Sapropterin as a Treatment for Autistic Disorder


The purpose of the study is to determine whether a compound called Sapropterin, a naturally occurring substance, can improve overall functioning in young children with Autism.

Autism Spectrum Disorder
Sapropterin or Placebo
Study Type: 
A Phase II Randomized, Double Blind, Placebo Controlled Trial
Study Design: 

Participants will be randomly assigned to receive either Sapropterin (active treatment) or a placebo (sugar pill or inactive treatment). He/she  have an equal chance of getting Sapropterin or placebo. The study lasts about 16 weeks. Over the course of study, both the participants and their parents come in for 8 visits. Three visits (baseline, week 8, week 16) last about 90 minutes and involve some pyschological testing, taking vitals, and discussing any progress noted.  Five visits are short, about 20-30 minutes to just take vitals and discuss progress or any side effects. At the end of the study, participants are invited to continue with an Open Label Extension for another 16 weeks. However, there is no requirement to participate in both studies. Participants may withdraw from the study at any time.

Primary Outcome Measures: 

Preschool Language Scale- Fourth Edition (PLS-4)

Vineland Adaptive Behavior Scale- Second Edition, Interview Edition, Survey Form (Vineland)

Autism Diagnostic Interview- Revised (ADI-R)

Autism Diagnostic Observation Schedule (ADOS)

Conners' Parent Rating Scale- Revised, Long Form

Clinical Global Impression Scale (CGI)

Secondary Outcome Measures: 

Aberrant Behavior Checklist (ABC)

Social Responsiveness Scale (SRS)

Children's Yale-Brown Obsessive Compulsive Scale (CYBOCS)


Ongoing- goal to finish enrolling by August 2010
Assigned Interventions: 

1. Drug: Sapropterin

2. Drug: Placebo

Ages of Eligibility: 
Inclusion Criteria: 

- Child must have a diagnosis of Autistic Disorder, PDD-NOS, or Asperger's.

- Must be over 3 years old and under 7 years old.

- Child must have an IQ or developmental quotient of  at least 50.

- The study is being conducted in Palo Alto, CA, so families must be willing and able to make the necessary appointments to our site.

Exclusion Criteria: 

- Child has seizures, or had one in the last 6 months

- Other neurologic disorders

- Genetic disorders

- Child is on concurrent meds (any psychoactive medications- anti depressants, anti psychotics, stimulants)

- Intention to add new medications during the trial

- Inability to administer the drug to the child every day.


Glen Elliott, M.D., Ph.D. (650) 688-3649

Lynne Huffman, M.D. (650) 688-3609





Children's Health Council

650 Clark Way

Palo Alto, CA 94304

United States

Sponsors & Collaborators: 

Glen R. Elliott, M.D., Ph.D.

Palo Alto, CA 94304

United States


Principal Investigator: Glen R. Elliott, Chief Psychiatrist and Medical Director

Sub-investigator: Lynne C. Huffman, M.D.

Responsible Party: 
Children's Health Council

Please contact Lauren Masaki, Study Coordinator, if you would like to hear more about the study or follow through with a phone screening. Thank you.

(650) 617-3888