Efficacy and Safety of the α7-Nicotinic Acetylcholine Receptor Agonist ABT-126 in the Treatment of Cognitive Impairment Associated With Schizophrenia: Results From a Phase 2b Randomized Controlled Study in Smokers.

OBJECTIVE: To evaluate the efficacy and safety of the α7-nicotinic receptor agonist ABT-126 for treatment of cognitive impairment in stable subjects with schizophrenia who smoke. METHODS: A 12-week double-blind, placebo-controlled, parallel-group study was conducted from August 2012 to March 2014. Subjects with a diagnosis of schizophrenia based on DSM-IV-TR criteria (confirmed by the Mini-International Neuropsychiatric Interview version 6.0.0) were randomized 1:1:1 to ABT-126 25 mg, ABT-126 75 mg, or placebo once daily while maintained on their background antipsychotic medication. The primary endpoint was the change from baseline on the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery (MCCB) neurocognitive composite score; the primary analysis compared ABT-126 with placebo at week 12 using a mixed-effects model for repeated measures. Secondary endpoints included the change from baseline on the University of California San Diego Performance-based Skills Assessment-2 Extended-Range, the 16-item Negative Symptom Assessment scale (NSA-16), and safety assessments. RESULTS: Of the 157 randomized subjects, 82% completed the study. The mean baseline MCCB neurocognitive composite score for the entire study sample was 28.8; scores were similar across groups. No statistical difference in the change from baseline score between any of the ABT-126 dose groups and placebo was observed on the MCCB neurocognitive composite score (ABT-126 25 mg, +0.28; ABT-126 75 mg, +0.41; placebo, +1.42). Differences in the NSA-16 total score were seen with ABT-126 75 mg versus placebo at week 6 (-2.79; P = .011) and week 12 (-1.94; P = .053). Adverse events with ABT-126 were similar to placebo, except for constipation (5.8% for ABT-126 vs 0% for placebo). CONCLUSIONS: ABT-126 did not demonstrate a procognitive effect in subjects with stable schizophrenia who smoke. A trend for improvement in negative symptoms was observed with the high dose. The safety profile of ABT-126 was similar to placebo. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01678755​.

Preclinical abuse liability assessment of ABT-126, an agonist at the α7 nicotinic acetylcholine receptor (nAChR).

ABT-126 is a nicotinic acetylcholine receptor (nAChR) agonist that is selective for the α7 subtype of the receptor. nAChRs are thought to play a role in a variety of neurocognitive processes and have been a pharmacologic target for disorders with cognitive impairment, including schizophrenia and Alzheimer's disease. As part of the preclinical safety package for ABT-126, its potential for abuse was assessed. While the involvement of the α4ß2 subtype of the nicotinic receptor in the addictive properties of nicotine has been demonstrated, the role of the α7 receptor has been studied much less extensively. A number of preclinical assays of abuse potential including open-field, drug discrimination and self-administration were employed in male rats. ABT-126 had modest effects on locomotor activity in the open-field assay. In nicotine and d-amphetamine drug discrimination assays, ABT-126 administration failed to produce appreciable d-amphetamine-like or nicotine-like responding, suggesting that its interoceptive effects are distinct from those of these drugs of abuse. In rats trained to self-administer cocaine, substitution with ABT-126 was similar to substitution with saline, indicating that it lacks reinforcing effects. No evidence of physical dependence was noted following subchronic administration. Overall, these data suggest that ABT-126 has a low potential for abuse. Together with other literature on this drug class, it appears that drugs that selectively activate α7 nAChRs are not likely to result in abuse or dependence.

Placebo Response and Practice Effects in Schizophrenia Cognition Trials.

