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CompletedNCT00850070Updated May 1, 2018Results posted

Sapropterin as a Treatment for Autistic Disorder

A Phase 2 interventional study of sapropterin and Placebo in Autistic Disorder, sponsored by The Children's Health Council. Completed at 1 site in United States. Open to participants aged 3 Years to 6 Years. Per ClinicalTrials.gov, last updated 2018-05-01.

Sponsored by The Children's Health Council · Phase 2, Interventional, and Treatment

Phase
Phase 2
Study type
Interventional
Enrollment
46
Allocation
Randomized
Ages
3 Years to 6 Years
Sex
All
01

Study summary

This study is intended to provide a definitive test of the hypothesis that elevating sapropterin (tetrahydrobiopterin, a cofactor for several key brain enzymes)concentrations in the CNS will result in measurable improvements in core symptoms of autism in young individuals, under age 6 years. The study will entail a double-blind, placebo-controlled 16-week intervention.

Read the detailed description

Over the past 20 years, several studies have suggested that sapropterin (tetrahydrobiopterin) might ameliorate core symptoms of autism at least in young (under age 6) subjects. However, those studies had somewhat questionable methodologies, a major one being that the doses of sapropterin used were roughly one tenth that thought to be needed to provide physiologically meaningful increases of sapropterin in the central nervous system (CNS). This study will look at the impact of a sustained exposure to this higher dose in well-diagnosed young children with autism.

02

Conditions studied

  • Autistic Disorder

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Keywords

  • autism
03

In context

Autistic Disorder

1,360 studies on the registry are indexed under Autistic Disorder; 332 are open to participants now.

This study's enrollment of 46 is close to the median of 46 across 1,058 interventional studies indexed under Autistic Disorder.

Browse Autistic Disorder studies →

Lead sponsor

The Children's Health Council is the lead sponsor of 2 studies on the registry; none are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
3 Years to 6 Years
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Parents sign informed consent
  • Child meets criteria for autistic disorder (based on score on the Autism Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule (ADOS), given by a certified administrator, research reliable)
  • Child has a Developmental Quotient (DQ) ≥ 50 (Vineland Adaptive Scales, Interview Edition)
  • Parents agree to delay initiation of other treatments during double-blind trial

Exclusion criteria

Exclusion Criteria:

  • Child has had seizures in past 6 months or a change in seizure medications in past 4 weeks.
  • Child has > 18 points on subscale of (Autism Behavior Checklist) ABC-I
  • Child is taking any psychoactive medication other than supplements, anticonvulsants, or soporifics (melatonin, diphenhydramine)
  • Child has had any change in standing medications in the past 4 weeks.
  • Child has known genetic disorders
  • Child has known severe neurological disorders, including cerebral palsy
05

Study design

Phase
Phase 2
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Quadruple (Participant, Care provider, Investigator, Outcomes assessor)
Enrollment
46 participants (actual)

Study arms

  • Experimental
    sapropterin, 100 mg capsules

    Sapropterin was supplied as a 100 mg tablet and dosage was based on 20 mg/kg/d, rounding to the nearest 100 mg. Most subjects crushed the tablets and administered it in liquid or a food to mask the taste. Subjects took the same dose daily for 16 weeks.

    Drug: sapropterin

  • Placebo comparator
    Placebo, matching active drug

    The placebo was supplied as a 100 mg tablet, and dosage was based on 20 mg/kg/d, rounding to the nearest 100 mg. Most subjects crushed the tablets and administered it in liquid or a food to mask the taste. Subjects took the same dose daily for 16 weeks.

    Drug: Placebo

Interventions

  • Patients will receive sapropterin 20 mg per kilogram per day for 16 weeks

    Also known as: Kuvan, tetrahydrobiopterin

  • DrugPlacebo

    Patients will receive a placebo identical in form and dosage to the active drug daily for 16 weeks.

    Also known as: sugar pill

06

What researchers measure

Primary outcomes

  1. Clinical Global Impression -- Improvement (CGI-I) Scale

    The CGI-I assessed the number of participants showing much or very much improvement on the CGI-I scale. This is a summary judgment made by a trained clinician based on observed and reported behaviors of the child compared to baseline. It is a 7-point scale from very much worse (1) to very much improved (7). Chi-square analyses were used to assess change in CHI-I scores (by group, post-test). Mixed-effects regression models via SPSS MIXED determined the main effects attributed to differences by group (BH4 and placebo), time (treated as categorical at levels baseline, 8 weeks, and 16 weeks) and the group-by-time interaction. We used random intercept and trend modeling that accounts for each individual's initial level of symptom severity/functioning and rate of change/time

    Time frame: Weekly for 4 weeks, then monthly, with 16-week end point. Primary outcome assessment used two time points, baseline and 16 weeks.

