A preliminary analysis of data from this trial failed to demonstrate any signal of activity.

This is a randomized, double-blind, 2-arm, placebo-controlled crossover study in pediatric patients with autism spectrum disorder with all patients receiving 16-weeks of TSO treatment and 16 weeks of placebo.

Inclusion Criteria:

• Male or female patients, 5 to 17 years of age
• Patients must fulfill DSM-V diagnostic criteria for autism spectrum disorder ascertained at screening, using a clinical review confirmed by the Autism Diagnosis Observation Schedule - Second edition (ADOS-2)
• Written informed consent from parent(s) or legal guardian(s) with sufficient intellectual capacity to understand the study and support patients' adherence to the study procedures must be obtained for patients who are not emancipated. In accordance with Institutional Review Board (IRB) requirements, the patient will complete an informed assent when developmentally appropriate, to participate in the study before conduct of any study-specific procedures.
• Patients are able and willing to swallow study medication suspension.

Exclusion Criteria:

• Known diagnosis of syndromal form of Autism (e.g. Rett Syndrome, Childhood Disintegrative Disorder, Fragile X Syndrome, etc.)
• Patients who cannot discontinue anti-psychotic medication
• Patients with current active seizure disorder or who have had a seizure within the last 6 months prior to screening
• Female patient who is pregnant or breastfeeding or wishing to become pregnant during study participation or unwilling to use birth control.
• Patients who have received helminthic treatment