Efficacy and tolerability of rufinamide in the treatment of Lennox–Gastaut syndrome (experience of the Svt. Luka’s Association of Medical Institutions)

Abstract

Background. Lennox–Gastaut syndrome (LGS) is a classic developmental and epileptic encephalopathy with a debut in childhood, characterized by resistance to therapy, a severe course, and an unfavorable prognosis. Due to the existing difficulties in treatment of LGS, hopes are pinned on development of new antiepileptic drugs with fundamentally different mechanisms of action, aimed specifically at the treatment of this severe form of epilepsy.Rufinamide (Inovelon®) is a new antiepileptic drug registered in the Russian Federation for use in the adjunctive therapy of LGS in patients older than 1 year. The main mechanism of action of rufinamide is the restriction of neuronal discharges associated with the blocking effect on sodium channels (regulation of sodium channels activity by increasing duration of their inactive state), and stabilization of neuronal membranes. The drug has a number of advantages concernung pharmacokinetic parameters and efficacy (including a wide spectrum of antiepileptic activity, good oral absorption, absence of active metabolites, urinary excretion, low affinity for plasma proteins, biotransformation without cytochrome P450 isoenzymes, low risk of drug interactions) and fairly good tolerability. The daily dose of rufinamide varies from 600 mg (with simultaneous administration of valproate) to 1000 mg (if the patient does not take valproate) in children over 4 years of age with a body weight of less than 30 kg and up to 2200–3200 mg in children over 4 years of age with a body weight of more than 30 kg and in adults; in children under 4 years of age, the maximum daily dose in combination with valproate is 30 mg/kg, and without valproic acid – 45 mg/kg.Aim. To analyze the efficacy and tolerability of rufinamide in the treatment of epilepsy based on the long-term experience of using the drug in the Svt. Luka’s Association of Medical Institutions.Materials and methods. We observed 64 patients aged from 1.5 to 26 years (44 men, 20 women) treated with rufinamide (Inovelon®). Among them, the structural etiology LGS was diagnosed in 36 patients, the genetic and presumably genetic etiology LGS – in 28. In all cases, rufinamide was used in accordance with approved indications as an additional antiepileptic drug, more often in combination with valproate, topiramate, levetiracetam or lamotrigine. Titration of the drug was carried out according to the recommendations in the instructions for use, up to a therapeutic dose that ranged from 200 to 1600 mg/day (in most cases from 400 to 1200 mg/day), depending on age and concomitant therapy.Results and conclusion. Remission of all types of seizures was registered in 17 (26.6 %) patients, and a decrease in the incidence of seizures by more than 50 % was recorded in 28 (43.8 %) patients. Of them, 13 patients demonstrated reduction in seizures frequency by more than 75–90 % and remission of one of several types of seizures. In general, the therapeutic effect (reduction of seizures frequency by at least 50 %) was achieved in 45 (70.3 %) of 64 patients. A decrease in seizures frequency of by at least 50 % was observed in 8 (12.5 %) patients; in 10 (15.6 %) patients, rufinamide therapy was not effective; in 1 (1.56 %) case an aggravation of bilateral convulsive seizures was noted when rufinamide was administered.In most cases, rufinamide is well tolerated. Our patients had side effects in 10 (15.6 %) cases. Only in 2 (3.1 %) cases, rufinamide was withdrawn directly due to side effects (the reason for withdrawal in these cases was an allergic reaction and psychosis).The retention rate for therapy lasting 1 year or more is 65.6 % (42 of 64 patients).Thus, our data have demonstrated efficacy and good tolerability of rufinamide in treating epileptic seizures associated with LGS, confirming numerous literature data. However, in our analysis, a higher rate of seizure remission was obtained, although we have included patients with mainly resistant forms of epilepsy in the analysis.