Randomized Therapy In Status Epilepticus

This study will evaluate the effectiveness and safety of an investigational product (IP), intravenous (IV) ganaxolone, to treat participants with status epilepticus (SE).

This is a double-blind, randomized, placebo-controlled study to evaluate the efficacy and safety of IV ganaxolone in status epilepticus. Investigational product will be added to standard of care following failure of any two or more antiseizure medications (benzodiazepine and one IV antiepileptic drug (AED) or two IV AEDs. Participants will be screened for inclusion/exclusion criteria prior to receiving investigational product by continuous IV infusion. Participants will be followed for approximately 4 weeks. Participants who are known to be at risk for SE may be consented or assented prior to an SE event.

Eligibility Criteria:
Inclusion Criteria:

1. Participant, participant's parent, guardian, or legal authorized representative (LAR) must provide signed of informed consent/assent, and once capable (per institution guidelines), there must be documentation of consent/assent by the participant demonstrating they are willing and aware of the investigational nature of the study and related procedures. Where allowed by law, where the participant lacks the capacity to make informed decisions regarding his/her medical treatment options, the treating clinician may follow their deferred consenting practices. The clinician will make the final decision based on the best interests of the particiapant.
2. Male or females 12 years of age and older at the time of the first dose of IP
3. SE meeting the following criteria:

   a. A diagnosis of SE with or without prominent motor features based on clinical and EEG findings:

   i. Diagnosis is established by:
   * For SE with prominent motor features: Clinical and EEG seizure activity indicative of convulsive, myoclonic or focal motor SE.
   * For SE without prominent motor features (nonconvulsive SE): Appropriate clinical features and an EEG indicative of non-convulsive status epilepticus (NCSE)

   ii. For any type of SE:
   * At least 6 minutes of cumulative seizure activity over a 30-minute period within the hour before IP initiation, AND
   * Seizure activity during the 30 minutes immediately prior to IP initiation

     b. The treating clinician(s) anticipate that IV anesthesia is likely to be the next treatment for SE that persists following initiation of IP
4. Participants must have received any two or more of the following agents for treatment of the current episode of SE administered at an adequate dose and for a sufficient duration, in the judgment of the investigator, to demonstrate efficacy

   * Benzodiazepines,
   * IV Fosphenytoin/phenytoin,
   * IV Valproic acid,
   * IV Levetiracetam,
   * IV Lacosamide,
   * IV Brivaracetam, or
   * IV Phenobarbital
5. Body mass index (BMI) \< 40 or, if BMI is not able to be calculated at screening, participant is assessed by investigator as not morbidly obese

Exclusion Criteria:

1. Life expectancy of less than 24 hours
2. Anoxic brain injury or an uncorrected rapidly reversable metabolic condition as the primary cause of SE (e.g., hypoglycemia \< 50 milligram per deciliter \[mg/dL\] or hyperglycemia \> 400 mg/dL)
3. Participants who have received high-dose IV anesthetics (e.g., midazolam, propofol, thiopental, or pentobarbital) during the current episode of SE for more than 18 hours, or who continue to have clinical or electrographic evidence of persistent seizures while receiving high-dose IV anesthetics.
4. Clinical condition or advance directive that would NOT permit use of IV anesthesia
5. Participants known or suspected to be pregnant
6. Participants with known allergy or sensitivity to progesterone or allopregnanolone medications/supplements
7. Receiving a concomitant IV product containing Captisol®
8. Known or suspected hepatic insufficiency or hepatic failure leading to impaired synthetic liver function.
9. Known or suspected stage 3B (moderate to severe; estimated glomerular filtration rate \[eGFR\] 44-30 milliliter/minutes/1.73-meter square \[mL/min/1.73m\^2\]), stage 4 (severe; eGFR 29-15 mL/min/1.73m\^2), or stage 5 (kidney failure; eGFR \< 15 mL/min/1.73m\^2 or dialysis) kidney disease
10. Use of an investigational product for which less than 30 days or 5 half-lives have elapsed from the final product administration. Participation in a non-interventional clinical study does not exclude eligibility.