  2. Clinical Global Impression -- Severity (CGI-S) Scale

    The CGI-S assessed the number of participants with improved severity illness on the CGI-S scale. This is a summary judgment made by a trained clinician of symptom severity. It is a 7-point scale that rates the severity of the patient's illness at time of assessment with 1 - normal, not at all, to 7 - extremely ill. Mixed-effects regression models via SPSS MIXED determined the main effects attributed to differences by group (BH4 and placebo), time (treated as categorical at levels baseline, 8 weeks, and 16 weeks) and the group-by-time interaction. We used random intercept and trend modeling that accounts for each individual's initial level of symptom severity/functioning and rate of change/time

    Time frame: Baseline, 8 weeks, and 16 weeks. Primary outcome assessment used 2 time points, baseline and 16 weeks.

Secondary outcomes

  1. Preschool Language Scale-Fourth Edition (PLS-4). Assesses Expressive and Receptive Language Skills in Ages Birth Through 6 Years, 11 Months.

    Measures expressive \& receptive language and total scores in ages birth to 6 years 11 months. The scales generate raw, standard, and age-equivalent scores; raw scores for the total scale were selected for use in this study. Total is average of subscales. Minimum raw score = 0, maximum = 130. Higher scores indicate better language abilities. Mixed-effects regression models via SPSS MIXED determined the main effects attributed to differences by group (BH4 and placebo), time (treated as categorical at levels baseline, 8 weeks, and 16 weeks) and the group-by-time interaction. For the outcome effect, the difference between baseline and 16 weeks was determined as an indicator for change.

    Time frame: Primary outcome assessment examined the difference in scores between baseline and week 16.

  2. Vineland Adaptive Behavior Scale-II.

    the Vineland-2 is a semi-structured interview designed to assess communicatino, daily living, socialization and motor skills. The Vineland-2 is comprised of a total Adaptive Composite scale; we chose to use 10 subscales that specifically address functional domains relevant for a young ASD sample - Receptive Communication, Expressive Communication, Personal Daily Living Skills, Domestic Daily Living Skills, Community Daily Living Skills, Interpersonal Relations, Play Skills, Coping Skills, Gross Motor Skills, Fine Motor Skills. Scales generate raw or sum, V-, and age-equivalent scores; raw scores were selected for use in the study. Raw score ranges from 0 to 108 depending on the scale. Total raw scale range is from 0 to 766. Subscale scores are averaged to create the total adaptive behavior composite. Higher subscale scores indicate more skills. Difference between baseline and week 16 was used as an indicator of change.

    Time frame: Primary outcome assessment used two time points, baseline and 16 weeks.

  3. Children's Yale Brown Obsessive Compulsive Scale (C-YBOCS)

    The C-YBOCS is a scale is designed to rate the severity of obsessive and compulsive symptoms in children and adolescents, ages 6 to 17 years. It can be administered by a clinican or trained interviewer in a semi-structured fashion. In general, the ratings depend on the child's and parent's report; however, the final rating is based on the clinical judgement of the interviewer. Rate the characteristics of each item over the prior week up until, and including, the time of the interview. Scores should reflect the average of each item for the entire week, unless otherwise specified.

    Time frame: Baseline, 8 weeks, and 16 weeks

  4. Connor's Preschool ADHD Questionnaire

    Conners Early Childhood, addresses child behavior for ages 2 years to 6 years with a variety of scales, including an ADHD subdomain.

    Time frame: Baseline, 8 weeks, and 16 weeks

  5. Adverse Events Scale

    This was not a standardized scale but a set of questions that was asked of each family - some standard and others open ended.

    Time frame: Every 1-2 weeks for 16 weeks

  6. Aberrant Behavior Checklist (ABC) - Inappropriate Speech

    Subscale assessing echolalia \& other odd speech. Higher subscale scores indicate more symptoms. 4 items comprise the subscale, with range of scores from 0-4. Total score range on this subscale is 0 to 16. Scores are averaged to compute overall score. Difference in scores between baseline and week 16 were used as indicator of change.

    Time frame: Primary outcome assessment used two time points, baseline and 16 weeks.

