Objective: To evaluate the efficacy, safety and economics of levetiracetam (LEV) for epilepsy.
Materials and methods: PubMed, Scopus, the Cochrane Library, OpenGrey.eu and ClinicalTrials.gov were searched for systematic reviews (SRs), meta-analyses, randomized controlled trials (RCTs), observational studies, case reports and economic studies published from January 2007 to April 2018. We used a bubble plot to graphically display information of included studies and conducted meta-analyses to quantitatively synthesize the evidence.
Results: A total of 14,803 records were obtained. We included 30 SRs/meta-analyses, 34 RCTs, 18 observational studies, 58 case reports and 2 economic studies after the screening process. The included SRs enrolled patients with pediatric epilepsy, epilepsy in pregnancy, focal epilepsy, generalized epilepsy and refractory focal epilepsy. Meta-analysis of the included RCTs indicated that LEV was as effective as carbamazepine (CBZ; treatment for 6 months: 58.9% vs 64.8%, OR=0.76, 95% CI: 0.50–1.16; 12 months: 54.9% vs 55.5%, OR=1.24, 95% CI: 0.79–1.93), oxcarbazepine (57.7% vs 59.8%, OR=1.34, 95% CI: 0.34–5.23), phenobarbital (50.0% vs 50.9%, OR=1.20, 95% CI: 0.51–2.82) and lamotrigine (LTG; 61.5% vs 57.7%, OR=1.22, 95% CI: 0.90–1.66). SRs and observational studies indicated a low malformation rate and intrauterine death rate for pregnant women, as well as low risk of cognitive side effects. But psychiatric and behavioral side effects could not be ruled out. LEV decreased discontinuation due to adverse events compared with CBZ (OR=0.52, 95% CI: 0.41–0.65), while no difference was found when LEV was compared with placebo and LTG. Two cost-effectiveness evaluations for refractory epilepsy with decision-tree model showed US$ 76.18 per seizure-free day gained in Canada and US$ 44 per seizure-free day gained in Korea.
Conclusion: LEV is as effective as CBZ, oxcarbazepine, phenobarbital and LTG and has an advantage for pregnant women and in cognitive functions. Limited evidence supports its cost-effectiveness
Epilepsy ranks fourth after tension-type headache, migraine and Alzheimer disease in the world’s neurological disorders burden.1 A systematic review (SR) and meta-analysis of international studies reported that the point prevalence of active epilepsy was 6.38 per 1,000 people, while the lifetime prevalence was 7.60 per 1,000 people. The annual cumulative incidence of epilepsy was 67.77 per 100,000 people, while the incidence rate was 61.44 per 100,000 person-years.2 As a fairly common clinical condition affecting all ages and requiring long-term, sometimes lifelong, treatment, epilepsy incurs high health care costs for the society.1 In 2010, the total annual cost for epilepsy was 13.8 billion and the total cost per patient was €5,221 in Europe.3 Meanwhile, in the USA, epilepsy-related costs ranged from $1,022 to $19,749 per person annually.4 What is more, drug-refractory epilepsy was a major cost driver,5 with main costs from anticonvulsants, hospitalization and early retirement.6
Currently, antiepileptic drugs (AEDs) are the main treatment method for epilepsy patients, and it was reported that approximately two-thirds of epileptic seizures were controlled by AEDs.7 Conventional AEDs such as carbamazepine (CBZ) and sodium valproate (VPA) have been proven to have good therapeutic effects and low treatment cost. However, some adverse events (AEs) related to these drugs, such as Stevens–Johnson syndrome, menstrual disorder and memory deterioration seriously affect the tolerance and compliance of patients. Compared with conventional AEDs, new AEDs have the potential to be safer, but also more expensive.8
Levetiracetam (LEV) is a novel AED that has been approved as an adjunctive therapy for adults with focal epilepsy since 1999 in the US. In 2006, it was licensed as monotherapy for adults and adolescents above 16 years of age with newly diagnosed focal-onset seizures with or without secondary generalization in Europe. Also, it has been indicated as an adjunctive therapy for partial-onset seizures in patients above 4 years of age in China since 2007. Although the precise mechanism of LEV is still unclear, current researches suggest that its pharmacological mechanism is different from those of other AEDs. It may bind to the synaptic vesicle protein 2A (SV2A), which presents on the synaptic vesicles and some neuroendocrine cells. SV2A may participate in the exocytosis of synaptic vesicles and regulate the release of neurotransmitters, especially the release of excitatory amino acids, and thus depress the epilepsy discharge.9,10 Other possible mechanisms of LEV include the following: selective inhibition of voltage-dependent N-type calcium channels in hippocampal pyramidal cells and reduction of the negative allosteric agents’ inhibition, such as zinc ions and B-carbolines, on glycine and γ-aminobutyric acid neurons, which results in indirectly increasing central nervous system inhibition.11
LEV is almost completely absorbed after oral administration and the absorption is unaffected by food. The bioavailability is nearly 100% and the steady-state concentrations are achieved in 2 days if LEV is taken twice daily. Sixty-six percent of LEV is renally excreted unchanged and its major metabolic pathway is enzymatic hydrolysis of the acetamide group, which is independent of liver CYP/CYP450; so, no clinically meaningful drug–drug interactions with other AEDs were found.12 One published SR of LEV suggested LEV has an equal efficacy compared with conventional AEDs and it is well tolerated for long-term therapy without significant effect on the immune system.13 But in recent years, apart from the most frequent AEs of LEV, such as nausea, gastrointestinal symptoms, dizziness, irritability and aggressive behavior, some rare AEs of LEV have been reported, including eosinophilic pneumonia, rhabdomyolysis, thrombocytopenia, elevated kinase and reduced sperm quality.14–17
Thus, we conducted a mapping review to evaluate the efficacy, safety and economic profiles of LEV compared with all other AEDs for epilepsy, to provide evidence-based information for the rational use of LEV and research agendas.