Effect of levetiracetam on epilepsy-related quality of life. N132 Study Group.

PURPOSE: To evaluate the short-term effect of levetiracetam (LEV; UCB L059) as add-on therapy on health-related quality of life in the treatment of refractory partial-onset seizures. METHODS: Patients were enrolled in protocol UCB N132 if they had >/=12 partial-onset seizures with or without secondary generalization during the 12-week baseline period with a minimum of two seizures every 4 weeks. Randomization was made to placebo, LEV 1,000 mg, or LEV 3,000 mg, with sample size based on seizure frequency reduction. The 31-item Quality of Life in Epilepsy (QOLIE-31) questionnaire was completed by 246 patients at the end of baseline and at 18-week follow-up, or earlier if withdrawn. RESULTS: Significant differences were found among the three treatment groups for Seizure Worry (p = 0. 0003), Overall Quality of Life (p = 0.04), and Cognitive Functioning domains (p = 0.01), as well as the Total Score (p = 0.009). Responders (>/=50% partial onset seizure reduction) had significant improvements in all areas, except Medication Effect, compared with nonresponders (all p > 0.006). Clinically noticeable improvement (>/=10% change from baseline to follow-up) was perceived by LEV 3, 000 mg responders in all areas, except Emotional Well-Being, by LEV 1,000 mg responders in 5 of 9 areas, and by placebo responders in 2 of 9 areas. CONCLUSIONS: Addition of LEV to standard medication seems to have a positive impact on health-related quality of life, particularly among responders in this short-term study. These exploratory analyses require additional studies to evaluate long-term changes in a larger population.

Levetiracetam for partial seizures: results of a double-blind, randomized clinical trial.

OBJECTIVE: To evaluate the efficacy and safety of 500 mg bid and 1500 mg bid levetiracetam as adjunctive therapy for refractory partial seizures in a double-blind, randomized, placebo-controlled, parallel-group, multicenter trial. METHODS: The authors studied patients with uncontrolled partial seizures (minimum 12 per 12 weeks), regardless of whether they became secondarily generalized, for 38 weeks. A 12-week baseline was followed by random assignment to adjunctive therapy with placebo (n = 95), levetiracetam 1000 mg/day (n = 98), or levetiracetam 3000 mg/day (n = 101). Upward titration over 4 weeks was followed by 14 weeks of fixed dose treatment, and concluded with an 8-week medication withdrawal period or entering a follow-up study. RESULTS: Of 294 patients randomized, 268 completed the study. Partial seizure frequency during the entire evaluation period (primary efficacy variable) was lower with levetiracetam compared to placebo (p /=10%), mostly mild to moderate in severity, with incidences higher than placebo were asthenia, dizziness, flu syndrome, headache, infection, rhinitis, and somnolence. CONCLUSION: Adjunctive therapy with levetiracetam was effective and well tolerated in controlling partial seizures.

An open-label study of repeated use of diazepam rectal gel (Diastat) for episodes of acute breakthrough seizures and clusters: safety, efficacy, and tolerance. North American Diastat Group.

PURPOSE: To assess safety of diazepam rectal gel (DZPRG) for control of acute seizures in epilepsy patients and to evaluate tolerance with repeated use of DZPRG at intervals of > or =5 days. METHODS: Subjects were persons with epilepsy, age 2 years or older, with seizure clusters or prolonged seizures. Onset of a treatable episode was defined; caregivers were trained to administer DZPRG and to monitor respiration, seizures, and adverse effects (AEs). DZPRG was dispensed in a single-use, prefilled syringe; dosage was determined by age and weight. Maximal use was > or =5-day intervals, < or =5 times/month. After use, caregivers returned data booklets and syringe. Caregivers and physicians completed global ratings yearly. RESULTS: In 149 subjects treated, 77% of 1,578 administrations resulted in seizure freedom for the next 12 h. One hundred twenty-five received two or more treatments (two to 78; median, 8), 0.03-4.3/month (median, 0.4). To evaluate tolerance, subjects with two or more episodes were divided into low (two to seven episodes) and high use (eight to 78 episodes treated). There was no difference in proportion seizure free 12 h after the first administration versus last administration, for either infrequent or frequent administration. Sedation occurred in 17%, attributed to DZPRG in 9%. No respiratory depression was attributable to DZPRG. Three subjects withdrew because of AEs attributable to (agitation) or possibly attributable to DZPRG (chest pain, rash). Five subjects withdrew because of AEs unrelated to DZPRG. Caregiver and physician global ratings were highly positive at both 12 and 24 months. CONCLUSIONS: DZPRG is safe and effective in children and adults with epilepsy with breakthrough seizures. Neither tolerance nor significant medication-related AEs were seen with repeated DZPRG administration at intervals > or =5 days.