  7. Social Responsiveness Scale (SRS)

    The SRS is a 65-item scale used to measure the severity of symptoms in ASD as they occur in natural social settings. The SRS is comprised of 1 Total scale and 5 subscales that generate raw scores that can be converted to standard T-scores (with mean of 50 and standard deviation of 10) for gender and rater type; standard scores were selected for use in this study. A total T-score of 76 or higher is considered severe and strongly associated with a clinical diagnosis of autistic disorder. A t-score of 60-75 is in the mild to moderate range and considered typical for children with mild or 'high-functioning' ASD, while a T-score of 59 or less suggests an absence of ASD symptoms. A total raw score of \>75 were associated with a sensitivity value of .85 and a specificity value of .75 for ASD. Difference in scores between baseline and week 16 were used as an indicator of change.

    Time frame: Primary outcome assessment used two time points, baseline and 16 weeks.

  8. Parent Global Assessment (PGA) Scale

    This is a measure where parents rate their impression of their child's improvement, in a global manner.

    Time frame: Baseline, 8 weeks, and 16 weeks

07

Results

Posted Feb 28, 2014

Participant flow

Recruitment spanned from 4/09 to 6/11. A variety of methods were used to advertise the study, but most successful recruitment was word-of-mouth from study participants.

Participant flow — Overall Study
MilestoneSapropterinPlacebo
Started2323
Completed2022
Not completed31
Withdrew: Lack of efficacy11
Withdrew: Adverse event20

Outcome measures

PrimaryClinical Global Impression -- Improvement (CGI-I) Scale

The CGI-I assessed the number of participants showing much or very much improvement on the CGI-I scale. This is a summary judgment made by a trained clinician based on observed and reported behaviors of the child compared to baseline. It is a 7-point scale from very much worse (1) to very much improved (7). Chi-square analyses were used to assess change in CHI-I scores (by group, post-test). Mixed-effects regression models via SPSS MIXED determined the main effects attributed to differences by group (BH4 and placebo), time (treated as categorical at levels baseline, 8 weeks, and 16 weeks) and the group-by-time interaction. We used random intercept and trend modeling that accounts for each individual's initial level of symptom severity/functioning and rate of change/time

Time frame:
Weekly for 4 weeks, then monthly, with 16-week end point. Primary outcome assessment used two time points, baseline and 16 weeks.
Reported as:
Number · participants
Clinical Global Impression -- Improvement (CGI-I) Scale
participantsSapropterinPlacebo
Clinical Global Impression -- Improvement (CGI-I) Scale53
Statistical analysis
  • Sapropterin vs Placebo · Chi-squared · p = <.35 · Mean difference (final values): 2Estimated value comparison was active treatment minus placebo.
PrimaryClinical Global Impression -- Severity (CGI-S) Scale

The CGI-S assessed the number of participants with improved severity illness on the CGI-S scale. This is a summary judgment made by a trained clinician of symptom severity. It is a 7-point scale that rates the severity of the patient's illness at time of assessment with 1 - normal, not at all, to 7 - extremely ill. Mixed-effects regression models via SPSS MIXED determined the main effects attributed to differences by group (BH4 and placebo), time (treated as categorical at levels baseline, 8 weeks, and 16 weeks) and the group-by-time interaction. We used random intercept and trend modeling that accounts for each individual's initial level of symptom severity/functioning and rate of change/time

Time frame:
Baseline, 8 weeks, and 16 weeks. Primary outcome assessment used 2 time points, baseline and 16 weeks.
Reported as:
Number · participants
Clinical Global Impression -- Severity (CGI-S) Scale
participantsSapropterinPlacebo
Clinical Global Impression -- Severity (CGI-S) Scale31
Statistical analysis
  • Sapropterin vs Placebo · Chi-squared · p = <0.06 · Mean difference (final values): 2
SecondaryPreschool Language Scale-Fourth Edition (PLS-4). Assesses Expressive and Receptive Language Skills in Ages Birth Through 6 Years, 11 Months.

Measures expressive \& receptive language and total scores in ages birth to 6 years 11 months. The scales generate raw, standard, and age-equivalent scores; raw scores for the total scale were selected for use in this study. Total is average of subscales. Minimum raw score = 0, maximum = 130. Higher scores indicate better language abilities. Mixed-effects regression models via SPSS MIXED determined the main effects attributed to differences by group (BH4 and placebo), time (treated as categorical at levels baseline, 8 weeks, and 16 weeks) and the group-by-time interaction. For the outcome effect, the difference between baseline and 16 weeks was determined as an indicator for change.

