Adaptive, dose-finding phase 2 trial evaluating the safety and efficacy of ABT-089 in mild to moderate Alzheimer disease.

ABT-089, an α4ß2 neuronal nicotinic receptor partial agonist, was evaluated for efficacy and safety in mild to moderate Alzheimer disease patients receiving stable doses of acetylcholinesterase inhibitors. This phase 2 double-blind, placebo-controlled, proof-of-concept, and dose-finding study adaptively randomized patients to receive ABT-089 (5, 10, 15, 20, 30, or 35 mg once daily) or placebo for 12 weeks. The primary efficacy endpoint was the Alzheimer's Disease Assessment Scale, cognition subscale (ADAS-Cog) total score. A Bayesian response-adaptive randomization algorithm dynamically assigned allocation probabilities based on interim ADAS-Cog total scores. A normal dynamic linear model for dose-response relationships and a longitudinal model for predicting final ADAS-cog score were employed in the algorithm. Stopping criteria for futility or success were defined. The futility stopping criterion was met, terminating the study with 337 patients randomized. No dose-response relationship was observed and no dose demonstrated statistically significant improvement over placebo on ADAS-Cog or any secondary endpoint. ABT-089 was well tolerated at all dose levels. When administered as adjunctive therapy to acetylcholinesterase inhibitors, ABT-089 was not efficacious in mild to moderate Alzheimer disease. The adaptive study design enabled the examination of a broad dose range, enabled rapid determination of futility, and reduced patient exposure to nonefficacious doses of the investigational compound.

A randomized pilot study of the efficacy and safety of ABT-089, a novel α4ß2 neuronal nicotinic receptor agonist, in adults with attention-deficit/hyperactivity disorder.

OBJECTIVE: ABT-089, an α4ß2 neuronal nicotinic receptor partial agonist (generic name pozanicline), has demonstrated efficacy in adults with attention-deficit/hyperactivity disorder (ADHD) at doses of 40 mg once daily and 40 mg twice daily. The purpose of this exploratory pilot study was to obtain initial safety, tolerability, and efficacy data for an ABT-089 80-mg once-daily regimen to inform a decision of whether to include an 80-mg once-daily dose regimen in subsequent, definitive (phase 3) efficacy studies. METHOD: This phase 2, randomized, double-blind, parallel-group, placebo-controlled pilot study was conducted at 12 sites from March to August 2008. A screening/washout period of up to 4 weeks was followed by an 8-week double-blind treatment period. Eligible subjects met DSM-IV-TR criteria for ADHD and were randomized in a 1:1:1 ratio to ABT-089 40 mg once daily, ABT-089 80 mg once daily, or placebo. The primary efficacy variable was reduction from baseline to the final evaluation in the investigator-rated Conners' Adult ADHD Rating Scale for each active treatment group versus placebo. Safety assessments and pharmacokinetic sampling were also conducted. RESULTS: A total of 160 subjects were randomized, with 137 (86%) completing the trial. No statistically significant treatment effects were observed with either ABT-089 dose for any efficacy measures. The most commonly reported adverse events in the active treatment groups were nasopharyngitis (6.6%), upper respiratory tract infection (6.6%), and somnolence (5.7%). The incidence of adverse events did not differ significantly between active groups and placebo. There were no clinically significant laboratory, electrocardiogram, or physical examination findings. CONCLUSIONS: ABT-089 was generally well tolerated at doses up to 80 mg. Because ABT-089 is a weak partial neuronal nicotinic receptor agonist, the results may not predict the potential efficacy for other, more potent neuronal nicotinic receptor agonists. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT00640185.

A double-blind, randomized, placebo-controlled study of the dopamine D3 receptor antagonist ABT-925 in patients with acute schizophrenia.

