Suramin has been found to correct the symptoms, metabolism, and brain synaptic abnormalities in two classical genetic and environmental mouse models of autism. A preliminary clinical trial (SAT-1) examined the safety and activity of a single low-dose of suramin in children with ASD and concluded suramin showed promise as a novel approach to treatment of ASD. The current study, STAT-2A, will be a randomized, double-blind, crossover, 30-week study to evaluate the preliminary proof of concept, safety, and PK of suramin sodium (KZ101) with repeat dosing by IV infusion in males 5-14 years of age who have been diagnosed with ASD. The study will be conducted at approximately 3 sites contributing approximately 15 subjects per site. Total enrollment of approximately 45 subjects is planned to achieve approximately 36 participants completing the study.

After up to a 4-week screening period, participants will undergo 8 weeks of active or placebo treatment (Period 1), followed by an 8-week washout period, and then cross over to 8 weeks of placebo or active treatment (Period 2). Patients will be followed for 2 weeks after completion of Period 2. Two dosing groups are designated as Group A, who are randomly assigned to active treatment with KZ101 in Period 1 and saline in Period 2, and Group B, who are randomly assigned to saline infusion in Period 1 and active treatment with KZ101 in Period 2. Dosing in both periods will consist of 2 IV infusions of either saline (placebo) or KZ101 (active treatment), given 4 weeks apart.

Inclusion Criteria:

- Subject must meet all of the following criteria to be enrolled in this study.

1. Male, aged 5-14 years
2. Clinical diagnosis of ASD by DSM-5 criteria
3. ADOS-2 ≥ 7 on the comparison score for Modules 2-4 (completed within the last 2 years).
4. CGI-S ≥ 4 for socialization specific symptoms of ASD
5. Leiter-3 non-verbal IQ > 70
6. Standard score < 75 on the Socialization Domain of the Comprehensive Interview Form of the Vineland Adaptive Behavior Scale Third Edition
7. Subjects who are sexually active or potentially sexually active agree to use condoms with a spermicidal as a barrier method of contraception during the treatment period and for at least 30 days after the last dose of study medication
8. Subjects agree to wear sunscreen and to wear skin covering to the maximal degree tolerated by the child for the duration of the treatment period and for at least 30 days after the last dose of study medication
9. Subjects must have a ≤ 90 minutes car ride from the study site
10. English-speaking child and parent/guardian or caregiver
11. Parent or their legal guardians must be willing to sign informed consent

Exclusion Criteria:

• Subjects who meet any of the following criteria will be excluded from the study.

  1. ASD diagnosis with underlying syndromic diagnosis (e.g., Fragile X, Angelman, Down's Syndrome, etc.)
  2. ≤ 5th percentile for weight
  3. Unable to tolerate venipuncture or urine collection
  4. Acute infection (e.g., upper respiratory tract infection, common cold, flu, strep, COVID-19)
  5. Severe co-morbid conditions (e.g., psychosis, seizures/epilepsy uncontrolled by medication, presence of severe visual or hearing impairment) that may interact with study procedures. Controlled epilepsy is allowed providing there has not been a breakthrough seizure in the past year.
  6. Any organ system dysfunction, especially liver (e.g., ALT or AST ≥ 1.5x the upper limit of normal), kidney (estimated glomerular filtration rate or eGFR < 90 mL/min/1.73 m2; hematuria confirmed by urine microscopy [ > 5 red blood cells/high power field]; proteinuria [> 1+ that does not resolve on repeat testing or urine protein to creatinine ratio > 0.3]; and/or presence of any granular, mixed cellular, red blood cell, white blood cell, or muddy brown casts on urine microscopy), or clinically relevant heart or adrenal abnormalities
  7. Hospitalization within the previous 2 months from screening
  8. Initiation or change in pharmacotherapy within previous 2 months from screening
  9. Initiation or change in psychosocial interventions (formal behavioral, cognitive, or cognitive-behavior therapy) within previous 2 months from screening
  10. Plan to initiate or change pharmacotherapy or psychosocial interventions during the study
  11. Taking prescription medication that may interact adversely with KZ101 or expose the subject to increased risk of harm such as medications with plasma bound substances including sulfonamides, chlorpromazine, and anti-coagulants
  12. Currently enrolled in another clinical study or has received any investigational treatment within 30 days of screening
  13. Taking > 3 medications addressing behavioral symptoms related to ASD (ie typical/atypical antipsychotics and alpha-adrenergic agonists) or comorbid medical conditions such as ADHD, anxiety, or depression. Anti-seizure medications and other medications not related to neurobehavioral symptoms do not count towards the total number of medications allowed.
  14. History of serious dermatological reactions
  15. History of allergy, intolerance, or photosensitivity to any drug
  16. Unable or unwilling to adhere to study requirements

There is no plan to share IPD at this time.