After initially successful treatment, many children with infantile spasms unfortunately have a relapse, and relapse is linked to poor long-term outcomes such as autism and other forms of epilepsy. The aim of this study is to determine if treatment with low-dose prednisolone is safe, well tolerated, and effective in reducing the risk of relapse.

In this study, the investigators will enroll infants who have responded to standard therapy for treatment of Infantile Epileptic Spasms Syndrome (IESS). Patients will be randomized to receive either low-dose prednsiolone or placebo for 4 months. During the first 7 months, patients will be evaluated monthly, with clinic visits and electroencephalography (EEG). Patients will then return for a final visit at age 2 years. Key outcomes will be determination of IESS relapse, emergence of other types of seizures/epilepsy, and evaluation of developmental/behavioral status at age 2 years. We will attempt to determine whether or not the prednisolone intervention reduces the risk of any adverse outcome, but this may not be possible given the study design. We will also evaluate the feasibility of the intervention, study procedures, and recruitment.

Inclusion Criteria:

1. Age 2 to 18 months, inclusive
2. Clinical diagnosis of infantile spasms syndrome, with EEG-confirmed complete response to standard treatment (prednisolone, ACTH, and/or vigabatrin)

Exclusion Criteria:

1. Presence of clinically significant hypertension, infection, or any other diagnosis which poses unreasonable risk in the setting of extended corticosteroid therapy, in the view of the study physician
2. Exposure to any artisanal cannabinoid product within 14 days of screening
3. Ongoing therapy with the ketogenic diet
4. Implantation of a vagal nerve stimulator within 3 months of screening, or any change in stimulation parameters within 1 month of screening
5. Treatment of IESS via epilepsy surgery

Deidentified study data will be shared with other researchers upon reasonable request, after publication of results.

IPD will be shared upon reasonable request after publication of study results.

Deidentified patient data, study protocol, statistical analysis plan, informed consent form, clinical study report, and analytic code.