There is substantial preclinical and clinical evidence to suggest a potential role for the dopamine D3 receptor in the treatment of schizophrenia. ABT-925 is a selective dopamine D3 receptor antagonist with an approximately 100-fold higher in vitro affinity for dopamine D3 versus D2 receptors. This double-blind, randomized, placebo-controlled, escalating-dose, parallel-group study assessed the efficacy and safety of ABT-925 in the treatment of patients with acute exacerbation of schizophrenia. One hundred fifty-five patients were assessed over a 6-week double-blind treatment period (placebo: n = 48; ABT-925 50 mg once daily [QD]: n = 53; ABT-925 150 mg QD: n = 54). The primary efficacy measure was mean change from baseline to final evaluation on the Positive and Negative Syndrome Scale total score. Secondary measures of efficacy and pharmacokinetic parameters were also assessed. Safety assessments included adverse event monitoring, laboratory tests, vital signs, movement rating scales, and electrocardiogram measures. No statistically significant treatment effect was observed with ABT-925 50 mg QD or 150 mg QD compared with placebo on primary or secondary efficacy end points. Pharmacokinetic parameter estimates increased with dose in a linear fashion. ABT-925 50 mg QD and 150 mg QD were generally well tolerated, with adverse event profiles similar to that of placebo. Findings from a concurrent positron emission tomography study among healthy volunteers suggest that the ABT-925 doses used in this study may not have been sufficient to adequately occupy D3 receptors, thereby underscoring the importance of pharmacodynamic markers, such as PET, in determining appropriate compound doses before embarking on studies in a target population.

Safety and efficacy of ABT-089 in pediatric attention-deficit/hyperactivity disorder: results from two randomized placebo-controlled clinical trials.

OBJECTIVE: To assess the safety and efficacy of ABT-089, a novel α(4)ß(2) neuronal nicotinic receptor partial agonist, vs. placebo in children with attention-deficit/hyperactivity disorder (ADHD). METHOD: Two multicenter, randomized, double-blind, placebo-controlled, parallel-group studies of children 6 through 12 years of age were conducted. Study 1 (n = 274) assessed six treatment groups over 8 weeks: 4 once-daily (QD) ABT-089 doses (0.085-0.700 mg/kg), QD atomoxetine, and placebo. Study 2 (n = 119) assessed three treatment groups over 6 weeks: 2 QD ABT-089 doses (0.7 mg/kg, 1.4 mg/kg) and placebo. The primary efficacy variable was the investigator-administered Attention-Deficit/Hyperactivity Disorder Rating Scale-IV: Home Version (ADHD-RS-IV [HV]) Total Score. Safety was assessed by adverse event (AE) monitoring, laboratory tests, vital signs, physical examinations, and electrocardiogram measures. RESULTS: There was no statistically significant difference between ABT-089 and placebo in mean change from baseline to final evaluation of ADHD-RS-IV (HV) Total Score or other outcome measures at any dose in either study. In Study 1, atomoxetine showed statistically significant improvement for the primary and most secondary endpoints. ABT-089 was generally safe and well tolerated, with no statistically significant difference between any ABT-089 dose and placebo in the overall incidence of any specific AE, and no clinically significant changes in other safety measures. CONCLUSIONS: ABT-089 did not show efficacy on the primary efficacy variable, the ADHD-RS-IV (HV) Total Score, or other measures of ADHD symptomatology in children with ADHD, and had a safety profile similar to placebo. These results contrast with published reports of efficacy of nicotinic modulators in adults with ADHD.

Safety and tolerability of divalproex sodium extended-release in the prophylaxis of migraine headaches: results of an open-label extension trial in adolescents.

