Published in Pipeline

Belite Bio reports phase 3 topline data on oral tinlarebant for Stargardt disease

Alex Delaney-Gesing

This is editorially independent content
6 min read

Belite Bio, Inc. released positive topline findings from a global phase 3 study evaluating oral tinlarebant in patients with Stargardt disease type 1 (STGD1).

First, what should we know about Belite Bio?

The San Diego, California-headquartered, clinical-stage biopharmaceutical drug development company is targeting degenerative retinal diseases with unmet needs.

How: By developing investigational therapies based on a retinal binding protein 4 (RBP4) intellectual property portfolio. See here for a refresh on RBP4 and why it’s crucial for healthy retinal function.

Now to tinlarebant.

Belite’s lead asset is currently under clinical development as a potential early intervention for retinal tissue health maintenance in two patients diagnosed with STGD1 and geographic atrophy (GA).

What to know about it:

  • This is a once-daily, orally-administered tablet
  • Ideally, it works by reducing toxic accumulation within the eye (which leads to STGD1 and plays a role in GA development)
  • On the regulatory side, it’s already received four key FDA designations for STGD1

And, before we get to this phase 3 trial, how has it performed in clinical trials so far?

Favorably—and promising, based on what we’ve seen from both phase 1 and 2 studies.

Specifically, tinlarebant has been found to:

  • Stabilize visual acuity (VA; especially among patients with severe vision loss)
  • Halt atrophic lesion growth within the macula among 75% of patients by year 2 of treatment

Sounds promising … now to the latest data.

That would be based on the multicenter, double-masked, phase 3 DRAGON trial (NCT05244304).

  • Its purpose: To evaluate tinlarebant’s safety and efficacy (versus a placebo)
  • The patients: 104 STGD1 patients (aged 12 to 20) ABCA4 gene
    • n = 69 (tinlarebant)
    • n = 35 (placebo)
  • The setup: Patients randomized 2:1 to receive either 5 mg of tinlarebant or a placebo (once a day)
  • The duration: 24 months

And what was measured?

Tracked from baseline to month 24, the following:

The primary outcome: Change in atrophic lesion size (via definitely decreased autofluorescence [DDAF]), as obtained by fundus AF (FAF)

The secondary outcomes:

  • Change in retinal thickness (via spectral-domain optical coherence tomography [SD-OCT])
  • Change in retinal morphology (via SD-OCT)
  • Change in best-corrected visual acuity (BCVA), as measured via the Early Treatment Diabetic Retinopathy Scale (ETDRS) method

And other outcomes included:

  • Change in total DAF (via FAF)
  • Change in questionably-decreased AF (QDAF) via FAF

Next up: these (topline) findings.

First thing’s first: The study met its primary endpoint, demonstrating “a statistically significant and clinically meaningful" 36% reduction in retinal lesion growth versus placebo.

To be more specific: Belite reported that:

  • This statistical significance was reached “when applying the pre-specified analysis (p-value = 0.0033)”
  • A further post-hoc analysis with a “specific data correlation showed that the treatment effect remained consistent with a p-value < 0.0001”

Go on …

Belite also reported a “statistically significant treatment effect” observed in the fellow eye, with a 33.6% lesion growth reduction (p = 0.041).”

This reduced lesion growth continued for DAF, with a decrease of 33.7% (p = 0.027) and 32.7% (p = 0.017) observed in the study eye and fellow eye, respectively.

And how did VA fare?

Overall change was minimal for both study groups over the 24-month evaluation period, which the company expected.

  • This was also reportedly consistent with natural history data.

How about tinlarebant’s safety profile?

Sticking with the consistency theme: This was also aligned with its previous clinical performance.

  • As Belite noted: “Tinlarebant was well tolerated with only four treatment-related discontinuations” and none due to non-ocular adverse events (AEs).
    • The most commonly reported non-ocular AE was headache.

For common drug-related ocular AEs: The majority of xanthopsia, delayed dark adaptation, and night vision impairment were reportedly “mild,” with most resolving during the trial.

Nice! So what’s the feedback on this?

CEO and Chairman Tom Lin, PhD, referred to the topline data as a “historic breakthrough” in Stargardt disease.

  • “Not only was tinlarebant shown to be efficacious in slowing retinal degeneration,” he noted, “but this is also the first time that an oral treatment was able to demonstrate a clinically meaningful outcome in retinal degenerative disease.

Check out a clinical investigator's input on this, as well as Belite’s chief medical officer.

Also: Pending the completion of a full analysis of the study’s findings, the company report plans to release additional details at upcoming medical meetings.

So … what’s the plan for tinlarebant moving forward?

Next up on the agenda is a potential new drug application (NDA) submission to the FDA within the first half (H1) of 2026.

  • Belite shared that it’s planning to engage with regulatory authorities in several countries (including Europe and Japan) to discuss these submissions.

And beyond these: Tinlarebant is still undergoing clinical evaluation in two other trials:

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