NCT06541704 · Regeneron Pharmaceuticals
A Study Investigating Subcutaneously Administered Pozelimab in Combination With Cemdisiran or Cemdisiran Alone in Adult Participants With Geographic Atrophy
(SIENNA)
What this study is about
This study is researching experimental (study) drugs called pozelimab and cemdisiran. The study is focused on participants who have Geographic Atrophy (GA) caused by Age-related Macular Degeneration (AMD). Geographic atrophy is a medical term that refers to later-stage cases of AMD which is an eye condition affecting central vision (what one sees straight ahead).
View original scientific description
This study is researching experimental (study) drugs called pozelimab and cemdisiran. The study is focused on participants who have Geographic Atrophy (GA) caused by Age-related Macular Degeneration (AMD). Geographic atrophy is a medical term that refers to later-stage cases of AMD which is an eye condition affecting central vision (what one sees straight ahead).
Interventions
DRUG
Pozelimab
Subcutaneous (SC) injection
DRUG
Cemdisiran
SC injection
DRUG
Placebo
SC injection
Primary outcome measures
Growth rate (slope) of total GA lesion area (mm^2 /year) from baseline, measured by Fundus Autofluorescence (FAF)
Time frame: To week 52
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Study eye with diagnosis of GA of the macula secondary to AMD as described in the protocol
- Total GA area in the study eye measuring between ≥2.5 mm\^2 and ≤17.5 mm\^2 as described in the protocol
- BCVA of 55 letters or better using ETDRS charts (20/80 Snellen equivalent) in the study eye as described in the protocol
- Sufficiently clear ocular media, adequate pupillary dilation and fixation to permit quality fundus imaging in the study eye as described in the protocol
- Willing and able to comply with clinic visits and study-related procedures, including completion of the full series of meningococcal vaccinations and pneumococcal vaccination required per protocol Key
Exclusion criteria
- GA in either eye due to causes other than AMD, such as Stargardt disease, cone rod dystrophy or toxic maculopathies like hydroxychloroquine maculopathy
- History or current evidence of Macular Neovascularization (MNV) and/or exudation or Peripapillary Choroidal Neovascularization (PPCNV) in either eye as described in the protocol
- Prior or current Intravitreal (IVT) treatment of any kind for any indication in study eye or fellow eye, except approved or investigational IVT complement inhibitor therapy or anti-VEGF therapy, as long as last dose was ≥6 months prior to randomization
- Prior intraocular surgery except cataract extraction or minimally invasive glaucoma surgery in study eye as long as date of these procedures was ≥3 months prior to randomization
- Comorbid progressive ocular condition (eg, diabetic retinopathy, macular edema, uncontrolled glaucoma, full thickness macular hole) in study eye that could affect central vision and confound study
- Any ophthalmologic condition that reduces the clarity of the media and that, in the opinion of the investigator interferes with ophthalmologic examination of the study eye (e.g., advanced cataract or corneal abnormalities) as described in the protocol Systemic Exclusion criteria
- History or current use of systemic complement inhibitor therapy within 6 months prior to randomization as described in the protocol
- History of solid organ or bone marrow transplantation
- Use of chronic (\>14 days) systemic corticosteroids (oral or parenteral, ≥20 mg oral prednisone or equivalent) within the previous 30 days prior to the first screening visit as described in the protocol
- Current or prior use of systemic immunosuppressive therapy other than corticosteroids within 12 months prior to randomization or the likelihood of treatment with any such agent during the study inclusive of the screening period as described in the protocol
- Not meeting meningococcal or pneumococcal vaccination requirements as described in the protocol
- Carrier of Neisseria meningitidis based on culture collected during screening
- Has a hemoglobin A1C ≥ 8.0% during screening as described in the protocol NOTE: Other protocol-defined Inclusion/ Exclusion Criteria apply
Where
- Chandler, Arizona
- Phoenix, Arizona
- Scottsdale, Arizona
- Tucson, Arizona
- Springdale, Arkansas
- Beverly Hills, California
- Encino, California
- Fresno, California
- Fullerton, California
- Huntington Beach, California
- Irvine, California
- La Jolla, California
And 116 more locations — see the full list below.
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Oct 13, 2026 · Source of record for eligibility and locations