondary to dry age-related macular degeneration. Company leaders and invited retinal experts emphasized that GA is a progressive neurodegenerative disease marked by photoreceptor loss and central vision decline, and argued that preserving visual function—rather than solely slowing lesion growth—should be the clinical priority.
Company focus and C1q rationale
President and CEO Doug Love described Annexon’s platform as targeting harmful inflammation driven by C1q, the initiating molecule of the classical complement pathway. Love said the company’s approach is intended to stop inflammation “where it starts on diseased tissue,” which he characterized as a competitive advantage over downstream complement approaches such as C3 and C5.
GA viewed as a neurodegenerative disease with major unmet need
SVP of Ophthalmology and Strategy & Innovation Lloyd Clark, a practicing retina specialist, framed GA as “the largest unmet need in retina today,” stating that there are currently no approved therapies that preserve vision in GA. He described common patient difficulties—especially low-light impairment—and said patients fear loss of independence.
Clark cited prevalence figures discussed during the event, including about 8 million people affected worldwide and about 1.5 million in the U.S. He also emphasized that visual acuity remains the “gold standard” endpoint for transformative retinal therapies, noting that historically meaningful approvals in other retinal diseases have been tied to 15-letter visual acuity outcomes.
Expert overview: C1q upstream vs. downstream complement targets
Dr. Eleonora (Nora) Lad of Duke University provided a scientific overview linking GA-related vision loss to early photoreceptor and synapse dysfunction. She contrasted C1q inhibition with recently approved complement inhibitors that target C3 and C5, which she said were designed to address retinal pigment epithelium (RPE) atrophy and lesion growth. Lad said those therapies have not demonstrated predefined vision preservation in their pivotal trials, while photoreceptor injury—associated with vision decline—appears to precede RPE loss.
Lad presented C1q as an upstream trigger that aberrantly tags functional synapses in aging and neurodegenerative disease, recruiting microglia and driving synaptic loss. She said C3 and C5 are downstream and more involved in clearing dysfunctional cells at the lesion edge, occurring later in the disease process. Lad also discussed preclinical findings described during the event showing that C1q inhibition reduced inflammation and preserved photoreceptor synapses and retinal function in animal models, and she showed histopathology images described as demonstrating C1q deposition on synapses in human GA tissue.
ARCHER phase II: structural signals and vision outcomes
Dr. Charles Wykoff, Chair of Clinical Trials for Retina Consultants of America, reviewed results from the 270-patient phase II ARCHER trial. He described vonoprument as a small biologic (50 kDa), non-PEGylated, low-viscosity product administered in a small injection volume (25 microliters in the phase III program). Wykoff said early clinical data presented showed complete target engagement at 29 days following a single injection in a small trial in glaucoma patients.
In ARCHER, patients were randomized to monthly dosing, every-other-month dosing, or sham, with 12 months of treatment followed by six months off treatment. Wykoff said the trial’s primary endpoint—GA lesion growth measured by fundus autofluorescence (FAF)—was not met. He noted a numerical 6% slowing with monthly dosing overall and described a larger signal in the second six months of treatment than in the first. In patients with subfoveal lesions, he described a larger second-half signal of 14% to 16% growth reduction in that period.
Wykoff also emphasized OCT-based measures of photoreceptor integrity, focusing on ellipsoid zone (EZ) loss, which he said is strongly associated with visual function. In a subset of 192 patients with Heidelberg imaging, he described reductions in EZ-based lesion growth of 27% across a 6×6 mm scan, increasing to 48% and 59% when analyzing areas closer to the foveal center.
On functional outcomes, Wykoff said ARCHER showed dose-dependent protection against confirmed 15-letter best-corrected visual acuity (BCVA) loss, including a reported 73% reduction in risk in a Kaplan-Meier analysis for monthly dosing. He also reviewed supportive findings on mean visual acuity and low-luminance measures, and he discussed subgroup analyses indicating higher event rates in eyes with foveal involvement—an observation presented as relevant for phase III trial enrichment.
Regarding safety, Wykoff said ARCHER did not show an increased rate of choroidal neovascularization compared with sham. He reported one retinal vascular occlusion event in an every-other-month patient that was described as not associated with vasculitis and believed related to comorbid disease. He also reported three cases of mild or moderate intraocular inflammation that resolved with topical steroids, and no cases of vasculitis or ischemic optic neuropathy.
ARCHER II phase III program: design, enrichment, and timeline
Chief Medical Officer Jamie Dananberg detailed the global ARCHER II phase III study, which randomized 659 patients in a double-masked, sham-controlled design with a 2:1 active-to-control ratio. Sites include the U.S. and Canada, Europe and the U.K., and Australia and New Zealand. Dananberg said the primary time point is when all patients have data through 15 months, with top-line results expected in Q4 of this year; the trial continues masked through 24 months.
Dananberg said the program was designed for global registration using a single protocol. He noted the European Medicines Agency supports a single study for registration and said Annexon has PRIME designation. He also said the FDA agreed to the single protocol but recommended partitioning sites into two independent sub-studies for separate analyses consistent with historical precedent.
He described three key phase III design adjustments based on phase II learnings:
- Exclude patients with very low baseline vision: ARCHER II excludes baseline BCVA of 45 letters or less, which Dananberg said were less likely to experience additional 15-letter loss events.
- Enrich for subfoveal lesions: The trial aims for a higher proportion of subfoveal GA, which was presented as having higher event rates.
- Extend the primary endpoint to 15 months: This was described as capturing additional vision-loss events beyond 12 months.
Dananberg said event accrual is tracking in line with expectations, patient retention has been strong, and a data safety monitoring committee has not recommended protocol changes based on its unmasked reviews.
During Q&A, presenters discussed the clinical significance of a 15-letter loss threshold, with Lad describing the impact on daily functioning and independence, and Wykoff noting regulators’ longstanding preference for the endpoint due to reproducibility and clinical meaning. Company representatives also said work is underway on a pre-filled syringe and discussed pricing considerations in general terms, indicating current GA therapy pricing would likely serve as a floor while emphasizing alignment with patient value.
About Annexon (NASDAQ:ANNX)
Annexon Inc is a clinical-stage biotechnology company focused on the discovery and development of complement-targeted therapies for patients with neurodegenerative and neuroimmune diseases. The company’s research platform centers on the inhibition of the C1 complex, a key initiator of the classical complement pathway implicated in several rare and life-threatening disorders. By selectively targeting upstream complement activation, Annexon aims to prevent the aberrant immune-mediated damage that characterizes conditions such as Guillain-Barré syndrome (GBS) and autoimmune neuropathies.
At the core of Annexon’s pipeline is ANX005, a humanized monoclonal antibody directed against the C1q subcomponent, currently in Phase 2 clinical trials for acute GBS and chronic neurodegenerative indications.
