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(383) Effect of concomitant neuropathic pain medications on pregabalin-mediated improvements in pain and pain-related sleep interference in patients with spinal cord injury
Abstracts
F10 Neuropathic Pain – Pharmacological Treatment (380) Withdrawn
The Journal of Pain
S71
(382) Shifts in pain severity categories among patients with neuropathic pain due to spinal cord injury treated with pregabalin B Parsons and B Emir; Pfizer Inc, New York, NY Pregabalin is approved in the United States for the treatment of neuropathic pain due to spinal cord injury (SCI). This approval was based on findings from two randomized placebo-controlled trials. In both trials, pregabalin treatment resulted in significantly greater change, from baseline to endpoint, in patientreported pain scores relative to placebo. However, statistical difference from placebo alone may not equate to clinically meaningful pain relief. Therefore, we pooled data from these two trials and compared shifts in pain severity categories between placebo (n=173) and pregabalin (n=174; flexible 150-600 mg/ day) treated patients. Pain severity was rated on a scale from 0=no pain to 10=worst possible pain and scores were categorized as mild (0 to <4), moderate ($4 to <7), or severe ($7 to #10). Only patients in the intent-to-treat population reporting moderate or severe pain at baseline were analyzed. The percentage of patients shifting from moderate or severe at baseline to mild, moderate, or severe at endpoint were determined for each group and compared using a Cochran-Mantel-Haenszel test (modified ridit transformation of the calculated ordinal shift scales) and a baseline-observation-carried-forward approach to missing data. Significantly more patients shifted to a less severe pain category at endpoint in the pregabalin group compared with placebo (p=0.01). The percentage of patients shifting from severe at baseline to mild at endpoint was 14.3% for pregabalin compared with 7.7% for placebo. Likewise, the percentage of patients shifting from severe to moderate was 35.7% for pregabalin compared with 28.2% for placebo. Finally, the percentage of patients shifting from moderate to mild was 38.6% for pregabalin and 27.2% for placebo. Overall, pregabalin treatment results in a beneficial shift among pain severity categories, relative to placebo, in patients with SCI-related neuropathic pain. Sponsored by Pfizer Inc.
(381) Analgesic efficacy of subcutaneous botulinum toxin type A for scar neuroma pain: a randomized, double-blind, placebo-controlled, crossover trial R Moericke, S Mackey, C Wang, G Ruchelli, E Dixon, J Hah, R McCue, and I Carroll; Stanford University, Palo Alto, CA Case studies have shown subcutaneous treatment of botulinum toxin type A (BTX-A) provides a promising alternative treatment for patients with chronic neuropathic pain. The current study aims to determine the clinical effectiveness of subcutaneous injection of BTX-A for treating scar neuroma pain. We designed a randomized, double-blind, placebo-controlled, crossover, trial to examine the analgesic effect of BTX-A versus placebo (saline solution). Screening procedures involved physical examination of the scar as well as subcutaneous injection of local anesthetic. Patients experiencing $80% analgesia with a subcutaneous bupivacaine injection of the scar met diagnostic criteria for scar neuroma. After completing a baseline pain reporting period of $30 days, patients were randomized to receive study injection 1 of either BTX-A or placebo. Study injections were preceded by an injection of local anesthetic to numb the area and ensure accuracy localizing the scar neuroma. Post-injection, patients were followed until analgesic failure then entered a $30 day washout period before receiving the crossover study injection 2. Days until analgesic failure were calculated for 27 patients who reached study completion receiving both study injections of BTX-A and placebo. Results indicated no evidence of a difference between local anesthetic alone and local anesthetic plus BTX-A (log rank p<0.88). Interestingly, approximately one quarter of patients did not return to baseline pain for over 200 days post-injection. Further analysis is needed to examine factors contributing to analgesic response. Supported by unrestricted gift funding from Allergan.
