Belite Bio announces promising phase 3 results for Stargardt disease
Belite Bio has announced promising results from a completed global phase 3 clinical trial of tinlarebant for Stargardt disease. It is important to note that this study is separate from a different phase 2/3 trial of tinlarebant that is still recruiting in some parts of the world, including the UK.
This article provides an update from the phase 3 trial of tinlarebant, not to be confused with our recent article about a separate phase 2/3 trial of the same drug that is still recruiting in some areas of the world, including the UK. In this unusual case, a phase 3 was completed before a separate phase 2/3 with different parameters was fully recruited. The original phase 3 study is now finished and this article refers to that trial’s results.
If you would like to hear more about the current phase 2/3 trial or how tinlarebant works, please visit this article.
The results:
In Stargardt disease, certain areas of the retina get progressively damaged and die. This can be observed using a special imaging technique called Fundus Autofluorescence (FAF), where a light is shone into the eye and a camera captures images. These images provide a ‘map’ of how healthy the Retinal Pigment Epithelium (RPE) is – the retina’s supportive layer. Areas that glow normally suggest a healthy RPE, whereas areas that are darker can indicate cell damage or loss. These damaged areas are called areas of ‘atrophy’ or ‘atrophic lesions.’
By repeating FAF tests, doctors can track disease progression by comparing images to see if dark areas grow or if new ones appear. In Stargardt disease, increased atrophy means that the retina is progressively losing healthy cells, and as such vision progressively declines.
This phase 3 trial, known as DRAGON, involved 104 patients aged 12-20 globally. Participants in the trial were randomized in the ratio 2:1 to receive tinlarebant or a placebo. Tinlarebant was shown to reduce the growth rate of atrophic lesions by 36% compared to those who received the placebo. Belite Bio also report that the safety profile remained consistent with previous studies and the drug was well tolerated by participants.
What does this mean?
This means that for those who received tinlarebant, the retina was shown to be degenerating more slowly compared to the control group. It is important to note that due to the natural history of Stargardt disease, and the relatively short trial length of 24 months, the reduced atrophy in the treated group did not translate immediately into better or preserved vision compared to the control group. As such, visual acuity measures remained stable for participants in both groups.
However, we know that as Stargardt disease progresses, increased areas of atrophy eventually correlate with a decline in vision so it is expected that tinlarebant’s effects will ultimately translate into slower sight loss. Belite Bio expect to observe this over the coming years as they continue to track trial participants.
What happens next?
Belite Bio is now engaging with medicine regulators, who would decide whether to license tinlarebant for wider availability. Please note that different regulatory bodies operate in the US, UK, Europe and elsewhere, and obtaining regulatory approval can take a long time, even if Belite Bio seeks to work with all of them. Reaching agreement for NHS availability is a further, separate process. As a result, there may be a significant wait before the treatment becomes widely available.
The results of this phase 3 trial provide new hope for our Stargardts community, with tinlarebant being the first therapeutic candidate to demonstrate clinical efficacy in a global phase 3 trial for Stargardt disease. To read more about Belite Bio, please visit their website here.
Keep up to date with research developments in the inherited retinal disease field by visiting the News and Events section on the Retina UK website.