Study to Investigate LP352 in Subjects With Developmental and Epileptic Encephalopathies

This is a randomized, double-blind, parallel-group, dose-escalation, placebo-controlled study of LP352 in adults and adolescents with developmental and epileptic encephalopathies (DEE) with an average of ≥ 4 observed/countable motor seizures per 4-week period during the 12 weeks before screening while on stable antiseizure medicine (ASM).

Subjects will be randomized 4:1 to LP352 or placebo. The study will have a baseline period of 28 days, followed by a 15 day up-titration period during which time subjects will titrate up to their highest tolerated doses, and a 60-day maintenance period. After Day 75, subjects will be tapered down over a period of up to 15 days, with a follow-up visit 30 days after last dose. Enrolled subjects will be allowed to continue treatment with up to 4 concomitant ASMs at a stable dose.

Key Inclusion Criteria:

• Male or non-pregnant, non-lactating female, age 12 to 65 years
• Diagnosis of Dravet syndrome, Lennox-Gastaut syndrome, or other developmental and epileptic encephalopathy
• Has a minimum number of seizures per 4-week period while taking 1 to 4 anti-seizure medications
• All medications and epilepsy interventions must be stable for 4 weeks before screening and are expected to remain stable during the study
• The patient/parent/caregiver is able and willing to attend study visits, complete the diary and take study drug as instructed

Key Exclusion Criteria:

• Current or past history of cardiovascular or cerebrovascular disease, such as cardiac valvulopathy, myocardial infarction, stroke, pulmonary arterial hypertension or abnormal blood pressure
• Has glaucoma, renal impairment, liver disease or any other medical condition that would affect study participation or pose a risk to the subject
• Current or recent history of moderate or severe depression, anorexia nervosa, bulimia or at risk of suicidal behavior
• Currently taking anorectic agents, monoamine oxidase inhibitors; serotonin agonists or antagonists including fenfluramine, atomoxetine, vortioxetine, or other medications for weight loss
• Positive test result on the drug screen, except tetrahydrocannabinol (THC) for patients taking prescribed cannabidiol