Refer a Patient

If your patient or any of your patient’s family members have a confirmed or suspected diagnosis of Alpha-1 Antitrypsin Deficiency–Associated Liver Disease, they may be eligible for this study.

About The Redwood Study

Study Purpose

The purpose of The Redwood Study is to evaluate the safety and effectiveness of an investigational study drug, TAK-999 (fazirsiran), compared to a placebo in the treatment of adults with Alpha-1 Liver Disease.

Primary objective:

  • To evaluate the efficacy of TAK-999 compared with placebo at improving measures of histologic fibrosis in Alpha-1 Liver Disease.

Secondary objectives:

  • To evaluate the pharmacodynamic (PD) effect of TAK-999 via measurement of intrahepatic Z-alpha-1 antitrypsin (Z-AAT) protein (total).
  • To evaluate the impact of TAK-999 versus placebo on modulating disease progression as defined by progression to cirrhosis or decompensating liver-related clinical events.
  • To evaluate the safety and tolerability of TAK-999 compared with placebo with an emphasis on monitoring lung function, lung injury, and associated symptoms.
  • To evaluate the PD effect of TAK-999 via measurement of serum Z-AAT.
  • To evaluate the efficacy of TAK-999 compared with placebo at reducing histologic evidence of portal inflammation and Z-AAT polymer burden in the liver.
  • To use non-invasive measures of liver fibrosis (including biomarkers) to evaluate the efficacy of TAK-999 compared with placebo.
  • To evaluate the pharmacokinetics (PK) of TAK-999.

Study Design

The Redwood Study is a randomized, double-blind, placebo-controlled study to evaluate the safety and efficacy of the investigational study drug, TAK-999, in participants with Alpha-1 Liver Disease. Participants will be randomized such that each participant has an equal chance of being assigned to either the investigational study drug or a placebo.

About the Investigational Study Drug

There is currently no approved treatment available for Alpha-1 Liver Disease. The investigational study drug, TAK-999, aims to reduce the production of the abnormal Z-AAT protein and its buildup in the liver. The reduction in levels of the protein may result in a decrease in liver scarring.

Study Duration

Participation will last approximately 4.5 years, including screening (up to 10 weeks), treatment (up to 196 weeks), and safety follow-up (6 months).

Key Eligibility Criteria

Eligible participants must:

  • Be 18 to 75 years of age, inclusive.
  • Not have smoked any substance for the past 12 months.
  • Have a confirmed diagnosis of the PiZZ genotype Alpha-1 Antitrypsin Deficiency. PiZZ diagnosis from source verifiable medical records is permitted. NOTE: Participants may not yet have a diagnosis, but they can undergo PiZZ confirmatory testing (genotyping for PiS and protease inhibitor Z alleles) at screening.
  • Not have hepatocellular carcinoma (HCC).
  • Not have a history of liver decompensating events.

Additional eligibility criteria apply.

The Redwood Study Research Sites

If you have a patient who may be interested in participating and you think may qualify, refer your patient to this study website to take the prescreening questionnaire to determine eligibility, or fill out a contact request form if you would like to request contact directly from an active research site.

Find the Site Nearest You

Enter your zip code below or click on the map to find the participating research site(s) nearest you.

View full list of locations.

Active site locations

Future site locations