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Zilebesiran

Phase 3

High Risk Cardiovascular Disease | RNA therapy | Cardiovascular |Alnylam Pharmaceuticals, Inc.|Trials Updated: Oct 15, 2026

Zilebesiran development status

Highest phase Phase 3
Registered trials 7 across 1 sponsor since May 2019

Zilebesiran target and mechanism

Target class-Siran (Sirna)
ModalityRNA therapy

Also known as ALN-AGT01

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindPLACEBO_CONTROLLEDDMC
Total Trials5
Total Enrollment11,929

FDA Designations

No designations recorded

Zilebesiran clinical trials

Zilebesiran · 5 trials · 4 indications

Phase 3 1Phase 2 2Phase 1 2
NCT07181109Zilebesiran in Patients With Hypertension Not Adequately Controlled and With Either Established Cardiovascular Disease or High Risk for Cardiovascular DiseaseHigh Risk Cardiovascular Disease
RECRUITING11,000 Analytics
PHASE3RECRUITING
Zilebesiran in Patients With Hypertension Not Adequately Controlled and With Either Established Cardiovascular Disease or High Risk for Cardiovascular Disease
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Study Endpoints

Primary Endpoints

Time to First Occurrence of a Composite Endpoint of Cardiovascular (CV) Death, Nonfatal Myocardial Infarction (MI), Nonfatal Stroke, or Heart Failure (HF) Event (Hospitalization for HF or Urgent HF Visit)
Up to approximately 5 years
Change from Baseline at Month 3 in Mean Seated Office Systolic Blood Pressure (SBP)
Baseline and Month 3
Change From Baseline at Month 3 in 24-hour Mean SBP Assessed by ABPM
Baseline and Month 3

24-hour ABPM was programmed to take readings every 20 minutes during the day (6 am to 9:59 pm) and every 30 minutes during the night (10 pm to 5:59 am). An ABPM was considered adequate if: 1. the number of successful daytime readings were ≥33, 2. the number of successful nighttime readings were ≥11, 3. no more than 3 hours are not represented (i.e., 3 sections of 60 minutes where 0 valid readings were obtained). To summarize the 24-hour ABPM, the hourly adjusted mean was calculated. Hourly mean was the average of BP by each hour of the day. The 24-hour mean was the average of the hourly means. Least squares (LS) mean and standard error (SE) were calculated using a mixed model repeated measures (MMRM) approach.

Number of Participants With Adverse Events (AEs)
Up to 12 months

An AE is any untoward medical occurrence in a patient or clinical investigational subject administered a medicinal product and which does not necessarily have a causal relationship with this treatment.

Secondary Endpoints

Change from Baseline in Mean Seated Office Systolic Blood Pressure (SBP) at Month 6
Baseline and Month 6
Time to First Occurrence of a Composite Endpoint of CV Death, Nonfatal MI, or Nonfatal Stroke
Up to approximately 5 years
Composite Endpoint of CV Death and Total (First and Subsequent) HF Events (Hospitalization for HF or Urgent HF Visit)
Up to approximately 5 years
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Study Design & Arms

AllocationRANDOMIZED
MaskingQUADRUPLE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Zilebesiran 300 mgEXPERIMENTALParticipants will be administered 300 mg zilebesiran subcutaneously (SC) once every 6 months as add-on therapy to their standard of care antihypertensive medications.
PlaceboPLACEBO_COMPARATORParticipants will be administered placebo SC once every 6 months as add-on therapy to their standard of care antihypertensive medications.
ZilebesiranEXPERIMENTALParticipants will receive zilebesiran on Day 1 of the 6-month double-blind (DB) treatment period. Participants must be on stable doses of at least 2, but not more than 4, antihypertensive medications for at least 30 days prior to screening and plan to remain on stable doses of these medications during screening and through the DB treatment period.
Zilebesiran 150 Milligrams (mg) Once Every 6 Months (Q6M)EXPERIMENTALParticipants receive zilebesiran, 150 mg, SC injection, Q6M, during the 12-month DB period. Participants will continue receiving the same zilebesiran regimen for up to 24 additional months in the DB Extension period. Participants in this arm will receive a placebo during those dosing visits when they do not receive zilebesiran to maintain the blind. Upon implementation of Amendment 6, the DB Extension period was closed.
Zilebesiran 300 mg Q6MEXPERIMENTALParticipants receive zilebesiran, 300 mg, SC injection, Q6M, during the 12-month DB period. Participants will continue receiving the same zilebesiran regimen for up to 24 additional months in the DB Extension period. Participants in this arm will receive a placebo during those dosing visits when they do not receive zilebesiran to maintain the blind. Upon implementation of Amendment 6, the DB Extension period was closed.
Zilebesiran 300 mg Q3MEXPERIMENTALParticipants receive zilebesiran, 300 mg, SC injection, Q3M, during the 12-month DB period. Participants continue receiving the same zilebesiran regimen for up to 24 additional months in the DB Extension period. Upon implementation of Amendment 6, the DB Extension period was closed.
Zilebesiran 600 mg Q6MEXPERIMENTALParticipants receive zilebesiran, 600 mg, SC injection, Q6M, during the 12-month DB period. Participants will continue receiving the same zilebesiran regimen for up to 24 additional months in the DB Extension period. Participants in this arm will receive a placebo during those dosing visits when they do not receive zilebesiran to maintain the blind. Upon implementation of Amendment 6, the DB Extension period was closed.
Part A: SAD: ALN-AGT01EXPERIMENTALParticipants will be administered a single dose of ALN-AGT01.
Part A: SAD: ALN-AGT01-Matching PlaceboPLACEBO_COMPARATORParticipants will be administered a single dose of ALN-AGT01-matching placebo.
Part B: SD: ALN-AGT01EXPERIMENTALParticipants with controlled salt intake will be administered a single dose of ALN-AGT01.
Part B: SD: ALN-AGT01-Matching PlaceboPLACEBO_COMPARATORParticipants with controlled salt intake will be administered a single dose of ALN-AGT01-matching placebo.
Part D: MD: ALN-AGT01 + Irbesartan-Matching PlaceboEXPERIMENTALParticipants, who are obese, will be administered multiple doses of ALN-AGT01 and irbesartan-matching placebo.
Part D: MD: ALN-AGT01-Matching Placebo + IrbesartanACTIVE_COMPARATORParticipants, who are obese, will be administered multiple doses of ALN-AGT01-matching placebo and irbesartan.
Part E: Open Label: ALN-AGT01 + IrbesartanEXPERIMENTALParticipants will be administered a single dose of ALN-AGT01 and multiple doses of irbesartan.

