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Fazirsiran

Phase 3

Alpha1-Antitrypsin Deficiency | RNA therapy | Rare Disease |Takeda Pharmaceutical Company Limited|Trials Updated: May 13, 2026

Fazirsiran development status

Highest phase Phase 3
Registered trials 1 across 1 sponsor since Jun 2023

Fazirsiran target and mechanism

Target class-Siran (Sirna)
ModalityRNA therapy

Also known as Fazirsiran Injection, TAK-999

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindPLACEBO_CONTROLLEDDMC
Total Trials4
Total Enrollment275

FDA Designations

No designations recorded

Fazirsiran clinical trials

Fazirsiran · 4 trials · 2 indications

Phase 3 3Phase 1 1
NCT06165341Study to Learn About the Safety of Fazirsiran and if it Can Help People With Alpha-1 Antitrypsin Liver Disease With Mild Liver Scarring (Fibrosis)Alpha1-Antitrypsin Deficiency
RECRUITING50 Analytics
NCT05899673An Extension Study to Learn About the Long-Term Safety of Fazirsiran and if Fazirsiran Can Help People With Alpha-1 Antitrypsin Liver DiseaseAlpha1-Antitrypsin Deficiency
ACTIVE NOT_RECRUITING31 Analytics
NCT05677971Study to Check the Safety of Fazirsiran and Learn if Fazirsiran Can Help People With Liver Disease and Scarring (Fibrosis) Due to an Abnormal Version of Alpha-1 Antitrypsin ProteinAlpha1-Antitrypsin Deficiency
RECRUITING160 Analytics
PHASE3RECRUITING
Study to Learn About the Safety of Fazirsiran and if it Can Help People With Alpha-1 Antitrypsin Liver Disease With Mild Liver Scarring (Fibrosis)
Alpha1-Antitrypsin DeficiencyUnlock trial analytics
PHASE3ACTIVE NOT_RECRUITING
An Extension Study to Learn About the Long-Term Safety of Fazirsiran and if Fazirsiran Can Help People With Alpha-1 Antitrypsin Liver Disease
Alpha1-Antitrypsin DeficiencyUnlock trial analytics
PHASE3RECRUITING
Study to Check the Safety of Fazirsiran and Learn if Fazirsiran Can Help People With Liver Disease and Scarring (Fibrosis) Due to an Abnormal Version of Alpha-1 Antitrypsin Protein
Alpha1-Antitrypsin DeficiencyUnlock trial analytics

Study Endpoints

Primary Endpoints

Number of Participants With Adverse Events (AEs) and Serious AEs (SAEs)
From start of study drug administration up to End of study (EOS) (Week 124)

An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of the study intervention, whether or not it is considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of the study intervention. An SAE is defined as any untoward medical occurrence that results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, congenital anomaly/birth defect, suspected transmission of any infectious agent, an important medical event. AEs and SAEs including any pulmonary AEs or SAEs indicative of worsening pulmonary condition (example, pulmonary exacerbation, respiratory infection, significant pulmonary function test decline) will be reported.

Number of Participants With Clinically Significant Change From Baseline in Pulmonary Function Parameters
From start of study drug administration up to EOS (Week 124)

Standard pulmonary function parameters will be used to study lung function. Clinical significance of pulmonary function parameters will be determined at the investigator's discretion.

Change From Baseline in Whole Lung 15th Percentile Density as Measured by Computed Tomography (CT) Lung Densitometry
Baseline up to Week 100

Change from baseline in whole lung 15th percentile density as measured by CT lung densitometry will be assessed.

Number of Participants With Clinically Significant Changes in Vital Signs
From start of study drug administration up to EOS (Week 124)

Vital signs include body temperature, respiratory rate, blood pressure (systolic and diastolic), pulse (beats per minute) and pulse oximetry. Clinical significance of vital signs will be determined at the investigator's discretion.

Number of Participants with Clinically Significant Changes in Electrocardiogram (ECG) Parameters
From start of study drug administration up to EOS (Week 124)

12-lead ECG will be evaluated. Any clinically significant change in ECG assessments will be determined at the investigator's discretion.

Number of Participants With Clinically Significant Changes in Clinical Laboratory Parameters
From start of study drug administration up to EOS (Week 124)

Laboratory parameters assessments include hematology, biochemistry including liver tests, coagulation, and urinalysis. Clinical significance of laboratory parameters will be determined at the investigator's discretion.

Number of Participants With Clinically Significant Changes From Baseline in Pulmonary Function Parameters
Baseline (current study), up to EOS (current study up to 10 years])

Standard pulmonary function parameters measured will be used to study lung function. Clinical significance of pulmonary function parameters will be determined at the investigator's discretion.

Number of Participants With Clinically Significant Changes in Laboratory Parameters
From start of study drug administration (in current study) up to EOS (current study [up to 10 years])

Laboratory parameters include hematology, biochemistry including liver tests, coagulation, and urinalysis. Clinical significance of laboratory parameters will be determined at the investigator's discretion.

Reduction From Baseline of at Least 1 Stage of Histologic Fibrosis (METAVIR Staging) in the Centrally Read Liver Biopsy at Week 106 in AATD-LD With METAVIR Stage F2 and F3 Fibrosis
Baseline, Week 106

Reduction from baseline of at least 1 stage of histologic fibrosis METAVIR staging in the centrally read liver biopsy at Week 106 in AATD-LD with METAVIR stage F2 and F3 fibrosis will be assessed.

