Human anti-α3(IV)NC1 antibody drug conjugates target glomeruli to resolve nephritis

Current therapies to limit kidney disease progression lack specificity and often have systemic toxicity. To approach this problem, we postulated that a human monoclonal antibody (F1.1), directed against the noncollagenous-1 domain (NC1) of α3(IV) collagen that localizes in glomeruli, could serve as a vehicle for targeted drug delivery. Given enhanced exposure of the NC1 domain of α3(IV) during glomerular diseases, with limited epitope expression in other organs, α3(IV)NC1 provides an ideal target for delivery of disease-modifying agents. As a potential disease-modifying agent, we initially took advantage of recent observations that PGE2 promoted recovery after established injury during the course of nephrotoxic nephritis. To address the general applicability of the approach, the efficacy of glomerular delivery of dexamethasone was also examined. To achieve glomerular targeted therapy, PGE2 and dexamethasone were coupled to F1.1. After confirmation of the composition and activity of the conjugates, both glomerular localization and the capacity of the conjugates to modify disease were evaluated. After injection into mice with established nephritis, resolution of disease was enhanced with both agents, with normalization of histology and improved blood urea nitrogen levels in conjugate-treated mice compared with untreated mice. The results provide a novel means of targeting glomeruli during nephritis, irrespective of cause, by providing efficient drug delivery, with the potential of limiting systemic effects.