Table 1 Inclusion and exclusion criteria for study entry are listed

Inclusion criteria

1) Subjects aged ≥18 years

2) Females of childbearing potential must have a negative urine pregnancy test performed, and all subjects were required to be practicing an effective form of contraception as required

3) A diagnosis of NeP due to DPN with NeP severity of ≥4 on a Visual Analog Score

4) Ability to complete pain diary and quality of life questionnaires and to perform GaitMeter™ and associated testing; and

5) The subject must be willing and able to comply with scheduled study procedures.

Exclusion criteria

1) Another co-existing pain for which the subject or a qualified pain physician cannot differentiate from NeP due to DPN

2) Clinically significant or unstable medical or psychological conditions

3) Any history of malignancy, except either where there has been no ongoing treatment for at least 6 months or for a basal cell carcinoma

4) A history of seizures, clinically significant cardiac arrhythmias, postural hypotension, uncontrolled hypertension, severe cardiovascular disease, severe hepatic impairment (evidence from medical history), renal failure or pulmonary disease

5) A history of another diagnosed disorder which could interfere with gait and testing, such as with stroke, dementia, Parkinsonism, spinal cord disorder, muscle weakness, or use of a medication which causes significant sedation or incoordination

6) Hepatic dysfunction at screening (aspartate transaminase [AST] or alanine transaminase [ALT] greater than twice the upper limit of normal, or a total bilirubin greater than the upper limit of normal

7) Estimated creatinine clearance of < 60 mL/min based on the Cockcroft and Gault equation

8) A positive urine drug screen

9) A lack of willingness to discontinue and wash-out use of prohibited medications or treatments

10) Inability to walk a total of 50 metres without any pauses or use of a cane, walker, or motorized device

11) Identification of the presence of another potential cause for peripheral neuropathy, presence of impaired glucose tolerance only or juvenile onset of diabetes with requirement for insulin at time of diagnosis (i.e. possible type 1 diabetes)

12) Refusal to perform concurrent laboratory and physiological testing.