As a transition from preclinical investigations to clinical development in this first-in-human trial, safety, tolerability, and pharmacokinetics of BI 660848 will be assessed in human male volunteers using single rising oral doses in order to provide the basis for a potential ongoing clinical development of BI 660848 in the indication of neuropathic pain.

Inclusion criteria

1. Healthy male based upon a complete medical history, including the physical examination, regarding vital signs (BP, PR), 12 lead ECG measurement, and clinical laboratory tests. There is no finding deviating from normal and of clinical relevance. There is no evidence of a clinically relevant concomitant disease.
2. Age 21 and 50 years
3. BMI 18.5 and <30 kg/m2 (Body Mass Index)
4. Signed and dated written informed consent prior to admission to the study in accordance with GCP and the local legislation

Exclusion criteria

1. Any finding of the medical examination (including BP, PR, and ECG measurements) deviating from normal and of clinical relevance
2. Evidence of a clinically relevant concomitant disease
3. Gastrointestinal, hepatic, renal, respiratory, cardiovascular, metabolic, immunological or hormonal disorders
4. Diseases of the central nervous system (such as epilepsy) or psychiatric disorders or neurological disorders
5. History of relevant orthostatic hypotension, fainting spells or blackouts
6. Chronic or relevant acute infections
7. History of relevant allergy/hypersensitivity (including allergy to the drug or its excipients) as judged clinically relevant by the investigator
8. Intake of drugs with a long half-life (24 hours) within at least 1 month or less than 10 half-lives of the respective drug prior to randomisation
9. Use of drugs which might reasonably influence the results of the trial based on the knowledge at the time of protocol preparation within 10 days prior to randomisation
10. Participation in another trial with an investigational drug within 2 months prior to randomisation
11. Smoker (>10 cigarettes or >3 cigars or >3 pipes/day)
12. Inability to refrain from smoking on trial days as judged by the investigator
13. Alcohol abuse (more than 30 g alcohol a day)
14. Drug abuse
15. Blood donation (more than 100 mL blood within 4 weeks prior to randomisation or during the trial)
16. Excessive physical activities within 1 week prior to randomisation or during the trial
17. Any laboratory value outside the reference range that is of clinical relevance
18. Inability to comply with dietary regimen of the study centre