Ocular Disease and Drug Development
Ocular or eye disease is a condition that can result in either complete loss of vision or in blurred vision. This can be major or minor and adversely affects the quality of life in both cases. Approximately 80% of eye diseases are caused by inherited defects. The retina (at the back of the eyeball) is affected by a variety of eye diseases which causes major blindness. If not cured, then it may lead to retinal cancer.
Some common types of ocular diseases which result in vision impairment are diabetic retinopathy, age-related macular degeneration (AMD), color blindness, retinoblastoma, glaucoma, and dry eye. However, corneal dystrophies, neurotrophic keratitis, iridocorneal anomalies, and congenital glaucoma are very rare disorders of the anterior segment of eyes.
The eye disorders are diagnosed by measuring intraocular pressure and ocular blood flow which require regular eye check-ups. After confirmed diagnosis, the conventional drug-delivery systems like eye drops, suspension, ointments, implants, etc have been developed for treating the ocular diseases.
For treating rare ocular diseases (or inherited conditions), Food and Drug Administration (FDA) has approved treatment with gene therapy. Recent drug development in treating inherited ocular disease is Luxturna™ (by Spark Therapeutics), as the first ocular gene therapy product, approved in 2017. It delivers the RPE65 gene to retinal cells to prevent retinal dystrophy. An exciting new challenges being tackled in the drug discovery process are anti-vascular endothelial growth factor (VEGF) therapies used as a potential mediator of intraocular neovascularization for the treatment of AMD, non-viral ocular gene therapy, retinoblastoma chemotherapy to treat ophthalmic sicknesses, hydrogel-based formulation therapy i.e ocular therapeutix, and gel-shaping drops that effectively treat near-sightedness and mild astigmatism.
The stem cell therapy has also been used safely and effectively for ocular surface reconstruction in rare diseases such as aniridia. A study on 11 neonates and young infants (19 eyes) with retinoblastoma were conducted. The intravenous carboplatin combined with cryotherapy and laser and Intra-arterial chemotherapy was proved to be safe and effective to treat retinoblastoma in neonates and young infants. Electroretinography showed no deterioration of retinal function.
Retinoblastoma (RB) and choroidal melanoma are the major forms of cancer that affect the eyes. Retinoblastoma has opened a new opportunity for the researchers for drug development. Nanoscience and nanotechnology are playing an important role in drug development strategies for ocular disease therapy.
Drug development and gene therapy are new treatment strategies that are currently being developed in several clinical trials for a variety of diseases. The purpose of both drug development and gene therapy is to alter the inherited diseases with a single treatment to stop the transfer of defected genes to the next generation.