Importance: Patients' previous experience with performance-based cognitive tests in clinical trials for cognitive impairment associated with schizophrenia can create practice-related improvements. Placebo-controlled trials for cognitive impairment associated with schizophrenia are at risk for these practice effects, which can be difficult to distinguish from placebo effects. Objectives: To conduct a systematic evaluation of the magnitude of practice effects on the Measurement and Treatment Research to Improve Cognition in Schizophrenia Consensus Cognitive Battery (MCCB) in cognitive impairment associated with schizophrenia and to examine which demographic, clinical, and cognitive characteristics were associated with improvement in placebo conditions. Design, Setting, and Participants: A blinded review was conducted of data from 813 patients with schizophrenia who were treated with placebo in 12 randomized placebo-controlled clinical trials conducted mostly in outpatient clinics in North America, Europe, Asia, and Latin America from February 22, 2007, to March 1, 2014. A total of 779 patients provided data for the primary outcome measure at baseline and at least 1 follow-up. Seven trials had prebaseline assessments wherein the patients knew that they were not receiving treatment, allowing a comparison of practice and placebo effects in the same patients. Interventions: Placebo compared with various experimental drug treatments. Main Outcomes and Measures: Composite score on the MCCB. Results: Of the 813 patients in the study (260 women and 553 men; mean [SD] age, 41.2 [11.5] years), the mean MCCB composite score at baseline was 22.8 points below the normative mean, and the mean (SEM) total change in the MCCB during receipt of placebo was 1.8 (0.2) T-score points (95% CI, 1.40-2.18), equivalent to a change of 0.18 SD. Practice effects in the 7 studies in which there was a prebaseline assessment were essentially identical to the postbaseline placebo changes. Baseline factors associated with greater improvements in the MCCB during receipt of placebo included more depression/anxiety (F1,438 = 5.41; P = .02), more motivation (F1,272 = 4.63; P = .03), and less improvement from screening to baseline (F1,421 = 59.32; P < .001). Conclusions and Relevance: Placebo effects were minimal and associated with the number of postbaseline assessments and several patient characteristics. Given that the patients performed 2.28 SDs below normative standards on average at baseline, a mean placebo-associated improvement of less than 0.2 SD provides evidence that ceiling effects do not occur in these trials. These minimal changes in the MCCB could not be responsible for effective active treatments failing to separate from placebo.

Psychometric characteristics of the MATRICS Consensus Cognitive Battery in a large pooled cohort of stable schizophrenia patients.

The MATRICS Consensus Cognitive Battery (MCCB) was developed to assess cognitive treatment effects in schizophrenia clinical trials, and is considered the FDA gold standard outcome measure for that purpose. The aim of the present study was to establish pre-treatment psychometric characteristics of the MCCB in a large pooled sample. The dataset included 2616 stable schizophrenia patients enrolled in 15 different clinical trials between 2007 and 2016 within the United States (94%) and Canada (6%). The MCCB was administered twice prior to the initiation of treatment in 1908 patients. Test-retest reliability and practice effects of the cognitive composite score, the neurocognitive composite score, which excludes the domain Social Cognition, and the subtests/domains were examined using Intra-Class Correlations (ICC) and Cohen's d. Simulated regression models explored which domains explained the greatest portion of variance in composite scores. Test-retest reliability was high (ICC=0.88) for both composite scores. Practice effects were small for the cognitive (d=0.15) and neurocognitive (d=0.17) composites. Simulated bootstrap regression analyses revealed that 3 of the 7 domains explained 86% of the variance for both composite scores. The domains that entered most frequently in the top 3 positions of the regression models were Speed of Processing, Working Memory, and Visual Learning. Findings provide definitive psychometric characteristics and a benchmark comparison for clinical trials using the MCCB. The test-retest reliability of the MCCB composite scores is considered excellent and the learning effects are small, fulfilling two of the key criteria for outcome measures in cognition clinical trials.

The α7 Nicotinic Agonist ABT-126 in the Treatment of Cognitive Impairment Associated with Schizophrenia in Nonsmokers: Results from a Randomized Controlled Phase 2b Study.

A double-blind, placebo-controlled, parallel-group, 24-week, multicenter trial was conducted to evaluate the efficacy and safety of 3 doses of ABT-126, an α7 nicotinic receptor agonist, for the treatment of cognitive impairment in nonsmoking subjects with schizophrenia. Clinically stable subjects were randomized in 2 stages: placebo, ABT-126 25 mg, 50 mg or 75 mg once daily (stage 1) and placebo or ABT-126 50 mg (stage 2). The primary analysis was the change from baseline to week 12 on the MATRICS Consensus Cognitive Battery (MCCB) neurocognitive composite score for ABT-126 50 mg vs placebo using a mixed-model for repeated-measures. A key secondary measure was the University of California Performance-based Assessment-Extended Range (UPSA-2ER). A total of 432 subjects were randomized and 80% (344/431) completed the study. No statistically significant differences were observed in either the change from baseline for the MCCB neurocognitive composite score (+2.66 [±0.54] for ABT-126 50 mg vs +2.46 [±0.56] for placebo at week 12; P>0.05) or the UPSA-2ER. A trend for improvement was seen at week 24 on the 16-item Negative Symptom Assessment Scale total score for ABT-126 50 mg (change from baseline -4.27±[0.58] vs -3.00±[0.60] for placebo; P=0.059). Other secondary analyses were generally consistent with the primary end point results. Adverse event rates were similar for ABT-126 and placebo. ABT-126 did not demonstrate a consistent effect on cognition in nonsmoking subjects with schizophrenia; however, a trend toward an effect was observed on negative symptoms. ClincalTrials.gov registration: NCT01655680.