Area Under the Plasma Concentration-time Curve From Time 0 to the Time of the Last Quantifiable Concentration (AUClast) for Fazirsiran
From pre-dose up to Month 6 post-dose
Area Under the Plasma Concentration-time Curve from Time 0 to Infinity (AUC0-inf) for Fazirsiran
From pre-dose up to Month 6 post-dose
Maximum Observed Plasma Concentration (Cmax) for Fazirsiran
From pre-dose up to Month 6 post-dose

Secondary Endpoints

Change From Baseline in Serum Z-AAT Protein Over Time to Week 106
Baseline up to Week 106
Percent Change From Baseline in Intrahepatic Liver Z-AAT Protein at Week 106
Baseline up to Week 106
Change From Baseline in Intrahepatic Z-AAT Protein Polymer Burden Assessed by Periodic Acid Schiff Plus Diastase (PAS+D) Staining in Liver Biopsy at Week 106
Baseline up to Week 106
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Study Design & Arms

AllocationRANDOMIZED
MaskingDOUBLE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Fazirsiran 200 mgEXPERIMENTALParticipants will receive fazirsiran 200 milligrams (mg), injection, subcutaneously on Day 1, at Week 4 and then every 12 weeks (Q12W) for up to Week 100.
PlaceboPLACEBO_COMPARATORParticipants will receive fazirsiran matching placebo injection, subcutaneously on Day 1, at Week 4 and Q12W for up to Week 100.
FazirsiranEXPERIMENTALParticipants will receive fazirsiran 200 milligram per milliliter (mg/ml) subcutaneous (SC) injection on Day 1, at Week 4, and then every 12 weeks (Q12 W) thereafter up to Week 196.
Arm 1, Mild HI: Fazirsiran 200 mgEXPERIMENTALParticipants with mild hepatic impairment (HI) will receive fazirsiran 200 milligrams (mg) subcutaneous (SC) injection on Day 1.
Arm 2, Moderate HI: Fazirsiran 200 mgEXPERIMENTALParticipants with moderate HI will receive fazirsiran 200 mg SC injection on Day 1. The dose may be modified after review of available safety and PK data by the sponsor study team in consultation with the investigator.
Arm 3, Severe HI: Fazirsiran 200 mgEXPERIMENTALParticipants with severe HI will receive fazirsiran 200 mg SC injection on Day 1. The dose may be modified after review of available safety and PK data by the sponsor study team in consultation with the investigator.
Arm 4, Normal Hepatic Function: Fazirsiran 200 mgEXPERIMENTALParticipants with normal hepatic function will receive fazirsiran 200 mg SC injection on Day 1. The dose may be modified after review of available safety and PK data by the sponsor study team in consultation with the investigator.

Interventions

NameTypeDescription
Fazirsiran InjectionDRUGFazirsiran will be injected subcutaneously.
PlaceboDRUGFazirsiran matching placebo.
FazirsiranDRUGFazirsiran SC injection
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Eligibility Criteria

Age Range18 Years to 75 Years
SexALL
Healthy VolunteersNo
Study Sites41

Inclusion Criteria: * In the opinion of the investigator, the participant is capable of understanding and fully complying with the protocol requirements and adhering to the protocol schedule. * The participant is able to read, understand, and complete the study questionnaires electronically per the...

Countries:United StatesAustriaBelgiumCanadaFranceGermanyItalyPolandPortugalSpainSwedenSwitzerlandUnited KingdomAustraliaBrazilCzechiaDenmarkIrelandNetherlandsHungarySlovakia
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Frequently asked questions about Fazirsiran

What is Fazirsiran used for?

Fazirsiran is an investigational RNA therapy being developed for alpha-1 antitrypsin deficiency with associated liver disease, including hepatic impairment and liver fibrosis. It is designed to reduce production of the abnormal alpha-1 antitrypsin protein that accumulates in the liver. It is not yet approved for any indication.

How does Fazirsiran work?

Fazirsiran is a small interfering RNA (siRNA) therapy, belonging to the -siran drug class. It targets the production of alpha-1 antitrypsin protein in the liver, aiming to reduce the accumulation of abnormal protein that causes liver damage in alpha-1 antitrypsin deficiency.

Who is developing Fazirsiran?

Fazirsiran is being developed by Takeda Pharmaceutical Company Limited, which trades on the New York Stock Exchange under the ticker TAK. Takeda is responsible for the clinical development program evaluating fazirsiran in alpha-1 antitrypsin deficiency liver disease.

What phase is Fazirsiran in?

Fazirsiran is in Phase 3 clinical development. The program includes three Phase 3 trials and one completed Phase 1 trial. It is an investigational therapy and has not been approved by the FDA or any regulatory agency for commercial use.

What clinical trials is Fazirsiran in?

Fazirsiran is being studied in several clinical trials. Phase 3 trials include NCT06165341, NCT05899673, and NCT05677971, evaluating safety and efficacy in alpha-1 antitrypsin liver disease. A completed Phase 1 trial, NCT05891158, assessed the drug in people with and without liver problems.

Is Fazirsiran the same as Fazirsiran Injection?

Yes, Fazirsiran Injection is an alternative name for fazirsiran. Both terms refer to the same investigational siRNA therapy developed by Takeda for alpha-1 antitrypsin deficiency liver disease.