Rectal diazepam gel for treatment of acute repetitive seizures. The North American Diastat Study Group.

The purpose of these investigations was to determine from combined data the response to rectal diazepam (DZP) gel (Diastat [Athena Neurosciences, South San Francisco, CA]) in home treatment of children with episodes of acute repetitive seizures (ARS). A subset of patients aged 2-17 years were selected from two prospective placebo-controlled studies of children and adults. In both studies a prospective, double-blind, placebo-controlled design was used. The treatment groups (68 DZP; 65 placebo) did not differ significantly in age, race, seizure type or etiology, or in the median number of ARS episodes per month before study entry. DZP-treated children demonstrated a significant reduction in median seizure frequency compared with the placebo group (0.00 vs 0.25 seizures per hour, P = 0.001). Significantly more DZP-treated children remained seizure free during the observation period (40 vs 20, P = 0.001). Somnolence was the only adverse effect present significantly more often in the DZP-treated children (25.0% vs 7.7%, P = 0.0095). There were no instances of serious respiratory depression. Rectal DZP was demonstrated to be an effective and safe treatment to abort an episode of ARS in a child and, additionally, lessened the likelihood of seizure recurrence within the next 12 hours.

Six-month evaluation of Carbatrol (extended-release carbamazepine) in complex partial seizures.

We evaluated the use of a new, controlled-release capsule form of carbamazepine, Carbatrol capsules, in an open-label, multicenter study of 124 patients with complex partial seizures. Ninety-one percent of the patients successfully completed the 6-month trial with good seizure control, with a significant improvement in quality of life. We conclude that switching patients with complex partial seizures from multiple daily-dose carbamazepine to twice-daily Carbatrol on a milligram-to-milligram basis is relatively safe.

Treating repetitive seizures with a rectal diazepam formulation: a randomized study. The North American Diastat Study Group.

OBJECTIVE: To evaluate the effectiveness and safety of a single-dose treatment for acute repetitive seizure (ARS) episodes (e.g., clusters) administered in a nonmedical setting by caregivers. BACKGROUND: Patients with epilepsy may experience ARS episodes despite optimal anticonvulsant treatment. Such episodes require rapid treatment as medical emergencies. Typically, the patient is treated in an emergency medical setting with i.v. medication by trained medical personnel. METHODS: The authors undertook a multicenter, randomized, parallel, double-blind study of a single administration of Diastat (diazepam rectal gel) for treating episodes of ARS. ARS episodes and treatment criteria were defined for each patient at the start of the study. Caregivers were taught to determine ARS episode onset, administer a predetermined dose of study medication, monitor outcome, count respirations, and record seizures and adverse events. RESULTS: A total of 29 centers enrolled 158 patients, of whom 114 patients had a treated ARS episode (Diastat, n = 56; placebo, n = 58). Diastat treatment reduced median seizure frequency (p = 0.029). More Diastat patients were seizure free post-treatment (Diastat, 55%; placebo, 34%; p = 0.031). Kaplan-Meier analysis of the time to the next seizure favored Diastat treatment (p < 0.007). The most common adverse event was somnolence. CONCLUSION: Administration of a single rectal dose of Diastat was significantly more effective than placebo in reducing the number of seizures following an episode of ARS. Caregivers could administer treatment safely and effectively in a nonmedical setting.

Dezinamide for partial seizures: results of an n-of-1 design trial.

BACKGROUND: Dezinamide (DZM, ADD 94057) is a potential antiepileptic drug that binds to the voltage-sensitive sodium channel and showed preliminary evidence of efficacy and safety in an open-label study. METHODS: Our double-blind, placebo-controlled trial at two sites used an n-of-1 (single-patient) design. All 15 patients had medically intractable partial-onset seizures and were comedicated with phenytoin (PHT) only. Treatment was for six 5-week periods (three active paired with three placebo in random sequence). Assuming nonlinear kinetics, we used an initial pharmacokinetic profile to estimate dosages for reaching target plasma concentrations of DZM. RESULTS: Statistically significant seizure reduction was found by both a randomization test (p = 0.0025) and a signed rank test (p = 0.048). Median seizure frequency decreased 37.9%, and 40% of patients had > 50% seizure reduction, both compared with placebo. Pharmacokinetic predictions were not accurate; mean plasma concentrations fell well below target values. Plasma PHT concentrations increased (mean = 17.1%) during DZM treatment. The most common adverse experiences were fatigue, light-headedness, and abnormal gait; five patients required DZM dosage reductions. CONCLUSIONS: DZM showed minimal clinical toxicity and significant efficacy despite lower plasma concentrations than predicted by pharmacokinetics. This trial establishes the suitability of the n-of-1 design to investigational antiepileptic drug trials.

