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A study comparing under-the-skin and into-the-vein alpha1-proteinase inhibitor treatment in patients with alpha1-antitrypsin deficiency

Fast replyInvestigationalNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study is looking at Alpha-1 Antitrypsin Deficiency, which is an inherited condition where the body does not produce enough of a protective protein that helps keep the lungs healthy. People with this condition can develop breathing problems because their lungs may become damaged over time. The study will use two different forms of a treatment called human alpha1-proteinase inhibitor. One form is given through a needle into a vein, which is called intravenous infusion, and uses a product known as Liquid Alpha1-Proteinase Inhibitor or Prolastin-C Liquid. The other form is given under the skin and is called Alpha1-Proteinase Inhibitor Subcutaneous 15% or Alpha-1 15%. Both treatments work by replacing the missing protein in the body.

The purpose of this study is to find out whether two different weekly doses of the under-the-skin treatment produce similar levels of the protective protein in the blood compared to the standard doses of the into-the-vein treatment. The study will also look at how safe these treatments are and how well they are tolerated by patients. During the study, participants will first receive the into-the-vein treatment for eight weeks, and then they will switch to receiving the under-the-skin treatment for another eight weeks. Throughout this time, blood samples will be taken regularly to measure the amount of the protective protein in the blood and to see how the body processes the medication. The study will also monitor any side effects that may occur and check lung function to see how well the treatment is working.

Participants in this study will be people between 18 and 80 years old who have been diagnosed with Alpha-1 Antitrypsin Deficiency through genetic testing and have certain breathing difficulties. They may be new to this type of treatment or may already be receiving it, but they will need to stop any other similar treatments during the study. The study will track various measurements including heart rate, blood pressure, breathing rate, temperature, and lung function tests to ensure the safety of participants. Blood tests will also be done to check for any immune system reactions to the treatment and to monitor overall health.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial treatment period with intravenous medication

    During the first 8 weeks, intravenous infusions will be administered. An intravenous infusion means the medication is delivered directly into a vein through a needle or tube.

    The medication used is called Liquid Alpha1-Proteinase Inhibitor, also known as Prolastin-C Liquid. This is a solution that replaces the protein your body is lacking.

    The dose will be either 60 mg per kilogram of body weight per week or 120 mg per kilogram of body weight per week, depending on the treatment group assigned to you.

    The infusions will be given once weekly for a total of 8 weeks.

  2. Step 2

    Blood tests during intravenous treatment

    Blood samples will be collected at specific times to measure the level of alpha1-proteinase inhibitor in your blood. This measurement helps determine how your body processes the medication.

    Samples will be taken at weeks 6, 7, 8, and 9 to measure the lowest level of medication in your blood before the next dose.

    Additional blood samples will be collected during week 9 at specific time points throughout the week to create a detailed picture of medication levels over time.

  3. Step 3

    Second treatment period with subcutaneous medication

    After completing the first 8 weeks, the treatment method will change to subcutaneous administration. Subcutaneous means the medication is injected under the skin rather than into a vein.

    The medication used is called Alpha1-Proteinase Inhibitor Subcutaneous 15%, also known as Alpha-1 15%. This is also a solution that replaces the missing protein.

    The dose will be either 90 mg per kilogram of body weight per week or 180 mg per kilogram of body weight per week, depending on the treatment group assigned to you.

    These subcutaneous injections will be given once weekly for another 8 weeks.

  4. Step 4

    Blood tests during subcutaneous treatment

    Similar to the first treatment period, blood samples will be collected to measure medication levels in your blood.

    Samples will be taken at weeks 14, 15, 16, and 17 to measure the lowest level of medication before the next dose.

    Additional blood samples will be collected during week 17 at specific time points throughout the week.

  5. Step 5

    Follow-up period after treatment completion

    After completing both treatment periods, a follow-up period of 4 weeks will occur.

    At week 20, a final blood sample will be collected to measure the natural level of alpha1-proteinase inhibitor in your body without any treatment.

    This measurement helps to understand how much of the protein your body produces on its own.

  6. Step 6

    Monitoring throughout the study

    Throughout all treatment periods, vital signs will be measured regularly. These include heart rate, blood pressure, breathing rate, and body temperature.

    Lung function tests will be performed to assess how well your lungs are working. These tests measure how much air you can breathe out and how quickly.

