Lynne Pauer

Pregabalin rectifies aberrant brain chemistry, connectivity, and functional response in chronic pain patients.

Background:Chronic pain remains a significant challenge for modern health care as its pathologic mechanisms are largely unknown and preclinical animal models suffer from limitations in assessing this complex subjective experience. However, human brain neuroimaging techniques enable the assessment of functional and neurochemical alterations in patients experiencing chronic pain and how these factors may dynamically change with pharmacologic treatment. Methods:To identify the clinical action of pregabalin, a proven analgesic, the authors performed three complementary brain neuroimaging procedures: (proton magnetic resonance spectroscopy, functional magnetic resonance imaging, and functional connectivity magnetic resonance imaging) in 17 chronic pain patients diagnosed with fibromyalgia. Results:The authors found that pregabalin but not placebo reduces combined glutamate + glutamine levels within the posterior insula (pregabalin P = 0.016; placebo P = 0.71). Interestingly, reductions in clinical pain were associated with reductions in brain connectivity of this structure to brain regions within the default mode network during pregabalin (r = 0.82; P = 0.001) but not placebo (r = −0.13; P = 0.63). Response of default mode network regions to experimental pain was also reduced with pregabalin (P = 0.018) but not placebo (P = 0.182). Perhaps most importantly, baseline values for all three neuroimaging markers predicted subsequent analgesic response to pregabalin but not placebo. Conclusions:The results of this study suggest that pregabalin works in part by reducing insular glutamatergic activity, leading to a reduction of the increased functional connectivity seen between brain regions in chronic pain states. The study also supports a role for human brain imaging in the development, assessment, and personalized use of central-acting analgesics.

Efficacy and safety of pregabalin in elderly people with generalised anxiety disorder.

BACKGROUND Pregabalin is a novel compound that has been shown to have efficacy in the treatment of generalised anxiety disorder and is licensed for the treatment of the disorder in the European Union. AIMS The current study was designed to evaluate the safety and efficacy of pregabalin, an alpha(2)delta-ligand, in the treatment of generalised anxiety disorder in people 65 years and older. METHOD This was a double-blind, randomised (2:1), placebo-controlled, 8-week trial of pregabalin, in flexible doses of 150-600 mg/day, in the treatment of DSM-IV generalised anxiety disorder with a baseline Hamilton Rating Scale for Anxiety (HRSA) total score >/=20. The primary outcome was end-point (week 8 or last visit, with last observation carried forward (LOCF)) change in HRSA total score. RESULTS A total of 273 patients (women, 78%; mean age, 72 years (s.d.=6); mean baseline HRSA total score, 26 (s.d.=4.6)) were randomised and received study treatment. On the primary intent-to-treat LOCF analysis, pregabalin was associated with a 2-point greater reduction in HRSA total score than placebo (12.87 v. 10.7; P<0.05). In a post hoc repeated measures mixed-effect model analysis, pregabalin was associated with significantly greater improvement than placebo in the HRSA total score from week 2 (-9.8 (s.d.=0.6) v. -7.2 (s.d.=0.8); P=0.0052) through week 8 (-14.4 (s.d.=0.6) v. -11.6 (s.d.=0.8); P=0.0070). Significant improvement was observed in the pregabalin group on both the HRSA psychic and somatic anxiety factors. There was a significantly greater decrease from baseline in mean Hamilton Rating Scale for Depression (HRSD) score with pregabalin compared with placebo (-5.48 (s.d.=0.46) v. -4.02 (s.d.=0.59); P=0.041). Pregabalin was well-tolerated, with almost all adverse events in the mild-to-moderate range, and self-limiting (median duration of 4-16 days). Discontinuations due to adverse events were similar for pregabalin (10.7%) and placebo (9.4%). CONCLUSIONS Pregabalin, in doses of 150-600 mg/day, was a safe and effective treatment of generalised anxiety disorder in patients 65 years and older. The anxiolytic efficacy of pregabalin had an early onset (by 2 weeks) and significantly improved both psychic and somatic symptoms of anxiety.

