• Investigation of safety and tolerability of BI 653048 H3PO4 following the administration of single rising doses of an aqueous solution in healthy male subjects
• Pharmacokinetic and pharmacodynamic characteristics of BI 653048, including the investigation of dose proportionality
• Investigation of relative bioavailability of capsules versus aqueous solution

Inclusion Criteria:

• Healthy males according to the following criteria: Based upon a complete medical history, including the physical examination, vital signs (blood pressure (BP), pulse rate (PR)), 12-lead electrocardiogram (ECG), clinical laboratory tests
• Age ≥21 years and ≤50 years
• Body Mass Index (BMI) ≥18.5 kg/m2 and BMI ≤29.9 kg/m2
• Signed and dated written informed consent prior to admission to the trial in accordance with Good Clinical Practice (GCP) and the local legislation

Exclusion Criteria:

• Any finding of the medical examination (including BP, PR and ECG) deviating from normal and of clinical relevance
• Any evidence of a clinically relevant concomitant disease
• Gastrointestinal, hepatic, renal, respiratory, cardiovascular, metabolic, immunological or hormonal disorders
• Surgery of the gastrointestinal tract (except appendectomy)
• Diseases of the central nervous system (such as epilepsy) or psychiatric disorders or neurological disorders
• History of relevant orthostatic hypotension, fainting spells or blackouts
• Chronic or relevant acute infections
• History of relevant allergy/hypersensitivity (including allergy to drug or its excipients)
• Intake of drugs with a long half-life (>24 h) within at least one month or less than 10 half-lives of the respective drug prior to administration or during the trial
• Use of drugs which might reasonably influence the results of the trial or that prolong the QT/QTc interval based on the knowledge at the time of protocol preparation within 10 days prior to administration or during the trial
• Participation in another trial with an investigational drug within 2 months prior to administration or during the trial
• Smoker (>10 cigarettes or >3 cigars or >3 pipes/day)
• Inability to refrain from smoking on trial days
• Alcohol abuse (more than 60 g/day)
• Drug abuse
• Blood donation (more than 100 mL within 4 weeks prior to administration or during the trial)
• Excessive physical activities (within 1 week prior to administration or during the trial)
• Any laboratory value outside the reference range that was of clinical relevance
• Inability to comply with dietary regimen of trial site
• A marked baseline prolongation of QT/QTc interval (e.g., repeated demonstration of a QTc interval >450 ms)
• A history of additional risk factors for Torsades des Pointes (e.g., heart failure, hypokalaemia, family history of Long QT Syndrome)
• Not willing to use adequate contraception (condom use plus another form of contraception e.g., spermicide, oral contraceptive taken by female partner, sterilisation, intrauterine device) during the whole trial period from the time of the first intake of trial drug until 3 months after the last intake