Abstract
Purpose:
Bolus injections of intravitreal (IVT) anti-Vascular Endothelial Growth Factor (VEGF) monoclonal antibodies are the standard of care for Age-Related Macular Degeneration (AMD), Diabetic Macular Edema (DME), and other ocular diseases, but current therapies require frequent dosing due to the short half-life of these proteins in the vitreous. The development of extended release delivery systems of anti-VEGF therapies would significantly decrease this treatment burden and improve outcomes. The implant is engineered to provide extended release of bevacizumab by combining solid state protein PRINT® microparticles with biodegradable hydrogel matrices.
Methods:
The IVT implant was formulated with size- and shape-specific protein PRINT microparticles that were uniformly distributed and embedded in extended release hydrogel formulations. Three adult male African Green Monkeys (1/group) were administered a single bilateral IVT injection of active or placebo implant(s) using a custom implant applicator, and were followed for 56 days. Endpoints included body weights, clinical observations, ophthalmic exams with slit lamp biomicroscopy and indirect ophthalmoscopy, laser flare photometry, and fundus photography.
Results:
There were no complications associated with the dose administration, and the implants were well tolerated. There was no effect on body weight or clinical observations throughout the study. Findings noted during ophthalmic exams were limited to mild vitreous cell infiltrate, and laser flare photometry was within normal limits for this species. There was no evidence of pathology in the posterior segment in any group.
Conclusions:
The bevacizumab intravitreal implant was developed using a unique formulation approach for sustained release of anti-VEGF agents, combining precision protein particle fabrication with sustained release polymers. Active and placebo implants were well tolerated in the African Green monkey for 56 days.