Study to Evaluate the Analgesic Efficacy of 28 Days' Oral Administration of AZD2066 Compared With Placebo in Patients With Painful Diabetic Neuropathy

Change of mean pain intensity from 5-day baseline to the last 5 days of treatment, measured twice daily with NRS (12 hours recall).

Mean pain intensity for 5-day baseline period (evening Day -6 to moning Day-1) and mean pain intensity for last 5 days on treatment (ie, last dose day and the 4 preceding calendar days) was calculated based on the numerical rating scale (NRS)(0-10). 0=No pain, 10=Worst pain imaginable.

Mean pain intensity per day (mean of morning and evening NRS values) and change from baseline were calculated for each study day. Baseline value= mean pain intensity for the 5-day baseline period. NRS scale (0- 10) where 0= No pain and 10= Worst pain imaginable.

Pain intensity score reduction=(change from baseline at D28/baseline)*100 Responder= pain intensity score reduction ≥30% (yes/no)? Responder rate= (no. of responders/total no. of patients)*100

Pain intensity score reduction= (change from baseline D28/baseline)*100 Responder=pain intensity score reduction ≥50% (Yes/No)? Responder rate= (no. of responders/total no. of patients)*100

Patient Global Impression of Change (PGIC) scale ranges from 1-7, where 1= Very much improved and 7= Very much worse.

Responder= Patient with a response of "much improved" or "very much improved" Responder rate= (no. of responders/total no. of patients)*100

Sensory index= sum of the intensity scale values of the words chosen for the descriptors 1-11 in the questionnaire. Range of scores for the sensory index= 0-33 (higher score represents a worse condition).

Change from baseline (measured prior to randomization) to Day 28 was calculated.

Affective index= sum of the intensity scale values of the words chosen for the descriptors 12-15 in the questionnaire. Range of scores for the affective index=0-12 (higher score represents a worse condition).

Change from baseline (measured prior to randomization) to Day 28 was calculated.

Change from baseline (measured prior to randomization) to Day 28 was calculated for the pain severity (mean of 4 intensity items). Each intensity item is recorded on a Numerical rating Scale (NRS) 0-10, where 0=No pain and 10= The worst pain.

Change from baseline (measured prior to randomization) to Day 28 was calculated for pain interference (mean of 7 interference items). Each interference item is recorded on a Numerical Rating Scale (NRS 0-10), where 0= No interference and 10= Interferes completely.