Antiseizure medication withdrawal in seizure-free patients with PCDH19-related epilepsy: A multinational cohort survey

Purpose: PCDH19-related epilepsy is usually refractory to current antiseizure medications (ASM), but seizures are easier to control especially after the second decade of life. Nonetheless, there is no evidence regarding the withdrawal of ASM in this clinical scenario. We aimed to evaluate the outcomes of attempts to discontinue ASM in seizure-free patients with PCDH19-related epilepsy. Methods: This survey was a cross-sectional study of patients with PCDH19-related epilepsy open between June 2019 and February 2020 and implemented in collaboration with international patient advocacy groups. Caregivers or patients were asked to fill out an anonymous questionnaire of clinical data about the attempts of ASM reduction. Results: The survey received 42 unique responses with collected data of 77 attempts of ASM withdrawal. Median age at the ASM reduction was 10 years and mean duration of the previous seizure-free period was 35.8 months. Overall, 88.3 % had seizure recurrence (p< 0.001). After seizure recurrence, the medication had to be increased above the previous ASM dose in 36.5 % and come back to the previous one in 25.4 % cases. 5.2 % did not become seizure-free again. Only 2.6 % cases had their ASM totally withdrawn. Patients without seizure recurrence were significantly older and showed longer seizure-free period (p< 0.001). Conclusion: This pilot study in PCDH19-related epilepsy shows that the withdrawal of ASM seems to be associated with a high risk of seizure recurrence. Despite this novel methodology is useful for rare diseases, it has some limitations and biases. Additional studies are warranted in more extensive samples.