    Blood tests will be conducted to check general health parameters and to look for any immune system responses to the medication.

    Any health changes or symptoms will be recorded to assess the safety of the treatments.

Who can join the trial?

7 criteria

  • You must be between 18 and 80 years old at the time of the first visit
  • You must have a confirmed diagnosis of Alpha-1 Antitrypsin Deficiency, which is an inherited condition where your body does not produce enough of a protective protein. Your specific genetic type must be one of the following: ZZ, SZ, Z(null), (null)(null), S(null), or certain other at-risk genetic variations. If your genetic type has not been confirmed yet, a blood test will be done at the first visit
  • You may have never received treatment for Alpha-1 Antitrypsin Deficiency before, or you may be currently receiving treatment, or you may have received treatment in the past
  • Your blood level of the alpha-1 proteinase inhibitor protein must be documented as low (less than 11 μM or 80 mg/dL or 50 mg/dL depending on the test method used). This measurement must be from before you started any treatment if you are currently receiving treatment
  • Your lung function test must show that your FEV1 (the amount of air you can forcefully breathe out in one second) is between 25% and 80% of what is expected for someone of your age and size. This test is done after using an inhaler that opens your airways. Your FEV1/FVC ratio (a comparison of how much air you can breathe out quickly versus the total amount you can breathe out) must be less than 70%
  • If you are currently receiving any type of alpha-1 proteinase inhibitor treatment, you must be willing to stop that treatment when the study begins and not use any other alpha-1 proteinase inhibitor treatment during the study except for the study medication
  • You must be willing and able to sign a consent form showing that you understand what the study involves and agree to participate

Who cannot join the trial?

1 criterion

  • The study does not list specific exclusion criteria in the provided information. Please consult with the research team to learn about conditions or situations that would prevent participation in this clinical trial.
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Investigated drugs

  • Alpha1-Proteinase Inhibitor Subcutaneous 15%

    is a medicine given as an injection under the skin (subcutaneous injection) to treat people who have a condition called alpha1-antitrypsin deficiency. This condition means the body does not make enough of a certain protein that helps protect the lungs. This medicine replaces the missing protein to help protect the lungs from damage.

  • Liquid Alpha1-Proteinase Inhibitor

    is a medicine given through a vein (intravenous infusion) to treat people with alpha1-antitrypsin deficiency. Like the subcutaneous version, it works by replacing the protein that the body is not making enough of, helping to protect the lungs from damage. This is the standard treatment method that has been used for this condition.

What is already known about the treatment

  • Alpha1-Proteinase Inhibitor Subcutaneous (Human) 15%

    This medication is given as a weekly injection under the skin and is being studied as a treatment for people with Alpha-1 Antitrypsin Deficiency, a genetic condition that can lead to lung and liver problems. The drug works by replacing the missing or defective alpha-1 protein in the blood, which normally protects the lungs from damage caused by enzymes released during inflammation. This subcutaneous form is being tested to see if it can maintain similar levels of the protective protein in the body compared to the standard intravenous version, while offering patients a more convenient way to receive treatment at home.

  • Liquid Alpha1-Proteinase Inhibitor (Human) Intravenous

    This is the standard form of the medication that is given directly into a vein on a weekly basis and serves as the comparison treatment in this clinical trial for Alpha-1 Antitrypsin Deficiency. Like the subcutaneous version, it provides replacement therapy by supplying the body with the alpha-1 protein that patients are missing, helping to protect lung tissue from progressive damage. This intravenous formulation is currently the established method of treatment and requires administration at a healthcare facility or through home infusion services.

Investigated diseases

Alpha-1 Antitrypsin Deficiency – Alpha-1 Antitrypsin Deficiency is a genetic disorder that occurs when the body does not produce enough of a protein called alpha-1 antitrypsin. This protein is made in the liver and normally travels through the bloodstream to protect the lungs from damage. When levels of this protein are too low, the lungs become vulnerable to harm from infections and irritants like tobacco smoke. The condition can also cause liver problems because abnormal forms of the protein may build up in liver cells. Over time, the lack of protection in the lungs can lead to breathing difficulties and lung tissue damage. The severity of the condition varies from person to person, with some experiencing symptoms early in life while others may not notice problems until adulthood.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-522792-29-00Protocol codeGC2501Estimated enrolment57 patientsSponsorGrifols Therapeutics LLC

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