Korian Topiramate Study Group. Low dose and slow titration of topiramate as adjunctive therapy in refractory partial epilepsies: a multicentre open clinical trial

Effectiveness of dose-escalated topiramate monotherapy and add-on therapy in neurosurgery-related epilepsy: A prospective study

BACKGROUND

Lesional and symptomatic causes of epilepsy are the most common neurological disorders of the brain. Topiramate effectively controls newly diagnosed epilepsy and refractory focal seizures, but high-dose topiramate does not improve seizure control. This study aimed to evaluate the clinical efficacy and safety of dose-escalated topiramate as first-line monotherapy and add-on therapy in patients with neurosurgery-related epilepsy.

MATERIAL AND METHODS

A total of 55 neurosurgical patients with epilepsy were divided into monotherapy and add-on therapy groups and both groups received topiramate via the dose-escalation method. The primary efficacy outcomes were seizure-free rate and seizure response rate. Adverse events and seizure frequency were recorded.

RESULTS

The seizure response rate in the first month of monotherapy was significantly better than that of add-on therapy (89% vs 65%, P < .05), but no significant differences were found in seizure response rates between the 2 groups after 2 months of treatment. Both monotherapy and add-on therapy were effective in controlling seizures, with mean seizure frequency of 0.725 vs 0.536 and seizure-free rate of 88% vs 78.6%. Both treatments showed good improvement of seizure frequency in patients without tumor. The efficacy of monotherapy was better than that of add-on therapy (80% vs 29.2%) in patients with body mass index (BMI) ≤24. However, add-on therapy was better than monotherapy (76.7% vs 21.4%) in patients with BMI > 24. Dizziness (25.5%) and headache (16.4%) were the most common adverse events. No severe adverse event such as cognitive impairment was observed.

CONCLUSIONS

Dose-escalated topiramate monotherapy and add-on therapy demonstrate good efficacy and safety, with fewer adverse events in seizure control in neurosurgical patients.

A randomized, open-label, multicenter comparative trial of levetiracetam and topiramate as adjunctive treatment for patients with focal epilepsy in Korea

OBJECTIVE

The objective of this trial was to compare the effectiveness of levetiracetam (LEV) and topiramate (TPM) as adjunctive treatment for patients with focal seizures in Korea.

METHODS

In this Phase IV, open-label, multicenter trial (NCT01229735), adults were randomized to treatment with LEV (1000-3000 mg/day) or TPM (200-400 mg/day). Only patients achieving LEV ≥1000 mg/day or TPM ≥100 mg/day after a 4-week up-titration entered the 20-week dose-finding and subsequent 28-week maintenance periods. The primary outcome was the 52-week retention rate; others included safety and exploratory efficacy outcomes.

RESULTS

Of 343 randomized patients (LEV 177; TPM 166), 211 (61.5%) completed the trial. In the full analysis set (FAS), retention rate was 59.1% with LEV vs 56.6% with TPM (p = 0.7007), while in the prespecified sensitivity analysis, based on data from patients who received drug doses in the recommended range (LEV 176; TPM 113), it was 59.1% with LEV vs 42.5% with TPM (p = 0.0086). In the FAS, median percent reduction in seizure frequency from baseline was 74.47% with LEV and 67.86% with TPM (p = 0.0665); ≥50% responder rate was 69.0% vs 64.8% (p = 0.4205), and the 6-month seizure-freedom rate was 35.8% vs 22.3% (p = 0.0061). In the sensitivity analysis, differences between groups were greater, favoring LEV. Incidences of treatment-emergent adverse events (TEAEs) were 70.6% with LEV vs 77.1% with TPM; most frequently somnolence (20.3%), dizziness (18.1%), and nasopharyngitis (13.6%) with LEV; and decreased appetite (15.7%), dizziness (14.5%), and headache (14.5%) with TPM. Discontinuations due to TEAEs were 7.9% with LEV and 12.7% with TPM.

CONCLUSIONS

In this open-label trial, the 52-week retention rate was not significantly different between LEV and TPM. However, LEV was associated with a substantially higher seizure freedom rate and a more favorable safety profile than TPM in this population of Korean patients with focal seizures.

Influence of titration schedule and maintenance dose on the tolerability of adjunctive eslicarbazepine acetate: An integrated analysis of three randomized placebo-controlled trials

OBJECTIVE

To examine the influence of titration schedule and maintenance dose on the incidence and type of treatment-emergent adverse events (TEAEs) associated with adjunctive eslicarbazepine acetate (ESL).

METHODS

Data from three randomized, double-blind, placebo-controlled trials were analyzed. Patients with refractory partial-onset seizures were randomized to maintenance doses of ESL 400, 800, or 1200mg QD (dosing was initiated at 400 or 800mg QD) or placebo. The incidence of TEAEs was analyzed during the double-blind period (2-week titration phase; 12-week maintenance phase), according to the randomized maintenance dose and the titration schedule.