A Randomized Trial to Assess the Efficacy and Safety of ABT-126, a Selective α7 Nicotinic Acetylcholine Receptor Agonist, in the Treatment of Cognitive Impairment in Schizophrenia.

OBJECTIVE: The authors sought to evaluate the efficacy and safety of ABT-126, a selective α7 nicotinic receptor partial agonist, in stable patients with schizophrenia. METHOD: A 12-week, double-blind, placebo-controlled, parallel-group phase 2 study was conducted in 22 centers in the United States. Clinically stable patients with schizophrenia were randomly assigned to receive once-daily dosing with 10 mg of ABT-126, 25 mg of ABT-126, or placebo. The primary efficacy measure was change from baseline to week 12 on the MATRICS Consensus Cognitive Battery (MCCB) composite score compared with placebo, tested by a one-sided t test. Secondary measures included MCCB domain scores and UCSD Performance-Based Skills Assessment total score, each tested by two-sided t tests. RESULTS: A total of 207 subjects were randomized, of whom 165 (81%) completed the study. ABT-126 showed an improvement that fell short of significance on the MCCB composite score at week 12 (least squares mean difference from placebo, 1.3 and 1.5 for the 10 mg and 25 mg groups, respectively). A significant treatment-by-smoking status interaction was observed on the mean change from baseline to final MCCB composite score: nonsmokers (N=69) demonstrated a difference from placebo of 2.9 (SE=1.4) in the 10 mg group and 5.2 (SE=1.6) in the 25 mg group, whereas no differences were observed in smokers (N=113). Among the nonsmokers in the ABT-126 25 mg group (N=19), significant improvements compared with placebo occurred at final assessment for verbal learning (least squares mean difference=5.5, SE=1.9), working memory (least squares mean difference=5.4, SE=2.0), and attention/vigilance (least squares mean difference=8.7, SE=2.5). The most frequently reported adverse events for ABT-126 were dizziness, diarrhea, and fatigue (all <8% incidence). CONCLUSIONS: ABT-126 demonstrated a procognitive effect in nonsmoking subjects, particularly in verbal learning, working memory, and attention.

Report on ISCTM Consensus Meeting on Clinical Assessment of Response to Treatment of Cognitive Impairment in Schizophrenia.

If treatments for cognitive impairment are to be utilized successfully, clinicians must be able to determine whether they are effective and which patients should receive them. In order to develop consensus on these issues, the International Society for CNS Clinical Trials and Methodology (ISCTM) held a meeting of experts on March 20, 2014, in Washington, DC. Consensus was reached on several important issues. Cognitive impairment and functional disability were viewed as equally important treatment targets. The group supported the notion that sufficient data are not available to exclude patients from available treatments on the basis of age, severity of cognitive impairment, severity of positive symptoms, or the potential to benefit functionally from treatment. The group reached consensus that cognitive remediation is likely to provide substantial benefits in combination with procognitive medications, although a substantial minority believed that medications can be administered without nonpharmacological therapy. There was little consensus on the best methods for assessing cognitive change in clinical practice. Some participants supported the view that performance-based measures are essential for measurement of cognitive change; others pointed to their cost and time requirements as evidence of impracticality. Interview-based measures of cognitive and functional change were viewed as more practical, but lacking validity without informant involvement or frequent contact from clinicians. The lack of consensus on assessment methods was viewed as attributable to differences in experience and education among key stakeholders and significant gaps in available empirical data. Research on the reliability, validity, sensitivity, and practicality of competing methods will facilitate consensus.

Circadian rhythms in cognitive functioning among patients with schizophrenia: impact on signal detection in clinical trials of potential pro-cognitive therapies.

