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Efficacy and Safety of Berotralstat for Preventing Angioedema Attacks in Patients with Acquired Angioedema due to C1 Inhibitor Deficiency

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What is this trial about?

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

The study focuses on people who have Acquired angioedema due to C1 inhibitor deficiency, a rare condition in which a missing protein called C1 inhibitor leads to sudden swelling under the skin and in the throat. The medication being tested is oral capsules containing the active substance BEROTRALSTAT, which is intended to reduce the frequency of these swelling attacks. The purpose of the study is to explore whether this drug can prevent such attacks.

Participants will take one hard capsule each day for about six months while keeping a simple diary of any swelling episodes, any other health problems, and any use of emergency treatment. Regular check‑ins with study staff will be scheduled to review the diary, assess safety, and record any side effects, known as adverse events. The overall design is open‑label and single‑arm, meaning all participants receive the same medication and know they are receiving the active treatment.

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

    Enrollment and baseline assessment

    After joining the study, you will undergo initial evaluations that include a review of your medical history and documentation of how often you have experienced angioedema attacks before starting treatment.

  2. Step 2

    Start of medication

    You will begin taking orladeyo 150 mg hard capsules, which contain the active substance berotralstat.

    The prescribed dose is one capsule taken by mouth each day.

    Treatment will continue for a total period of 24 weeks (approximately six months).

  3. Step 3

    Daily medication routine

    Each day you will swallow the capsule with water, following the same time each day to maintain a consistent schedule.

    If you miss a dose, follow the instructions provided by the study team regarding how to handle missed doses.

  4. Step 4

    Recording attacks and symptoms

    You will keep a simple diary in which you note any angioedema attacks, the severity of each attack, and any rescue treatments you use.

    The diary helps the study evaluate how the medication changes the number and severity of attacks over time.

  5. Step 5

    Regular safety and effectiveness visits

    Throughout the 24‑week treatment period you will attend scheduled study visits where healthcare professionals will check your overall health, review the diary entries, and monitor for any side effects.

    These visits may occur at intervals such as every few weeks and at the end of the treatment period.

  6. Step 6

    Final assessment

    At the end of the 24‑week period you will have a final evaluation that includes a summary of the number of angioedema attacks during treatment compared with the period before you started the medication.

    The study will also assess any adverse events that occurred while you were taking the medication.

Who can join the trial?

14 criteria

  • Males and non‑pregnant, non‑lactating females who are 18 years old or older.
  • Ability to sign a written, informed consent form (a document that explains the study and your permission).
  • Body weight must be at least 40 kilograms (about 88 pounds).
  • A confirmed diagnosis of Acquired angioedema (AAE) based on:
    • recurrent swelling episodes (angioedema) that do not have itchy hives (wheals);
    • no family history of similar swelling or of an inherited C1‑inhibitor deficiency;
    • a lab test showing C1‑inhibitor activity less than 50 % of normal, plus at least one of the following:
      • first swelling symptoms began at age 40 or older;
      • low level of a protein called C1q;
      • genetic testing shows no disease‑causing change in the SERPING1 gene, which makes the C1‑inhibitor protein;
      • blood test shows antibodies that attack the C1‑inhibitor.
      • Must have access to and be able to use at least one approved medication for treating an acute swelling attack, such as icatibant or a plasma‑derived C1‑INH product.
      • During the initial observation (the run‑in period) you must experience at least two AAE attacks that meet all of these conditions:
        • the attacks are “unique,” meaning each new attack starts at least 48 hours after the previous one ends;
        • each attack includes swelling, which may be visible on the skin or felt inside the throat or abdomen;
        • the study doctor confirms that each attack is an AAE attack.
        • The study doctor must believe that you will follow all study procedures, including keeping a diary of your attacks, for the entire study duration.

Who cannot join the trial?

4 criteria

  • If you have a clinically significant (serious) medical or psychiatric (mental health) condition, or a medical history that the study doctor (Investigator) or the study sponsor thinks could make participation difficult or increase your risk, you cannot join.
  • If you have been diagnosed with any other type of frequent swelling episodes (recurrent angioedema) at the same time (concurrent) as your current condition, you cannot join.
  • If any of your initial test results (such as blood tests, urine tests, or physical exam findings) are abnormal and the study doctor believes they are a problem, or if the official medicine information (SmPC) lists a reason not to use the drug (contraindication), you cannot join.
  • If you are known to have an allergy (hypersensitivity) to berotralstat itself or to any of its inactive ingredients (excipients), you cannot join.
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Investigated drugs

Orladeyo is a hard‑capsule medication taken by mouth. It contains the active ingredient berotralstat, which is being studied to see if it can stop or reduce the swelling attacks (angioedema) that occur in people who have acquired angioedema because their body lacks enough C1 inhibitor. In this trial, participants will take Orladeyo as the only active treatment, and researchers will watch how well it works to prevent these attacks and whether it causes any side effects. The drug is classified as an orphan medication, meaning it is intended for a rare condition.

What is already known about the treatment

Orladeyo - Orladeyo is taken by mouth as a hard capsule that contains 150 mg of the active ingredient berotralstat. It is an approved orphan drug used to prevent swelling attacks in patients with acquired angioedema caused by C1‑inhibitor deficiency. Berotralstat works by blocking the enzyme kallikrein, which lowers the amount of bradykinin, a substance that makes blood vessels leak and swell. It belongs to the class of oral kallikrein inhibitors.

Investigated diseases

Acquired angioedema due to C1 inhibitor deficiency - This is a rare condition where the body lacks enough functional C1 inhibitor, a protein that helps control swelling. Without sufficient inhibitor, episodes of sudden swelling can appear in the face, lips, tongue, or throat. The swelling develops quickly and can last from several hours to a few days. Attacks may occur sporadically or become more frequent over time. Triggers such as stress, trauma, or certain foods can increase the likelihood of an episode. The condition tends to progress slowly, with the frequency and severity of attacks varying between individuals.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2025-524747-13-00Estimated enrolment16 patientsSponsorPoliclinico San Donato S.p.A.

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