RESULTS

1447 patients were included in the analysis. During the first week of treatment, 62% of patients taking ESL 800mg QD had ≥1 TEAE, vs 35% of those taking 400mg QD and 32% of the placebo group; dizziness, somnolence, nausea, and headache were numerically more frequent in patients taking ESL 800mg than those taking ESL 400mg QD. During the double-blind period, the incidences of common TEAEs were lower in patients who initiated ESL at 400mg vs 800mg QD. For the 800 and 1200mg QD maintenance doses, rates of TEAEs leading to discontinuation were lower in patients who began treatment with 400mg than in those who began taking ESL 800mg QD.

CONCLUSIONS

Initiation of ESL at 800mg QD is feasible. However, initiating treatment with ESL 400mg QD for 1 or 2 weeks is recommended, being associated with a lower incidence of TEAEs, and related discontinuations. For some patients, treatment may be initiated at 800mg QD, if the need for more immediate seizure reduction outweighs concerns about increased risk of adverse reactions during initiation.

Topiramate: Effects on cognition in patients with epilepsy, migraine headache and obesity

This paper reviews the clinical implications of topiramate (TPM)-induced cognitive deficits in patients with epilepsy, migraine headache, obesity, and in normal populations, followed by reviews of the literature describing the reversal of such deficits upon medication discontinuation. It also discusses animal investigations of TPM's role of neuroprotection in brain injury. TPM's most intolerable adverse effects (AEs) are on verbal fluency and reaction time, resulting in high discontinuation rates in patients taking it for epilepsy and migraine headache. However, because TPM is so effective in the treatment of epilepsy and migraine headache, its use is expected to continue. There appears to be greater tolerance of TPM's cognitive AEs when it is used in the treatment of obesity, perhaps because of the lower doses required. Research attempting to predict the populations most vulnerable to the cognitive effects caused by TPM is ongoing. Studies suggest that one such population may include patients with a past psychiatric history. Slow titration and administration of the lowest possible doses may decrease risk of cognitive deficits.

Review of topiramate for the treatment of epilepsy in elderly patients

Individuals over 65 years of age experience the new onset of seizures at a prevalence rate of roughly twice that of younger adults. Differences in physiology, need of concomitant medications, and liability for cognitive deficits in this population, make the choice of anticonvulsant drugs especially important. This paper reviews topiramate (TPM), a treatment for many types of seizures, with the above risks in mind. In particular, we discuss efficacy and pharmacokinetics with emphasis on the older patient, and adverse events in both the younger and older adult. With most studies of TPM-induced cognitive deficits having been performed in younger adults and volunteers, we discuss the implications for the older adult. Even in studies of younger individuals, up to 50% discontinue TPM because of intolerable cognitive deficits. Most studies find specific declines in working memory and verbal fluency. In conclusion, we give recommendations for use of this antiepileptic drug in this population.

Topiramate: a review of its use in the treatment of epilepsy

Topiramate (Topamax) is a structurally novel broad-spectrum antiepileptic drug (AED) with established efficacy as monotherapy or adjunctive therapy in the treatment of adult and paediatric patients with generalised tonic-clonic seizures, partial seizures with or without generalised seizures, and seizures associated with Lennox-Gastaut syndrome. The incidence and severity of many adverse events, including CNS-related events, may be reduced through the use of slow titration to effective and well tolerated dosages. It is associated with few clinically significant interactions with other drugs, is effective when used with other AEDs, is not associated with drug-induced weight gain and, at lower dosages, does not interfere with the effectiveness of oral contraceptives. Therefore, topiramate is a valuable option as monotherapy or adjunctive therapy in the treatment of epilepsy in adult and paediatric patients.

Topiramate slow dose titration: improved efficacy and tolerability

Topiramate is an effective treatment for several types of seizures. The aim of this study is to assess the efficacy and tolerability of slow topiramate dose titration as add-on therapy in childhood epilepsy. This investigation is a prospective open-label, single-center, add-on study in 22 children with a diagnosis of refractory epilepsy. Topiramate (dose 0.5-2 mg/kg/day) was titrated at 2-week intervals up to the recommended dose of 6-12 mg/kg/day. Seizure frequency rate reduction was significant, declining from 23 +/- 5.1 seizures/week (mean +/- S.E.M.) at baseline phase to 3.5 +/- 1.2 seizures/week at the end of the 16-week stabilization phase (P < 0.001). After 16 weeks of stabilization, 19 patients (86%) had more than 50% seizure reduction. Seven patients (31%) were 100% seizure-free. Two patients (9%) manifested no improvement; only one patient (5%) did not tolerate the added drug and discontinued topiramate. One patient manifested severe side effects, whereas 21 patients experienced mild to moderate side effects mostly represented by somnolence, nervousness, and anorexia with or without weight loss. We conclude that slow dose titration improves efficacy and tolerability of topiramate as add-on therapy in the treatment in refractory epilepsy.