A Study of Ketamine in Patients With Treatment-resistant Depression

• The change from Day 1 (baseline) to Day 15 in depressive symptoms using the Montgomery Asberg Depression Rating Scale (MADRS) total score [ Time Frame: Day 1, Day 15 ] [ Designated as safety issue: No ]
  The MADRS is a scale designed to measure depression severity and detects changes due to antidepressant treatment. The test consists of 10 items, each of which is scored from 0 (item not present or normal) to 6 (severe or continuous presence of the symptoms), for a total score of 60. Higher scores represent a more severe condition.
  
  

• Number of patients with sustained response [ Time Frame: 15 days ] [ Designated as safety issue: No ]
  Sustained response is defined as achieving an onset of antidepressant response within the first week that is maintained to study Day 15.
  
  
• The change from Day 1 (baseline) to Day 29 in major depressive disorder (MMD) symptoms using the Montgomery Asberg Depression Rating Scale (MADRS) total score [ Time Frame: Day 1, Day 29 ] [ Designated as safety issue: No ]
  The MADRS is a scale designed to measure depression severity and detects changes due to antidepressant treatment. The test consists of 10 items, each of which is scored from 0 (item not present or normal) to 6 (severe or continuous presence of the symptoms), for a total score of 60. Higher scores represent a more severe condition.
  
  
• The change from Day 1 (baseline) to Day 29 in severity of illness using the Clinical Global Impression - Severity (CGI-S) [ Time Frame: Day 1, Day 29 ] [ Designated as safety issue: No ]
  The CGI-S rating scale is a 7 point global assessment that measures the clinician's impression of the severity of illness exhibited by a patient. A rating of 1 is equivalent to "Normal, not at all ill" and a rating of 7 is equivalent to "Among the most extremely ill patients". Higher scores indicate worsening.
  
  
• The change from Day 29 through Day 47 in severity of illness using the Clinical Global Impression - Severity (CGI-S) [ Time Frame: Day 29, Day 47 ] [ Designated as safety issue: No ]
  The CGI-S rating scale is a 7 point global assessment that measures the clinician's impression of the severity of illness exhibited by a patient. A rating of 1 is equivalent to "Normal, not at all ill" and a rating of 7 is equivalent to "Among the most extremely ill patients". Higher scores indicate worsening.
  
  
• Assessment of major depressive disorder (MDD) as measured by the Clinical Global Impression - Improvement (CGI-I) [ Time Frame: 29 days ] [ Designated as safety issue: No ]
  The CGI-I is a 7-point scale that requires the clinician to assess how much the patient's illness has improved or worsened relative to a baseline state at the beginning of the intervention and rated as: 1=very much improved; 2=much improved; 3=minimally improved; 4=no change; 5=minimally worse; 6=much worse; 7=very much worse.
  
  
• The change from Day 1 (baseline) to Day 29 in severity of illness using the Patient Global Impression - Severity (PGI-S) [ Time Frame: Day 1, Day 29 ] [ Designated as safety issue: No ]
  The PGI-S is an 11-point (0= very well; 10= very poor) scale that requires the patients to rate the severity of their illness at the time of assessment, relative to the patient's past experience.
  
  
• The change from Day 29 through Day 47 in severity of illness using the Patient Global Impression - Severity (PGI-S) [ Time Frame: Day 29, Day 47 ] [ Designated as safety issue: No ]
  The PGI-S is an 11-point (0= very well; 10= very poor) scale that requires the patients to rate the severity of their illness at the time of assessment, relative to the patient's past experience.
  
  
• The change in patient perspective of global change in major depressive disorder (MDD) since start of study treatment, as measured by the Patient Global Impression of Change (PGI-C) [ Time Frame: 29 days ] [ Designated as safety issue: No ]
  The PGI-C is a 7-point scale that requires the patients to assess how much their illness has improved or worsened relative to a baseline state at the beginning of the intervention. The response options are: very much improved; much improved; improved (just enough to make a difference); no change; worse (just enough to make a difference); much worse; or very much worse.
  
  

This is a double-blind (patients and study personnel do not know the identity of the administered treatments), randomized (the drug is assigned by chance), placebo-controlled (placebo is a substance that appears identical to the treatment and has no active ingredients), parallel arm study (each group of patients will be treated at the same time). The study will consist of a screening phase of up to 4 weeks, a 4-week double-blind treatment phase (Day 1 to Day 29), and a 3-week post treatment (follow up) phase. In the double-blind phase, patients will receive over 4 weeks either intravenous (IV) infusions of placebo (2 or 3 times weekly) or IV infusions of ketamine (2 or 3 times weekly). The total study duration for each patient will be a maximum of 13 weeks.