21 Dec 2017
Researchers from the Stanford University School of Medicine have identified four existing drugs that can treat a rare genetic eye disease, called neovascular inflammatory vitreoretinopathy (NIV), using proteomics.
‘Patients with rare diseases often have few therapeutic options, and many conventional therapies fail them,’ said Gabriel Velez, lead author and MD-PhD student at the University of Iowa. ‘Proteomic profiling allows for clinicians to analyse a patient's diseased tissue in real time and identify proteins that are targeted by already-approved drugs.’
The disease, which is currently untreatable, is a progressive, inflammatory condition, with early symptoms including internal inflammation of the eye, cataract, and problems with vision – patients eventually go blind – and is caused by a mutation to the CAPN5 gene.
Studying the symptoms individually using liquid biopsies, the team identified abnormal levels of proteins associated with each indicator to match to an existing drug. Researchers found 64 cytokines – immune-signalling molecules – that were abundant in NIV patients.
‘This constant uphill battle to save the vision of NIV patients made us determined to find the molecules active inside the eye that can lead us to better therapies,’ said Vinit Mahajan, senior author and Associate Professor of Ophthalmology. ‘Analysing fluid samples from the eye can totally change how we treat patients.’
Patients can experience cloudy vision from the inflammation and protein leakage caused by NIV, which researchers found could can be treated with steroids.
Using implants developed to release steroids over a period of two years, the three patients treated saw reduced levels of 31 inflammatory proteins. However, these individuals experienced scarring in the area surrounding the implant and still expressed abnormal levels of interleukin-6, another protein associate with inflammation.
Problems with scar tissue can be particularly damaging around the retina, which can detach if scarring is extensive. The extent of scarring means that corrective surgery is not always effective.
Knowing of the elevated interleukin-6 levels in NIV patients, researchers treated one individual who underwent the surgery with tocilizumab, an interleukin-6 blocker. The treatment ensured the surgery became the first success of its kind and Mahajan suggested this drug could be beneficial to other NIV patients who suffer from excessive scarring.
‘This is a fantastic example of the precision health approach we're taking in ophthalmology at Stanford,’ said Jeffrey Goldberg, Professor and Chair of Ophthalmology at the university. ‘It's innovative, has broad applicability and, most importantly, is helping patients.’
By Georgina Hines