Klitgaard H, Matagne A, Nicolas JM, Gillard M, Lamberty Y,
De Ryck M, Kaminski RM, Leclercq K, Niespodziany I, Wolff C, Wood M, Hannestad
J, Kervyn S, Kenda B. Brivaracetam: Rationale for discovery and preclinical
profile of a selective SV2A ligand for epilepsy treatment. Epilepsia. 2016
Apr;57(4):538-48.
Abstract
Despite availability of effective antiepileptic drugs
(AEDs), many patients with epilepsy continue to experience refractory seizures
and adverse events. Achievement of better seizure control and fewer side
effects is key to improving quality of life. This review describes the
rationale for the discovery and preclinical profile of brivaracetam (BRV),
currently under regulatory review as adjunctive therapy for adults with
partial-onset seizures. The discovery of BRV was triggered by the novel
mechanism of action and atypical properties of levetiracetam (LEV) in
preclinical seizure and epilepsy models. LEV is associated with several
mechanisms that may contribute to its antiepileptic properties and adverse
effect profile. Early findings observed a moderate affinity for a unique
brain-specific LEV binding site (LBS) that correlated with anticonvulsant
effects in animal models of epilepsy. This provided a promising molecular
target and rationale for identifying selective, high-affinity ligands for LBS
with potential for improved antiepileptic properties. The later discovery that
synaptic vesicle protein 2A (SV2A) was the molecular correlate of LBS confirmed
the novelty of the target. A drug discovery program resulted in the
identification of anticonvulsants, comprising two distinct families of
high-affinity SV2A ligands possessing different pharmacologic properties. Among
these, BRV differed significantly from LEV by its selective, high affinity and
differential interaction with SV2A as well as a higher lipophilicity,
correlating with more potent and complete seizure suppression, as well as a
more rapid brain penetration in preclinical models. Initial studies in animal
models also revealed BRV had a greater antiepileptogenic potential than LEV.
These properties of BRV highlight its promising potential as an AED that might
provide broad-spectrum efficacy, associated with a promising tolerability
profile and a fast onset of action. BRV represents the first selective SV2A
ligand for epilepsy treatment and may add a significant contribution to the
existing armamentarium of AEDs.
Strzelczyk A, Klein KM, Willems LM, Rosenow F, Bauer S. Brivaracetam in the treatment of focal and idiopathic generalized epilepsies and of status epilepticus. Expert Rev Clin Pharmacol. 2016 May;9(5):637-45.
ReplyDeleteAbstract
Brivaracetam is the latest approved antiepileptic drug in focal epilepsy and exhibits high affinity as SV2A-ligand. More than two thousand patients have received brivaracetam within randomized placebo-controlled trials. Significant median seizure reduction rates of 30.5% to 53.1% for 50 mg/d, 32.5% to 37.2% for 100 mg/d and 35.6% for 200 mg/d were reported. Likewise, 50% responder rates were 32.7% to 55.8% for 50 mg/d, 36% to 38.9% for 100 mg/d and 37.8% for 200 mg/d. Overall, brivaracetam is well tolerated. The main adverse events are fatigue, dizziness, and somnolence. Immediate switch from levetiracetam to brivaracetam at a conversion ratio between 10:1 to 15:1 is feasible, and might alleviate the behavioral side effects associated with levetiracetam. Brivaracetam has the potential to perform as an important, possibly broad-spectrum AED, initially in patients with drug-refractory epilepsies. Its intravenous formulation may be a new and desirable alternative for status epilepticus, but there is so far no experience in these patients.
Lattanzi S, Cagnetti C, Foschi N, Provinciali L, Silvestrini M. Brivaracetam add-on for refractory focal epilepsy: A systematic review and meta-analysis. Neurology. 2016 Apr 5;86(14):1344-52.
ReplyDeleteAbstract
OBJECTIVE:
To evaluate the efficacy and safety of the new antiepileptic drug brivaracetam (BRV) as add-on treatment for drug-resistant partial epilepsy using meta-analytical techniques.
METHODS:
Randomized, placebo-controlled, single- or double-blind, add-on trials of BRV in adult patients with drug-resistant partial epilepsy were identified through a systematic literature search. The following outcomes were assessed: 50% or greater reduction in seizure frequency, seizure freedom, incidence of treatment-emergent adverse events (TEAEs), and treatment withdrawal. Risk ratio (RR) with 95% confidence interval was estimated for each outcome.
RESULTS:
Six trials were included involving 2,399 participants according to the intent-to-treat, 1,715 for BRV, and 684 for placebo groups, respectively. The pooled RRs for the 50% responders and seizure freedom were 1.79 (1.51-2.12) and 4.74 (2.00-11.25), respectively. The subanalysis by levetiracetam (LEV) status did not show a statistically significant difference in the 50% responder rate when comparing BRV with placebo in patients with concomitant assumption of LEV. The TEAEs significantly associated with BRV were irritability (2.99 [1.28-6.97]), fatigue (2.19 [1.44-3.33]), somnolence (1.97 [1.45-2.68]), and dizziness (1.66 [1.19-2.31]). The overall RRs for treatment withdrawal due to TEAEs or any reason were 1.58 (1.04-2.40) and 1.27 (0.93-1.73), respectively.
CONCLUSIONS:
In adults with drug-refractory focal epilepsy, add-on BRV was effective to reduce seizure frequency and fairly well-tolerated. Further studies are needed to draw definitive conclusions about its efficacy in non-LEV-naive participants and evaluate its long-term safety profile.