New therapeutic approach to treat retinitis pigmentosa and other serious eye diseases

Retinitis pigmentosa (RP) is a severe visual disorder affecting the retina. It is a rare genetic disease, whose symptoms usually begin in childhood and which in most cases results in severe vision loss. Researchers at the University of Barcelona are participating in a new consortium to design a drug with an innovative approach against this disease, which could also be used to treat other hereditary retinal dystrophies. The compound, which has already shown efficacy in animal models of the disease, would be applied by drops and could be combined with other treatments such as gene therapy.

“The main advantage of this innovative pharmacological approach is its potential applicability to a broad spectrum of cases of retinitis pigmentosa and other hereditary retinal dystrophies, caused by mutations in more than 350 genes involved in very diverse biological pathways, but which converge in common pathways that lead to the death of retinal photoreceptors,” explains Ana Méndez Zunzunegui, a researcher at the Faculty of Medicine and Health Sciences and the coordinator of the UB team involved in the project.

The consortium is led by Miramoon Pharma and involves, in addition to the UB, the University of the Basque Country (UPV/EHU), the Cádiz Biomedical Research Management Foundation (INiBICA) and the Margarita Salas Biological Research Centre (CIB).

Delaying retinal degeneration

Hereditary retinal dystrophies are a group of degenerative and generally progressive disorders caused by the deterioration of the photoreceptors and pigment epithelium of the retina. Although these diseases are mostly rare, they affect a combined total of one in 4,000 individuals. They are responsible for 5% of blindness in the Western world, and are the most common cause of vision loss in children and young adults. “All these diseases present a gradual loss of the two types of photoreceptors (rods and cones), and retinitis pigmentosa is the most prevalent disease without a standardised and effective treatment”, says Méndez Zunzunegui.

Miramoon Pharma has developed a compound that has demonstrated efficacy in delaying retinal neurodegeneration in an animal model of retinitis pigmentosa. “It is a small molecule with a new neuroprotective mechanism of action, consisting of the double modulation of intracellular calcium levels and the neutralisation of reactive oxygen species, both of which are related to the death of photoreceptors,” adds Méndez Zunzunegui.

The main competitive advantage of this compound is its broad spectrum of action. In fact, one of the aims of the project is to extend the study of the drug to models of other hereditary retinal diseases, such as Leber congenital amaurosis, and the most prevalent retinal disorders, such as macular degeneration and diabetic retinopathy. According to this UB researcher, who has worked in this field for over 25 years and has extensive experience in research with animal models of these types of retinal disorders, these diseases “are currently treated using very limited therapeutic approaches and represent a high cost for the health system as a whole.”

A non-invasive treatment

Another important feature of the new compound is that it is administered by eye drops, in contrast to the highly invasive therapeutic treatments that have been used so far or are currently under development. Such therapies are expensive and often involve intraocular injections into the fundus of the eye to access the retina, an intervention that usually requires a hospital stay and a complex surgical procedure. “As a non-invasive retinal neuroprotective approach, the new compound would reduce the additional costs of current treatments, as well as the risks of infection and potential side effects,” claims Méndez Zunzunegui.

The project, with reference number SCPP2200C009867 and a three-year duration, hopes to successfully advance the drug to a phase I/II clinical trial, as well as to increase our knowledge of the pathogenic mechanism of different hereditary retinal dystrophies. For this reason, the University of Barcelona has obtained 124,403 euros in funding under the 2022 call for public-private collaboration projects of the 2021-2023 Spanish National Plan for Scientific, Technical and Innovation Research, as part of the Recovery, Transformation and Resilience Plan.

Image: Members of the research group