(383) Effect of concomitant neuropathic pain medications on pregabalin-mediated improvements in pain and painrelated sleep interference in patients with spinal cord injury B Parsons, M Almas, E Whalen, and B Emir; Pfizer Inc, New York, NY Pregabalin improved both pain and pain-related sleep interference (PRSI) in two large, placebo-controlled trials of neuropathic pain due to spinal cord injury (SCI). Concomitant neuropathic pain medications, such as opioids, serotonin–norepinephrine reuptake inhibitors, tricyclic antidepressants, tramadol, and anti-epileptic drugs, were allowed during both trials. The current study pooled data from these two trials (placebo n = 173; flexible 150-600 mg/day pregabalin n = 174) and examined the effect of concomitant neuropathic pain medications on pregabalin-mediated improvements in pain and PRSI. Pain and PRSI were assessed using a numeric rating scale from 0-10, with higher scores indicating greater severity. Changes in pain and PRSI were analyzed by analysis of covariance with interaction model and baseline-observation-carried-forward imputation. In total, 79 (46%) of patients in the placebo cohort received concomitant neuropathic pain medications compared with 73 (42%) in the pregabalin cohort. Pregabalin significantly reduced pain scores, compared with placebo, when both cohorts received concomitant neuropathic pain medications (difference from placebo = -0.62; p=0.027) and when both cohorts did not receive concomitant neuropathic pain medications (difference from placebo = -0.91; p<0.001). Further, there was no significant difference between pregabalin-treated patients who received concomitant neuropathic pain medications and pregabalin-treated patients who did not receive concomitant neuropathic pain medications (p=0.081). Pregabalin also significantly reduced PRSI scores, compared with placebo, when both cohorts received concomitant neuropathic pain medications (difference from placebo = -0.81; p=0.003) and when both cohorts did not receive concomitant neuropathic pain medications (difference from placebo = -0.97; p<0.001). There was no significant difference between pregabalin-treated patients who received concomitant neuropathic pain medications and pregabalin-treated patients who did not receive concomitant neuropathic pain medications (p=0.144). Overall, these data demonstrate that pregabalin-mediated improvements in pain and PRSI are evident regardless of the concomitant use of other treatments for SCI-related neuropathic pain. Sponsored by Pfizer Inc.
F10 Neuropathic Pain – Pharmacological Treatment (380) Withdrawn
The Journal of Pain
S71
(382) Shifts in pain severity categories among patients with neuropathic pain due to spinal cord injury treated with pregabalin B Parsons and B Emir; Pfizer Inc, New York, NY Pregabalin is approved in the United States for the treatment of neuropathic pain due to spinal cord injury (SCI). This approval was based on findings from two randomized placebo-controlled trials. In both trials, pregabalin treatment resulted in significantly greater change, from baseline to endpoint, in patientreported pain scores relative to placebo. However, statistical difference from placebo alone may not equate to clinically meaningful pain relief. Therefore, we pooled data from these two trials and compared shifts in pain severity categories between placebo (n=173) and pregabalin (n=174; flexible 150-600 mg/ day) treated patients. Pain severity was rated on a scale from 0=no pain to 10=worst possible pain and scores were categorized as mild (0 to <4), moderate ($4 to <7), or severe ($7 to #10). Only patients in the intent-to-treat population reporting moderate or severe pain at baseline were analyzed. The percentage of patients shifting from moderate or severe at baseline to mild, moderate, or severe at endpoint were determined for each group and compared using a Cochran-Mantel-Haenszel test (modified ridit transformation of the calculated ordinal shift scales) and a baseline-observation-carried-forward approach to missing data. Significantly more patients shifted to a less severe pain category at endpoint in the pregabalin group compared with placebo (p=0.01). The percentage of patients shifting from severe at baseline to mild at endpoint was 14.3% for pregabalin compared with 7.7% for placebo. Likewise, the percentage of patients shifting from severe to moderate was 35.7% for pregabalin compared with 28.2% for placebo. Finally, the percentage of patients shifting from moderate to mild was 38.6% for pregabalin and 27.2% for placebo. Overall, pregabalin treatment results in a beneficial shift among pain severity categories, relative to placebo, in patients with SCI-related neuropathic pain. Sponsored by Pfizer Inc.
