Update on phase III therapies for hereditary vision disorders

When discussing the treatment for prevalent disorders such as hypertension or asthma, hardly ever do we stop and consider the time and effort that are needed to move from the characterization of the pathology at the clinical level to the implementation of an effective therapy. Nevertheless, this long, highly regulated process is an unavoidable step to secure a safe and effective medicine.

The last critical steps in the development of a new therapy are the clinical stages or phases.  Only the compounds that have satisfactorily overcome all the toxicity and effectivity trials in the preclinical stage can be tested in humans. In phase I, the toxicity of the product is tested and any secondary outcome carefully annotated. After passing this test, phase II can start, in which the treatment must prove not only that it will not harm the patients, but also that it has a measurable beneficial effect. Once the therapy has proven beyond doubts to be safe and effective, it may enter the last stage before its approval for general clinical use. This is phase III, in which the results from the previous phases are tested in a large group of patients. If the results are confirmed, specialized agencies will start the paper trail for the formal approval of the therapy.

Hereditary vision dystrophies are considered rare diseases, they can be caused by a variety of genes and, in many cases, the same gene can be associated to more than one clinical entity. As a result, the therapy for most of these pathologies is costly and requires many previous studies and complex methodologies. For all these reasons, achieving phase III can be rated as a huge success and are great news for the patients. This is why we wish  to share a list of gene therapies for rare hereditary vision disorders that have recently achieved phase III, and whose candidate recruitment is now open.


– Chromosome X associated Retinitis Pigmentosa. MeiraGTx, in collaboration with Janssen Pharmaceuticals, sponsors two twin clinical assays for the treatment of this pathology caused by mutations in the gene RGPR. Lumeos’ therapy lies in the intravitreal administration of vectors carrying the functional (normal) copy of the gen RPGR. Previous phases I and II have obtained positive results. The procedure is performed in 6 centers in the USA. In order to participate in this therapy as a patient you can obtain more information in the web of the study.


– Leber’s Congenital Amaurosis. ProQR Therapeutic’s Brighten therapy is aimed to pediatric patients (<8 years old) diagnosed with a specific mutation in the gene CEP290 (c.2991+1655A>G; p.C998X). Patients carrying this mutation synthesize a defective RNA that hinders the production of functional proteins. The compound Sepofarsen is injected intravitreously and binds the defective RNA, modifying it towards the correct protein formation. This procedure, besides successfully passing all safety concerns, has improved visual response in most of the participants in previous studies. In order to participate in this study that takes place in centers in Canada, Brazil, Belgium, Germany, Italy and Netherlands, the parents or legal guardians of the patients may contact <info@proqr.com>. More information in the web of the study.


– Retinitis Pigmentosa and Usher’s Syndrome Type II. ProQR Therapeutics has developed two assays for the treatment of these pathologies caused by mutations in the exon 13 of the gene USH2ASirius (advanced vision loss) and Celeste (moderate or early vision loss) are based in antisense oligonucleotide technology to block the expression of the mutated exon 13 with the aim of obtaining a shorter, yet effective, version of the gene. The treatment is administered in the Retina Foundation of the Southwest, Texas (USA). Candidates may contact <info@proqr.com>. More information in the web of the study.


We encourage those who may be interested in participating in these studies to get more information on their respective websites and to consult their ophthalmologist over the inclusion criteria and the suitability of the treatment for each patient. It is also recommended to check on the benefits (travel expenses, medical visits,…) that some of the centers offer.

These clinical assays are a great opportunity to benefit from a gene therapy treatment in their last step before general commercialization. The success of these studies opens new scenarios for personalized medicine and promotes the development of similar therapies for other pathologies.

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