Comparison of the effectiveness of anterior thalamic stimulation in a European registry and a phase III study—English version

Abstract

Besides the data of the phase III study (SANTE), the results of the MORE registry on the use of anterior thalamic deep brain stimulation (ANT-DBS) have recently become available. In which aspects do the phase III study and the MORE registry differ? A literature-based comparison was performed for the 2‑year outcomes of the prospective, randomized-controlled SANTE trial which included 110 patients and the prospective (nonrandomized, nonstandardized) MORE registry of 170 patients. The data analysis was focused on patient selection, surgical management, stimulation setting, therapeutic effects, and safety aspects. The median 2‑year seizure frequency reduction rate in the MORE registry remained clearly behind that of the SANTE trial (33% vs. 56%). Also in the subgroup of temporal lobe epilepsies, the seizure frequency reduction was not higher than 33%. Patients with cognitive impairment tended to have a poorer outcome compared to patients without cognitive impairment (26% vs. 36% median seizure frequency reduction rate). The MORE registry and the SANTE trial differed in several methodological aspects and patient selection: The SANTE trial included a higher percentage of patients with unifocal epilepsy (p = 0.007), temporal seizure onset (p = 0.0005), more frequent focal to bilateral tonic–clonic seizures (p = 0.02), and excluded patients with cognitive impairment (p < 0.0001). In the MORE registry, not only the trans- but also an extraventricular implantation approach was used and the achieved therapeutic effects were associated with the treating center’s level of expertise. The stimulation parameters and observed side-effects in the two studies were comparable. The registry data confirm the safe and effective use of ANT-DBS in drug-resistant epilepsy. They reflect the clinical routine use of the ANT-DBS therapy. While the results remained behind the outcomes of the phase III trial, they are within the effectiveness range of other neurostimulation therapies for epilepsy. The observed differences might be mainly due to differences in the cohort characteristics and differences in the implantation techniques.