Shares of Annexon (ANNX) fell 6.75% to $4.075 following the company's presentation at the 12th Annual Cantor Fitzgerald Global Healthcare Conference on Thursday, Sept. 10, as investors digested clinical update details rather than financial results.
The biotech reported that its phase III ARCHER II trial of vonoprument (ANX007), a complement inhibitor targeting geographic atrophy (GA), has enrolled 659 patients across the U.S. and Europe — approximately 30 above its target. The trial employs a 2-to-1 randomization favoring the active monthly treatment arm. According to CEO Doug Love, the dropout rate sits below 10% and compliance exceeds 90%. Dual primary readouts are scheduled for month 15 and month 24, with a Data Monitoring Committee review anticipated in Q4 2026.
Love provided further detail on the phase II ARCHER study outcomes, disclosed in May 2023, which showed a 73% reduction in the risk of greater than 15-letter visual acuity loss at 12 months. Three out of four patients had their vision protected in the trial, according to Love, while 50% to 60% protection was observed in the central foveal region measured by ellipsoid zone data. A patient subgroup with low light visual deficit under 30 saw zero out of 56 patients on the monthly treatment arm experience 15-letter vision loss events compared to 17% in the sham group. In the second six months of treatment, vonoprument produced a 10.5% reduction in retinal pigment epithelium lesion growth.
Lloyd Clark, Annexon's senior vice president of ophthalmology strategy and a former practicing retina specialist, emphasized the clinical significance of the 15-letter loss endpoint, noting that losing that threshold typically renders a patient unable to drive or read small print. He added that protecting photoreceptors appears to subsequently protect underlying RPE cells, consistent with observed study findings.
On the Guillain-Barré syndrome front, Annexon reported open-label data showing a 100% response rate at week 1. The company previously reported a 90% response rate from its phase III GBS data. Regulatory filings have already been submitted in Europe, with an FDA filing planned by year-end 2024.
The GA market affects an estimated 8 million people worldwide. Current treatment penetration remains low, with only about 20% of patients receiving therapy and only 20% of retina specialists using available treatments, according to the conference presentation.
Financially, Annexon burned through approximately $193 million in free cash flow over the trailing twelve months. Shares have traded between $2.27 and $7.18 over the past year and are up roughly 91% over that period. Previous close was $4.37. Patent protection is expected through the 2040s, Love said.
"We are a complement-focused company, really stopping neuroinflammation right where it starts, on disease tissue in the body, brain, and eye," Love told attendees at the conference, held Thursday.
