A Phase 2 interventional study of STL303 and Placebo in Geographic Atrophy, sponsored by Sitala Bio LTD. Recruiting at 56 sites in 7 countries. Open to participants aged 60 Years and older. Per ClinicalTrials.gov, last updated 2026-09-21.
Sponsored by Sitala Bio LTD · Phase 2, Interventional, and Treatment
Among 131 studies in Geographic Atrophy with a site in United States — 35 open to participants now, 46 under way, 5 of them phase 3. Geographic Atrophy · United States.
Among the 131 studies in Geographic Atrophy with a site in United States, this one is the 24th largest by planned enrollment of the 107 interventional ones, is one of 9 that started in 2026, is one of 43 in phase 2, reaches primary completion later than 29 of the 45 other live ones, and was the 128th registered.
188 studies on the registry are indexed under Geographic Atrophy; 52 are open to participants now.
This study's planned enrollment of 300 is above the median of 70 across 141 interventional studies indexed under Geographic Atrophy.
Browse Geographic Atrophy studies →35 of the 131 studies in Geographic Atrophy with a site in United States are open now, in 12 countries. Each count lists the studies.
Of the 40 Geographic Atrophy studies recruiting now, 31 (78%) set no upper age limit and 0 (0%) stop at 75 or younger; 2 take children under 18; 4 take healthy volunteers.
This study: 60 Years and older · all sexes · no healthy volunteers.
The full table on the hub →131 studies; the count open now beside each. This study's row is marked.
First in 2000; this study’s year is marked. 9 started in 2026.
Median enrollment 98 across the 107 interventional studies, 138 across the 24 observational. Of the 78 that completed or were terminated, 40 (51%) have results posted.
109 of 131 have an industry lead sponsor. The 10 most frequent:
Sitala Bio LTD is the lead sponsor of 2 studies on the registry; 2 are open to participants now.
Sitala Bio LTD has 1 study filed under Geographic Atrophy — fewer than ten, so there is no comparison to draw.
12 of the studies in Geographic Atrophy with a site in United States that are under way reach primary completion within a year, 2 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT05949593Phase 3Belite Bio, IncPhase 3, Randomized, Placebo-Controlled Study of Tinlarebant to Explore Safety and Efficacy in Geographic Atrophy | 2027-06-30 |
| NCT06510816Phase 3Annexon, Inc.A Study Investigating the Efficacy and Safety of Intravitreal (IVT) Injections of Vonaprument (Formerly ANX007) in Participants With Dry Age-Related Macular Degeneration (AMD) With Geographic Atrophy (GA) | 2027-07-31 |
| NCT06769048Boehringer IngelheimA Study to Test Different Doses of BI 1584862 in People With a Distinct Form of Age-related Macular Degeneration (AMD) Called Geographic Atrophy | 2026-12-22 |
| NCT07747662University of Wisconsin, MadisonAdaptive Optics Scanning Light Ophthalmoscopy (AOSLO) and Microperimetry (MP) Sub-study | 2027-02 |
| NCT07144137Complement TherapeuticsA Non-Interventional Study Observing Short-Term Progression in Geographic Atrophy (GA) | 2027-03-31 |
Among the 131 studies in Geographic Atrophy with a site in United States, from their registry updates:
The purpose of this clinical research study is to look at how safe STL303 is and whether it works when given to people with Geographic Atrophy (GA) secondary to Age-related Macular Degeneration (AMD). Geographic atrophy secondary to AMD is a condition where cells in the back part of the eye slowly die, causing a blurry, or missing spot in the centre of vision.
This study is designed as a randomized, multi-center, double-masked, dose-range finding study to characterize the efficacy and safety of STL303.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
The study eye must meet all inclusion criteria. If both eyes meet the inclusion criteria, the eye with the better visual acuity at the Screening visit will be designated as the study eye. If both eyes have the same visual acuity, the right eye will be selected as the study eye.
The GA lesion in the study eye must meet the following criteria as determined by the central Reading Centre's assessment at Screening:
Meets the following criteria related to microperimetry:
Exclusion Criteria:
Ocular conditions - either eye:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Postmenopausal
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
QT and QTc
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Excipients
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants will receive STL303 dose level 1
Drug: STL303
Participants will receive STL303 dose level 2
Drug: STL303
Participants will receive placebo
Drug: Placebo
STL303 arm participants will receive a specific dose of STL303
Placebo arm participants will receive placebo
Reduction of rate of total EZ area loss
Rate of change in the area of photoreceptor loss
Time frame: From baseline to Week 52
Number of reported treatment-emergent adverse events (TEAE) and serious adverse events (SAEs)
Assess safety and tolerability of STL303
Time frame: Baseline to week 108
Change in Retinal sensitivity
Mesopic microperimetry using participant-customised peri-lesional grid.
Time frame: From enrolment to end of treatment at week 104
Rate of disease progression (photoreceptor loss)
Rate of change in the area of photoreceptor loss (defined as ellipsoid zone to retinal pigment epithelium thickness of 0 μm) in the study eye, as assessed by spectral-domain optical coherence tomography (SD-OCT)
Time frame: From enrolment to end of treatment at week 104
Change in Vision-Related Quality of Life
Change from baseline in the National Eye Institute 25 item Visual Functioning Questionnaire (NEI VFQ-25). Range: 0-100, where higher scores indicate better vision-related quality of life.
Time frame: From Baseline to end of treatment at week 104
Maximum serum concertation at steady-state (Cmax, ss) of STL303
Measure maximum plasma concentration at steady-state (Cmax, ss) at steady state.
Time frame: Weeks 0, 4, 12, 26, 52, 78, and 104 pre and 2 hours post dose.
Determine pharmacodynamic profile of STL 303
Change from baseline in complement alternative pathway (AP) functional activity as measured by the Wieslab assay in serum
Time frame: Weeks 0, 4, 12, 26, 52, 78 and 104 pre and 2 hours post dose.
Trough plasma concentration at steady-state of STL303
Measure trough plasma concentration at steady-state (Cmin, ss /Ctrough, ss),
Time frame: Weeks 0, 4, 12, 26, 52, 78, and 104 pre and 2 hours post dose.
Area under plasma concentration-time curve for STL303
Measure the area under the plasma concentration-time curve over one dosing interval at steady state (AUCtau)
Time frame: Weeks 0, 4, 12, 26, 52, 78, and 104 pre and 2 hours post dose.
Plan to share: No — Individual participant data (IPD) will not be shared because participant consent and ethics approvals do not permit public data sharing. A clinical study report will be prepared at the end of the study and result will be shared with research sites and investigators will be able to discuss results with participants if needed.
No publications or documents are linked to this record.
Started Sep 2026 (actual). Primary completion is estimated for Jul 2028, 22 months after the start.
Of 24 phase 2 interventional studies under Geographic Atrophy, half reached primary completion within 36 months of starting (the median), counting those still running; a quarter within 25 and three quarters within 54. This study's planned 22 months is below that.
How these figures are worked out, and which studies are left out of them.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
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Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
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