Stargardt Disease 1Phase 1NCT07836452
A Phase 1, First-in-Human Study of CITY-RBP4 in Healthy Volunteers and STGD1 Participants
A Phase 1 study testing CITY-RBP4 in people with Stargardt Disease 1 and STGD1, run by City Therapeutics at 1 site in Australia.
Trial summary
This is a first-in-human (FIH), multicenter, randomized, double-masked, placebo-controlled adaptive clinical study evaluating the safety, tolerability, pharmacokinetic (PK), and pharmacodynamic (PD) of CITY-RBP4, following single-ascending doses and multiple doses, via subcutaneous (SC) administration. Read more about this study
- Who is it for?
- Ages 12 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Stargardt Disease 1, STGD1, Healthy Volunteers
- What is being tested?
- CITY-RBP4
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 48 participants
- Where
- 1 siteAustralia
- Study dates
- Sep 2026to Apr 2028
- Phase
- Phase 1
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 12 to 45 years
- All sexes
- Healthy volunteers accepted
- Child, Adult
Who may be able to join
- Willing and able to provide written informed consent form
- Be aged 18 to 45 years (inclusive) at the time of signing the informed consent form
- Generally healthy on medical history, exam, labs, and ECG
- BCVA 20/25 or better in each eye
- Serum retinol above protocol threshold
- Body weight ≥40 kg and BMI of 18.0 to 32.0 kg/m2
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- Men and WOCBP must agree to use highly effective methods of contraception or practice abstinence from 30 days before the first dose of CITY-RBP4, throughout the study, and for at least 180 days after treatment with CITY-RBP4 or the last study visit, whichever is longer; men must refrain from donating or banking sperm during the same period
- Female participants who are not WOCBP should meet at least 1 of the following criteria: have undergone a documented hysterectomy, bilateral oophorectomy, and/or bilateral salpingectomy; have medically confirmed ovarian failure, or achieved postmenopausal status
- Participants aged 12 to 45 years
- Clinical diagnosis of STGD1 with documented ABCA4 pathogenic/likely pathogenic variant
- Minimum BCVA is required in the study eye
- Subjects must have a defined aggregate atrophic lesion in 1 or both eyes
- Body weight ≥40 kg
- Able to complete key ophthalmic safety assessments and comply with study precautions
Who cannot join
- Clinically significant ocular disease or prior ocular surgery that could interfere with safety assessments
- History of vitamin A deficiency, malabsorption, or chronic diarrhea
- Clinically significant cardiac, hepatic, renal, pulmonary, neurologic, or psychiatric disease
- Positive hepatitis B, hepatitis C, or HIV screening
- Prior RNAi/oligonucleotide therapy or recent investigational treatment
- Recent vitamin A-related supplements, retinoids, or medications affecting vitamin A metabolism
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- Pregnancy or breastfeeding, if applicable
- Ocular conditions that could confound retinal imaging or safety evaluation
- Prior ocular gene therapy, stem cell therapy, or retinal implant
- Vitamin A deficiency or recent prohibited vitamin A-related treatments
- Recent interventional study participation
- Clinically significant non-ophthalmic disease, abnormal screening labs/ECG, or positive hepatitis B, hepatitis C, or HIV screening
- Pregnancy or breastfeeding, if applicable
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Australia1 site, 1 recruiting
- Recruiting
Nucleus Network
Melbourne, Victoria, 3004
Nucleus Network Melbourne, +61-1800-243-733, melbourne@nucleusnetwork.com
About this study
Official title: A Phase 1, Randomized, Double-Masked, Placebo-Controlled, Single-Ascending and Multiple Dose Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of CITY-RBP4 Administered Subcutaneously in Healthy Volunteers and Participants With Stargardt Disease Type 1 (STGD1)
This is a first-in-human (FIH), multicenter, randomized, double-masked, placebo-controlled adaptive clinical study evaluating the safety, tolerability, pharmacokinetic (PK), and pharmacodynamic (PD) of CITY-RBP4, following single-ascending doses and multiple doses, via subcutaneous (SC) administration.
