The trial aims to study the safety, tolerability, and pharmacokinetics of single and multiple rising doses of BI 3776528.

Inclusion criteria:

1. Healthy male subjects according to the assessment of the investigator, as based on a complete medical history including a physical examination and clinical laboratory.
2. Age of 18 to 50 years (inclusive)
3. BMI of 18.5 to 29.9 kg/m² (inclusive), body weight above 60 kg (inclusive)
4. Signed and dated written informed consent in accordance with ICH-GCP and local legislation prior to admission to the trial.

Exclusion criteria:

1. Any finding in the medical examination (including blood pressure (BP), pulse rate (PR) or electrocardiogram (ECG)) deviating from normal and assessed as clinically relevant by the investigator
2. Repeated measurement at screening of systolic blood pressure outside the range of 90 to 140 mmHg, diastolic blood pressure outside the range of 50 to 90 mmHg, or pulse rate outside the range of 50 to 90 beats per minute (bpm)
3. Any laboratory value outside the (age-adapted) reference range that the investigator considers to be of clinical relevance, in particular, hepatic parameters (alanine transaminase (ALT), aspartate transaminase (AST), total bilirubin), renal parameters (creatinine) exceeding the upper limit of normal (ULN) after repeated measurements or abnormal thyroid stimulating hormone (TSH) values outside of the normal range after repeated measurements.
4. Any evidence of a concomitant disease assessed as clinically relevant by the investigator Further exclusion criteria apply.

Clinical studies sponsored by Boehringer Ingelheim, phases I to IV, interventional and non-interventional, are in scope for sharing of the raw clinical study data and clinical study documents. Exceptions might apply, e.g. studies in products where Boehringer Ingelheim is not the license holder; studies regarding pharmaceutical formulations and associated analytical methods, and studies pertinent to pharmacokinetics using human biomaterials; studies conducted in a single center or targeting rare diseases (in case of low number of patients and therefore limitations with anonymization).

For more details refer to: https://www.clinicalstudies.boehringer-ingelheim.com/msw/datasharing

Part 1a of this trial is a randomized, single-blind, and placebo-controlled. Part 1b of the trial is randomized, open-label, and with a two-way crossover design.

Part 2 of the trial is single-blind, randomized, and placebo-controlled.