Here you will find content from CRFC’s quarterly newsletter FOCUS and other CHM-related updates.
Update from the University of Alberta on the Canadian trials
Update provided by Stephanie Chan, Genetic Counsellor and Trial Co-ordinator at the University of Alberta
As many of you know, our team at the University of Alberta has been hard at work preparing for our upcoming choroideremia gene therapy clinical trial. The study details, including the criteria for participation can be found here: http://clinicaltrials.gov/ct2/show/NCT02077361. We will begin recruiting participants in Fall 2014 when we receive final approval from Health Canada. Until we have that final approval we cannot recruit participants. At present, we have preliminary approval from Health Canada but need to provide some more information on the vector that we will be using in our clinical trial. We expect the information from the company providing the vector shortly.
Since our clinical trial will be a small Phase 1 study, we will only be enrolling 12 participants over the course of a year. We have put in place a formal process for selecting participants. Selection will be made by an external board of Canadian ophthalmologists. We need participants whose clinical symptoms are at the specific stage to give us the best possible results in the clinical trial. We also need to select participants who will stick to the follow-up schedule. The most important parts of the trial are the follow-up visits where we collect the results. Approval for any further, larger clinical trials will be based on the results of this trial.
We need to be prepared so that we can recruit as soon as we receive final Health Canada approval. We are therefore doing three things:
1. We are looking at anonymous records in the Foundation Fighting Blindness Canada Patient Registry (http://www.ffb.ca/patient_resources/patient_registry.html) to later identify individuals who might meet our selection criteria.
2. We are going over the clinical records of Dr. MacDonald’s patients.
3. We have been fine-tuning the methods and equipment we will eventually be using to assess vision in the clinical trial. Vision is the main outcome measure to assess the results of the clinical trial. Local choroideremia patients have been helping us by allowing us to test our equipment on them. This testing also allows us to tell whether a patient meets the eligibility criteria for the clinical trial. However, this data is very similar to the clinical data that potential participants from across Canada have been sending us.
We want to make clear that the clinical data we will be using to assess eligibility does not need to come from our centre in Edmonton. We want to encourage interested people with choroideremia to register with the FFB Canada Patient Registry as we have full access to this data. This is also beneficial because other gene therapy research teams may also apply for access to this registry data.
We expect enrollment for our clinical trial to begin sometime in Fall 2014. You can keep up to date with our activities on our website: http://www.chmgenetherapy.ca/.
Stephanie Chan, MSc, CGC, CCGC
Genetic Counsellor and Study Coordinator
UK Clinical Trial Results Published in The Lancet
Below are very promising details released Thursday, January 16th describing the results from the Oxford CHM gene therapy clinical trials:
A new gene therapy has restored some sight in people born with an inherited, progressive form of blindness. The technique replaces a defective gene in the eye with a normal working copy of the gene using a single injection.
The findings of this phase 1 trial, published in The Lancet, support the further development of this state-of-the-art treatment for other more common genetic causes of blindness including degenerative diseases of old age, such as macular degeneration, and inherited defects like retinitis pigmentosa.
Choroideremia is caused by a mutation in the CHM gene on the X chromosome and affects an estimated 1 in every 50 000 people. The condition causes progressive loss of vision due to degeneration of the choroid, retinal pigment epithelium, and retina. There is no treatment for choroideremia and eventually the photoreceptor cells-the rods and cones in the retina that respond to light by sending signals to the visual processing areas of the brain-also degenerate leading to complete blindness by middle age.
“The cellular degeneration in this disease is fairly slow, providing a reasonably large window of time in which to intervene before the onset of visual loss”*, explains Professor Robert E MacLaren from the University of Oxford in the UK who led the research.
MacLaren and colleagues assessed the effect of gene therapy on retinal and visual function in six patients aged 35-63 years with different stages of choroideremia. They injected patients’ retinas with a vector-a genetically engineered adeno-associated virus (AAV)-to deliver a corrective copy of the gene into the appropriate part of the eye to halt photoreceptor cell death.
The treatment caused no harm and resulted in improvements in subjective measurements of vision. Six months after delivery of the gene, all patients recovered their visual acuity from before the procedure, and two patients showed substantial improvements in how well they could see, with one reading over three additional lines on an eye chart. Importantly, the patients developed increased sensitivity to light, compared to a loss in sensitivity in the untreated eyes.
According to Professor MacLaren, “This is first time that gene therapy has been used to treat patients with normal visual acuity before the onset of clinically significant retinal thinning. Our findings hold great promise for gene therapy to prevent loss of sight in other retinal diseases such as age-related macular degeneration.”*
Writing in a linked Comment, Hendrik Scholl from John Hopkins University, Baltimore, USA, and José Sahel from the Institut de la Vision, Paris, France, say, “The ultimate goal of gene therapy in choroideremia would be to save the central retina from further degeneration. The short follow-up of the new study prevents any conclusion about preventing degeneration in the long term; indeed, results from the morphological assessment suggested that degeneration is rather continuous.It remains to be determined if gene therapy targeting REP1 will have an effect on the progression of photoreceptor degeneration. Even if the effect turns out to be only slight, this might have important positive implications because there are additional therapeutic avenues targeting photoreceptors that could help to save or restore visual function.”
To view an amazing video of a test patient discussing the improvements on his eye from the UK trials, click here.
This exciting news only galvanizes the importance of CRF-C and donor support for the work of Dr. MacDonald and his team at the U of A. Please consider giving today to help fund the upcoming trials.
- Choroideremia: gene therapy shows promise
- Gene Therapy Shows Promise in Treating Rare Eye Disease
- Gene therapy may improve incurable form of blindness
- Scientists use new gene therapy to treat hereditary blindness
- Early gene therapy results tout a promising treatment for blindness
- New gene therapy for blindness shows promise
- Gene therapy improves vision in inherited blindness
- Gene therapy improves eye sight in patients with vision loss
- Gene therapy trial shows promising results in treating rare type of blindness
- Promising first results in gen therapy trial for inherited blindness
FOCUS Summer 2013 Edition
Welcome to FOCUS: The Newsletter of the Choroideremia Research Foundation Canada!
The last few years have been very exciting for the CRFC and choroideremia research. With Canadian human trials starting soon, a cure or treatment for choroideremia has never been closer!
The CRFC: Making Vision a Reality
Here’s a quick recap of the last two years – it’s clear that the hard work of the CRFC, its partners and those researching the disease is really paying off!
- In September 2011, researchers from Canada, the United States, Germany, France, and the United Kingdom came together for the first ever International Choroideremia Symposium. These researchers presented their findings to their peers, showing that the search for a cure is an international endeavour.
- In October 2011, the first choroideremia gene therapy trial began at Oxford University in England. This was a human trial involving 15 subjects. The results, which will be published soon, look very promising!
- In 2012, gene therapy trials began in the United States, funded in part by the Choroideremia Research Foundation, a sister organization to the CRFC.
- In Canada in 2012, a research team at the University of Alberta received a grant funded by the CRFC, the Foundation Fighting Blindness (FFB), and the Canadian Institutes of Health Research to begin human trials of gene therapy treatment.
The next few years could be amazing ones for those with choroideremia as Canadian human trials begin! To date, the CRFC has raised over $275 000 in the fight against choroideremia, with $125 000 going to the researchers at the University of Alberta.