An International, Randomized, Double-blind, Placebo-controlled, Phase III Trial of Pregabalin Monotherapy in Treatment of Patients with Fibromyalgia

Objective. To evaluate the efficacy and safety of pregabalin monotherapy versus placebo for symptomatic pain relief and improvement of patient global assessment in patients with fibromyalgia (FM) enrolled from countries outside the United States. Methods. This international, multicenter, double-blind, placebo-controlled trial randomly assigned 747 patients with FM to placebo or 300, 450, or 600 mg/day pregabalin twice daily for 14 weeks. Primary efficacy measures were endpoint mean pain scores and Patient Global Impression of Change (PGIC). Secondary outcomes included assessments of sleep and function. Results. Patients in the 450 mg/day pregabalin group showed significant improvements versus placebo in endpoint mean pain score (−0.56; p = 0.0132), PGIC (73% improved vs 56% placebo; p = 0.0017), and function [Fibromyalgia Impact Questionnaire (FIQ) total score −5.85; p = 0.0012]. PGIC was also significant for 600 mg/day pregabalin (69% improved; p = 0.0227). Results for these endpoints were nonsignificant for pregabalin at 300 mg/day and for pain and FIQ score at 600 mg/day. Early onset of pain relief was seen, with separation from placebo detected by Week 1 in all pregabalin groups. All pregabalin doses demonstrated superiority to placebo on the Medical Outcomes Study-Sleep Scale Sleep Disturbance subscale and the Sleep Quality diary. Dizziness and somnolence were the most frequently reported adverse events. Conclusion. Pregabalin demonstrated modest efficacy in pain, global assessment, and function in FM at 450 mg/day, and improved sleep across all dose levels, but it did not provide consistent evidence of benefit at 300 and 600 mg/day in this study. Pregabalin was generally well tolerated for the treatment of FM. (Clinical trial registry NCT00333866).

Safety Profile and Tolerability of Up to 1 Year of Pregabalin Treatment in 3 Open-Label Extension Studies in Patients With Fibromyalgia

BACKGROUND Pain relief and an acceptable safety profile have been reported in randomized controlled trials (RCTs) of pregabalin in the treatment of fibromyalgia (FM) for up to 14 weeks. OBJECTIVE To evaluate the safety profile and tolerability of pregabalin (75-300 mg BID) treatment for up to 1 year in patients with FM. METHODS Twelve-week data were pooled from 3 open-label extension studies of pivotal RCTs. Study 1 was a 1-year extension of a 13-week RCT, and studies 2 and 3 were 12-week extensions of 14-week RCTs. The 1-year data were separately evaluated. The open-label data are summarized using descriptive statistics. RESULTS Overall, 1206 patients (92.4% female) with a mean (SD) age of 48.8 (10.7) years received open-label extended pregabalin treatment. A total of 119 of 1206 patients (9.9%) permanently discontinued study participation due to treatment-emergent adverse events (all causality) at 12 weeks (pooled data) and 53 of 429 (12.4%) within 1 year. Consistent with previous RCTs, the most commonly reported treatment-emergent adverse events with open-label pregabalin treatment were dizziness, somnolence, headache, peripheral edema, and increased weight. The highest incidence rates in the pooled 12-week data were for dizziness (214 of 1206; 17.7%) and somnolence (96 of 1206; 8.0%). In ratings of severity (mild, moderate, severe), most were reported as mild to moderate. The mean (SD) change in patient-reported visual analog scale pain scores (0-100) from the open-label baseline to the end of treatment was -21 (30.5) in study 1 (1 year), -26.7 (28.8) in study 2 (12 weeks), and -20.1 (26.8) in study 3 (12 weeks). CONCLUSIONS The data from these extension studies suggest that the adverse event safety profile and tolerability of patients with FM treated with open-label pregabalin (75-300 mg BID) for up to 1 year were stable and were consistent with those of previous studies. ClinicalTrials.gov identifiers: NCT00151528 (A0081057 [study 1]), NCT00282997 (A0081078 [study 2]), and NCT00346034 (A0081101 [study 3]).

Efficacy and Safety of Pregabalin in Patients with Fibromyalgia and Comorbid Depression Taking Concurrent Antidepressant Medication: A Randomized, Placebo-controlled Study

Objective. To assess pregabalin efficacy and safety in patients with fibromyalgia (FM) with comorbid depression taking concurrent antidepressant medication. Methods. This randomized, placebo-controlled, double-blind, 2-period, 2-way crossover study was composed of two 6-week treatment periods separated by a 2-week taper/washout phase. Patients with FM (aged ≥ 18 yrs) taking a stable dose of a selective serotonin reuptake inhibitor (SSRI) or a serotonin/norepinephrine reuptake inhibitor (SNRI) for depression were randomized 1:1 to receive pregabalin/placebo or placebo/pregabalin (optimized to 300 or 450 mg/day). Antidepressant medication was continued throughout the study. The primary efficacy outcome was the mean pain score on an 11-point numerical rating scale. Secondary efficacy outcomes included measures of anxiety, depression, patient function, and sleep. Results. Of 197 patients randomized to treatment, 181 and 177 received ≥ 1 dose of pregabalin and placebo, respectively. At baseline, 52.3% of patients were taking an SSRI and 47.7% an SNRI, and mean pain score was 6.7. Mean pain scores at endpoint were statistically significantly reduced with pregabalin (least squares mean difference from placebo −0.61, 95% CI −0.91 – −0.31, p = 0.0001). Pregabalin significantly improved Hospital Anxiety and Depression Scale-Anxiety (difference −0.95, p < 0.0001) and -Depression (difference −0.88, p = 0.0005) scores, Fibromyalgia Impact Questionnaire total score (difference −6.60, p < 0.0001), and sleep quality (difference 0.57, p < 0.0001), but not EuroQol 5-Dimensions score (difference 0.02, p = 0.3854). Pregabalin safety was consistent with previous studies and current product labeling. Conclusion. Compared with placebo, pregabalin statistically significantly improved FM pain and other symptoms in patients taking antidepressant medication for comorbid depression. ClinicalTrials.gov identifier: NCT01432236.

