An Open-Label Extension Study of STK-001 for Patients With Dravet Syndrome

Inclusion Criteria:

• Completed dosing with STK-001 and the End of Study Visit in Study STK-001-DS-101 orStudy STK-001-DS-102, with an acceptable safety profile per Investigator judgment.

• Had satisfactory compliance with study visits and procedures in Study STK-001-DS-101or Study STK-001-DS-102 per Investigator and Sponsor judgment.

• Completed Study STK-001-DS-101 or STK-001-DS-102 within 4 weeks of the start oftheir participation in Study STK-001-DS-501 unless approved by sponsor.

Exclusion Criteria:

• Met any withdrawal criteria from Study STK-001-DS-101 or STK-001-DS-102.

• Currently treated with an antiepileptic drug (AED) acting primarily as a sodiumchannel blocker, as maintenance therapy, including phenytoin, carbamazepine,oxcarbazepine, lamotrigine, lacosamide, rufinamide or cenobamate.

• Clinically significant unstable medical conditions other than epilepsy.

• Clinically relevant symptoms or a clinically significant illness (in the judgment ofthe Investigator) at Screening or prior to dosing on Day 1, other than epilepsy.

• Spinal deformity or other condition that may alter the free flow of CSF or has animplanted CSF drainage shunt.

• Treated (or is being treated) with an investigational product (other than STK-001)since participating in Study STK-001-DS-101 or STK-001-DS-102.

• Participating in an observational study, they are excluded unless approved by theSponsor.