Objective: Epilepsy is a major manifestation of tuberous sclerosis complex (TSC). Everolimus is an mammalian target of rapamycin complex 1 inhibitor with demonstrated benefit in several aspects of TSC. We report the first prospective human clinical trial to directly assess whether everolimus will also benefit epilepsy in TSC patients. Methods: The effect of everolimus on seizure control was assessed using a prospective, multicenter, open-label, phase I/II clinical trial. Patients 2 years of age with confirmed diagnosis of TSC and medically refractory epilepsy were treated for a total of 12 weeks. The primary endpoint was percentage of patients with a 50% reduction in seizure frequency over a 4-week period before and after treatment. Secondary endpoints assessed impact on electroencephalography (EEG), behavior, and quality of life. Results: Twenty-three patients were enrolled, and 20 patients were treated with everolimus. Seizure frequency was reduced by 50% in 12 of 20 subjects. Overall, seizures were reduced in 17 of the 20 by a median reduction of 73% (p < 0.001). Seizure frequency was also reduced during 23-hour EEG monitoring (p 5 0.007). Significant reductions in seizure duration and improvement in parent-reported behavior and quality of life were also observed. There were 83 reported adverse events that were thought to be treatment-related, all of which were mild or moderate in severity. Interpretation: Seizure control improved in the majority of TSC patients with medically refractory epilepsy following treatment with everolimus. Everolimus demonstrated additional benefits on behavior and quality of life. Treatment was safe and well tolerated. Everolimus may be a therapeutic option for refractory epilepsy in this population.

Objective: To evaluate the long-term benefit and safety of everolimus for the treatment of medically refractory epilepsy in patients with tuberous sclerosis complex (TSC).Methods: Everolimus was titrated over 4 weeks and continued an additional 8 weeks in a prospective, open-label, phase I/II clinical trial design. Participants demonstrating initial benefit continued treatment until study completion (48 months). The primary endpoint was percentage of patients with a $50% reduction in seizure frequency compared to baseline. Secondary endpoints assessed absolute seizure frequency, adverse events (AEs), behavior, and quality of life.Results: Of the 20 participants who completed the initial study phase, 18 continued extended treatment. Fourteen of 18 (78%) participants completed the study, all but 1 of whom reported $50% reduction in seizure frequency at 48 months. All participants reported at least 1 AE, the vast majority (94%) of which were graded mild or moderate severity. Improvements in behavior and quality of life were also observed, but failed to achieve statistical significance at 48 months.Conclusions: Improved seizure control was maintained for 4 years in the majority of patients with TSC with medically refractory epilepsy treated with everolimus. Long-term treatment with everolimus is safe and well-tolerated in this population. Everolimus may be a therapeutic option for refractory epilepsy in TSC. More than 80% of individuals with tuberous sclerosis complex (TSC) develop epilepsy, usually within the first year of life.1 Epilepsy in an estimated third of these individuals is refractory to conventional anticonvulsant medications, 2 heightening the urgency for development of effective treatments. TSC1 and TSC2, the causative genes for TSC, regulate the protein kinase mammalian target of rapamycin complex 1 (mTORC1). Pharmacologic inhibitors of mTORC1 are now approved to treat multiple clinical aspects of TSC, including subependymal giant cell astrocytomas (SEGA), 3,4 renal angiomyolipomas, 5 and pulmonary lymphangioleiomyomatosis. 6 mTORC1 inhibitors also have been reported to be effective for treatment of topical angiofibromas and cardiac rhabdomyomas in TSC. 7,8 Preclinical studies in TSC mouse models demonstrate that mTORC1 inhibitors effectively prevent seizures.9,10 TSC patients in early (open-label) clinical trials to treat SEGA with everolimus reported reduced frequency of daily seizures and increased rates of seizure freedom, 4,[11][12][13] but seizure benefit could not be demonstrated in more recent (placebo-controlled, randomized) From the Departments of Pediatrics and Neurology