A type of eye drop which could potentially revolutionize the treatment of one of the leading causes of blindness has been developed by scientists at the University of Birmingham. The results of the research could spell the end of painful injections directly into the eye to treat the increasingly common eye disorder known as age-related macular degeneration (AMD).
AMD affects more than 600,000 people in the UK and predictions suggest this figure could rise sharply in future because of an ageing population.
A painless condition which causes people to gradually lose their central vision, usually in both eyes, AMD is currently treated by repeated injections into the eye on a monthly basis over at least three years. This is problematic because, apart from being an unpleasant procedure for patients to undergo, the injections can cause tearing and infections inside the eye and an increased risk of blindness.
Led by biochemist Dr Felicity de Cogan, from the University of Birmingham’s Institute of Inflammation and Ageing, the researchers have invented a method of delivering the injected drug as an eye drop instead, and their laboratory research has obtained the same outcomes as the injected drug.
The drop uses a cell-penetrating peptide (CPP) to deliver the drug to the relevant part of the eye within minutes.
Anti–vascular endothelial growth factor therapy, also known as anti-VEGF therapy or anti-VEGF medication, is the use of medications that block vascular endothelial growth factor. This is done in the treatment of certain cancers and in age-related macular degeneration. They can involve monoclonal antibodies such as bevacizumab, antibody derivatives such as ranibizumab (Lucentis), or orally-available small molecules that inhibit the tyrosine kinases stimulated by VEGF: lapatinib, sunitinib, sorafenib, axitinib, and pazopanib.
Dr de Cogan said:
“The CPP-drug has the potential to have a significant impact on the treatment of AMD by revolutionising drug-delivery options. Efficacious self-administered drug application by eye drop would lead to a significant reduction in adverse outcomes and health care costs compared with current treatments. The CPP-plus drug complex also has potential application to other chronic ocular diseases that require drug delivery to the posterior chamber of the eye. We believe this is going to be very important in terms of empowering of patients and reducing the cost of treatment to the NHS.“
Vascular Endothelial Growth Factor
Vascular endothelial growth factor (VEGF), originally known as vascular permeability factor, is a signal protein produced by cells that stimulates vasculogenesis and angiogenesis. It is part of the system that restores the oxygen supply to tissues when blood circulation is inadequate such as in hypoxic conditions.
Serum concentration of VEGF is high in bronchial asthma and diabetes mellitus.
VEGF’s normal function is to create new blood vessels during embryonic development, new blood vessels after injury, muscle following exercise, and new vessels (collateral circulation) to bypass blocked vessels.
The research was supported by an ARVO fellowship. In vitro testing of the drug-delivery peptides was funded by the National Institute of Health Research, Surgical Reconstruction and Microbiology Research Centre, Birmingham.
Felicity de Cogan et al Topical Delivery of Anti-VEGF Drugs to the Ocular Posterior Segment Using Cell-Penetrating Peptides, Investigative Opthalmology & Visual Science (2017). DOI: 10.1167/iovs.16-20072
Image: Corey Butler/flickr