Belite Bio releases topline results from phase 3 DRAGON trial of Tinlarebant for STGD1

Belite Bio has released topline results from the global phase 3 DRAGON trial of Tinlarebant in patients with Stargardt disease type 1 (STGD1). According to the company, this marks the first successful pivotal trial in patients with the disease.

Tinlarebant is a novel oral therapy intended to reduce the accumulation of vitamin A-based toxins (bisretinoids) that cause retinal disease in STGD1 and contribute to disease progression in geographic atrophy (GA), or advanced dry age-related macular degeneration (AMD). The company notes that Tinlarebant works by reducing and maintaining levels of serum retinol binding protein 4 (RBP4), the sole carrier protein for retinol transport from the liver to the eye, reducing the formation of bisretinoids.

The DRAGON trial was a 24-month, randomized (2:1, active: placebo), double-masked, placebo-controlled, global, multi-center, pivotal phase 3 trial in adolescent STGD1 patients. A total of 104 patients ranging from ages 12 to 20 were enrolled (n=69 in the Tinlarebant arm and n=35 in the placebo arm). All patients had been diagnosed with STGD1 with at least 1 mutation identified in the ABCA4 gene, an atrophic lesion size within 3 disc areas (7.62 mm²), and a best corrected visual acuity (BCVA) of 20/200 or better.

According to the company, the DRAGON trial met its primary efficacy endpoint, demonstrating a “statistically significant and clinically meaningful” 36% reduction in the growth rate of retinal lesions, measured as definitely decreased autofluorescence (DDAF) by fundus autofluorescence imaging, compared with placebo. Statistical significance was reached when applying an unstructured covariance matrix under the Mixed Model for Repeated Measures (MMRM) (p-value = 0.0033). Additionally, a post-hoc analysis providing a specific data correlation showed the treatment effect remained consistent with a p-value < 0.0001.

The company noted a statistically significant treatment effect was seen in the fellow eye for the primary endpoint with 33.6% lesion growth reduction (p = 0.041). Additionally, Tinlarebant slowed decreased autofluorescence (DAF) lesion growth, the key secondary endpoint calculated as the sum of DDAF and questionably decreased autofluorescence (QDAF), in the study eye by 33.7% (p = 0.027) and in the fellow eye by 32.7% (p = 0.017).

Patients in the 5 mg dosing achieved a reduction in RBP4 levels by an average of approximately 80% compared to baseline.

The overall change in visual acuity was minimal over the period of 24 months in both study groups, which the company specified was “expected” as it is consistent with natural history data.

Tom Lin, PhD, chairman and CEO of Belite Bio, commented on the trial results in a press release from the company, saying, “The final results from the DRAGON trial mark a historic breakthrough in Stargardt disease, paving the way for the first potential treatment for this devastating condition and bringing new hope to patients and families who have long faced a disease once considered untreatable.

“Not only was Tinlarebant shown to be efficacious in slowing retinal degeneration, but this is also the first time that an oral treatment was able to demonstrate a clinically meaningful outcome in retinal degenerative disease. With this data, we are advancing our regulatory interactions globally and moving closer to delivering the first approved treatment for people living with Stargardt disease,” concluded Lin.

Quan Dong Nguyen, MD, MSc, FAAO, FARVO, FASRS, professor of ophthalmology at the Byers Eye Institute at Stanford, and professor of medicine and pediatrics at Stanford University School of Medicine, added, “It is remarkable to recognize that with the robust results of the DRAGON trial, we may soon have Tinlarebant as the first treatment ever for Stargardt disease. It is only a matter of time before the observed reduction in lesion growth translates into measurable benefits in visual function. Previous studies have demonstrated that if left untreated, progressive lesion enlargement caused by Stargardt disease is expected to compromise visual acuity and visual field. Tinlarebant has demonstrated that it can significantly reduce lesion growth.”

Belite Bio noted it plans to discuss potential next steps and submit a New Drug Application for Tinlarebant in the first half of 2026. Tinlarebant has been granted Breakthrough Therapy Designation, Fast Track Designation, and Rare Pediatric Disease Designation in the US.

References:

1. New Hope for People Living with a Disease Once Deemed Untreatable: Belite Bio Announces Positive Topline Results from the Pivotal Global, Phase 3 DRAGON Trial of Tinlarebant in Adolescents with Stargardt Disease. Published December 1, 2025. Accessed December 1, 2025. https://investors.belitebio.com/news-releases/news-release-details/new-hope-people-living-disease-once-deemed-untreatable-belite

2. Filkins K. Belite Bio concludes phase 3 DRAGON study for Stargardt disease. Published September 16, 2025. Accessed December 1, 2025. https://www.ophthalmologytimes.com/view/belite-bio-concludes-phase-3-dragon-study-for-stargardt-disease