Cell-penetrating peptides as non-invasive drug delivery vehicles for ranibizumab and bevacizumab.

Abstract

Purpose : To investigate the efficacy of non-invasive delivery of ranibizumab and bevacizumab to the posterior segment using cell-penetrating peptides (CPP).

Methods : CPPs were synthesised using standard peptide synthesis. Delivery of ranibizumab and bevacizumab to the posterior segment was determined in rat eyes in vivo and porcine eyes ex vivo using ELISA. Synthesised CPPs were mixed with anti-VEGF and their efficacy was tested using an established model of choridal neovascularization. Neovascularisation was stimulated using a laser, the animals were then treated with i) CPP+anti-VEGF eye drop, ii) anti-VEGF eye drop, iii) CPP eye drop, iv) dexamethasone gavage v) anti-VEGF intravitreal injection (ivit), vi) saline eye drop. Outcomes were measured using retinal imaging and immunohistochemistry.

Results : After topical delivery in a rat model, a CPP+bevacizumab eye drop delivered 1.1±0.3µg/mL, significantly higher concentrations of bevacizumab to the vitreous than measured with the CPP, saline or bevacizumab eye drops which all gave readings below 0.01µg, (p= 0.001). Drug concentration peaked in the retina at 45 minutes after eye drop administration to the cornea and was cleared from the retina over 24 hours. In porcine eyes the CPP+ranibizumab eye drop delivered 1.7±0.4µg and the CPP+bevacizumab eye drop delivered 1.1±0.3µg of drug to the vitreous all significantly higher levels (p=0.004) than that measured after CPP, saline, ranibizumab or bevacizumab alone (<0.007µg) eye drops. After laser stimulation, neovascularization was observed in all mouse eyes. Mice which had an anti-VEGF ivit, CPP+anti-VEGF eye drop and dexamethasone gavage all had significantly lower (p<0.000) areas of neovascularization (498338 ±11015, 48338±5521 and 49898±10207µm² respectively) than eyes with no treatment (176195±43396µm²). Eyes treated with anti-VEGF eye drop (112802±18855µm²), CPP eye drop (89540±14706µm²) and PBS eye drop (105714±25149µm²) were not significantly different from the untreated eyes.

Conclusions : CPP can be used to deliver both ranibizumab and bevacizumab to the posterior segment in mouse, rat and pig eyes. The CPP delivered bevacizumab gave a 24 hour clearance time allowing a daily eye drop dosing regimen. The CPP delivered anti-VEGF showed efficacy in a disease model of neovascularization, with no significant differences between intravitreally injected anti-VEGF and topically delivered CPP anti-VEGF.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.