Efficacy and tolerability of levetiracetam as adjunctive therapy in Japanese patients with uncontrolled partial-onset seizures

AIMS

The aim of this study was to confirm the efficacy and safety of adjunctive levetiracetam in adult Japanese patients with uncontrolled partial-onset seizures.

METHODS

In a double-blind, placebo-controlled, confirmatory trial, eligible patients were randomized to receive levetiracetam 500, 1000, 2000, or 3000 mg/day or placebo for 16 weeks. The primary end-point was percentage reduction from baseline in seizure frequency/week over a 12-week evaluation period. Tolerability assessments were also conducted. Findings of this and a previous randomized, double-blind trial were compared.

RESULTS

Of 401 patients screened, 352 were randomized and 316 completed the study. Median percentage reduction in seizure frequency/week from baseline was 12.92%, 18.00%, 11.11% and 31.67% in the levetiracetam 500, 1000, 2000 and 3000-mg groups, respectively, compared with 12.50% in the placebo group. Unlike the previous trial, the primary efficacy analysis between the levetiracetam 1000 and 3000-mg and placebo groups did not reach statistical significance (P = 0.067). Exploratory analyses demonstrated that the difference in seizure reduction versus placebo was 14.93% (95% confidence interval, 1.98-27.64; P = 0.025) for the levetiracetam 3000-mg group. All levetiracetam doses were well tolerated. The main difference between the two trials was a high placebo response in the present trial.

CONCLUSIONS

The primary efficacy analysis did not reach statistical significance, a finding that could be attributed to an unexpectedly high placebo response. Nonetheless, exploratory analysis suggests that levetiracetam at 3000 mg/day may, at least marginally, be beneficial for patients with uncontrolled partial-onset seizures.

Levetiracetam pharmacokinetics in Japanese subjects with renal impairment

BACKGROUND AND OBJECTIVE

The anti-epileptic drug levetiracetam is excreted renally. The objective of this trial was to evaluate the pharmacokinetics of levetiracetam in Japanese patients with renal impairment including end-stage renal disease (ESRD) to confirm that existing dosing instructions-based on data from European patients-are appropriate in a Japanese population.

METHODS

This was a nonrandomised, open-label trial. Six participants were allocated to each of five groups (normal renal function, mild, moderate and severe renal impairment and ESRD); 30 participants in total. Participants received a single dose of levetiracetam 500 mg (normal or mild), 250 mg (moderate or severe), or 500 mg followed by 250 mg post-haemodialysis (ESRD). Blood and urine samples were obtained serially for levetiracetam and metabolite determinations. Noncompartmental pharmacokinetic parameters were calculated and steady-state profiles were simulated using the superposition method.

RESULTS

In this trial, levetiracetam total clearance decreased proportionally with creatinine clearance: 52, 31, 25, 20 and 11 mL/min/1.73 m(2) in healthy controls and in patients with mild, moderate, severe renal impairment, and ESRD, respectively. Simulated levetiracetam plasma profiles using the recommended dose adjustments were within the range for normal renal function. Overall, results from this trial were consistent with historical European data.

CONCLUSION

These findings confirm that the dosing instructions are appropriate for Japanese patients with renal impairment including ESRD.

Population pharmacokinetics modeling of levetiracetam in Chinese children with epilepsy

AIM

To establish a population pharmacokinetics (PPK) model of levetiracetam in Chinese children with epilepsy.

METHODS

A total of 418 samples from 361 epileptic children in Peking University First Hospital were analyzed. These patients were divided into two groups: the PPK model group (n=311) and the PPK validation group (n=50). Levetiracetam concentrations were determined by HPLC. The PPK model of levetiracetam was established using NONMEM, according to a one-compartment model with first-order absorption and elimination. To validate the model, the mean prediction error (MPE), mean squared prediction error (MSPE), root mean-squared prediction error (RMSPE), weight residues (WRES), and the 95% confidence intervals (95% CI) were calculated.

RESULTS

A regression equation of the basic model of levetiracetam was obtained, with clearance (CL/F)=0.988 L/h, volume of distribution (V/F)=12.3 L, and K(a)=1.95 h(-1). The final model was as follows: K(a)=1.56 h(-1), V/F=12.1 (L), CL/F=1.04×(WEIG/25)(0.583) (L/h). For the basic model, the MPE, MSPE, RMSPE, WRES, and the 95%CI were 9.834 (-0.587-197.720), 50.919 (0.012-1286.429), 1.680 (0.021-34.184), and 0.0621 (-1.100-1.980). For the final model, the MPE, MSPE, RMSPE, WRES, and the 95% CI were 0.199 (-0.369-0.563), 0.002082 (0.00001-0.01054), 0.0293 (0.001-0.110), and 0.153 (-0.030-1.950).

CONCLUSION

A one-compartment model with first-order absorption adequately described the levetiracetam concentrations. Body weight was identified as a significant covariate for levetiracetam clearance in this study. This model will be valuable to facilitate individualized dosage regimens.

Neurocognitive effects of brivaracetam, levetiracetam, and lorazepam

PURPOSE

Brivaracetam (BRV) is a new anticonvulsant under development. Although BRV is an analog of levetiracetam (LEV), in addition to being an SV2A ligand, it also inhibits sodium channels in a voltage-dependent manner. The cognitive effects of BRV are uncertain.

METHODS

A randomized, double-blind, placebo-controlled, four-way cross-over design was employed in 16 healthy volunteers comparing acute dosing (i.e., two doses) of BRV 10 mg, LEV 500 mg, lorazepam (LZP) 2 mg, and placebo. The primary outcome was the summary score from the cognitive neurophysiologic test (CNT), which combines electrophysiologic and performance measures. Secondary outcomes included CNT cognitive and electrophysiologic subscores, traditional neuropsychological measures, and treatment-emergent adverse events (TEAEs).

RESULTS

Compared to BRV, LEV, and placebo, LZP adversely affected the CNT summary score and the majority of CNT subscores and neuropsychological measures. In contrast, BRV did not differ from placebo or LEV on any measure. More TEAEs occurred with LZP compared to each of the other treatment conditions.

DISCUSSION

The differential pattern of drug effects was consistent across multiple electrophysiologic, cognitive, and subjective measures. The profile of cognitive, subjective, and electrophysiologic effects for BRV was similar to the analog compound LEV and to placebo. The findings suggest that BRV should be tolerated well from a neuropsychological perspective, but additional studies are needed.