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Mivelsiran

Phase 2

Down Syndrome-Associated Alzheimer's Disease (DS-AD) | RNA therapy | Neurology |Alnylam Pharmaceuticals, Inc.|Trials Updated: Oct 13, 2026

Mivelsiran development status

Highest phase Phase 2
Registered trials 3 across 1 sponsor since Feb 2022

Mivelsiran target and mechanism

Target class-Siran (Sirna)
ModalityRNA therapy

Also known as ALN-APP

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindPLACEBO_CONTROLLEDDMCBiomarker
Total Trials3
Total Enrollment328

FDA Designations

No designations recorded

Mivelsiran clinical trials

Mivelsiran · 3 trials · 3 indications

Phase 2 2Phase 1 1
NCT07636811A Study to Evaluate Mivelsiran in Adult Participants With Early-Stage Down Syndrome-Associated Alzheimer's Disease (DS-AD)Down Syndrome-Associated Alzheimer's Disease (DS-AD)
RECRUITING58 Analytics
NCT06393712A Phase 2 Trial of ALN-APP in Patients With Cerebral Amyloid AngiopathyCerebral Amyloid Angiopathy
ACTIVE NOT_RECRUITING210 Analytics
PHASE2RECRUITING
A Study to Evaluate Mivelsiran in Adult Participants With Early-Stage Down Syndrome-Associated Alzheimer's Disease (DS-AD)
Down Syndrome-Associated Alzheimer's Disease (DS-AD)Unlock trial analytics
PHASE2ACTIVE NOT_RECRUITING
A Phase 2 Trial of ALN-APP in Patients With Cerebral Amyloid Angiopathy
Cerebral Amyloid AngiopathyUnlock trial analytics

Study Endpoints

Primary Endpoints

Double-Blind Period: Change from baseline in brain amyloid burden measured in centiloids (CLs)
Up to 24 months
Double-blind Treatment Period: Annualized Rate of New Lobar Cerebral Microbleeds (CMBs) Assessed on Magnetic Resonance Imaging (MRI) of Brain in Patients with Sporadic Cerebral Amyloid Angiopathy (sCAA)
Up to 24 months
Part A: Frequency of Adverse Events
Up to 12 months
Part B: Frequency of Adverse Events
Up to 42 months

Secondary Endpoints

Double-Blind Period: Change from baseline in APP protein concentration in cerebrospinal fluid (CSF)
Up to 24 months
Double-Blind Period: Change from baseline in the concentration of amyloid beta proteins in CSF
Up to 24 months
Double-Blind Period: Change from baseline in the concentration of tau proteins in plasma
Up to 24 months
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Study Design & Arms

AllocationRANDOMIZED
MaskingQUADRUPLE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Mivelsiran (Treatment Group A)EXPERIMENTALParticipants will be administered multiple low doses of mivelsiran.
Mivelsiran (Treatment Group B)EXPERIMENTALParticipants will be administered multiple high doses of mivelsiran.
Placebo (Treatment Group C)PLACEBO_COMPARATORParticipants will be administered multiple doses of placebo.
ALN-APPEXPERIMENTALParticipants will be administered multiple doses of ALN-APP during the double-blind treatment period and optional open-label extension period.
Placebo/ALN-APPPLACEBO_COMPARATORParticipants will be administered multiple doses of placebo during the double-blind treatment period. Participants who continue into the optional open-label extension period will be administered multiple doses of ALN-APP.
Part A: ALN-APPEXPERIMENTALParticipants will be administered a single dose of ALN-APP.
Part A: PlaceboPLACEBO_COMPARATORParticipants will be administered a single dose of placebo.
Part B:EXPERIMENTALParticipants will be administered multiple doses of ALN-APP.

