Table of Contents
- What is Fazirsiran?
- How Does Fazirsiran Work?
- What Conditions Does Fazirsiran Treat?
- Ongoing Clinical Trials
- Administration and Dosage
- Potential Benefits
- Safety and Side Effects
What is Fazirsiran?
Fazirsiran is an investigational medication that is being studied for the treatment of liver disease associated with Alpha-1 Antitrypsin Deficiency (AATD). It is also known by several other names, including TAK-999, ARO-AAT, and ADS-001[1]. This drug is currently undergoing clinical trials to evaluate its safety and effectiveness in patients with AATD-related liver problems.
How Does Fazirsiran Work?
Fazirsiran works by reducing the production of an abnormal protein called Z-alpha-1 antitrypsin (Z-AAT) in the liver. In people with AATD, the liver produces this abnormal version of the alpha-1 antitrypsin (AAT) protein, which can accumulate in liver cells and lead to various liver problems[2]. By decreasing the creation of Z-AAT, fazirsiran aims to reduce the buildup of this abnormal protein in the liver and potentially slow down or prevent liver damage.
What Conditions Does Fazirsiran Treat?
Fazirsiran is specifically being developed to treat Alpha-1 Antitrypsin Deficiency-Associated Liver Disease (AATD-LD). This condition occurs when the abnormal Z-AAT protein accumulates in the liver, leading to various liver problems, including:
- Liver fibrosis: Scarring of the liver tissue
- Cirrhosis: Advanced scarring that can lead to liver failure
- End-stage liver disease: Severe liver damage that may require a liver transplant
The clinical trials are focusing on patients with different stages of liver fibrosis, ranging from mild (F1) to more advanced stages (F2-F4)[2][1].
Ongoing Clinical Trials
Several clinical trials are currently underway to evaluate fazirsiran’s effectiveness and safety:
- A study in patients with mild liver fibrosis (METAVIR stage F1)[2]
- A study in patients with more advanced liver fibrosis (METAVIR stages F2 to F4)[1]
- A long-term extension study for patients who have completed previous fazirsiran trials[3]
- A study to evaluate how the body processes fazirsiran in people with various degrees of liver problems[4]
These trials aim to assess the drug’s ability to reduce liver fibrosis, slow disease progression, and improve various markers of liver health.
Administration and Dosage
Fazirsiran is administered as a subcutaneous injection, which means it is injected under the skin. The typical dosing schedule in the clinical trials involves:
- An initial dose on Day 1
- A second dose at Week 4
- Subsequent doses every 12 weeks (approximately every 3 months)[1]
The standard dose being studied is 200 milligrams (mg) per injection, although this may be adjusted based on safety and effectiveness data collected during the trials[4].
Potential Benefits
The clinical trials are investigating several potential benefits of fazirsiran, including:
- Reduction in liver fibrosis[1]
- Decrease in the amount of abnormal Z-AAT protein in the liver[5]
- Improvement in liver function tests and other markers of liver health[5]
- Slowing or prevention of liver disease progression[3]
These potential benefits could significantly improve the quality of life for patients with AATD-associated liver disease and potentially reduce the need for liver transplantation in the future.
Safety and Side Effects
As fazirsiran is still in clinical trials, its full safety profile is not yet established. The ongoing studies are closely monitoring for any side effects or adverse events. Some of the safety measures being evaluated include:
- Changes in vital signs, such as blood pressure and heart rate[1]
- Changes in laboratory tests, including liver function tests[1]
- Effects on lung function, as AATD can also affect the lungs[1]
- Any unexpected medical events that occur during treatment[5]
It’s important to note that as an investigational drug, fazirsiran is not yet approved for general use, and its safety and effectiveness are still being determined through these clinical trials.



