Sabeluzole (R58 735) increases consistent retrieval during serial learning and relearning of nonsense syllables.

Consistent retrieval during serial learning of nonsense syllables was investigated under sabeluzole (10 mg b.i.d. for 7 days) and placebo. The same material was relearned 1 week after withdrawal of the drug. During learning a twofold improvement in retrieval efficiency was seen when volunteers learned new material under steady-state levels of sabeluzole. During relearning, material originally learned under sabeluzole was significantly better retrieved than material learned under placebo. The results suggest that sabeluzole influences basic mechanisms involved in storage and retrieval of new information.

The effect of sabeluzole (R 58735) on memory retrieval functions.

In a first double-blind, placebo-controlled parallel experiment, 20 volunteers with a median age of 45 years were treated for 1 week with either sabeluzole (R 58735) or placebo. Before and after the treatment period, they were subjected to a Selective Reminding Procedure in which a 20-word list had to be learned. No differences between the two groups were seen for total recall, short-term retrieval, total long-term retrieval, random long-term retrieval and long-term storage. However, a significant improvement in consistent long-term retrieval (cLTR) was seen for the subjects treated with sabeluzole. This effect was restricted to the group of the poor performers, i.e. those with a baseline cLTR of 50% or less. In a second experiment, 12 healthy elderly volunteers with a median age of 59 years were subjected to the same test procedure. They were treated with sabeluzole in a single-blind fashion. Again the cLTR improved significantly in the group of poor performers. It was thus confirmed that sabeluzole ameliorates retrieval functions and primarily so in poor performers.

The effect of R 58 735 (Sabeluzole) on memory functions in healthy elderly volunteers.

The effects of chronic treatment (5 mg b.i.d. for 2 days followed by 10 mg b.i.d. for 5 days) with R 58 735 on human memory functions were studied in healthy elderly (age greater than or equal to 50 years) volunteers in a double-blind placebo-controlled study. Serial learning of nonsense syllables was better under R 58 735, and relearning 1 week after termination of the treatment was superior to relearning of similar material initially learned under placebo. Free recall of nonsense syllables was significantly better when these were learned under active compound. Proactive inhibition induced by consecutive presentation of word lists was attenuated by R 58 735. Short-term memory functions, retrieval accuracy from semantic memory and unprepared reaction times were unchanged. R 58 735 ameliorated both learning and recall in conditions of age-related mild hypofunction in healthy volunteers. The compound seems to have had positive effects on encoding and consolidation of new material.

Safety and pharmacokinetics of the neuroprotective drug lubeluzole in patients with ischemic stroke.

A total of 22 patients with acute ischemic stroke participated in two randomized, single-masked, placebo-controlled studies that evaluated the safety and pharmacokinetics of single escalating intravenous doses of lubeluzole. The first dose of study medication in all patients was given within 6 hours of the first sign of stroke onset. In the first study, 6 patients received a single 1-hour intravenous infusion of 5 mg of lubeluzole; 4 of these patients received an additional 10-mg dose 3 to 4 days later. Two additional patients received placebo. In the second study, 4 patients received a single 1-hour infusion of 10 mg of lubeluzole, and 2 patients received placebo. After a safety evaluation of the second study, 6 additional patients received 15 mg of lubeluzole, and 2 other patients received placebo. Lubeluzole had no clinically relevant effects on any cardiovascular variable compared with placebo. The majority of adverse experiences were mild to moderate and resolved during treatment. No unexpected electroencephalogram abnormalities were observed, and no evidence of epileptiform discharges was found in any of the patients. At the end of the infusion, plasma lubeluzole concentrations decayed biphasically, with mean distribution half-lives of 46.3 to 101.0 minutes and mean terminal half-lives of 20.8 to 27.7 hours. Comparisons of the dose-normalized value of the individual plasma concentrations at the end of the infusion and the total area under the curve from time 0 to infinity suggested that lubeluzole exhibited linear kinetics over the dose range evaluated in patients with ischemic stroke. In the small number of patients studied, lubeluzole's favorable safety profile was demonstrated by the lack of clinically relevant effects on cardiovascular variables and by neurologic examination and clinical laboratory findings.

The safety and tolerability of single intravenous doses of lubeluzole (Prosynap) in healthy volunteers.

The safety and tolerability of single escalating doses of lubeluzole were evaluated in healthy male volunteers in 2 studies. In the first of 2 randomized, single-blind, placebo-controlled, dose-escalation studies, 6 subjects received single 30-minute infusions of 2.5, 5, and 10 mg of lubeluzole, and 2 additional subjects received placebo. In the second study 6 different subjects received a 1-hour infusion of 15 mg of lubeluzole, 5 of whom received the 20-mg dose, and 2 received 25 mg of lubeluzole. Two additional subjects received placebo. Small increases and decreases in PQ, QRS, QT, QTc, and QTm intervals were noted after infusion of all lubeluzole doses and placebo, however, these changes were within the normal ranges for these values except for the QTc for the 25-mg dose of lubeluzole. Significant prolongation of the QTc interval was observed at the end of the 1-hour infusion in both subjects receiving the 25-mg dose of lubeluzole. No clinically relevant changes in systolic time intervals, heart rate, blood pressure, and clinical laboratory values were noted in subjects receiving 2.5-25 mg of lubeluzole or placebo. Adverse experiences, predominantly lightheadedness and dizziness, were reported by subjects receiving doses of lubeluzole greater than or equal to 10 mg. Lubeluzole, administered as single intravenous doses of 2.5-15 mg, is safe and well tolerated in healthy male volunteers.

Hospital referral of stroke patients: a survey of attitudes in general practice, and consideration of entry times for clinical trials.

Two major issues in clinical trials in stroke are the criteria used for the selection of patients expected to benefit from the proposed treatment, and the entry time of those patients. We surveyed 507 Belgian general practitioners (GPs) on their opinions on referral of stroke patients to hospital and also on their actual referral behaviour. The feasibility of a 6-hour entry time was included in the investigation. Stroke is considered to require an urgent response: 88% of GPs visited the patient immediately on concluding that such an event had occurred. The mean time between the onset of the first clinical symptoms and the arrival of the GP at the patient's residence was about 30 minutes. Within 6 h of the insult, 95% of the patients referred to hospital had been admitted. Information on the GP's most recent stroke patient revealed that 72.4% of these stroke patients were admitted to hospital. Patients referred to hospital were significantly younger, had a significantly more severe stroke, and were significantly more likely to have had a first stroke and to have lived independently before the insult than patients not admitted to hospital. We think that Belgian GPs need to change their referral behaviour with respect to stroke patients and refer more of those who have suffered more mildly. There is every reason to be optimistic about this re-education, since the patients whom GPs do refer to hospital are referred rapidly enough to profit from a possibly efficacious treatment.