OBJECTIVE: Cognition is affected by circadian rhythms over the course of a day. Circadian rhythms in cognitive functioning are driven by a variety of both endogenous and exogenous factors. Patients with schizophrenia are known to have disturbed circadian rhythms that can affect their cognitive functioning. We examined the impact of time of day on cognitive test scores from subjects participating in clinical trials of potential pro-cognitive therapies for schizophrenia and then explored how this diurnal variation affected signal detection. METHOD: Baseline data from 8 separate schizophrenia clinical trials using the MATRICS Consensus Cognitive Battery (MCCB) were aggregated (Total N=2032). The MCCB assessments were divided into five 2-hour time intervals based on the start-time of the assessments (varying from 8:00 am to 5:59 pm) and then analyzed for differences by time interval. Next, data from two Phase 2 schizophrenia clinical trials of potential pro-cognitive therapies were analyzed to explore the impact of this diurnal variation on placebo separation. RESULTS: Time of day exerted a significant effect on baseline composite MCCB scores (p=.002). Follow-up comparisons revealed significant differences among multiple temporal epochs. In both Phase 2 clinical trials, subjects whose cognitive functioning was assessed at consistent times of day between their baseline and endpoint visits showed a more robust treatment response as compared to subjects assessed at inconsistent times of day. CONCLUSION: Cognitive functioning ebbs and flows over the course of the day. Maintaining consistency in the time of day of cognitive test administrations between visits can help to reduce the noise introduced by circadian rhythms, thereby enhancing signal detection in clinical trials of potential pro-cognitive therapies.

A randomized study of H3 antagonist ABT-288 in mild-to-moderate Alzheimer's dementia.

BACKGROUND: ABT-288, a highly selective histamine-3 receptor antagonist, demonstrated efficacy across several preclinical cognitive domains, and safety in healthy subjects and elderly volunteers. OBJECTIVE: Evaluate the efficacy and safety of ABT-288 in subjects with mild-to-moderate Alzheimer's dementia. METHODS: The study used a randomized, double-blind, placebo- and active-controlled, parallel group design with pre-defined futility criteria to permit early study termination. A total of 242 subjects were randomized in an equal ratio to ABT-288 1 mg or 3 mg, donepezil 10 mg, or placebo once daily for 12 weeks. The primary efficacy endpoint was the change from baseline to final evaluation on the 13-item Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-Cog) total score. RESULTS: The study was prematurely terminated because futility criteria were met. Point estimates on the ADAS-Cog scores for both ABT-288 dose groups were numerically inferior to placebo but no statistical differences were detected. Donepezil demonstrated statistically significant improvement. Adverse events were generally mild and self-limiting. CONCLUSION: ABT-288 did not demonstrate efficacy in the symptomatic treatment of Alzheimer's dementia.

A randomized trial of the efficacy and safety of the H3 antagonist ABT-288 in cognitive impairment associated with schizophrenia.

INTRODUCTION: ABT-288 is a highly potent histamine-3 receptor antagonist that has demonstrated pro-cognitive effects in preclinical models relevant to schizophrenia. This study evaluated the efficacy and safety of two doses of ABT-288 in the treatment of cognitive impairment associated with schizophrenia. METHODS: A randomized, double-blind, placebo-controlled, parallel-group 12-week study was conducted at 23 centers in the United States. Clinically stable subjects with schizophrenia were randomized in an equal ratio to ABT-288 10 mg, ABT-288 25 mg, or placebo once daily while continuing their antipsychotic regimen. The primary efficacy measure was the change from baseline to day 84 evaluation on the Measurement and Treatment Research to Improve Cognition in Schizophrenia Consensus Cognitive Battery (MCCB) composite score vs placebo. Secondary measures included cognitive functioning and psychiatric scales. Safety assessments and sparse pharmacokinetic sampling were also conducted. RESULTS: A total of 214 subjects were randomized. The mean baseline MCCB composite score was 28.4. Approximately 80% of subjects completed the study. The MCCB composite score mean change from baseline to day 84 was numerically worse for both the 10 mg (1.90, P = .618) and 25 mg (0.64, P = .946) doses of ABT-288 vs placebo (2.19). Results from the secondary measures were consistent with the primary analysis. Subjects' schizophrenia symptoms remained stable throughout the study as evidenced by stable Positive and Negative Syndrome Scale scores. Overall, study medication was tolerated; however, an increased incidence of psychosis-related and sleep-related adverse events was associated with ABT-288. DISCUSSION: Neither dose of ABT-288 resulted in cognitive improvement in clinically stable adults with schizophrenia.