(381) Analgesic efficacy of subcutaneous botulinum toxin type A for scar neuroma pain: a randomized, double-blind, placebo-controlled, crossover trial R Moericke, S Mackey, C Wang, G Ruchelli, E Dixon, J Hah, R McCue, and I Carroll; Stanford University, Palo Alto, CA Case studies have shown subcutaneous treatment of botulinum toxin type A (BTX-A) provides a promising alternative treatment for patients with chronic neuropathic pain. The current study aims to determine the clinical effectiveness of subcutaneous injection of BTX-A for treating scar neuroma pain. We designed a randomized, double-blind, placebo-controlled, crossover, trial to examine the analgesic effect of BTX-A versus placebo (saline solution). Screening procedures involved physical examination of the scar as well as subcutaneous injection of local anesthetic. Patients experiencing $80% analgesia with a subcutaneous bupivacaine injection of the scar met diagnostic criteria for scar neuroma. After completing a baseline pain reporting period of $30 days, patients were randomized to receive study injection 1 of either BTX-A or placebo. Study injections were preceded by an injection of local anesthetic to numb the area and ensure accuracy localizing the scar neuroma. Post-injection, patients were followed until analgesic failure then entered a $30 day washout period before receiving the crossover study injection 2. Days until analgesic failure were calculated for 27 patients who reached study completion receiving both study injections of BTX-A and placebo. Results indicated no evidence of a difference between local anesthetic alone and local anesthetic plus BTX-A (log rank p<0.88). Interestingly, approximately one quarter of patients did not return to baseline pain for over 200 days post-injection. Further analysis is needed to examine factors contributing to analgesic response. Supported by unrestricted gift funding from Allergan.
(383) Effect of concomitant neuropathic pain medications on pregabalin-mediated improvements in pain and painrelated sleep interference in patients with spinal cord injury B Parsons, M Almas, E Whalen, and B Emir; Pfizer Inc, New York, NY Pregabalin improved both pain and pain-related sleep interference (PRSI) in two large, placebo-controlled trials of neuropathic pain due to spinal cord injury (SCI). Concomitant neuropathic pain medications, such as opioids, serotonin–norepinephrine reuptake inhibitors, tricyclic antidepressants, tramadol, and anti-epileptic drugs, were allowed during both trials. The current study pooled data from these two trials (placebo n = 173; flexible 150-600 mg/day pregabalin n = 174) and examined the effect of concomitant neuropathic pain medications on pregabalin-mediated improvements in pain and PRSI. Pain and PRSI were assessed using a numeric rating scale from 0-10, with higher scores indicating greater severity. Changes in pain and PRSI were analyzed by analysis of covariance with interaction model and baseline-observation-carried-forward imputation. In total, 79 (46%) of patients in the placebo cohort received concomitant neuropathic pain medications compared with 73 (42%) in the pregabalin cohort. Pregabalin significantly reduced pain scores, compared with placebo, when both cohorts received concomitant neuropathic pain medications (difference from placebo = -0.62; p=0.027) and when both cohorts did not receive concomitant neuropathic pain medications (difference from placebo = -0.91; p<0.001). Further, there was no significant difference between pregabalin-treated patients who received concomitant neuropathic pain medications and pregabalin-treated patients who did not receive concomitant neuropathic pain medications (p=0.081). Pregabalin also significantly reduced PRSI scores, compared with placebo, when both cohorts received concomitant neuropathic pain medications (difference from placebo = -0.81; p=0.003) and when both cohorts did not receive concomitant neuropathic pain medications (difference from placebo = -0.97; p<0.001). There was no significant difference between pregabalin-treated patients who received concomitant neuropathic pain medications and pregabalin-treated patients who did not receive concomitant neuropathic pain medications (p=0.144). Overall, these data demonstrate that pregabalin-mediated improvements in pain and PRSI are evident regardless of the concomitant use of other treatments for SCI-related neuropathic pain. Sponsored by Pfizer Inc.