Read the detailed description
The study consists of 3 sequential parts:
- Part A: Single-ascending doses in healthy volunteers
- Part B: Single-ascending doses in participants with Stargardt Disease Type 1 (STGD1)
- Part C: Multiple doses in participants with Stargardt Disease Type 1 (STGD1)
- Conditions
- Stargardt Disease 1, STGD1, Healthy Volunteers
- Being tested
- CITY-RBP4, Placebo
- Medical subject headings
- Stargardt Disease
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CITY-RBP4Drug
siRNA (subcutaneous injection)
PlaceboDrug
Saline (subcutaneous injection)
| Study group | Role | What they receive |
|---|---|---|
| CITY-RBP4 in Healthy Adults (Part A) | Experimental | Not described Receives: Drug: CITY-RBP4 |
| In Healthy Adults (Part A) | Placebo comparator | Not described Receives: Drug: Placebo |
| CITY-RBP4 in Participants with STGD1 (Parts B & C) | Experimental | Not described Receives: Drug: CITY-RBP4 |
| In Participants with STGD1 (Parts B & C) | Placebo comparator | Not described Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Incidence, severity, and relationship of treatment-emergent adverse events (TEAEs)
To evaluate the safety and tolerability of single and multiple doses of CITY-RBP4 in healthy adults and participants with Stargardt disease Type 1 (STGD1)
Measured: Through study completion, up to Day 360
Secondary outcomes (10)
Plasma concentrations of CITY-RBP4
To characterize the pharmacokinetic (PK) profile of CITY-RBP4 after single and multiple doses of CITY-RBP4 in healthy adults and participants with STGD1
Measured: Day 1 to Day 2
Urine concentrations of CITY-RBP4
To characterize the pharmacokinetic (PK) profile of CITY-RBP4 after a single dose of CITY-RBP4 in healthy adults and participants with STGD1
Measured: Part A and B only: Day 1 to Day 2
Maximum plasma concentration (Cmax)
To characterize the pharmacokinetic (PK) profile of CITY-RBP4 after single and multiple doses of CITY-RBP4 in healthy adults and participants with STGD1
Measured: Day 1 to Day 2
Time to maximum plasma concentration (Tmax)
To characterize the pharmacokinetic (PK) profile of CITY-RBP4 after single and multiple doses of CITY-RBP4 in healthy adults and participants with STGD1
Measured: Day 1 to Day 2
Area under plasma concentration-time curve (AUC)
To characterize the pharmacokinetic (PK) profile of CITY-RBP4 after single and multiple doses of CITY-RBP4 in healthy adults and participants with STGD1
Measured: Day 1 to Day 2
Terminal elimination half-life (t1/2)
To characterize the pharmacokinetic (PK) profile of CITY-RBP4 after single and multiple doses of CITY-RBP4 in healthy adults and participants with STGD1
Measured: Day 1 to Day 2
Apparent clearance (CL/F)
To characterize the pharmacokinetic (PK) profile of CITY-RBP4 after single and multiple doses of CITY-RBP4 in healthy adults and participants with STGD1
Measured: Day 1 to Day 2
Amount excreted unchanged (Ae)
To characterize the pharmacokinetic (PK) profile of CITY-RBP4 after a single dose of CITY-RBP4 in healthy adults and participants with STGD1
Measured: Part A and B only: Day 1 to Day 2
Change from baseline in plasma RBP4 concentrations
evaluate the pharmacodynamic (PD) effects of CITY-RBP4 on plasma retinol-binding protein 4 (RBP4) levels after single and multiple doses of CITY-RBP4 in healthy adults and participants with STGD1
Measured: Up to Day 360
Change from baseline in serum retinol concentrations
To evaluate the pharmacodynamic (PD) effects of CITY-RBP4 on serum retinol levels after single and multiple doses of CITY-RBP4 in healthy adults and participants with STGD1
Measured: Up to Day 360
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Sep 2026
- Study startSep 2026 (estimated)
- Primary completionFeb 2028 (estimated)
- Study completionApr 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Stargardt Disease 1Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Sequential
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 48 participants (estimated)
Sponsor and investigators
- Lead sponsor
- City Therapeutics
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Medical Director, Study director, City Therapeutics
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07836452
- Sponsor's protocol ID
- CITY-RBP4-01
- Status last verified
- Sep 2026
- First submitted
- 16 Sep 2026
- Last updated
- 23 Sep 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 23 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 1, Randomized, Double-Masked, Placebo-Controlled, Single-Ascending and Multiple Dose Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of CITY-RBP4 Administered Subcutaneously in Healthy Volunteers and Participants With Stargardt Disease Type 1 (STGD1)
- ClinicalTrials.gov ID
- NCT07836452
- Acronym / sponsor ID
- CITY-RBP4-01
- Conditions
- Stargardt Disease 1, STGD1, Healthy Volunteers
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 48 participants (estimated)
- Lead sponsor
- City TherapeuticsIndustry (pharma, biotech, devices)
- Study start
- Sep 2026 (estimated)
- Primary completion
- Feb 2028 (estimated)
- Study completion
- Apr 2028 (estimated)
- First posted
- 23 Sep 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This is a first-in-human (FIH), multicenter, randomized, double-masked, placebo-controlled adaptive clinical study evaluating the safety, tolerability, pharmacokinetic (PK), and pharmacodynamic (PD) of CITY-RBP4, following single-ascending doses and multiple doses, via subcutaneous (SC) administration.