The H3 antagonist ABT-288 is tolerated at significantly higher exposures in subjects with schizophrenia than in healthy volunteers.

AIMS: ABT-288 is a potent and selective H3 receptor antagonist with procognitive effects in several preclinical models. In previous studies, 3 mg once daily was the maximal tolerated dose in healthy volunteers. This study characterized the safety, tolerability and pharmacokinetics of ABT-288 in stable subjects with schizophrenia. METHODS: This was a randomized, double-blind, placebo-controlled, dose-escalating study of ABT-288 (10 dose levels, from 1 to 60 mg once daily for 14 days) in stable subjects with schizophrenia treated with an atypical antipsychotic. In each dose group, five to seven and two to three participants were assigned to ABT-288 and placebo, respectively. RESULTS: Of the 67 participants enrolled, nine participants (on ABT-288) were prematurely discontinued, in seven of these due to adverse events. ABT-288 was generally safe and tolerated at doses up to 45 mg once daily. The most common adverse events, in decreasing frequency (from 31 to 5%), were abnormal dreams, headache, insomnia, dizziness, somnolence, dysgeusia, dry mouth, psychotic disorder, parosmia and tachycardia. Adverse events causing early termination were psychotic events (four) and increased creatine phosphokinase, pyrexia and insomnia (one each). The half-life of ABT-288 ranged from 28 to 51 h, and steady state was achieved by day 12 of dosing. At comparable multiple doses, ABT-288 exposure in subjects with schizophrenia was 45% lower than that previously observed in healthy subjects. At trough, ABT-288 cerebrospinal fluid concentrations were 40% of the total plasma concentrations. CONCLUSIONS: ABT-288 was tolerated at a 15-fold higher dose and 12-fold higher exposures in subjects with schizophrenia than previously observed in healthy volunteers. The greater ABT-288 tolerability was not due to limited brain uptake.

Safety, tolerability and pharmacokinetics of the histamine H3 receptor antagonist, ABT-288, in healthy young adults and elderly volunteers.

AIM: The objective of this work was to characterize the safety, tolerability and pharmacokinetics of ABT-288, a highly selective histamine H3 receptor antagonist, in healthy young adults and elderly subjects following single and multiple dosing in a phase 1 setting. METHODS: Single doses (0.1, 0.3, 1, 3, 10, 20 and 40 mg ABT-288) and multiple doses (0.5, 1.5, 3 and 6 mg ABT-288 once-daily for 14 days) were evaluated in young adults and multiple doses (0.5, 1.5, 3 and 5 mg ABT-288 once-daily for 12 days) were evaluated in elderly subjects using randomized, double-blind, placebo-controlled, dose-escalating study designs. The effect of food on ABT-288 pharmacokinetics (5 mg single dose) was evaluated using an open label, randomized, crossover design. RESULTS: ABT-288 safety, tolerability and pharmacokinetics were comparable in young and elderly subjects. Single doses up to 40 mg and multiple doses up to 3 mg once-daily were generally safe and well tolerated. The most frequently reported adverse events were hot flush, headache, abnormal dreams, insomnia, nausea and dizziness. ABT-288 exposure (AUC) was dose-proportional over the evaluated dose ranges. The mean elimination half-life ranged from 40 to 61 h across dose groups. Steady state was achieved by day 10 of once-daily dosing with 3.4- to 4.2-fold accumulation. Food did not have a clinically meaningful effect on ABT-288 exposure. CONCLUSIONS: Based on the above results, 1 and 3 mg once-daily doses of ABT-288 were advanced to phase 2 evaluation in Alzheimer's patients.

Evaluation of the subjective and reinforcing effects of diphenhydramine, levetiracetam, and valproic acid.

