Drug Therapy
There are a number of companies that are looking at using various different drugs as a form of treatment for Stargardt's disease.
Belite Bio
Belite Bio are currently conducting two Phase 3 Drug Therapy Trials for Adolescents aged 12-18 with genetically confirmed Stargardt's Disease (Dragon 1 and Dragon 2). These are double masked studies with participants being assigned either the study drug or the placebo. The trial oral drug is called Tinlarebant and aims to slow down the progression of the disease.
You can find out more about the trial and the study drug here: https://belitebio.com/product-008/
The trials will be over two years and will be taking place at sites in the UK, US, Germany, Taiwan, Australia, Belgium, France, Switzerland, China, Japan and Hong Kong.
Dragon 1 trial is now fully recruited. Dragon 2 trial is still recruiting.
A press release (27.02.25), following an interim analysis of Dragon 1 data, has led to Belite Bio starting the process to gain regulatory approval for Tinlarebant: https://finance.yahoo.com/news/belite-bio-announces-interim-analysis-070000841.html
Remofuscin
Professor Andrew Lotery, a professor of ophthalmology at the University of Southampton and consultant ophthalmologist at University Hospital Southampton NHS Foundation Trust, is the first in the UK to be trialling a pioneering drug in a £5 million study with colleagues at centres in the Netherlands, Italy, Germany and Norway. The drug remofuscin, which is taken orally, removes the fat deposits, known as lipofuscin, which build up in the back of the eye.
The trial presented promising evidence of safety and effectiveness. Further updates on development are awaited.
Acucela
Acucela enrolled patients into a Phase 3 placebo controlled clinical trial for the oral drug called Emixustat which has been developed to slow the build-up of toxic waste products which are believed to be responsible for the vision loss in Stargardt disease.
This trial did not demonstrate effectiveness in the entire study cohort. Analysis of a subset of patients with early disease did demonstrate a benefit. Further updates on development are awaited.
Systematic Review of Treatments for Dry AMD and Stargardt’s
Norman Waugh and a team of colleagues from the University of Warwick have published a systematic review of treatments for dry AMD and Stargardt’s (May 2018). They reviewed all the relevant studies in Stargardt’s and made some recommendations:
- NIHR may want to consider a trial of fenretinide to reduce damage to the macula and a pilot study of the nutritional supplements, lutein and zeaxanthin, to see if they protect the macula
- It could be useful for research studies to look for changes earlier in the diseases before vision is affected
https://www.journalslibrary.nihr.ac.uk/hta/hta22270#/abstract
Alkeus Pharmaceuticals
The cause of Stargardt’s disease is faults in the ABCA4 gene. The ABCA4 gene’s role is to produce a protein called a Rim protein. The Rim protein’s role is to help transport Vitamin A molecules (needed to form the light sensitive pigment in rod and cone cells) from the photoreceptors back to RPE cells, where these Vitamin A molecules are recycled to be reused for vision.
However, in Stargardt’s, the faulty ABCA4 gene produces a Rim protein that either is non-functional or has significantly reduced function, and thereby disrupts this process of transport. The Vitamin A molecules therefore tend to accumulate in the photoreceptors/RPE cells rather than being transported and recycled. This causes a waste management problem resulting in build-up of toxic products, including ‘Vitamin A dimers’, which are believed to be involved in vision loss, by damaging RPE cells and photoreceptors.
Alkeus Pharmaceuticals have developed an oral drug called ALK-001 which aims to prevent the formation of these toxic Vitamin dimers in the retina.
They have successfully completed their safety trial and now have fully enrolled a Phase II and Phase III clinical trial in adults and children with Stargardt disease.
A further Phase 3 trial in the USA, EU and UK is anticipated to start in 2025.
Further updates on development are awaited.
More information is available here:
Natural History Studies
The Foundation Fighting Blindness Clinical Research Institute has funded a $6 million multi-centre international (USA, UK, France and Germany) natural history study (ProgStar) for people affected by Stargardt's disease.
It has three primary goals:
- Determine the best outcome measures to accelerate evaluation of emerging treatments in clinical trials
- Better understand disease progression for selecting future clinical trial participants
- Identify potential participants for forthcoming clinical trials.
The natural history study uses retinal imaging and functional testing of patients with Stargardt’s disease who have been seen every six months for two years with the hope to get a better idea of the prognosis and how the disease progresses. Predominantly adults with milder Stargardt disease were recruited.
There are many published ProgStar papers. Here is a link to one of them:
What do Phases mean in a clinical trial?
A clinical trial is normally divided into four phases to test its safety and effectiveness.
- Phase I will test the safety of a drug, observing the side effects of it and will typically test a small number of people, usually who are healthy volunteers.
- Phase II will normally test the effectiveness of the drug on a larger group of people who have the disease, again looking at safety and if the treatment has an effect on the condition.
- Phase III will be tested on an even larger population and may involve using a placebo as well as the drug to see the effect of the treatment. The participants will not usually be aware if they have been given the placebo or the drug that is being tested.
- Phase IV is the final phase and is usually done after the treatment has been approved by the drug regulatory authorities. It will study the effect of the drug on a range of people and look at any long-term side effects.
More information can be found at:
http://www.ctu.mrc.ac.uk/about_clinical_trials/what_is_a_clinical_trial/
Information about clinical trials that are currently being conducted worldwide can be found on www.clinicaltrials.gov and can be searched by condition and trial location.