Abstract
Purpose :
Choroidal neovascularization (CNV) is a feature of neovascular age-related macular degeneration (nAMD) pathology. Apurinic/apyrimidinic endonuclease 1/reduction-oxidation factor 1 (APE1/Ref-1) is a potential therapeutic target for nAMD and other ocular diseases. The redox function of Ref-1 regulates key features of nAMD, such as inflammation and angiogenesis, via transcriptionally activating HIF-1α, NF-κB and STAT3. Ref-1 inhibitor APX3330 has recently completed a Phase IIb clinical trial for diabetic retinopathy. This study aimed to assess ocular pharmacokinetics (PK) and antiangiogenic efficacy of a second-generation Ref-1 inhibitor, APX2009 in human choroidal endothelial cells and intravitreally (IVT) in murine laser-induced CNV (L-CNV).
Methods :
Proliferation, tube formation and cell cycle analysis of induced pluripotent stem cell-derived choroidal endothelial cells (iCECs) treated with APX2009 were performed in vitro. APX2009 (10 µM) was injected IVT in 8-week old, C57BL/6J mouse eyes. Eyes were harvested over a time course to assess PK by LC-MS. L-CNV was generated in 7-week old, female mouse eyes. Mice received single IVT injections of APX2009 (25 and 50 µM), anti-VEGF antibody (5 ng), and vehicle on day 0, with eyes harvested on day 7. Fundus imaging, optical coherence tomography (OCT), fluorescein angiography (FA), and ex vivo isolectin B4 and agglutinin staining were performed to assess CNV.
Results :
In vitro, APX2009 reduced iCEC proliferation (GI50=3.0 µM) and tube formation. Further, APX2009 blocked the cell cycle at S-phase without causing apoptosis. APX2009 had an ocular half-life of 1.57 and 1.11 h in female and male mice respectively after IVT injection. In vivo OCT and FA and ex vivo confocal imaging analyses showed that APX2009 reduced lesion volume by >40% (p<0.05, n=8-15, ANOVA with Dunnett’s post hoc test) and decreased fluorescein leakage in mouse eyes with L-CNV.
Conclusions :
Sub-micromolar doses of APX2009 substantially inhibited proliferation, tube formation and cell cycle of iCECs and despite a short half-life, a single IVT dose of APX2009 markedly reduced L-CNV in mouse eyes 7 days post-treatment, suggesting the antiangiogenic potential of APX2009 in CNV. Overall, this study provides a rationale that APX2009 could be explored further for its clinical use alone or in combination with anti-VEGF therapies.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.