Open-label, Long-term Safety Study of LP352 in Subjects With Developmental and Epileptic Encephalopathy

Inclusion Criteria:

1. Male or non-pregnant, non-lactating female, age 12 to 65 years who havesatisfactorily completed study LP352-201

2. Diagnosis of Dravet syndrome, Lennox-Gastaut syndrome, or other developmental andepileptic encephalopathy

3. The patient/parent/caregiver is able and willing to attend study visits, completethe diary and take study drug as instructed

Exclusion Criteria:

1. Had an SAE in Study LP352-201 that was definitely, probably, or possibly related toexposure to study drug

2. Current or past history of cardiovascular or cerebrovascular disease, such ascardiac valvulopathy, myocardial infarction, stroke, pulmonary arterial hypertensionor abnormal blood pressure

3. Has glaucoma, renal impairment, liver disease or any other medical condition thatwould affect study participation or pose a risk to the subject

4. Current or recent history of moderate or severe depression, anorexia nervosa,bulimia or at risk of suicidal behavior

5. Currently taking anorectic agents, monoamine oxidase inhibitors; serotonin agonistsor antagonists including fenfluramine, atomoxetine, vortioxetine, or othermedications for weight loss

6. Positive test result on the drug screen, except tetrahydrocannabinol (THC) forpatients taking prescribed cannabidiol