Increasing plasma concentration tolerability study of flunarizine in comedicated epileptic patients.

Twelve patients with intractable partial seizures [4 receiving carbamazepine (CBZ), 4 phenytoin (PHT), and 4 both] entered a study of the tolerability of flunarizine (FNR) at specified plasma concentrations. After an 8-week baseline period, a single-dose pharmacokinetic study was performed for each patient to calculate a loading dose and maintenance dosage necessary to achieve a target plasma FNR concentration of 30 ng/ml. The first 8 patients received the loading dose (as divided doses) during a 1-week hospitalization and the maintenance dosage for the ensuing 8 weeks. These patients proceeded to treatment periods with target concentrations of 60 and then 120 ng/ml, using doses based on an assumed linear relation between dose and plasma concentration. The last 4 patients were studied only at the 120- ng/ml target level. Results indicated that this procedure successfully approximated target levels of 30 and 60 ng/ml, but observed concentrations in the last period exceeded the 120-ng/ml target level and continued to increase with time, often necessitating a dosage reduction owing to intolerability. Calculated doses for a given target concentration varied by a factor of 12. The most frequently reported adverse experiences were sedation and increased fatigue; reports of dizziness, headache, and lethargy were also common. Based on this study, a target concentration of at least 60 but < 120 ng/ml is recommended for a controlled clinical trial of the antiepileptic efficacy of FNR.

Pharmacokinetic and dose tolerability study of ADD 94057 in comedicated patients with partial seizures.

ADD 94057, a metabolite of fluzinamide, manufactured by the A. H. Robins Company, blocks chemically- and electrically-induced seizures in animals. The primary objective of this open add-on study was to evaluate patient tolerability of ADD 94057 at ascending target plasma concentrations. Nine subjects with medically refractory seizures were receiving phenytoin (PHT, 3), carbamazepine (CBZ, 3), or both (3). A pharmacokinetic profile after a single oral 400-mg dose of ADD 94057 was used to calculate ADD 94057 dosages. After a 4-week baseline period, patients were treated for 4 weeks with weekly ADD 94057 dosage escalations. Two patients completed the study at their assigned highest dosage level; the other patients finished the study at lower dosages. The patients receiving PHT (but not CBZ) tolerated higher plasma concentrations of ADD 94057 than did patients receiving CBZ, alone or in combination with PHT. Adverse experiences included headache, ataxia, blurred vision, diplopia, dizziness, lightheadedness, and mild confusion. Eight of nine patients had reductions in seizure frequency from baseline.

Felbamate for partial seizures: results of a controlled clinical trial.

Felbamate (2-phenyl-1,3-propanediol dicarbamate) has a favorable preclinical profile in animal models of epilepsy. We present the results of a double-blind, randomized, placebo-controlled clinical trial in patients with partial seizures. Criteria for entry included a requirement for four or more partial seizures per month despite concomitant therapeutic blood levels of phenytoin and carbamazepine. Fifty-six patients (mean age, 31.4 years; 32 men, 24 women) completed the trial. The mean seizure frequencies for the 8-week periods analyzed were felbamate = 34.9, placebo = 40.2. Felbamate was statistically superior to placebo in seizure reduction, percent seizure reduction, and truncated percent seizure reduction. The mean felbamate dosage was 2,300 mg/d. Plasma felbamate concentrations ranged from 18.4 to 51.9 mg/l, mean = 32.5 mg/l. Adverse experiences during felbamate therapy were minor and consisted primarily of nausea and CNS effects. This trial indicates that felbamate is safe and effective in the treatment of comedicated patients with severely refractory epilepsy.

Pharmacokinetic profile of flunarizine after single and multiple dosing in epileptic patients receiving comedication.

