Novel Oral Medication Developed to Treat a Form of Childhood Blindness

Researchers have developed a novel oral medication that promises to restore vision to those with a childhood blindness called Leber congenital amaurosis.

Leber congenital amaurosis (LCA) is an eye disorder that is known to primarily affect the retina. The disorder appears at birth or in the first few months of life and affects 1 in 80,000. The visual impairment worsens gradually over time. Till date, there has been no effective treatment for this inherited retinal disease.

But researchers at the McGill University Health Centre, Montreal have unveiled the new oral medication that helps restoring vision.

"This is the first time that an oral drug has improved the visual function of blind patients with LCA," said the study's lead author, Dr. Robert Koenekoop, who is director of the McGill Ocular Genetics Laboratory at The Montreal Children's Hospital of the MUHC, and a Professor of Human Genetics, Paediatric Surgery and Ophthalmology at McGill University. "It is giving hope to many patients who suffer from this devastating retinal degeneration."

The study was conducted on 14 people who had LCA. The participants selected worldwide were aged between 6-38 years. The blindness is caused due to mutation in the genes RPE65 or LRAT that eventually lead to a serious defect in the retinoid cycle.

Retinoid cycle is known to be the most critical cycle in the human retina as it produces a molecule 11-cis retinal that has the ability to capture light and initiate vision. Those with RPE65 or LRAT mutations fail to produce the same molecule due to which the retinal cells cannot create vision.

"By giving patients with RPE65 or LRAT mutations an oral retinoid intermediate (QLT091001) most patients' vision improved rapidly. We discovered that a certain portion of the retinal cells that were not working because of the lack of 11-cis retinal could be woken up," explains Dr. Koenekoop. "Contrary to what was previously thought, children with LCA and defects in RPE65 or LRAT are not born with dead retinal cells; the cells can simply go dormant, and they can remain dormant for years before they eventually die. The oral drug we tested awakened these cells and allowed patients to see."

The researchers noticed that 10 out of 14 patients had an expansion in their visual fields and the other showed an improvement in their visual acuity. Brain scans of the visual cortex was done and the scans presented a marked improvement in the brain activities in patients who had improvement in field size and acuity.

The researchers plan on conducting further studies to know more about the retinal function in bling people in relation to dosage and mythology.

"This revolutionary breakthrough to restore sight in children who are blind shows that investing in vision research over the long-term really can make miracles happen," said Sharon Colle, President and CEO of The Foundation Fighting Blindness, the largest charity funding sight-saving research in Canada.

The finding was documented in the journal The Lancet.