Sudden unexpected death in epilepsy in lamotrigine randomized-controlled trials

Area of Science:

• Neurology
• Clinical Pharmacology
• Epilepsy Research

Background:

• Nonrandomized studies on antiepileptic drugs (AEDs) and sudden unexpected death in epilepsy (SUDEP) risk are prone to confounding factors like seizure frequency and polypharmacy.
• Randomized controlled trials (RCTs) offer a more robust method to assess AEDs' relationship with SUDEP.
• Lamotrigine (LTG) is a widely used AED, necessitating a clear understanding of its SUDEP risk profile.

Purpose of the Study:

• To evaluate the risk of SUDEP associated with lamotrigine (LTG) compared to active comparators and placebo.
• To analyze data from randomized controlled clinical trials (RCTs) conducted between 1984 and 2009.
• To mitigate confounding factors inherent in nonrandomized SUDEP studies.

Main Methods:

• Analysis of 7,774 subjects across 42 RCTs, focusing on 39 on-treatment deaths.
• Independent blinded review of death narratives by three clinical experts to determine SUDEP classification (definite, probable, possible, non-SUDEP).
• Comparison of definite or probable SUDEP risk between LTG and comparator arms using exact statistical methods, stratified by trial type (placebo-controlled, active-comparator, crossover).

Main Results:

• Eight definite/probable SUDEP events occurred among 29 on-treatment deaths.
• The unadjusted rate of definite/probable SUDEP for LTG was 2.2 per 1,000-patient years (95% CI 0.70-5.4).
• Odds ratios for SUDEP showed no statistically significant differences between LTG and comparator groups across placebo-controlled (OR 0.22), active-comparator (OR 2.18), and crossover trials (OR 1.08), though confidence intervals were wide.

Conclusions:

• No statistically significant difference in SUDEP rates was observed between lamotrigine and comparator groups in the analyzed RCTs.
• The wide confidence intervals associated with the SUDEP risk estimates indicate that a clinically important effect cannot be excluded.
• Further research with larger sample sizes may be needed to definitively establish the SUDEP risk associated with LTG.