OBJECTIVE: To evaluate the long-term safety and tolerability of divalproex sodium extended-release in the prophylaxis of migraine headaches in adolescents. BACKGROUND: Divalproex sodium has been approved for migraine prophylaxis in adults. A previous double-blind, placebo-controlled study of the efficacy and safety of divalproex sodium extended-release for prevention of migraine in adolescents was followed by the present long-term extension trial, which was designed to collect additional safety and tolerability data. METHODS: This was a 12-month, Phase 3, open-label extension of a 3-month, double-blind, placebo-controlled, multicenter study of adolescents aged 12 to 17 years with migraine headaches who had either completed the previous study or had discontinued because of lack of efficacy. Subjects from the previous trial who had experienced serious adverse events possibly or probably related to study drug were excluded. Divalproex sodium extended-release 500 mg daily was administered for 15 days then increased to 1000 mg. Study visits were conducted at days 1 and 15 and months 1, 2, 3, 6, 9, and 12. Safety assessments included adverse event collection, laboratory testing, physical and neurological examinations, vital signs, and electrocardiograms, as well as reproductive endocrine analyses for postmenarchal female subjects. Efficacy was evaluated by sequential 4-week migraine headache rates calculated from subjects' headache diaries. RESULTS: A total of 112 subjects enrolled in the trial. The most common adverse events were weight gain (15%), nausea (14%), somnolence (12%), upper respiratory tract infection (11%), increased ammonia (8%), and sinusitis (8%). Five (4%) subjects experienced serious adverse events, and 15 (13%) subjects prematurely discontinued because of an adverse event. Increased ammonia levels were noted in some individuals, and the mean ammonia level for all subjects increased 19.2 microm from baseline. No other clinically significant changes were observed in laboratory values, vital signs, or electrocardiograms. Improvement in mean and median 4-week migraine headache rates occurred by the fourth month and lasted for the duration of the trial. CONCLUSIONS: In this long-term open-label extension study, the safety profile of divalproex sodium extended-release in adolescents with migraine was consistent with that observed in the preceding 3-month, double-blind trial and in previous adult studies. Overall, divalproex sodium extended-release was well-tolerated in adolescents aged 12 to 17 years.

Divalproex sodium extended-release for the prophylaxis of migraine headache in adolescents: results of a stand-alone, long-term open-label safety study.

OBJECTIVE: The objective of this long-term open-label study in adolescents was to assess the safety and tolerability of divalproex sodium extended-release in the prophylaxis of migraine headaches. BACKGROUND: Two formulations of divalproex sodium have demonstrated efficacy in the prevention of migraine headaches in adults. However, no medications are currently approved for this indication in adolescents, and long-term safety data on agents for migraine prevention are lacking for this younger population. Therefore, the current study was conducted to assess the long-term safety and tolerability of divalproex extended-release in adolescents with migraine headaches. METHODS: This was a 12-month, phase 3, open-label, multicenter study of adolescents aged 12 to 17 years with migraine headaches diagnosed by International Headache Society criteria. Divalproex sodium extended-release was initiated at 500 mg/day for 15 days then increased to 1000 mg daily, with subsequent adjustments permitted within a dosing range of 250-1000 mg daily. Study visits were conducted at days 1 and 15 and months 1, 2, 3, 6, 9, and 12. Safety was evaluated by adverse event collection, laboratory assessments, physical and neurological examinations, vital signs, electrocardiograms, the Udvalg for Kliniske Undersøgelser Side Effect Rating Scale, the Wechsler Abbreviated Scale of Intelligence, and the Behavioral Assessment Scale for Children. Efficacy was evaluated by following the number of migraine headache days reported in subjects' headache diaries over sequential 4-week intervals for the duration of the trial. RESULTS: A total of 241 subjects were enrolled and treated. The most frequently reported adverse events were nausea (19%), vomiting (18%), weight gain (12%), nasopharyngitis (11%), migraine (10%), and upper respiratory tract infection (10%). Ten (4%) subjects experienced serious adverse events, and 40 (17%) subjects discontinued because of an adverse event. Increases in ammonia levels were observed. No other clinically significant changes were observed in laboratory values, vital signs, rating scales, or electrocardiograms. Median 4-week migraine headache days decreased 75% between the first and the fourth months of the study (from 4.0 to 1.0) and remained at or below this level for the remainder of the study. CONCLUSIONS: In this long-term open-label study of adolescents with migraine, the safety and tolerability profile of divalproex sodium extended-release was consistent with findings from previous trials in adults, as well as 2 studies recently completed in adolescents. In general, divalproex sodium extended-release was well-tolerated in adolescents with migraine.

Divalproex extended-release in adolescent migraine prophylaxis: results of a randomized, double-blind, placebo-controlled study.

