Age-Related Macular Degeneration (AMD) is a progressive and usually painless eye disease causing vision loss for people 60 years or older. AMD is the leading cause of severe vision loss for the elderly and it is first seen when the eye’s macula starts to deteriorate, diminishing central vision. The macula is light-sensitive tissue lining the back of the eye or rather in other words the small central portion of the retina.
Exactly how it happens is; Abnormal blood vessels start growing underneath the macula and leak blood and fluid into the retina. These abnormal blood vessels are permanent loss of central vision. Also, it can be seen in some cases that dry AMD can turn into wet AMD. Symptoms of AMD are dark, blurry spots in the center of vision, and a decrease in the brightness of colors.
Unfortunately, there exists no treatment for early AMD and no cure for the dry form. According to the research by Age-Related Eye Disease Studies, certain nutritional supplements could help. These supplements consist of high doses of vitamins C – E, zinc, copper, lutein, and zeaxanthin. But these supplements could only slow the progression of intermediate or late AMD.
Dry AMD is the most common cause of blindness among the elderly, affecting between 38 and 45 million people globally. The SCOPE study run by Gyroscope Therapeutics is a global natural history study enrolling participants at approximately 60 sites globally, including centers throughout the UK, including the London Vision Clinic.
It is focused on a prospective, observational protocol designed to evaluate the natural progression of anatomical and functional visual parameters in genetically defined patients with Geographic Atrophy (GA). It is planned to genotype 2,000 people at centers throughout the country, with the goal of identifying patients with mutations in their Complement Factor I (CFI) gene.
This study is expected to allow the characterization of patient phenotype, including disease progression. In every sense of the word, it is groundbreaking.
As far as known, a genotyping study of this size has never been attempted before for dry AMD. There is compelling evidence that complement factors play a significant role in the condition. Now, there is a need to better understand the pathophysiology of GA to find a treatment for it.
By genotyping such a significant number of patients, a hugely valuable dataset will be generated. There is no reason to believe that there is going to be one dry AMD patient with a rare variant in every 30 screened and – there even could be other variants and associations.
Either way, the information from SCOPE will be critical in guiding the current Phase 1 interventional study FOCUS, and also guide future Phase 2 studies and beyond. As part of the SCOPE study, patients with GA are screened for eligibility and genotyped via saliva sample.
Patients who are found to have a rare variant are then observed for 96 weeks, with any eligible patients offered the opportunity to participate in FOCUS or another interventional study.
The primary objective of FOCUS is to evaluate the safety of three doses of GT005 – Gyroscope’s investigational, one-time gene therapy, designed to restore balance to an overactive complement system by increasing production of the CFI protein. There is no reason to believe a subset of GA patients with low CFI serum and rare variants may be best suited to treatment with GT005.
An adenoassociated virus type 2 vector method of CFI gene transfer is being used (essentially, what GT005 is) to ensure sustained expression of CFI. The idea is that patients will not need to have periodic injections of CFI because their eyes will be able to rebalance the complement cascade on their own, nudging the body to produce its own therapy. This is exciting – but it will only be possible with help.
The study needs as many patients as possible. Although some people are understandably reluctant to return to clinical settings, it is crucial that older patients with significant visual impairment take part in this research.
Specifically, the study is looking for patients with significant GA – preferably confirmed by autofluorescence, with best-corrected visual acuity of 34 letters or more – in late-stage disease.
A more precise diagnosis is needed to reduce noise in data analysis. It is very possible that new gene variations will be found, in turn, allowing them to develop new therapies.
For years, patients with dry AMD have been told there was nothing that could be done – some are still being told that. It is vital that patients and doctors know that there is hope.