Stargardt disease is a rare condition that causes vision loss due to the buildup of vitamin A byproducts in the retina. The byproduct causing the largest buildup is usually A2E. It is a progressive condition most commonly caused by a ABCA4 gene mutation. The photoreceptors gradually deteriorate and patient’s overall vision decreases over time. Typically, symptoms present during childhood and there are currently no approved treatments to slow the disease’s progression.
However, a new potential therapy has just received Orphan Designation by the European Medicines Agency (EMA) for Stargardt disease. It’s called emixustat hydrochloride.
Emixustat hydrochloride works by inhibiting RPE65 which in turn modulates the visual cycle. It is being developed by Acucela.
In animal models emixustat was effectively able to reverse A2E accumulation. It also successfully preserved the integrity of the retina. The therapy was also tested in clinical studies with humans. Thankfully, the treatment was found to be well tolerated when it was delivered orally. The most common AE which was ocular related was delayed adaptation to the dark.
With this new designation in hand, Acucela plans to continue examining the potential of this treatment in clinical studies. They ultimately believe that it could slow, or prevent all together, vision loss for Stargardt disease patients.
The EMA only provides Orphan Designation to medicines which they believe have significant potential to treat, prevent, or aid in the diagnosis of conditions which affect 5 or fewer individuals out of every 10,000 in the EU. This designation provides the drug developers with fee reductions, 10 years market exclusivity, protocol assistance, and other benefits. These incentives can aid in the development of these therapies, helping them get into the hands of patients sooner.
The FDA also granted this therapy Orphan Drug Designation back in January of 2017. The FDA has said the total number of drugs that have earned this designation has been soaring in the last few years. More than half of the therapies approved in 2018 by the organization were orphan drugs. This showcases the increased focus pharmaceutical companies have placed on rare diseases. The negative? They’re often priced at outrageous rates.
Hopefully, we will continue to see this therapy for Stargardt disease develop, and hopefully it will become an accessible treatment option for this patient population- one that is both efficacious and affordable.
You can read more about this therapy here.