A phase 3 study of Belite Bio’s tinlarebant in adolescents with an uncommon inherited eye disorder has achieved its main goal, prompting the company to include the U.S. among the countries where it intends to seek approval in 2026.
In the trial, 104 participants with Stargardt disease type 1 (STGD1) were assigned to receive either tinlarebant or a placebo. STGD1 causes toxic lesions in the retina and leads to progressive central vision loss. Tinlarebant is an oral therapy aimed at lowering the buildup of vitamin A–derived toxins that contribute to the disease.
Belite reported that tinlarebant slowed the expansion of retinal lesions by almost 36% compared with placebo, meeting the trial’s main goal. A post hoc assessment – designed to reflect the steadily worsening course of STGD1 – showed a comparable effect, and additional lesion-growth metrics pointed in the same direction.
After two years, both study arms showed little change in visual acuity, which Belite said aligned with expectations. In a statement, Quan Dong Nguyen, an ophthalmology professor at Stanford’s Byers Eye Institute, noted that the reduction in lesion progression should eventually lead to observable improvements in vision.
Four treatment-linked issues were reported, leading to discontinuations. The most frequent eye-related side effects tied to tinlarebant were xanthopsia (an alteration in color perception) and slower adjustment to low light. According to Belite, these vision problems were generally mild and tended to resolve while the trial was ongoing. Outside of eye symptoms, headaches emerged as the most common treatment-associated complaint.
Belite intends to submit its application to the FDA in the first half of next year. That move would place the U.S. alongside China and the U.K., where the company is also preparing regulatory filings. Authorities in China and the U.K. agreed to consider submissions after reviewing interim results in February, when the data safety monitoring board advised Belite to proceed with approval attempts based on those findings.
Belite’s shares climbed almost 18% in premarket trading, driven by the possibility that the company could become the first to introduce a U.S. treatment for STGD1. Several organizations are pursuing therapies for Stargardt disease – including Ocugen, whose phase 2/3 gene therapy OCU410ST is among the leading contenders – but Belite currently appears positioned to reach the U.S. market first.
The positive outcome in the STGD1 trial may also support Belite’s broader strategy to advance tinlarebant for geographic atrophy (GA). While Apellis’ Syfovre and Astellas’ Izervay are already approved treatments for GA, both require intravitreal injections. Tinlarebant, delivered orally, could offer patients a noninvasive alternative. Belite is currently conducting a phase 3 study in GA.
Belite’s success in this trial highlights the growing potential for oral therapies in inherited retinal disorders. The company’s focus on noninvasive treatment options may set a new standard in patient care, as oral administration is generally more convenient and less burdensome than frequent injections.
Looking ahead, Belite plans to expand patient access to tinlarebant through global regulatory submissions and collaborations with healthcare providers. The company is also exploring long-term outcomes, including the impact of sustained lesion reduction on visual acuity and quality of life for patients.
With STGD1 representing a rare condition with limited treatment options, Belite’s advancement underscores its commitment to tackling underserved diseases. The company’s continued research into both STGD1 and GA reflects a strategic focus on innovative therapies that address the root cause of retinal degeneration rather than just managing symptoms.
Belite’s achievement in the phase 3 STGD1 trial represents a major milestone for patients with rare inherited eye disorders. By demonstrating the ability of tinlarebant to significantly slow retinal lesion progression, the company not only advances toward FDA approval in the U.S. but also sets the stage for expanded global availability. This success reinforces Belite’s commitment to developing innovative, patient-friendly therapies that address the underlying causes of vision loss.
