The main objectives of this trial are to investigate safety, tolerability and pharmacokinetics of BI 765423 in healthy male subjects.

Inclusion criteria:

1. Healthy male subjects according to the assessment of the investigator, as based on a complete medical history including a physical examination, vital signs (blood pressure (BP), pulse rate (PR), respiratory rate (RR), temperature), 12-lead Electrocardiogram (ECG), and clinical laboratory tests

2. Age of 18 to 55 years (inclusive)

3. Body Mass Index (BMI) of 18.5 to 29.9 kg/m² (inclusive)

4. Signed and dated written informed consent in accordance with ICH-GCP and local legislation prior to admission to the trial

5. Male subjects who are willing to not donate sperm for the duration of the trial until completion of EoS visit and meet at least one of the following criteria:

   • Not sexually active with a partner of child-bearing potential or sexually abstinent. Women of non-childbearing potential are defined as postmenopausal for at least 1 year or surgically sterilised by hysterectomy, bilateral salpingectomy or bilateral oophorectomy. True abstinence is only acceptable, if it is in line with the subject's preferred and usual lifestyle. If a subject is usually not sexually active, but becomes active with their partner, they must comply with the contraceptive requirements detailed below.
   • Sexually active with a partner of child-bearing potential who is willing to use combined (estrogen and progestogen containing) hormonal contraception that prevents ovulation (oral, intravaginal or transdermal), plus condom in male subject from Screening until at least end of study (EoS) visit.
   • Sexually active with a partner of child-bearing potential who is willing to use progestogen-only hormonal contraception that inhibits ovulation (only injectables or implants), plus condom in male subject from Screening until at least EoS visit.
   • Sexually active with a partner of child-bearing potential who is willing to use intrauterine device (IUD) or intrauterine hormone-releasing system (IUS), plus condom in male subject from Screening until at least EoS visit.
   • Male subject is vasectomised (vasectomy at least 1 year prior to enrolment) and received medical assessment of the surgical success (documented absence of sperm). If sexually active with a partner of child-bearing potential, the subject is willing to use male condom from Screening until at least EoS visit.

Exclusion criteria:

1. Any finding in the medical examination (including BP, PR, RR, temperature or ECG) deviating from normal and assessed as clinically relevant by the investigator
2. Repeated measurement 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) (subjects with heart rate values between 45 and 50 bpm may be enrolled in case they have a normal thyroid function, no clinical symptoms associated with the bradycardia and no apparent signs of other diseases causing bradycardia such as hypothyroidism)
3. Any laboratory value outside the reference range that the investigator considers to be of clinical relevance
4. Any evidence of a concomitant disease assessed as clinically relevant by the investigator
5. Gastrointestinal, hepatic, renal, respiratory, cardiovascular, metabolic, immunological or hormonal disorders
6. Major surgery (major according to the investigator's assessment) performed within 3 months prior to screening or planned after screening during the study, e.g. hip replacement
7. Diseases of the central nervous system (including but not limited to any kind of seizures or stroke), and other relevant neurological or psychiatric disorders
8. History of relevant orthostatic hypotension, fainting spells, or blackouts 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.mystudywindow.com/msw/datatransparency

Participant: This trial is blinded to treatment but not to dose level. The dose level will be known to the participant.

Outcome assessor: ECG laboratory