Safety and Target Engagement of Complement C1q Inhibitor ANX007 in Neurodegenerative Eye Disease: Results from Phase I Studies in Glaucoma

Complement C1q, the initiating molecule of the classical complement cascade, is involved in synapse elimination and neuronal loss in neurodegenerative diseases including glaucoma. Here we report an evaluation of the safety, tolerability, and ocular pharmacokinetics (PK) and pharmacodynamics of intravitreal (IVT) injections of ANX007, an anti-C1q monoclonal antibody fragment that blocks activation of the classical complement cascade. An open-label, single-dose-escalation phase Ia study followed by a double-masked, randomized, sham-controlled, repeat-injection phase Ib study. A total of 26 patients with primary open-angle glaucoma. Nine patients with primary open-angle glaucoma (mean Humphrey visual field deviation between -3 and -18 decibels [dB]) were enrolled in phase Ia and received single doses of ANX007 (1.0 mg, n = 3; 2.5 mg, n = 3; or 5.0 mg, n = 3). Seventeen patients (mean Humphrey visual field deviation between -3 and -24 dB) were enrolled in phase Ib and randomized to 2 monthly doses of ANX007 (sham, n = 6; 2.5 mg ANX007, n = 6; or 5 mg ANX007, n = 5). Safety and tolerability (including laboratory evaluation of urinalysis, complete blood count, and serum chemistries), ANX007 PK, target engagement, and immunogenicity. The mean age overall was 70 years in phase Ia and 68 years in phase Ib. In both studies, no serious adverse events were observed, no non-ocular treatment-emergent adverse events (TEAEs) attributable to study drug were reported, and ocular TEAEs were mild. Intraocular pressure returned to normal levels for all patients within 45 minutes of IVT injection. No clinically significant deviations in laboratory results were observed. In the phase Ib study, C1q in the aqueous humor was reduced to undetectable levels in both the 2.5 mg and 5 mg cohorts 4 weeks after the first ANX007 dose. In these studies, single and repeat IVT ANX007 injections were well tolerated and demonstrated full target engagement 4 weeks after dosing with both low and high doses, supporting monthly or less-frequent dosing. Further investigation in neurodegenerative ocular diseases is warranted. Proprietary or commercial disclosure may be found after the references.