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ARO-AAT

Phase 2

Alpha 1-Antitrypsin Deficiency | Small molecule | Rare Disease |Arrowhead Pharmaceuticals, Inc.|Last Updated: Dec 24, 2025

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindPLACEBO_CONTROLLED
Total Trials2
Total Enrollment61

FDA Designations

No designations recorded

Clinical trial landscape

ARO-AAT · 2 trials · 1 indication

Phase 2 1Phase 1 1
NCT03946449Study of Fazirsiran (TAK-999, ARO-AAT) in Patients With Alpha-1 Antitrypsin Deficiency Associated Liver Disease (AATD)Alpha 1-Antitrypsin Deficiency
COMPLETED16 Analytics
PHASE2COMPLETED
Study of Fazirsiran (TAK-999, ARO-AAT) in Patients With Alpha-1 Antitrypsin Deficiency Associated Liver Disease (AATD)
Alpha 1-Antitrypsin DeficiencyUnlock trial analytics

Study Endpoints

Primary Endpoints

Percent Change From Baseline in Total Liver Z-AAT, Insoluble Liver-ZAAT, and Soluble Liver Z-AAT at Week 24: Cohorts 1/1b
Baseline, Week 24
Percent Change From Baseline in Total Liver Z-AAT, Insoluble Liver-ZAAT, and Soluble Liver Z-AAT at Week 48: Cohort 2
Baseline, Week 48
Number of Participants With Adverse Events (AEs) Possibly or Probably Related to Treatment
Part A (single-ascending dose [SAD] phase): up to 29 (+/- 2) days post-dose; Part B (multiple-ascending dose [MAD] phase): up to 113 (+/- 2) days post-dose

Secondary Endpoints

Percent Change From Baseline in Serum Z-AAT Over Time: Cohorts 1/1b
Baseline, Weeks 2, 4, 6, 16, 24
Percent Change From Baseline in Serum Z-AAT Over Time: Cohort 2
Baseline, Weeks 2, 4, 6, 16, 22, 28, 34, 40, 48
Alanine Aminotransferase (ALT) Values Over Time: Cohorts 1/1b
Baseline (Day 1), Day 2, Week 2, Week 4, Week 4 (24-48h post dose), Week 6, Week 16, Week 16 (24/48h post dose), Week 24
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Study Design & Arms

AllocationNON_RANDOMIZED
MaskingNONE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
ARO-AAT 100 mg Cohort 1bEXPERIMENTALPrimary Study Period (6-12 months): 100 mg dose of subcutaneous ARO-AAT for a minimum of 3 doses, with 2 optional treatment extension periods. Treatment Extension I (12 months): 100 mg dose of subcutaneous AROAAT every 12 weeks (Q12W). Treatment Extension II (up to 24 Months): 100 mg dose of subcutaneous ARO-AAT Q12W.
ARO-AAT 200 mg Cohort 1EXPERIMENTALPrimary Study Period (6-12 months): 200 mg dose of subcutaneous ARO-AAT for a minimum of 3 doses, with 2 optional treatment extension periods. Treatment Extension I (12 months): 200 mg dose of subcutaneous AROAAT Q12W. Treatment Extension II (up to 24 Months): 200 mg dose of subcutaneous ARO-AAT Q12W.
ARO-AAT 200 mg Cohort 2EXPERIMENTALPrimary Study Period (6-12 months): 200 mg dose of subcutaneous ARO-AAT for a minimum of 5 doses, with optional treatment extension periods. Treatment Extension I (12 months): 200 mg dose of subcutaneous AROAAT Q12W. Treatment Extension II (up to 24 Months): 200 mg dose of subcutaneous ARO-AAT Q12W.
ARO-AATACTIVE_COMPARATOR -
PlaceboPLACEBO_COMPARATOR -

Interventions

NameTypeDescription
ARO-AATDRUGsolution for subcutaneous injection
ARO-AAT InjectionDRUGSingle or multiple doses of ARO-AAT by subcutaneous (sc) injections
Sterile Normal Saline (0.9% NaCl)OTHERCalculated volume to match active comparator
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Eligibility Criteria

Age Range18 Years to 75 Years
SexALL
Healthy VolunteersNo
Study Sites4

Inclusion Criteria: * Diagnosis of AATD * Liver biopsy indicating Metavir F1-F3 liver fibrosis based on local pathology read. * Women of childbearing potential must have a negative pregnancy test, cannot be breast feeding, and must be willing to use contraception * Willing to provide written inform...

Countries:AustriaGermanyUnited KingdomNew Zealand
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Frequently asked questions about ARO-AAT

What is ARO-AAT used for?

ARO-AAT is an investigational drug being studied for the treatment of Alpha 1-Antitrypsin Deficiency, a rare genetic condition. It is being developed by Arrowhead Pharmaceuticals, Inc. (ARWR) and is currently in Phase 2 clinical development. ARO-AAT is also known as fazirsiran and TAK-999.

What does ARO-AAT target?

ARO-AAT is a small molecule designed to target the underlying cause of Alpha 1-Antitrypsin Deficiency. It works by reducing the production of the abnormal alpha-1 antitrypsin protein that accumulates in the liver and causes damage. This mechanism is intended to address the liver disease associated with the condition.

Who makes ARO-AAT?

ARO-AAT is being developed by Arrowhead Pharmaceuticals, Inc., a biopharmaceutical company traded on the NASDAQ under the ticker ARWR. The drug is also known as fazirsiran and TAK-999, and it is being studied for the treatment of Alpha 1-Antitrypsin Deficiency.

What phase is ARO-AAT in?

ARO-AAT is currently in Phase 2 clinical development. It has completed two clinical trials, including a Phase 1 study in healthy volunteers and a Phase 2 study in patients with Alpha-1 Antitrypsin Deficiency associated liver disease. The drug is investigational and has not been approved by regulatory authorities.

What clinical trials is ARO-AAT in?

ARO-AAT has been studied in two completed clinical trials. The first, NCT03362242, was a Phase 1 study in 45 healthy adult volunteers in New Zealand. The second, NCT03946449, was a Phase 2 study in 16 patients with Alpha-1 Antitrypsin Deficiency associated liver disease, conducted in Austria, Germany, and the United Kingdom.

Is ARO-AAT the same as fazirsiran?

Yes, ARO-AAT is the same as fazirsiran and TAK-999. These names refer to the same investigational drug being developed by Arrowhead Pharmaceuticals for the treatment of Alpha 1-Antitrypsin Deficiency. The drug is currently in Phase 2 clinical development and has completed two trials.