Few unscheduled sedating medications have been evaluated for their subjective and reinforcing effects in humans. To increase the information available about unscheduled sedating medications and to evaluate the ability of human laboratory measures to discriminate between scheduled and unscheduled sedating drugs, 24 subjects with a history of experience with several classes of drugs of abuse, including sedatives and/or alcohol, and who reported liking a test dose of pentobarbital 300 mg, were randomized to single doses of diphenhydramine 400 mg, levetiracetam 4000 mg, valproic acid 1500 mg, diazepam 30 mg or placebo in a double-blind, 5-way crossover study. On the Addiction Research Center Inventory-Morphine-Benzedrine Group and the Next Day Questionnaire measures 'Take Again' and 'Willing to Pay', diazepam produced a significantly greater effect than placebo; all three other active drugs did not. Levetiracetam significantly increased the crossover point on the Multiple Choice Procedure, whereas diazepam did not. For the doses studied, the rank order of statistically significant findings suggestive of abuse potential was diazepam (9/10 measures significant) > levetiracetam (6/10) > diphenhydramine (5/10) > valproic acid (2/10).

Clinical pharmacokinetics of pregabalin in healthy volunteers.

Pregabalin has shown clinical efficacy for treatment of neuropathic pain syndromes, partial seizures, and anxiety disorders. Five studies in healthy volunteers are performed to investigate single- and multiple-dose pharmacokinetics of pregabalin. Pregabalin is rapidly absorbed following oral administration, with peak plasma concentrations occurring between 0.7 and 1.3 hours. Pregabalin oral bioavailability is approximately 90% and is independent of dose and frequency of administration. Food reduces the rate of pregabalin absorption, resulting in lower and delayed maximum plasma concentrations, yet the extent of drug absorption is unaffected, suggesting that pregabalin may be administered without regard to meals. Pregabalin elimination half-life is approximately 6 hours and steady state is achieved within 1 to 2 days of repeated administration. Corrected for oral bioavailability, pregabalin plasma clearance is essentially equivalent to renal clearance, indicating that pregabalin undergoes negligible nonrenal elimination. Pregabalin demonstrates desirable, predictable pharmacokinetic properties that suggest ease of use. Because pregabalin is eliminated renally, renal function affects its pharmacokinetics.

Exposure-response analysis in patients with schizophrenia to assess the effect of asenapine on QTc prolongation.

An exposure-response (E-R) analysis using linear mixed effects modeling was conducted on data from a thorough QTc trial for asenapine in 148 patients with schizophrenia. In a parallel design, patients received asenapine 5 mg twice daily (BID) for 10 days (10d) followed by 10 mg BID (6d), asenapine 15 mg BID (10d) followed by 20 mg BID (6d), quetiapine 375 mg BID (for assay sensitivity; 16d) or placebo (16d). Triplicate 12-lead electrocardiograms and concentration measurements were obtained on day -1 (baseline), 1, 10, and 16 at 8 scheduled times on each day. At mean C(max) for all asenapine doses, the E-R model predicted that the mean QTcF increase was less than 5 milliseconds, the International Conference on Harmonisation-established threshold for clinical concern. The model predicted a mean increase of 7 to 8 milliseconds for quetiapine. The corresponding upper bounds of the 95% confidence intervals were 7.5 milliseconds and 11.2 milliseconds for asenapine and quetiapine, respectively.

Preliminary effects of pagoclone, a partial GABA(A) agonist, on neuropsychological performance.

Pagoclone is a novel cyclopyrrolone that acts as a partial GABA(A) receptor agonist. Preclinical studies suggest that pagoclone may have clinical utility as an anxiolytic agent, as well as a reduced incidence of side-effects. The present study was conducted to determine whether pagoclone would affect healthy individuals' performances on neuropsychological measures as a function of dose within the projected therapeutic range. Twelve healthy adult subjects were randomly assigned to dosage groups in a 3-way crossover study. Participants were administered neuropsychological measures six hours following dosing on Day 1 and Day 6 of administration of the drug. Dose effects were noted on measures of alertness, learning, and memory and movement time. Significant effects were also noted on measures of alertness, learning and memory, information processing and psychomotor speed. Overall, the results of this small, preliminary study do not support a finding of behavioral toxicity for these doses of pagoclone. Rather, a pattern was found of transient and mild negative effects on learning and memory scores at the highest dose administered, though these changes were small and no longer evident by the sixth day of use.

A 14-week, randomized, double-blinded, placebo-controlled monotherapy trial of pregabalin in patients with fibromyalgia.

