The program was shut down due to a lack of efficacy.

Children between the ages of 6-12 years who are diagnosed with impulsive aggression comorbid with ADHD and have participated in the 810P301 or 810P302 study were invited to participate in this study. This was a Phase 3 open-label extension (OLE) study to collect long-term safety data on the use of SPN-810 in treating impulsive aggression in pediatric subjects with ADHD when taken in conjunction with standard ADHD treatment. After confirmation of eligibility, all subjects were treated with SPN-810. Subjects were given a choice to extend participation in this study every 6 months for up to 36 months.

Study 810P304 is a multicenter, open-label, extension study aimed to assess safety of SPN-810 in the treatment of IA in patients aged 6-17 years with ADHD in conjunction with standard ADHD treatment.

The study has three phases: Optimization, Maintenance, and Taper. All subjects who complete the randomized, double-blind portion of study 810P301, 810P302, 810P503 or 810P204 will have the option to participate in the OLE study in which all subjects will receive active Study Medication (SM) treatment. Subjects who choose to participate in the OLE will receive blinded conversion medication kits at Visit 6 of the previous SPN-810 double-blind randomization study (810P301, 810P302) or at Visit 4 for subjects completing the 810P204 study. Subjects, who have completed the 810P503 study and, chose to participate in this study, will receive the blinded conversion card at Visit 7.

Inclusion Criteria:

1. Healthy male or female subjects, who completed and converted from a satisfactory participation in the study 810P301, 810P302, 810P503 and 810P204 or discontinued early from the previous study during the maintenance phase and allowed to enroll only after consultation between the Investigator, the Medical Monitor and the Sponsor.
2. Medically healthy and with clinically normal laboratory profiles, vital signs, and electrocardiograms (ECGs).
3. Existing diagnosis of ADHD, as described by DSM-5 and confirmed by the K-SADS PL 2013 from study 810P301 or 810P302 or by the MINI-KID from study 810P503 or 810P204.
4. Currently receiving monotherapy treatment with FDA-approved ADHD medication (stimulants and non-stimulants).
5. Weight of at least 20 kg.
6. Written Informed Consent obtained from the subject's parent or legally authorized representative (LAR), and written Informed Assent obtained from the subject if appropriate.

Exclusion Criteria:

1. Body Mass Index (BMI) in 99th percentile or above.
2. Clinically significant change in health status, safety concern or any other reason that, in the opinion of the Sponsor or the Investigator, would prevent the subject from participating in this study or successfully completing this study.
3. Pregnancy or refusal to practice contraception during the study (for female subjects of childbearing potential and sexually active males).
4. Current substance or alcohol use.
5. Suicidal thoughts or behaviors confirmed at Visit 7 for 810P301 or 810P302, Visit 8 for 810P503 or Visit 6 for 810P204 studies.

Safety Population: Safety population is defined as all subjects who received at least 1 dose of study drug during the study.

Adverse events were collected at each study visit: Visit 1 (last visit in the double-blind study), weeks 2,4 and 8, and Months 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48 and 60 (months).

Adverse events reporting pertains to the Safety Population, defined as all subjects who received at least 1 dose of study drug during the study.