Vision is the most important human sense. When visual acuity declines, or if it is lost, this can significantly impair the independence and therefore the quality of life of the patients.
Together with external partners, Bayer has been successfully working on new treatment options for a range of different disorders, primarily diseases of the back of the eye – i.e. the retina – in order to improve people's visual acuity when it is restricted by illness, and to prevent loss of vision. Of key relevance is the macula, the point of sharpest vision on the retina. If nerve cells in this area are destroyed, which can be triggered by different types of unfavorable factors, it can lead to severe visual impairment and finally blindness if left untreated.
Several retinal diseases are associated with pathological vessel growth (neovascularization). In these conditions, in particular the macula (the point of clearest vision) is damaged by fluid leaking into the tissue causing swelling (edema). Wet age-related macular degeneration (wet AMD) and diabetic macular edema (DME) are typical examples of such diseases. Wet AMD is the most common cause of severe visual impairment and blindness among people over the age of 65 in developed countries. Certain proteins known as growth factors are released and stimulate the formation of new, additional blood vessels. However, these new vessels are unstable and leaky. Fluid leaks and seeps into the tissue.
Bayer's development activities in the field of neovascular retinal diseases are currently concentrating on counteracting the formation of new, pathological blood vessels and leakage. The focus here is on inhibiting growth factors involved in the formation of new blood vessels. The introduction of VEGF inhibition was a significant advance in the treatment of neovascular retinal diseases. VEGF causes endothelial cells on the inside of the blood vessels to become detached, multiply, and in this way form new ramifications. As a result, the vessel walls are leaky and liquid (exudate) seeps out. VEGF inhibitor drugs can stop this process.
However, new pathological vessels that have already formed may become resistant to anti-VEGF treatment. This is caused by cells known as pericytes, which attach themselves to the outer wall of the blood vessels and stabilize them. Researchers are therefore looking for ways of destabilizing these maturated pathological vessels, initiating their remission. One therapeutic approach is to inhibit PDGF (Platelet Derived Growth Factor). PDGF inhibitors break down pericytes on the vascular surface, making solidified vessels sensitive to treatment with VEGF inhibitors.
In the field of PDGF inhibitors, Bayer is engaged in research and development, together with its collaboration partner Regeneron, to find ways of using this new therapeutic approach.
Bayer is also looking into possibilities beyond neovascular retinal diseases such as dry age-related macular degeneration (dry AMD).
Collaborations in ophthalmology
Partnerships are playing an important role in research in this field. In June 2015, Bayer entered into a five-year collaboration agreement with the Johns Hopkins University in Baltimore, Maryland, U.S, to develop new ophthalmic therapies targeting retinal diseases. In January 2014, Bayer entered into a new collaboration with Regeneron Pharmaceuticals to jointly develop an innovative antibody to Platelet Derived Growth Factor Receptor Beta (PDGFR-β) as a potential combination therapy with our VEGF-inhibitor antibody aflibercept for the treatment of wet AMD.