Trial Outcomes & Findings for Study to Determine if a Reduction in Pain Can be Measured in Spinal Cord Injured Patients Using a New Study Design (NCT NCT00978341)

Subjects were enrolled at 4 study centers and participated in the study between 13 February 2007 and 01 October 2008.

Subjects completed a 1-2 week screening period to determine eligibility criteria prior to enrollment. Of 24 subjects screened, 15 subjects were enrolled into the study and randomized.

Study to Determine if a Reduction in Pain Can be Measured in Spinal Cord Injured Patients Using a New Study Design

Present pain intensity score: 0-10 numeric rating scale (NRS), 0 (no pain) to 10 (worst possible pain).

Daily Pain Score: Day 1 pain intensity over past 24 hours recorded on waking every morning. 0-10 numeric rating scale (NRS): 0 (no pain) to 10 (worst possible pain).

Area of dynamic allodynia was assessed using a brush (SENSElab Brush 05; velocity approximately 20 millimeters per second \[mm/s\]) by stimulating along a pattern of 8 radial spokes. Stimulation was started from the non-painful perimetry. Subjects were asked to report change in sensation from non-painful to painful and the spot was marked onto the skin. The area of dynamic allodynia was determined from these 8 distances by calculating the area of an octagon (in centimeter squared \[cm2\]).

Five strokes (each approx. 6 centimeters \[cm\] long) were applied with a standardized brush (SENSELab Brush 05) across the painful site (and a control site) at a constant velocity (20 millimeters per second \[mm/sec\]). Pain in response to brush stimulation of the allodynic area was recorded using an 11-point numeric rating scale from 0 (no pain) to 10 (worst possible pain). Patients were asked to give a pain rating after each brush stroke. A painful sensation was considered as representing brush allodynia.

Area of punctate allodynia was determined using a von Frey filament (OptiHair2). Stimulation was started from the non-painful perimetry and repeated along a pattern of 8 radial spokes. With a movement along each spoke at steps of 5 millimeters (mm), the subjects reported sensation changes from non-painful to painful and the spot was marked on the skin. The area of punctate allodynia was determined from these 8 distances by calculating the area of an octagon (in square centimeter(s)\[cm2\]).

Mechanical pain sensitivity stimulus response function was assessed at the control and painful sites using calibrated von Frey monofilaments and the SENSElab brush. Seven different von Frey monofilaments (8 -512 milliNewtons \[mN\], force increases by a factor of two from filament to filament) and the brush were applied in a predetermined pseudo-random order. Pain rating for each stimulus: 11-point numeric rating scale (NRS) ranging from 0 (no pain) to 10 (worst possible pain).

NPSI: subject rated questionnaire to evaluate 5 dimensions of neuropathic pain (dimensions: burning \[superficial\] spontaneous pain, pressing \[deep\] spontaneous pain, paroxysmal pain, evoked pain, and paresthesia/dyesthesia). Includes 10 descriptors ranging from 0 (no symptoms) to 10 (worst symptoms imaginable) and 2 temporal items assessing duration of spontaneous ongoing and paroxysmal pain. Questionnaire generates a score in each relevant dimension. Total score is calculated as the sum of scores of the 10 descriptors, range: 0-100. Higher score indicates greater intensity of pain.

Pharmacokinetic (PK) results are not presented in this report due to early termination of the trial. Pregabalin PK was not measured as there was incomplete data to conduct pharmacokinetic/pharmacodynamic analyses.