AuthorisedTherapeutic exploratory (Phase II)Interventional

A Phase 2, Multicentre, Randomised, Double-masked, Placebo-controlled, Parallel-group, Dose-range Finding Study, to Assess the Efficacy and Safety of Oral STL303 in Adults with Geographic Atrophy Secondary to Age-related Macular Degeneration

Age-related macular degeneration (AMD) is a common condition that affects the central part of your vision. In its advanced dry stage, known as geographic atrophy, light-sensing cells at the back of the eye slowly break down and stop working. Currently, there are few treatment options available. This clinical trial is testing a new oral medication called STL303. Unlike many eye treatments that require regular injections into the eye, STL303 is taken as a capsule by mouth. The main goal of the study is to see whether STL303 can safely slow down the loss of light-sensing cells compared to an inactive dummy pill (placebo). Participants will take either the study drug or a placebo every day for about two years. Doctors will closely track changes in their vision, perform detailed eye scans, and monitor their overall health throughout the study.

At a glance

Status

Authorised

Phase

Therapeutic exploratory (Phase II)

Sponsor

Sitala Bio Limited

Enrolment target

Start

14 Oct 2026

Geographic Atrophy Secondary to Age-related Macular Degeneration

What is this study about?

Age-related macular degeneration (AMD) is a leading cause of sight problems in older adults. Geographic atrophy is an advanced stage of 'dry' AMD. Over time, patches of cells in the retina—the light-sensitive layer at the back of the eye—wear away and stop working. This causes blank or blurry spots in central vision, making everyday tasks like reading, driving, and recognising faces difficult. At present, options to stop this gradual damage are very limited.

This clinical trial is evaluating a new investigative drug called STL303. Researchers believe STL303 may help protect these delicate retinal cells from breaking down. A unique feature of this treatment is that it comes as a capsule taken by mouth, rather than an injection directly into the eye.

The trial is designed to find out which dose works best and to confirm if the drug is safe. Because it is a 'placebo-controlled' study, some people will receive STL303 while others will receive identical dummy capsules containing no active medicine. Neither you nor your study doctor will know which one you are taking until the study ends. This ensures the results are completely fair and reliable.

Over the course of two years, researchers will measure how quickly the patches of cell loss grow using detailed, painless eye scans. If STL303 proves effective, it could offer a much-needed, simple way to help people preserve their eyesight for longer.

Key takeaways

Tests an experimental daily capsule (STL303) designed to slow down dry age-related macular degeneration.
Aims to protect light-sensitive retinal cells without needing eye injections.
Participants take either the study drug or an inactive dummy capsule (placebo) for two years.
Involves regular clinic visits for non-invasive eye scans, vision checks, and routine health tests.
Participation is entirely voluntary and you may withdraw at any time.

Who may be eligible?

This study is open to adults aged 18 and older who have been diagnosed with geographic atrophy caused by age-related macular degeneration (AMD).

To be suitable, the area of cell loss in your eye must meet certain size criteria that can be clearly tracked using standard eye scans. You will also need to be able to swallow capsules and be willing to attend regular hospital or clinic appointments over a two-year period.

You may not be eligible if you have other serious eye conditions that could interfere with the study measurements, or if you have certain major medical conditions affecting your heart, liver, or kidneys. The study team will run detailed eye and health checks before you join to ensure taking part is safe for you.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

I am aged 18 or older.
I have been diagnosed with geographic atrophy (advanced dry AMD).
I am able to swallow capsules daily.
I am willing and able to travel to regular clinic visits over a two-year period.
I do not have other severe eye conditions that heavily interfere with my central vision.

Answer every question to see your result.

What does participation involve?

If you decide to join, your participation will last about two years (104 weeks). You will be asked to take study capsules by mouth every day at home. These will either be the active medicine (STL303) or an inactive dummy capsule (placebo).

You will visit the clinic regularly for check-ups. During these visits, doctors will perform detailed eye exams, take painless photographs and scans of your retina (such as OCT scans), and test your vision in different lighting conditions. You will also have routine health checks, including blood pressure readings, heart tracings (ECGs), and blood and urine samples. In addition, you will be asked questions about how your eyesight affects your day-to-day life.

Potential risks and benefits

There is no guarantee that STL303 will improve your vision or slow down your disease, and you might receive the dummy pill instead of the active medicine. However, taking part may provide very close monitoring of your eye health by specialists, and the findings could help develop new treatments for others in the future. As with any new medicine, there is a risk of unexpected side effects, and clinic visits require a significant commitment of your time. Your safety will be closely monitored throughout, and you are free to leave the trial at any time without your regular NHS care being affected.

Locations (2)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

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Unverified
Poland
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Unverified
Czechia

Common questions

Is this treatment an eye injection?

No. STL303 is taken as a capsule by mouth with water, meaning there are no eye injections involved in this study.

What is a placebo?

A placebo is a harmless dummy capsule that looks identical to the real medication but contains no active medicine. It helps researchers prove whether any health changes are truly caused by the study drug.

Will taking part cost me anything?

No, the study medication and all trial-related tests are provided free of charge. Most clinical trials also help cover reasonable travel expenses for hospital visits.

Will the scans hurt my eyes?

No. The eye scans and photography are non-invasive and painless, similar to the photos taken during a regular optician's check-up.

Can I leave the study if I change my mind?

Yes. Joining is completely voluntary. You can stop taking part at any time without giving a reason, and your everyday medical care will not be affected.