Long-term Maintenance of Response Across Multiple Fibromyalgia Symptom Domains in a Randomized Withdrawal Study of Pregabalin

Objective: To determine the incidence and duration of response of clinically meaningful improvements with pregabalin across several key symptoms of fibromyalgia (FM). Methods: This was a post hoc analysis of data from a multicenter, double-blind, placebo-controlled, randomized, withdrawal study, originally designed to evaluate the efficacy of pregabalin monotherapy for durability of effect on FM pain based on pain and Patient Global Impression of Change (PGIC) criteria. Responder criteria for Fibromyalgia Impact Questionnaire total score (≥16-point change), Medical Outcomes Study Sleep Scale Sleep Disturbance subscale (≥15.8-point change), and the 36-item Short-Form Health Survey Vitality scale (≥10-point change) were used to evaluate the incidence and duration of improvements in function, sleep, and fatigue for pregabalin versus placebo among pain and PGIC responders. A composite responder index consisting of pain, PGIC, function, and sleep endpoints was used to explore multidimensional response. Results: Approximately 80% of patients meeting pain and PGIC improvement criteria at randomization had clinically meaningful improvement in fatigue, sleep, or function. Higher proportions of patients in the pregabalin group maintained a clinically meaningful response, and pregabalin-treated patients had a significantly longer time to loss of therapeutic response compared with the placebo group. Composite responder Kaplan-Meier analysis, performed with patients demonstrating clinically meaningful improvements in pain, PGIC, function, and sleep at randomization showed a significantly longer median time to loss of therapeutic response for pregabalin-treated patients. Discussion: The results from this post hoc analysis indicate that pregabalin provides long-term effects across multiple domains of FM (ClinicalTrials.gov registry ID: NCT00151489).

Pregabalin in patients with inadequately treated painful diabetic peripheral neuropathy: a randomized withdrawal trial.

Objectives:This study used a randomized withdrawal design to evaluate the efficacy of pregabalin versus placebo for pain relief in patients with painful diabetic peripheral neuropathy inadequately treated by other therapies. Methods:A total of 665 patients received pregabalin in a 6-week single-blind phase. Two hundred ninety-four patients who achieved a ≥30% pain response were randomized to receive pregabalin or placebo in a double-blind phase for a further 13 weeks. The primary endpoint was the change in mean pain score from single-blind baseline to double-blind endpoint for pregabalin versus placebo (last observation carried forward [LOCF]). Secondary endpoints included a baseline observation carried forward (BOCF) analysis of mean pain score; time to loss of pain response; and other assessments of pain, sleep, function, and quality of life (QOL). Results:Pregabalin numerically improved all measures assessed during the single-blind phase. At the end of the double-blind withdrawal phase, there was no significant difference in the primary endpoint of mean pain score (LOCF) between pregabalin and placebo (least squares mean difference, −0.32), although there was a significant difference in the BOCF analysis (least squares mean difference, −0.51). Pregabalin was associated with a significantly longer time to loss of pain response versus placebo during double-blind treatment, and some aspects of sleep and QOL also showed significant improvements with pregabalin. Discussion:This is the first reported placebo-controlled trial of pregabalin in patients with inadequately treated painful diabetic peripheral neuropathy. Although the primary endpoint was not met, pregabalin was associated with clinically relevant improvements versus placebo in this difficult-to-treat population.