Interventions

NameTypeDescription
MivelsiranDRUGMivelsiran will be administered intrathecally
PlaceboDRUGPlacebo will be administered intrathecally
ALN-APPDRUGALN-APP will be administered intrathecally
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Eligibility Criteria

Age Range40 Years to 55 Years
SexALL
Healthy VolunteersNo
Study Sites10

Inclusion Criteria: * Clinical diagnosis of Down-Syndrome (DS) associated with trisomy 21 * Positive amyloid PET scan * Cognitively stable in the opinion of the investigator * Seizures must be well controlled with no occurrence of seizures in the 6 months prior to screening Exclusion Criteria: * ...

Countries:United StatesSpainAustraliaCanadaNetherlandsSwitzerlandUnited Kingdom
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Recent Changes (Last 90 Days)

LOWOct 13, 2026NCT07636811Completion: 2031-07-23 → 2031-07-30
LOWOct 13, 2026NCT07636811Completion: 2031-07-23 → 2031-07-30
LOWSep 19, 2026NCT06393712lastUpdatePostDate: changed
LOWSep 19, 2026NCT06393712lastUpdatePostDate: changed
LOWSep 19, 2026NCT06393712lastUpdatePostDate: changed
LOWSep 15, 2026NCT05231785lastUpdatePostDate: changed
LOWSep 15, 2026NCT05231785lastUpdatePostDate: changed
LOWSep 15, 2026NCT05231785lastUpdatePostDate: changed
LOWSep 4, 2026NCT07636811startDate: changed
LOWSep 4, 2026NCT07636811startDate: changed
MEDIUMSep 3, 2026NCT06393712Status: RECRUITING → ACTIVE_NOT_RECRUITING
MEDIUMSep 3, 2026NCT06393712Status: RECRUITING → ACTIVE_NOT_RECRUITING
LOWAug 12, 2026NCT05231785lastUpdatePostDate: changed
LOWAug 12, 2026NCT07636811Status: NOT_YET_RECRUITING → RECRUITING
LOWAug 12, 2026NCT05231785lastUpdatePostDate: changed
LOWAug 12, 2026NCT07636811Status: NOT_YET_RECRUITING → RECRUITING

Frequently asked questions about Mivelsiran

What is Mivelsiran?

Mivelsiran is an investigational RNA therapy being developed by Alnylam Pharmaceuticals, Inc. (ticker ALNY) for Down Syndrome-Associated Alzheimer's Disease, or DS-AD. It is in Phase 2 clinical development and has not been approved by the FDA. It is a small interfering RNA (siRNA) therapy, part of Alnylam's -siran naming class.

What is Mivelsiran used for in Down Syndrome-Associated Alzheimer's Disease?

Mivelsiran is being studied for the treatment of early-stage Down Syndrome-Associated Alzheimer's Disease (DS-AD) in adults. The Phase 2 trial enrolls participants aged 40 years and older with this condition. It is investigational and has not been approved for any indication.

How does Mivelsiran work?

Mivelsiran is a small interfering RNA (siRNA) therapy, a class of RNA therapeutics that uses RNA interference to reduce the production of a specific disease-related protein. Alnylam Pharmaceuticals develops this -siran class of siRNA medicines. The specific molecular target of mivelsiran in DS-AD has not been publicly disclosed.

Who makes Mivelsiran?

Mivelsiran is being developed by Alnylam Pharmaceuticals, Inc., which trades under the ticker ALNY. Alnylam is the sponsor of the Phase 2 clinical trial evaluating mivelsiran in adults with early-stage Down Syndrome-Associated Alzheimer's Disease.

What phase is Mivelsiran in?

Mivelsiran is in Phase 2 clinical development. It is investigational and has not been approved by the FDA for any indication. The ongoing Phase 2 study is currently recruiting participants.

What clinical trials is Mivelsiran in?

Mivelsiran is being evaluated in one active clinical trial: NCT07636811, titled "A Study to Evaluate Mivelsiran in Adult Participants With Early-Stage Down Syndrome-Associated Alzheimer's Disease (DS-AD)." This Phase 2 trial is randomized, double-blind, placebo-controlled, and enrolling 58 participants across the United States and Spain.