Advances in the field of retinal research in 2019
Research into retinal disease is a very active field worldwide. Over the past year, great progress has been made that is expected to bring improvements in prevention, treatment and research into eye diseases. Here is our guide to the most important developments in 2019
Developments in clinical trials
Many eye diseases are caused by the mutation of a single gene, which leads to a failure to produce a protein necessary for normal vision or for it to be defective. This genetic mutation is found in many existing rare eye diseases, such as Stargardt disease and retinitis pigmentosa. For such cases, gene therapy is based on the replacement of the defective gene with a normal one, thus restoring the normal development of the affected protein.
The first gene therapy for an eye disease was recently approved: Luxturna® (voretigene neparvovec), indicated for Leber's congenital amaurosis, another rare eye disease. The positive results with this treatment have fostered development for other inherited and rare disease of the retina.
Choroideraemia and X-linked retinitis pigmentosa (severe and progressive forms of night blindness and visual field loss) are other diseases in which there has been significant progress in this area. There are ongoing phase III studies1, 2 that, if they demonstrate positive results in 2020, could result in the first available treatment for these patients.
Idiopathic juxtafoveal macular telangiectasia type 2 (or MacTel 2) is a neurodegenerative retinal disease with vascular complications that characteristically begins in the temporal part of the fovea and progresses until it impairs reading and jeopardises the visual acuity of affected patients. There is currently no approved treatment.
Researchers from the “Macular Telangiectasia type 2 - Phase 2 CNTF Research Group” conducted a clinical trial on 97 eyes of 67 patients from Australia and the United States3. It was found that the intraocular implant of a device that releases a neuroprotective compound delayed the progression of the disease by up to 30%. The development of a phase III clinical trial with more patients is expected. The aim is to confirm these results and enable a treatment for MacTel 2 to be approved.
Developments in medicines
On October 7, the U.S. Food and Drug Administration (FDA, the body responsible for the authorisation of medicines for human use in the United States) approved Beovu® (brolucizumab 6 mg) for the treatment of exudative age-related macular degeneration (AMD).
This is a highly concentrated antiangiogenic drug that is administered by intravitreal injection. It has been shown to have an efficacy comparable to aflibercept, but with fewer treatments4. The Committee for Medicinal Products for Human Use issued a positive assessment on 12 December 2019, making it likely that the European Medicines Agency (the European equivalent of the FDA) will soon approve its use in Europe.
Others: myopia and Deep learning
Myopia affects thousands of millions of people worldwide and it is especially prevalent in Asia. For a small but important percentage of these patients, myopia will lead to potentially serious eye complications, such as retinal detachments, subretinal neovascular membranes, cataracts or glaucoma. Therefore, myopia prevention has become a public health objective in recent decades.
Asian researchers published the results of a clinical trial with the participation of almost 700 children. They showed that exposure to moderate levels of ambient light in outdoor environments had a protective effect on the onset and progression of myopia5.
In addition, studies based on Deep learning (a field of Artificial Intelligence) have continued to show the potential of these algorithms in certain tasks6. Examples of the applications of these methods include the automatic classification of the degree of severity of AMD and diabetic retinopathy from retinographs (colour images of the eye fundus), as well as the quantification of fluid to the retina in different exudative diseases (neovascular AMD, diabetic macular oedema or secondary to deep-vein thrombosis) from optical coherence tomography (OCT) images. These advances may have implications for how retinal consultations are organised, how tasks are distributed and how research in the field of retinal diseases will be approached in the next decade.
- https://clinicaltrials.gov/ct2/show/NCT03496012?cond=choroideremia&phase=2&draw=2&rank=1, accessed 13/01/2020.
- https://clinicaltrials.gov/ct2/show/NCT03116113?cond=X-Linked+Retinitis+Pigmentosa&phase=2&draw=2&rank=1, accessed 13/01/2020.
- Chew EY et al. Effect of CNTF on retinal neurodegeneration in patients with macular telangiectasia type 2: a randomized clinical trial. Ophthalmology 2019; 126: 540-9.
- Dugel PU et al. HAWK and HARRIER: phase 3, multicenter, randomized, double-masled trials of brolucizumab for neovascular AMD. Ophthalmology 2020; 127: 72-84.
- Pei-Chang W et al. Myopia prevention and outdoor light intensity in a school-based cluster randomized trial. Ophthalmology 2018; 125: 1239-50.
- Ting DSW et al. Deep learning in Ophthalmology: the Technical and Clinical considerations. Progress Retin Eye Res 2019; https://doi.org/10.1016/j.preteyeres.2019.04.003.