Once daily controlled-release pregabalin in the treatment of patients with fibromyalgia: a phase III, double-blind, randomized withdrawal, placebo-controlled study

Abstract Objective: Safety and efficacy of a once daily controlled-released (CR) formulation of pregabalin was evaluated in patients with fibromyalgia using a placebo-controlled, randomized withdrawal design. Research design and methods: This multicenter study included 6 week single-blind pregabalin CR treatment followed by 13 week double-blind treatment with placebo or pregabalin CR. The starting dose of 165 mg/day was escalated during the first 3 weeks, up to 495 mg/day based on efficacy and tolerability. Patients with ≥50% reduction in average daily pain score at the end of the single-blind phase were randomized to continue pregabalin CR at the optimized dose (330–495 mg/day) or to placebo. The primary endpoint was time to loss of therapeutic response (LTR), defined as <30% pain reduction relative to single-blind baseline or discontinuation owing to lack of efficacy or adverse event (AE). Secondary endpoints included measures of pain severity, global assessment, functional status, tiredness/fatigue, and sleep. Clinical trial registration: ClinicalTrials.gov identifier: NCT01271933. Results: A total of 441 patients entered the single-blind phase, and 63 were randomized to pregabalin CR and 58 to placebo. The median time to LTR (Kaplan–Meier analysis) was significantly longer in the pregabalin CR group than placebo (58 vs. 22 days, p = 0.02). By trial end, 34/63 (54.0%) pregabalin CR and 41/58 (70.7%) placebo patients experienced LTR. Significantly more patients reported ‘benefit from treatment’ (Benefit, Satisfaction, and Willingness to Continue Scale) in the pregabalin CR group; no other secondary endpoints were statistically significant. Most AEs were mild to moderate in severity (most frequent: dizziness, somnolence). The percentage of pregabalin CR patients discontinuing because of AEs was 12.2% and 4.8% in the single-blind and double-blind phases, respectively (placebo, 0%). Conclusions: Time to LTR was significantly longer with pregabalin CR versus placebo in fibromyalgia patients who initially showed improvement with pregabalin CR, indicating maintenance of response. Pregabalin CR was well tolerated in most patients. Generalizability may be limited by study duration and selective population.

Exposure‐Response Analyses of the Effects of Pregabalin in Patients With Fibromyalgia Using Daily Pain Scores and Patient Global Impression of Change

Data from 4 phase 2/3 studies were pooled to characterize the exposure response of daily pregabalin (150–600 mg) in patients with fibromyalgia using self‐assessed daily pain scores (PAIN) and end‐of‐treatment patient global impression of change (PGIC). The exposure responses of both endpoints were characterized by an Emax model using nonlinear mixed‐effects modeling (NONMEM). Drug effect on PAIN relative to placebo was significant with additional maximum effect of 1.51 points on the logit scale and EC50 of 1.54 ng/mL (dose of 174 mg) and a rapid onset (half‐life of 11 hours), consistent with the half‐life of the drug. The decrease in PAIN with placebo occurred more slowly, reaching maximum response (1.52 points on the logit scale) after 1 month. Drug response in fibromyalgia was dependent on age and sex, with greater PAIN reduction in older patients, in addition to the effect of creatinine clearance, and in females. For PGIC, administration of pregabalin resulted in an increase in the proportion of patients reporting improvement with an ED50 of 228 mg. The analyses support the recommended dose of pregabalin in patients with fibromyalgia of 300 to 450 mg/d.

Efficacy and safety of pregabalin in the treatment of patients with painful diabetic peripheral neuropathy and pain on walking

Objectives:This randomized, double-blind, placebo-controlled, multicenter, 2-period crossover study (two 6-week treatment periods separated by a 2-week washout period) evaluated the efficacy and safety of pregabalin (150 to 300 mg/d) for treatment of pain and pain on walking in patients with painful diabetic peripheral neuropathy (DPN) who experienced pain while walking. Methods:Co-primary efficacy endpoints were: (1) mean pain score (last 7 daily pain diary scores, 0 to 10 numeric rating scale at end of each treatment period) and (2) DPN pain on walking (0 to 10 numeric rating scale immediately after walking 50 feet [15.2 m] on flat surface). Secondary endpoints included other pain parameters, patient-reported sleep, health-related quality of life, and safety measures. Results:Two hundred three patients were treated (pregabalin, n=198; placebo, n=186), with no statistically significant treatment difference for pregabalin versus placebo in the co-primary efficacy endpoints, mean DPN pain (P=0.0656) and mean DPN pain on walking (P=0.412). A carryover effect was observed. Analysis of co-primary endpoints for period 1 showed significant treatment difference for DPN pain (P=0.034) and DPN pain on walking (P=0.001). Treatment with pregabalin resulted in significant improvements versus placebo on prespecified patient global impression of change (end of period 1; P=0.002), and sleep interference rating scale (end of period 2; P=0.011). Adverse events were more frequent with pregabalin than with placebo and caused discontinuation in 13 (6.6%) pregabalin patients versus 5 (2.7%) placebo patients. Discussion:Failure to meet the co-primary objectives may be related to carryover effect from period 1 to period 2, lower pregabalin dose (150 to 300 mg/d), and/or placebo response in painful DPN.