Detailed description
The study consists of 3 sequential parts:
- Part A: Single-ascending doses in healthy volunteers
- Part B: Single-ascending doses in participants with Stargardt Disease Type 1 (STGD1)
- Part C: Multiple doses in participants with Stargardt Disease Type 1 (STGD1)
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Sequential
- Masking
- Double blind (participant, investigator)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| CITY-RBP4 in Healthy Adults (Part A) | Experimental | Drug: CITY-RBP4 |
| In Healthy Adults (Part A) | Placebo comparator | Drug: Placebo |
| CITY-RBP4 in Participants with STGD1 (Parts B & C) | Experimental | Drug: CITY-RBP4 |
| In Participants with STGD1 (Parts B & C) | Placebo comparator | Drug: Placebo |
Who may qualify
- Ages
- 12 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult
Key inclusion criteria (14 listed)
- Willing and able to provide written informed consent form
- Be aged 18 to 45 years (inclusive) at the time of signing the informed consent form
- Generally healthy on medical history, exam, labs, and ECG
- BCVA 20/25 or better in each eye
- Serum retinol above protocol threshold
Key exclusion criteria (13 listed)
- Clinically significant ocular disease or prior ocular surgery that could interfere with safety assessments
- History of vitamin A deficiency, malabsorption, or chronic diarrhea
- Clinically significant cardiac, hepatic, renal, pulmonary, neurologic, or psychiatric disease
- Positive hepatitis B, hepatitis C, or HIV screening
- Prior RNAi/oligonucleotide therapy or recent investigational treatment
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| CITY-RBP4siRNA (subcutaneous injection) | Drug | CITY-RBP4 in Healthy Adults (Part A), CITY-RBP4 in Participants with STGD1 (Parts B & C) |
| PlaceboSaline (subcutaneous injection) | Drug | In Healthy Adults (Part A), In Participants with STGD1 (Parts B & C) |
Primary outcome
Incidence, severity, and relationship of treatment-emergent adverse events (TEAEs)
Time frame: Through study completion, up to Day 360
To evaluate the safety and tolerability of single and multiple doses of CITY-RBP4 in healthy adults and participants with Stargardt disease Type 1 (STGD1)
10 secondary outcomes
Plasma concentrations of CITY-RBP4
Time frame: Day 1 to Day 2
Urine concentrations of CITY-RBP4
Time frame: Part A and B only: Day 1 to Day 2
Maximum plasma concentration (Cmax)
Time frame: Day 1 to Day 2
Time to maximum plasma concentration (Tmax)
Time frame: Day 1 to Day 2
Area under plasma concentration-time curve (AUC)
Time frame: Day 1 to Day 2
Terminal elimination half-life (t1/2)
Time frame: Day 1 to Day 2
Apparent clearance (CL/F)
Time frame: Day 1 to Day 2
Amount excreted unchanged (Ae)
Time frame: Part A and B only: Day 1 to Day 2
Change from baseline in plasma RBP4 concentrations
Time frame: Up to Day 360
Change from baseline in serum retinol concentrations
Time frame: Up to Day 360
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Sep 2026.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Medical Director study director
City Therapeutics
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing CITY-RBP4 in people with Stargardt Disease 1 and STGD1, run by City Therapeutics at 1 site in Australia.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 14 inclusion and 13 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 23 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Australia. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact City Therapeutics (857-219-5440, clinicaltrials@citytx.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Incidence, severity, and relationship of treatment-emergent adverse events (TEAEs) (time frame: Through study completion, up to Day 360). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 23 Sep 2026.