This preliminary clinical study describes the pharmacokinetic characteristics of flunarizine (FLN) following single and multiple dosing in epileptic patients receiving comedication. Three groups [phenytoin (PHT) only, carbamazepine (CBZ) only, and PHT plus CBZ] of four patients each were studied. Large interindividual differences, but no statistically significant differences in pharmacokinetic parameters, were observed between the three groups. Following a single dose, mean values (and ranges) for apparent clearance, volume distribution, and elimination half-life (t1/2) were 0.504 L/h/kg (0.086-1.119), 12,431 L (1,959-20,920), and 308 h (61-506), respectively. FLN had no effect on PHT or CBZ steady-state levels but PHT or CBZ appeared to induce the metabolic disposition of FLN. The effect of dose on FLN kinetics could not be evaluated in this preliminary study.

Efficacy of nafimidone in the treatment of intractable partial seizures: report of a two-center pilot study.

Nafimidone is a potential new antiepileptic drug with a therapeutic profile in experimental animal seizure models similar to that of phenytoin (PHT). We report here the first clinical trial of nafimidone in epileptic patients. Twelve adult male patients with a mean of four or more medically intractable seizures per month were enrolled in a 14-week pilot study. Patients were stabilized on therapeutic levels of PHT and carbamazepine (CBZ) (nine patients) or on PHT alone (three patients) before entering a 4-week baseline period. Nafimidone, to a maximum dose of 600 mg/day, was added during 2 weeks in hospital. Patients were then evaluated weekly for 8 weeks. Eight patients experienced 33-98% improvement in seizure control. Three others did not show significant change in seizure frequency but experienced sufficient subjective improvement that they continued into long-term follow-up. One patient, who had a 63% improvement in mean weekly seizures during the pilot study, declined to continue. Thus, 10 patients entered long-term follow-up. Six of the 10 sustained 53 to greater than 99% improvement in seizure control compared with baseline over the course of 46-53 weeks of follow-up. Nafimidone had a marked inhibitory effect on the clearance of CBZ and PHT, resulting in higher plasma levels in nine patients. The possible role of the elevated CBZ levels in the apparent efficacy of nafimidone is discussed.

Advances in the clinical development of antiepileptic drugs.

In this paper we describe advances in the clinical development of antiepileptic drugs as a function of the Antiepileptic Drug Development Program of the National Institute of Neurological and Communicative Disorders and Stroke. This program encompasses both the preclinical and clinical elements of drug development through the Anticonvulsant Screening Project, the Toxicology Project, and the support of controlled clinical trials of potential new drugs that emerge from these projects and promise to be more effective and less toxic than those currently available for the treatment of epilepsy.

A single-dose study of mexiletine (Kö 1173).

Serum concentrations of mexiletine after a single dose were determined in 8 adult Caucasian males with complex partial seizures who were continuing to receive other antiepileptic drugs. Two patients each received a single dose of either 100, 200, 300, or 400 mg mexiletine. Serum concentrations were determined by two gas chromatographic methods. Serum concentrations ranged up to 795 ng/ml. Peak concentrations occurred 1 to 3 hr after administration of the drug and were significantly different between the 100- and 300-mg, 100- and 400-mg, 200- and 300-mg, and 200- and 400-mg doses. Differences between the other doses were not significant. Serum concentrations declined monoexponentially. Half-life ranged from 2.7 to 7.2 hr. Numerous papers have appeared in the European literature on the use of mexiletine to treat cardiac arrhythmias. Preliminary studies in the United States suggest the use of mexiletine as an adjunct for therapy of epilepsy.

A multiple-dose study of mexiletine (Kö 1173).

In preparation for a prospective controlled study of mexiletine in the treatment of epilepsy, a preliminary study of serum concentrations after multiple doses was performed with 8 institutionalized Caucasian adult males with uncontrolled seizures and similar weight, medical regimen, and seizure classification. Two patients each received daily dosages of 200, 400, 600 or 800 mg mexiletine administered in capsules four times a day for 7 days, in addition to their usual medication. Serum concentrations of mexiletine were determined by the Kupferberg-Yonekawa method. After the first day, serum concentrations of mexiletine were significantly higher for the 600 and 800-mg dosages than for the 200- and 400-mg dosages. The differences in serum concentration between the 200- and 400-mg dosages and between the 600- and 800-mg dosages were not significant. Serum concentrations for the 200-mg and 400-mg dosages were generally below 400 ng/ml, whereas at dosages of 600- and 800-mg, serum concentrations ranged from 400 to over 1,100 ng/ml, after the first day. Optimal dosage for this population appeared to be at least 800 mg/day. Half-life ranged from 3.5 to 7.8 hr.