ELB139 Given Orally to Patients With Concurrent Panic Disorder, Challenged by CO2 Inhalation After a Single Dose and One Week of Treatment

Inclusion Criteria: * Diagnosis of concurrent panic disorder * At least 2 panic attacks within the 4 weeks before the screening visit * Naïve to the CO2 challenge test * Age 18-65 years (inclusive) * Ability to comply with all procedures mandated by the study protocol * Negative pregnancy test and adequate contraceptive measures Exclusion Criteria: * History of poly-pharmacotherapy for panic disorder or treatment resistance * Any current psychiatric Axis I DSM-IV diagnosis other than panic disorder, except concurrent simple phobia * History of abuse of benzodiazepines or tolerance to effects of benzodiazepine * Any concomitant psychotropic medication * Evidence of impaired hepatic, renal or cardiac functions * Participation in any drug trial in the preceding 6 months