Annexon Biosciences announced the addition of a dual primary endpoint at Month 24, to complement the current Month 15 primary endpoint in its phase 3 ARCHER II trial, and launch of an open-label extension (OLE) study of vonaprument for the treatment of dry age-related macular degeneration (AMD) with geographic atrophy (GA). With a dual primary endpoint strategy, ARCHER II can achieve success in protecting against vision loss at either Month 15 or 24, which are independent efficacy timepoints, the company said in a press release.

In the ongoing global, double-masked phase 3 ARCHER II trial, all eligible patients received at least 12 months of treatment, and the company said the study retains strong statistical power and continues to be well-executed with a low discontinuation rate (<10%) and high compliance (>95%).

Upon completion of Month 24, all patients have the option to receive monthly vonaprument treatment in the OLE study, which is designed to evaluate the long-term safety and benefit of vonaprument in patients with GA.

An independent Data Monitoring Committee (DMC) will assess the primary endpoint of the overall study at Month 15, and the company said it expects to report the DMC’s assessment in the fourth quarter of 2026. Completion of ARCHER II, including the Month 24 analyses, is expected in the third quarter of 2027, the company said.

Vonaprument, which has received Fast Track Designation from the US Food and Drug Administration (FDA), is a clinical-stage investigational antigen-binding fragment designed as a first-in-kind therapeutic to selectively inhibit C1q, the initiating molecule of the classical complement pathway and a key driver of neurodegeneration. It is formulated for intravitreal administration, and involves a neuroprotective approach designed to protect photoreceptor cells and retinal function by blocking C1q and the entire classical pathway, while allowing for normal immune activity of the lectin and alternative complement pathways, the company said. RP