UNLABELLED: The purpose of the study was to assess the efficacy and safety of pregabalin monotherapy in patients with fibromyalgia in a randomized, double-blinded, placebo-controlled trial. After 1 week of single-blinded administration of placebo, 750 patients meeting American College of Rheumatology criteria for fibromyalgia were randomly assigned to pregabalin (300 mg/d, 450 mg/d, 600 mg/d) or placebo, administered twice daily for 14 weeks. The primary outcome variable was comparison of end point mean pain scores, derived from daily diary ratings of pain intensity (0 to 10 scale), between each of the pregabalin groups and the placebo group. If positive, additional primary efficacy parameters included the Patient Global Impression of Change (PGIC) and the Fibromyalgia Impact Questionnaire (FIQ) total score. Compared with placebo-treated patients, mean changes in pain scores at the end point in pregabalin-treated patients were significantly greater (P < .001: 300 mg/d, -0.71; 450 mg/d, -0.98; 600 mg/d, -1.00). Compared with placebo, significantly more pregabalin-treated patients reported improvement on PGIC (P < .01 for all 3 pregabalin doses) and significant improvements in total FIQ score for the 450 mg/d (P = .004) and the 600 mg/d (P = .003) doses. Compared with placebo, all 3 doses of pregabalin were associated with significant improvement in sleep. The most commonly reported pregabalin-related adverse events were dizziness and somnolence, which tended to be dose-related. PERSPECTIVE: This randomized, placebo-controlled trial of 300, 450, and 600 mg/d of pregabalin monotherapy demonstrated that all 3 doses were efficacious for up to 14 weeks for the treatment of fibromyalgia and were well tolerated by most patients. These results provide evidence that pregabalin is an important treatment option for patients with fibromyalgia.

Fibromyalgia relapse evaluation and efficacy for durability of meaningful relief (FREEDOM): a 6-month, double-blind, placebo-controlled trial with pregabalin.

This was a multicenter, double-blind (DB), placebo-controlled, randomized discontinuation trial to evaluate the efficacy of pregabalin monotherapy for durability of effect on fibromyalgia (FM) pain. The trial included a 6-week open-label (OL) pregabalin-treatment period followed by 26-week DB treatment with placebo or pregabalin. Adults with FM and 40-mm score on 100-mm pain visual analog scale (VAS) were eligible. During OL weeks 1-3, patients received escalating dosages of pregabalin to determine their optimal dosages. During OL weeks 4-6, patients received their optimal fixed dosages (300, 450, 600mg/d). To be randomized, patients must have had 50% decrease in pain VAS and a self-rating of "much" or "very much" improved on Patient Global Impression of Change (PGIC) at the end of OL. Double-blind treatment was with placebo or the patient's optimal fixed dosage of pregabalin. Primary outcome was time to loss of therapeutic response (LTR), defined as <30% reduction in pain (from OL baseline) or worsening of FM. A total of 1051 patients entered OL; 287 were randomized to placebo, 279 to pregabalin. Time to LTR was longer for pregabalin versus placebo (P<.0001). Kaplan-Meier estimates of time-to-event showed half the placebo group had LTR by Day 19; half the pregabalin group still had not lost response by trial end. At the end of DB, 174 (61%) placebo patients met LTR criteria versus 90 (32%) pregabalin patients. Pregabalin was well tolerated, though 178 (17%) discontinued during OL for treatment-related adverse events (AE), and more pregabalin than placebo patients discontinued for AEs during DB. In those who respond, pregabalin demonstrated durability of effect for relieving FM pain.

Evaluation of the abuse potential of pagoclone, a partial GABAA agonist.

This study assessed the abuse potential of pagoclone, a partial agonist at the gamma-aminobutyric acid type A (GABAA) benzodiazepine receptor site, in healthy recreational drug users. Twenty-three young adults, who reported past recreational use of sedative drugs or alcohol, participated in 4 sessions during which capsules containing pagoclone (doses: 1.2 mg, the higher end of the proposed therapeutic dose range, and 4.8 mg, a 4-fold higher dose), diazepam (dose, 30 mg), or placebo were randomly administered under double-blind conditions. Subjective ratings of mood, drug effects, and psychomotor tests were completed at regular intervals after ingesting the capsules. On most of the standardized measures of abuse potential, pagoclone (dose, 4.8 mg) was rated as being similar to diazepam. Both drugs increased the ratings of good effects and drug liking. However, pagoclone also produced some adverse mood effects that might limit its potential to be used recreationally, and it produced fewer sedativelike effects on some measures. In general, the results with these doses indicate that the abuse potential of pagoclone is similar to that of diazepam, although its profile as a partial agonist suggests that differences between the drugs may emerge at higher doses.