Long-term treatment with everolimus in TSC-associated therapy-resistant epilepsies

Purpose: To investigate the efficacy and tolerability of long-term treatment with Everolimus (EVO) in patients with tuberous sclerosis complex (TSC) and therapy-resistant epilepsy in a compassionate use trial. Methods: After a 3-month baseline, patients were treated with EVO. Treatment was divided into treatment phases each lasting at least 9 months. Patients started with one of three target serum levels. In case of insufficient seizure control, subsequent treatment phases with other target serum levels followed. The accompanying antiseizure medication (ASM) remained stable during the baseline phase and for at least the initial three treatment phases. We evaluated changes in seizure frequency and seizure-free days compared to baseline for each patient (CoxStuart-test). Results: Fifteen patients were followed up for up to 10 years (minimum 0.6 years, median 5.8 years). Twelve patients (80%) experienced a significant reduction in seizure frequency or an increase in seizure-free days: Six (40%) patients became seizure-free and four patients (26.7%) remained seizure free for > 7 years, of which three required no additional ASM. All participants reported at least one adverse effect, the vast majority (92.5%) of which were mild or moderate. Conclusion: Long-term treatment with EVO was highly efficacious, safe and well tolerated. While EVO can be a therapeutic option for therapy-resistant epilepsy in TSC, it can take a long time for seizure relief to manifest.