Dr Rafael Navarro, a retina specialist at IMO, director of the Bioimage study
IMO Foundation, dedicated to research, teaching and prevention of ocular diseases, has just launched a pioneering ophthalmology clinical trial at an international level. This is the Bioimage Study, which will be used to study if the response in 194 patients with wet AMD to a new antiangiogenic drug from Bayer (aflibercept) is related to their genotype.
This study, led by Dr Rafael Navarro, a retina specialist at the Ocular Microsurgery Institute (IMO) in Barcelona, will see the participation of over twenty hospitals throughout Spain, which will send peripheral blood samples taken from patients with wet AMD, included in the trial, to IMO's molecular biology laboratory, inaugurated into the Institute's premises this year, under the coordination of Dr Esther Pomares. The laboratory, after purifying the DNA from each blood sample, will study the polymorphisms and markers of 14 genes known to be related to the generation of harmful neovessels that cause the wet AMD.
The study could show that oncology discoveries are applicable to the ophthalmology field
The Bioimage study, which began this November, aims to clear up some unknown facts and discover if different therapeutic responses occur depending on each patient's genotype.
“Can we establish response profiles for genetic reasons? Is there a link between genes and the fact that some patients respond well to a treatment, while in others the same treatment is not effective?
The study hypothesis is based on recent discoveries in oncological treatments, which have confirmed that the response from patients to certain therapies using antiangiogenic drugs varies according to their genotype. “We suspect that we are going to see the transfer of oncological discoveries in this sense to the ophthalmology field, but we do not know for sure if this will be the case. This study will show us,” explains Dr Rafael Navarro.
This new drug has longer-lasting effects on the eye
The new drug that will be used for the study, sold in the United States since December 2011 and later in some European countries, has the advantage of its effects on the eye lasting longer than other anti-VEGF drugs (endothelial growth factor), which reduces the number of injections the patient needs during the treatment. The clinical study will last for one year, during which patients' samples will be analysed, and they will receive three monthly injections in the first phase and one injection every two months for the remainder of the treatment.
Dr Esther Pomares, IMO’s Genetics Department
“We are going to study the genetic profile of patients in relation to the genes involved in the signalling pathway that directs the creation of new blood vessels," announces Dr Esther Pomares. Of the human genome's 30,000 genes, researchers on the Bioimage study have selected 14 involved in the generation of retina neovessels. “For each of the genes we have selected an average of 15 markers, so we are going to analyse a total of 210 markers per patient. The alleles of these markers (two per marker) will give us the key to whether we can establish genetic treatment response groups," explains Dr Pomares.
According to the study's director, Dr. Rafael Navarro,
“If the research shows that the response to treatment depends on the patient's genotype, Bioimage will be an important step towards personalised medicine and, more specifically, the treatment of wet AMD, since it will allow us to know beforehand if a patient is going to present a satisfactory response to a certain drug."
“If we knew there would not be a good response, something we cannot currently know, we could opt directly for another treatment strategy. On the other hand, in some patients we could indicate a treatment knowing it will be effective before starting it," adds the ophthalmologist.
AMD, the main cause of severe vision loss in the elderly
Age-related Macular Degeneration (AMD) is the main cause of severe vision loss in the elderly in developed countries and affects the macula, which is located in the centre of the retina. As the pathology develops, central vision is reduced, making it difficult to carry out tasks that require seeing fine detail, such as reading, dialling phone numbers, driving or recognising faces. The disorder is age-related. It generally affects the over 50s and especially people over the age of 65.
Despite this disorder being very limiting, it is common for the patient not to notice symptoms in the early stages. Early diagnosis is, therefore, essential.
There are two forms of the disorder: dry, the most common, involving atrophy of the macula, and wet, which occurs in about 15% of patients with AMD, which results in abnormal growth of blood vessels under the macula and abruptly affects vision. Currently, wet AMD can be controlled with intravitreal antiangiogenic drugs (which have the function of slowing blood vessel growth) injected directly into the eye. These drugs block abnormal vascular growth, thus preventing the disease from progressing and causing damage to the retina's central area and, as a result, protecting the patient's central vision.
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