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Study of BI 1291583 oral tablets (1 mg and 5 mg) and intravenous microtracer in healthy male volunteers

Verified siteInvestigationalNo placebo
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What is this trial about?

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

The trial involves men who are healthy, meaning they have no known illness that could affect how the body handles a medication. No disease is being treated in this study.

Participants will receive a tablet containing BI 1291583 taken by mouth and, at another time, a very small amount of the same substance marked with a tiny radioactive tag ([14C]) given through a vein using an intravenous infusion. The oral tablet is a standard pill that is swallowed, while the infusion delivers the drug directly into the bloodstream. The radioactive tag is only a trace amount that helps researchers see where the drug goes without affecting the body.

The purpose of the study is to find out how much of the drug is absorbed when taken as a tablet compared with when it is delivered directly into the blood. Volunteers will have blood samples taken at several points after each dose to measure the amount of drug present, allowing researchers to compare the two ways of administration. The entire process takes place over a short period, with visits for dosing and blood draws scheduled accordingly.

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

    Baseline assessments

    After joining the study, basic health measurements such as weight, blood pressure, and heart rate are recorded.

    A short medical questionnaire is completed to confirm eligibility as a healthy volunteer.

  2. Step 2

    Oral tablet administration

    You receive a single oral tablet of BI 1291583.

    The tablet contains either 1 mg or 5 mg of the active substance, taken by mouth once.

    The tablet is not labeled with radioactivity; it is the test treatment used to assess how the body absorbs the medicine.

  3. Step 3

    Intravenous microtracer infusion

    A very small amount (50 µg) of BI 1291583 labeled with carbon‑14 is given through an intravenous infusion.

    The infusion is administered once, typically shortly after the oral tablet, to serve as a reference for measuring absorption.

    The label allows researchers to track the medicine in the blood without affecting safety.

  4. Step 4

    Blood sampling for concentration measurement

    Blood samples are drawn at several time points after each dose, such as immediately before dosing, and then at intervals of minutes to hours (for example, 0.5, 1, 2, 4, 6, 8, 12, and 24 hours).

    The samples are analyzed to determine the amount of medicine present in the plasma, which provides information about bioavailability and how quickly the drug is cleared.

  5. Step 5

    Observation period

    You remain at the study site for a period of several hours after dosing to allow monitoring of any immediate reactions.

    Vital signs are checked periodically, and any symptoms are recorded.

  6. Step 6

    Study completion

    Once the final blood sample is taken and monitoring is finished, the study procedures are concluded.

    You are free to leave the site after receiving a summary of the visit.

Who can join the trial?

4 criteria

  • Be a healthy man, as decided by the study doctor after reviewing your full medical history, a physical check‑up, your vital signs (such as blood pressure (BP) and pulse rate (PR)), a heart test called a 12‑lead ECG, and routine lab tests (blood and urine).
  • Be between 18 and 55 years old, including the ages at the ends of the range.
  • Have a body‑mass index (BMI) between 18 and 29.9 kg/m², which is a measure of weight relative to height.
  • Provide a signed and dated written informed consent, meaning you agree in writing to take part after the study has explained what will happen.

Who cannot join the trial?

4 criteria

  • Any result from the medical check‑up (including blood pressure, pulse rate or electrocardiogram (ECG)) that is not normal and that the doctor thinks is important.
  • Repeated measurements showing a systolic blood pressure (the top number) lower than 90 mmHg or higher than 140 mmHg, a diastolic blood pressure (the bottom number) lower than 50 mmHg or higher than 90 mmHg, or a pulse rate (heart beats per minute) lower than 45 bpm or higher than 90 bpm.
  • Any lab test result (such as blood or urine tests) that falls outside the normal range and the doctor believes it could affect the study.
  • Any sign of another illness (a concomitant disease) that the doctor considers important enough to keep you from taking part.
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Investigated drugs

  • BI 1291583

    oral tablet: This is the study drug taken by mouth in the form of a small tablet. Participants swallow the tablet, and the researchers measure how much of the medicine is absorbed into the bloodstream. The tablet is used as the “test” treatment to evaluate the drug’s oral availability.

  • BI 1291583

    intravenous infusion: This is the same medicine given as a very small amount (a microtracer) directly into a vein through an infusion solution. Because it is delivered straight into the bloodstream, it provides a reference point for how much of the drug can be absorbed when taken by mouth. This infusion is used as the “reference” treatment to calculate the absolute oral bioavailability.

What is already known about the treatment

  • BI 1291583 1 mg

    This medication is taken by swallowing a tablet with water. It is still an investigational drug and is not yet approved for any medical use. The study is looking at its ability to be absorbed when taken by mouth, and it belongs to a class of small‑molecule drugs that target specific proteins in the body.

  • BI 1291583 5 mg

    The 5 mg version is also a tablet that is swallowed with water. Like the 1 mg tablet, it is currently only being tested in research and has no approved therapeutic use. The trial aims to compare how much of the drug reaches the bloodstream at this higher dose, and it is classified as a small‑molecule inhibitor.

  • BI 1291583 (intravenous solution)

    This form is given as a short infusion into a vein, delivering a very small microdose of the drug. It is an experimental substance that has not been licensed for treatment. The IV dose is used as a reference to measure how much of the oral tablets are absorbed, and it is also a small‑molecule inhibitor.

Investigated diseases

Conditions this trial is registered against

Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase ITrial ID2023-505683-11-00Protocol code1397-0026Estimated enrolment25 patientsSponsorBoehringer Ingelheim International GmbH

sourced from the EU Clinical Trials Register and site verification

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