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Fazisiran

Phase 2

Alpha 1-Antitrypsin Deficiency | Small molecule | Rare Disease |Arrowhead Pharmaceuticals, Inc.|Last Updated: Nov 4, 2025

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindPLACEBO_CONTROLLEDDMC
Total Trials1
Total Enrollment40

FDA Designations

No designations recorded

Clinical trial landscape

Fazisiran · 1 trial · 1 indication

Phase 2 1
NCT03945292Safety, Tolerability and Pharmacodynamic Effect of Fazirsiran (TAK-999, ARO-AAT)Alpha 1-Antitrypsin Deficiency
COMPLETED40 Analytics
PHASE2COMPLETED
Safety, Tolerability and Pharmacodynamic Effect of Fazirsiran (TAK-999, ARO-AAT)
Alpha 1-Antitrypsin DeficiencyUnlock trial analytics

Study Endpoints

Primary Endpoints

Percent Change From Baseline in Serum Z-Alpha-1 Antitrypsin (Z-AAT) at Week 16
Baseline, Week 16 (+/- 2 weeks)

Secondary Endpoints

Number of Participants With Treatment-Emergent Adverse Events (TEAEs) in the Double-Blind Phase
Double Blind Phase (up to Week 48): dose administration through end of study (EOS) or Early Termination or first dose of open-label phase fazirsiran.
Number of Participants With Treatment-Emergent Adverse Events (TEAEs) in the Open-Label Phase
From dose administration of the first dose of open-label phase fazirsiran through EOS or Early Termination (up to Week 196).
Absolute Change From Baseline in Total Liver Z-AAT (Insoluble + Soluble) Protein at Post-dose Biopsy for Participants With Fibrosis
Baseline, Week 48 (+/- 2 weeks), or Week 72 (+/- 4 weeks), or Week 96 (+/- 4 weeks)
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Study Design & Arms

AllocationRANDOMIZED
MaskingQUADRUPLE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Fazirsiran 25 mg DB/200 mg OLEXPERIMENTALDouble-blind (DB) Period: Participants with no fibrosis: Administered on Day 1 and Week 4. Participants with fibrosis: Administered on Day 1, Week 4, and Week 16, then every 12 weeks up to 18 total doses. Open-label (OL) Period: Participants with fibrosis at Screening who received double-blind (DB) fazirsiran 25 mg and who completed the post-dose liver biopsy at Week 48 (or Week 72 or Week 96) entered the open-label phase and received fazirsiran 200 mg every 12 weeks for the duration of the study.
Fazirsiran 100 mg DB/200 mg OLEXPERIMENTALDB Period: Participants with no fibrosis: Fazirsiran 100 mg administered on Day 1 and Week 4. Participants with fibrosis: Fazirsiran 100 mg administered on Day 1, Week 4, and Week 16, then every 12 weeks up to 18 total doses. OL Period: Participants with fibrosis at Screening who received double-blind (DB) fazirsiran 100 mg and who completed the post-dose liver biopsy at Week 48 (or Week 72 or Week 96) entered the open-label phase and received fazirsiran 200 mg every 12 weeks for the duration of the study.
Fazirsiran 200 mg DB/200 mg OLEXPERIMENTALDB Period: Participants with no fibrosis: Fazirsiran 200 mg administered on Day 1 and Week 4. Participants with fibrosis: Fazirsiran 200 mg administered on Day 1, Week 4, and Week 16, then every 12 weeks up to 18 total doses. OL Period: Participants with fibrosis at Screening who received double-blind (DB) fazirsiran 200 mg and who completed the post-dose liver biopsy at Week 48 (or Week 72 or Week 96) entered the open-label phase and received fazirsiran 200 mg every 12 weeks for the duration of the study
Placebo DB / Fazirsiran 200 mg OLPLACEBO_COMPARATORDB Period: Participants with no fibrosis: Placebo administered on Day 1 and Week 4. Participants with fibrosis: Placebo administered on Day 1, Week 4, and Week 16, then every 12 weeks up to 18 total doses. OL Period: Participants with fibrosis at Screening who received double-blind (DB) placebo and who completed the post-dose liver biopsy at Week 48 (or Week 72 or Week 96) entered the open-label phase and received fazirsiran 200 mg every 12 weeks for the duration of the study.

Interventions

NameTypeDescription
Fazisiran InjectionDRUGsolution for subcutaneous (sc) injection
PlaceboOTHERsterile normal saline (0.9% NaCl), calculated to match active comparator, for sc injection
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Eligibility Criteria

Age Range18 Years to 75 Years
SexALL
Healthy VolunteersNo
Study Sites21

Inclusion Criteria: * Diagnosis of AATD * Liver biopsy at Screening indicating liver fibrosis (score less than F4); a patient with no fibrosis may participate based on a previous biopsy conducted within one year * Women of childbearing potential must have a negative pregnancy test, cannot be breast...

Countries:United StatesGermanyItalyNetherlandsPortugalSpain
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Frequently asked questions about Fazisiran

What is Fazisiran used for?

Fazisiran is an investigational small molecule being developed for the treatment of Alpha 1-Antitrypsin Deficiency, a rare genetic condition. It is currently in Phase 2 clinical development and has not been approved by regulatory authorities.

Who makes Fazisiran?

Fazisiran is being developed by Arrowhead Pharmaceuticals, Inc., a biopharmaceutical company traded on the NASDAQ under the ticker symbol ARWR. The drug is also known as TAK-999 and ARO-AAT in clinical research.

What phase is Fazisiran in?

Fazisiran is in Phase 2 clinical development. It is an investigational drug and has not been approved for commercial use. A Phase 2 clinical trial has been completed to evaluate its safety, tolerability, and pharmacodynamic effects in patients with Alpha 1-Antitrypsin Deficiency.

What clinical trials is Fazisiran in?

Fazisiran has one completed Phase 2 clinical trial registered under NCT03945292. The trial, titled 'Safety, Tolerability and Pharmacodynamic Effect of Fazirsiran (TAK-999, ARO-AAT)', enrolled 40 participants with Alpha 1-Antitrypsin Deficiency across the United States, Germany, Italy, Netherlands, Portugal, and Spain.

Is Fazisiran the same as TAK-999 or ARO-AAT?

Yes, Fazisiran is also known as TAK-999 and ARO-AAT. These alternative names appear in clinical trial records and research publications. The drug is being developed by Arrowhead Pharmaceuticals under the primary name Fazisiran.

Was the Fazisiran Phase 2 trial randomized and blinded?

Yes, the completed Phase 2 trial of Fazisiran (NCT03945292) was a randomized, double-blind, placebo-controlled study. It enrolled 40 adult participants aged 18 years and older with Alpha 1-Antitrypsin Deficiency, and did not include healthy volunteers.