A recent study presented at the 2024 American Epilepsy Society (AES) Annual Meeting indicates that long episode (LE) frequency, as detected by responsive neurostimulators (RNS), can predict the effectiveness of antiseizure medications (ASMs) in patients with drug-resistant focal epilepsy. The research, led by Jacqueline A. French, MD, suggests that a reduction of at least 30% in LE frequency correlates with a clinically meaningful reduction in seizure frequency, offering a potential biomarker for proof-of-concept studies in ASM development.
The study involved data from 45 patients with RNS devices, revealing a median LE frequency reduction of 30% and a median clinical seizure (CS) frequency reduction of 50%. Patients who achieved at least a 30% reduction in LE frequency were 70% more likely to experience at least a 50% reduction in CS frequency. These findings suggest that LE frequency could serve as a reliable early indicator of clinical efficacy in ASM development, potentially reducing the number of patients needed in initial trials.
Leveraging Neurostimulators for Drug Development
Dr. French, a professor of neurology at NYU Grossman School of Medicine and director of the Epilepsy Study Consortium, emphasized the importance of this approach for innovative startups developing novel epilepsy treatments. Traditional clinical trials often require large patient populations to detect treatment effects, but incorporating biomarkers like LE frequency into proof-of-concept designs may reduce the number of patients needed to identify treatment signals. She noted that many novel treatments are emerging from innovative startups, which need early evidence of efficacy to justify further development.
Clinical Implications and Future Directions
While RNS devices are not universally used, their increasing prevalence offers a valuable data source for optimizing epilepsy management. The study highlights that even in patients with RNS who continue to experience seizures, reductions in LE frequency can predict clinically meaningful improvements. However, Dr. French cautioned that this is just a starting point, and further research is needed to validate these findings.
Next-generation devices, such as UniEEG and Epiminder, which offer less invasive monitoring options, hold promise for expanding access to advanced seizure detection. The data recorded from these devices could further improve patient treatment and accelerate the identification of effective drugs. Dr. French expressed hope that the proof-of-concept study using LEs will pave the way for faster and more efficient development of new ASMs, ultimately benefiting people with epilepsy sooner.
Understanding Long Episode Frequency
Dr. French acknowledged that the clinical community's understanding of long episode frequency is still evolving. While specialists who implant and manage RNS devices are familiar with this metric, general neurologists may not be. Therefore, education and awareness are crucial to ensure that LE frequency is effectively utilized to optimize patient outcomes.