Interventions

NameTypeDescription
ZilebesiranDRUGZilebesiran will be administered SC
PlaceboDRUGPlacebo will be administered SC
ALN-AGT01DRUGALN-AGT01 administered by SC injection
ALN-AGT01-Matching PlaceboDRUGNormal saline (0.9% NaCl) matching volume of ALN-AGT01 doses will be administered SC.
IrbesartanDRUGIrbesartan will be administered orally.
Irbesartan-Matching PlaceboDRUGIrbesartan-matching placebo will be administered orally.
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites1190

Inclusion Criteria: * Is 18 years or older for patients with established cardiovascular disease (CVD) * Is 55 years or older for patients with high risk for CVD * Has established CVD (defined as coronary, cerebrovascular, or peripheral artery disease) or high risk for CVD * Has treated hypertension...

Countries:United StatesArgentinaAustraliaAustriaBelgiumBrazilBulgariaCanadaChileChinaColombiaCzechiaDenmarkFranceGermanyGreeceHungaryIndiaItalyJapanMexicoNetherlandsNew ZealandPolandPortugalRomaniaSerbiaSlovakiaSouth AfricaSouth KoreaSpainSwedenTaiwanTurkey (Türkiye)United KingdomPuerto RicoSwitzerlandUkraine
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Competitive Landscape -General Cardiovascular Diseases 67 trials (matched to "High Risk Cardiovascular Disease")

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Recent Changes (Last 90 Days)

LOWOct 15, 2026NCT07181109startDate: changed
LOWOct 15, 2026NCT07181109startDate: changed
LOWOct 13, 2026NCT07181109lastUpdatePostDate: changed
LOWOct 13, 2026NCT07181109lastUpdatePostDate: changed
LOWSep 19, 2026NCT07181109primaryCompletionDate: changed
LOWSep 19, 2026NCT07181109primaryCompletionDate: changed
LOWSep 19, 2026NCT07181109primaryCompletionDate: changed
LOWAug 20, 2026NCT07181109lastUpdatePostDate: changed
LOWAug 20, 2026NCT07181109lastUpdatePostDate: changed
LOWAug 20, 2026NCT07181109lastUpdatePostDate: changed
LOWAug 20, 2026NCT07181109lastUpdatePostDate: changed

Frequently asked questions about Zilebesiran

What is zilebesiran used for?

Zilebesiran is an investigational RNA therapy being developed for hypertension in patients at high cardiovascular risk or with established cardiovascular disease. It is also being studied in mild to moderate hypertension. It is designed to be given as an add-on to standard antihypertensive medications in patients whose blood pressure is not adequately controlled.

How does zilebesiran work?

Zilebesiran is a small interfering RNA (siRNA) therapy. It targets and reduces the production of a protein involved in blood pressure regulation, leading to sustained blood pressure lowering. As an siRNA, it works by silencing the messenger RNA that encodes this protein, which may allow for less frequent dosing than daily oral antihypertensives.

Who is developing zilebesiran?

Zilebesiran is being developed by Alnylam Pharmaceuticals, Inc., which trades on the Nasdaq under the ticker ALNY. Alnylam is a biopharmaceutical company focused on RNA interference therapeutics.

What phase is zilebesiran in?

Zilebesiran is in Phase 2 clinical development for hypertension, with a Phase 3 trial currently recruiting. The Phase 3 trial, NCT07181109, is evaluating zilebesiran in patients with hypertension not adequately controlled and with either established cardiovascular disease or high risk for cardiovascular disease.

What clinical trials is zilebesiran in?

Zilebesiran is being studied in three clinical trials. The Phase 3 trial NCT07181109 is recruiting 11,000 patients with hypertension and high cardiovascular risk. The Phase 2 KARDIA-3 trial (NCT06272487) completed with 375 patients. A Phase 1 trial in Japanese patients (NCT06423352) completed with 36 patients.

Is zilebesiran the same as any other drug?

Zilebesiran is an investigational siRNA therapy and is not approved by the FDA. It is distinct from other antihypertensive medications and is being developed as a potential add-on treatment for patients with hypertension and high cardiovascular risk.