Anti-seizure medications for Lennox-Gastaut syndrome

Background Lennox‐Gastaut syndrome (LGS) is an age‐specific epilepsy syndrome characterised by multiple seizure types. LGS has a characteristic electroencephalogram, an onset before age eight years, and drug resistance.

This is an updated version of the Cochrane Review published in 2013.

Objectives To assess the efficacy and tolerability of anti‐seizure medications (ASMs) for LGS.

Search methods We searched the Cochrane Register of Studies (CRS Web) and MEDLINE (Ovid, 1946 to 28 February 2020) on 2 March 2020. CRS Web includes randomised controlled trials (RCTs) or quasi‐RCTs from the Cochrane Central Register of Controlled Trials (CENTRAL); the Specialised Registers of Cochrane Review Groups, including Cochrane Epilepsy; PubMed; Embase; ClinicalTrials.gov; and the World Health Organization's International Clinical Trials Registry Platform (ICTRP). We imposed no language restrictions. We contacted pharmaceutical companies and colleagues in the field to seek any unpublished or ongoing studies.

Selection criteria We considered RCTs, including cross‐over trials, of ASMs for LGS in children and adults. We included studies of ASMs used as either monotherapy or as add‐on (adjunctive) therapy. We excluded studies comparing different doses of the same ASM.

Data collection and analysis We used standard Cochrane methodological procedures, including independent, dual assessment for risk of bias, and applying the GRADE approach to rate the evidence certainty for outcomes.

Main results We found no trials of ASM monotherapy. The review included 11 trials (1277 participants; approximately 11 weeks to 112 weeks follow‐up after randomisation) using add‐on ASMs for LGS in children, adolescents, and adults.

Two studies compared add‐on cannabidiol (two doses) with add‐on placebo in children, adolescents, and adults. Insufficient information was provided for calculation of different response rate proportions in all seizures. We found high‐certainty evidence that 82 more people per 1000 (confidence interval (CI) 19 more to 350 more) had adverse events (AE) leading to study discontinuation with add‐on cannabidiol, compared to add‐on placebo (two studies; 396 participants; risk ratio (RR) 6.62, 95% CI 1.56 to 28.15).

One study compared add‐on cinromide with add‐on placebo in children and adolescents only. We found very low‐certainty evidence that 35 more people per 1000 (CI 123 fewer to 434 more) had 50% or greater average reduction of overall seizures with add‐on cinromide compared to add‐on placebo (one study; 56 participants; RR 1.15, 95% CI 0.47 to 2.86). This study did not report participants with AE leading to study discontinuation.

One study compared add‐on clobazam (three doses) with add‐on placebo. This study did not report overall seizure cessation or reduction. We found high‐certainty evidence that 106 more people per 1000 (CI 0 more to 538 more) had AE leading to study discontinuation with add‐on clobazam compared to add‐on placebo (one study; 238 participants; RR 4.12, 95% CI 1.01 to 16.87).

One study compared add‐on felbamate with add‐on placebo. No cases of seizure cessation occurred in either regimen during the treatment phase (one study; 73 participants; low‐certainty evidence). There was low‐certainty evidence that 53 more people per 1000 (CI 19 fewer to 716 more) with add‐on felbamate were seizure‐free during an EEG recording at the end of the treatment phase, compared to add‐on placebo (RR 2.92, 95% CI 0.32 to 26.77). The study did not report overall seizure reduction. We found low‐certainty evidence that one fewer person per 1000 (CI 26 fewer to 388 more) with add‐on felbamate had AE leading to study discontinuation compared to add‐on placebo (one study, 73 participants; RR 0.97, 95% CI 0.06 to 14.97).

Two studies compared add‐on lamotrigine with add‐on placebo. Neither study reported overall seizure cessation. We found high‐certainty evidence that 176 more people per 1000 (CI 30 more to 434 more) had ≥ 50% average seizure reduction with add‐on lamotrigine compared to add‐on placebo (one study; 167 participants; RR 2.12, 95% CI 1.19 to 3.76). We found low‐certainty evidence that 40 fewer people per 1000 (CI 68 fewer to 64 more) had AE leading to study‐discontinuation with add‐on lamotrigine compared to add‐on placebo (one study; 169 participants; RR 0.49, 95% CI 0.13 to 1.82).

Two studies compared add‐on rufinamide with add‐on placebo. Neither study reported seizure cessation. We found high‐certainty evidence that 202 more people per 1000 (CI 34 to 567 more) had ≥ 50% average seizure reduction (one study; 138 participants; RR 2.84, 95% CI 1.31 to 6.18). We found low‐certainty evidence that 105 more people per 1000 (CI 17 fewer to 967 more) had AE leading to study discontinuation with add‐on rufinamide compared to add‐on placebo (one study; 59 participants; RR 4.14, 95% CI 0.49 to 34.86). One study compared add‐on rufinamide with another add‐on ASM. This study did not report overall seizure cessation or reduction. We found low‐certainty evidence that three fewer people per 1000 (CI 75 fewer to 715 more) had AE leading to study discontinuation with add‐on rufinamide compared to another add‐on ASM (one study; 37 participants; RR 0.96, 95% CI 0.10 to 9.57).

One study compared add‐on topiramate with add‐on placebo. This study did not report overall seizure cessation. We found low‐certainty evidence for ≥ 75% average seizure reduction with add‐on topiramate (one study; 98 participants; Peto odds ratio (Peto OR) 8.22, 99% CI 0.60 to 112.62) and little or no difference to AE leading to study discontinuation compared to add‐on placebo; no participants experienced AE leading to study discontinuation (one study; 98 participants; low‐certainty evidence).

Authors' conclusions RCTs of monotherapy and head‐to‐head comparison of add‐on ASMs are currently lacking. However, we found high‐certainty evidence for overall seizure reduction with add‐on lamotrigine and rufinamide, with low‐certainty evidence for AE leading to study discontinuation compared with add‐on placebo or another add‐on ASM. The evidence for other add‐on ASMs for overall seizure cessation or reduction was low to very low with high‐ to low‐certainty evidence for AE leading to study discontinuation.

Future research should consider outcome reporting of overall seizure reduction (applying automated seizure detection devices), impact on development, cognition and behaviour; future research should also investigate age‐specific efficacy of ASMs and target underlying aetiologies.