OBJECTIVE: To evaluate the efficacy, tolerability, and safety of 3 different doses of divalproex sodium extended-release vs placebo in the prophylaxis of migraine headaches in adolescents. BACKGROUND: Divalproex sodium has been approved for migraine prophylaxis in adults, and previous uncontrolled data suggest divalproex sodium may be effective in preventing migraine in children and adolescents with acceptable tolerability. METHODS: This was a 12-week, phase 3, randomized, placebo-controlled, double-blind, parallel-group, multicenter study in approximately 300 adolescents aged 12 to 17 years with migraine headaches. At the end of the baseline phase, subjects still meeting study criteria were randomized in a 1:1:1:1 ratio to receive divalproex sodium extended-release 250 mg, 500 mg, or 1000 mg once daily, or placebo. The primary efficacy variable was reduction from baseline in 4-week migraine headache rate for each active treatment group vs placebo. Standard safety assessments were conducted and testosterone and sex hormone-binding globulin levels were collected for postmenarchal females. RESULTS: There was no statistically significant treatment difference between any divalproex sodium extended-release dose group and placebo for the primary efficacy variable, reduction from baseline in 4-week migraine headache rate. There were no statistically significant differences in adverse events between any active treatment group and placebo. A notable dose-related decrease in platelets was observed, and individuals in all 4 treatment groups had increases in ammonia levels; treatment differences in other laboratory variables were generally small. Among postmenarchal female subjects who were not taking hormonal contraceptives or other steroids, there was no statistically significant change in testosterone levels, but a statistically significant dose-related increase in sex hormone-binding globulin was observed. CONCLUSIONS: In the current study, divalproex sodium extended-release did not differentiate from placebo in the prophylactic treatment of migraine headaches but was generally well-tolerated in adolescents aged 12 to 17 years.

Extracellular metabolites in the cortex and hippocampus of epileptic patients.

Interictal brain energy metabolism and glutamate-glutamine cycling are impaired in epilepsy and may contribute to seizure generation. We used the zero-flow microdialysis method to measure the extracellular levels of glutamate, glutamine, and the major energy substrates glucose and lactate in the epileptogenic and the nonepileptogenic cortex and hippocampus of 38 awake epileptic patients during the interictal period. Depth electrodes attached to microdialysis probes were used to identify the epileptogenic and the nonepileptogenic sites. The epileptogenic hippocampus had surprisingly high basal glutamate levels, low glutamine/glutamate ratio, high lactate levels, and indication for poor glucose utilization. The epileptogenic cortex had only marginally increased glutamate levels. We propose that interictal energetic deficiency in the epileptogenic hippocampus could contribute to impaired glutamate reuptake and glutamate-glutamine cycling, resulting in persistently increased extracellular glutamate, glial and neuronal toxicity, increased lactate production together with poor lactate and glucose utilization, and ultimately worsening energy metabolism. Our data suggest that a different neurometabolic process underlies the neocortical epilepsies.

Striking differences in glucose and lactate levels between brain extracellular fluid and plasma in conscious human subjects: effects of hyperglycemia and hypoglycemia.

Brain levels of glucose and lactate in the extracellular fluid (ECF), which reflects the environment to which neurons are exposed, have never been studied in humans under conditions of varying glycemia. The authors used intracerebral microdialysis in conscious human subjects undergoing electrophysiologic evaluation for medically intractable epilepsy and measured ECF levels of glucose and lactate under basal conditions and during a hyperglycemia-hypoglycemia clamp study. Only measurements from nonepileptogenic areas were included. Under basal conditions, the authors found the metabolic milieu in the brain to be strikingly different from that in the circulation. In contrast to plasma, lactate levels in brain ECF were threefold higher than glucose. Results from complementary studies in rats were consistent with the human data. During the hyperglycemia-hypoglycemia clamp study the relationship between plasma and brain ECF levels of glucose remained similar, but changes in brain ECF glucose lagged approximately 30 minutes behind changes in plasma. The data demonstrate that the brain is exposed to substantially lower levels of glucose and higher levels of lactate than those in plasma; moreover, the brain appears to be a site of significant anaerobic glycolysis, raising the possibility that glucose-derived lactate is an important fuel for the brain.