Time frame:
Primary outcome assessment examined the difference in scores between baseline and week 16.
Reported as:
Mean · units on a scale
Preschool Language Scale-Fourth Edition (PLS-4). Assesses Expressive and Receptive Language Skills in Ages Birth Through 6 Years, 11 Months.
units on a scaleSapropterinPlacebo
Preschool Language Scale-Fourth Edition (PLS-4). Assesses Expressive and Receptive Language Skills in Ages Birth Through 6 Years, 11 Months.84 ± 2960 ± 25
SecondaryVineland Adaptive Behavior Scale-II.

the Vineland-2 is a semi-structured interview designed to assess communicatino, daily living, socialization and motor skills. The Vineland-2 is comprised of a total Adaptive Composite scale; we chose to use 10 subscales that specifically address functional domains relevant for a young ASD sample - Receptive Communication, Expressive Communication, Personal Daily Living Skills, Domestic Daily Living Skills, Community Daily Living Skills, Interpersonal Relations, Play Skills, Coping Skills, Gross Motor Skills, Fine Motor Skills. Scales generate raw or sum, V-, and age-equivalent scores; raw scores were selected for use in the study. Raw score ranges from 0 to 108 depending on the scale. Total raw scale range is from 0 to 766. Subscale scores are averaged to create the total adaptive behavior composite. Higher subscale scores indicate more skills. Difference between baseline and week 16 was used as an indicator of change.

Time frame:
Primary outcome assessment used two time points, baseline and 16 weeks.
Reported as:
Mean · units on a scale
Vineland Adaptive Behavior Scale-II.
units on a scaleSapropterinPlacebo
Vineland Adaptive Behavior Scale-II.344.76 ± 50.0294.9 ± 70.1
SecondaryChildren's Yale Brown Obsessive Compulsive Scale (C-YBOCS)

The C-YBOCS is a scale is designed to rate the severity of obsessive and compulsive symptoms in children and adolescents, ages 6 to 17 years. It can be administered by a clinican or trained interviewer in a semi-structured fashion. In general, the ratings depend on the child's and parent's report; however, the final rating is based on the clinical judgement of the interviewer. Rate the characteristics of each item over the prior week up until, and including, the time of the interview. Scores should reflect the average of each item for the entire week, unless otherwise specified.

Time frame:
Baseline, 8 weeks, and 16 weeks

No measurements were reported for this outcome.

SecondaryConnor's Preschool ADHD Questionnaire

Conners Early Childhood, addresses child behavior for ages 2 years to 6 years with a variety of scales, including an ADHD subdomain.

Time frame:
Baseline, 8 weeks, and 16 weeks

No measurements were reported for this outcome.

SecondaryAdverse Events Scale

This was not a standardized scale but a set of questions that was asked of each family - some standard and others open ended.

Time frame:
Every 1-2 weeks for 16 weeks

No measurements were reported for this outcome.

SecondaryAberrant Behavior Checklist (ABC) - Inappropriate Speech

Subscale assessing echolalia \& other odd speech. Higher subscale scores indicate more symptoms. 4 items comprise the subscale, with range of scores from 0-4. Total score range on this subscale is 0 to 16. Scores are averaged to compute overall score. Difference in scores between baseline and week 16 were used as indicator of change.

Time frame:
Primary outcome assessment used two time points, baseline and 16 weeks.
Reported as:
Mean · units on a scale
Aberrant Behavior Checklist (ABC) - Inappropriate Speech
units on a scaleSapropterinPlacebo
Aberrant Behavior Checklist (ABC) - Inappropriate Speech2.6 ± 1.93.9 ± 3.6
Statistical analysis
  • Sapropterin vs Placebo · Mixed Models Analysis · p = 0.05 · Mean difference (final values): -2
SecondarySocial Responsiveness Scale (SRS)

The SRS is a 65-item scale used to measure the severity of symptoms in ASD as they occur in natural social settings. The SRS is comprised of 1 Total scale and 5 subscales that generate raw scores that can be converted to standard T-scores (with mean of 50 and standard deviation of 10) for gender and rater type; standard scores were selected for use in this study. A total T-score of 76 or higher is considered severe and strongly associated with a clinical diagnosis of autistic disorder. A t-score of 60-75 is in the mild to moderate range and considered typical for children with mild or 'high-functioning' ASD, while a T-score of 59 or less suggests an absence of ASD symptoms. A total raw score of \>75 were associated with a sensitivity value of .85 and a specificity value of .75 for ASD. Difference in scores between baseline and week 16 were used as an indicator of change.

Time frame:
Primary outcome assessment used two time points, baseline and 16 weeks.
Reported as:
Mean · units on a scale
Social Responsiveness Scale (SRS)
units on a scaleSapropterinPlacebo
Social Responsiveness Scale (SRS)76.7 ± 10.983.2 ± 10.4
SecondaryParent Global Assessment (PGA) Scale

This is a measure where parents rate their impression of their child's improvement, in a global manner.

Time frame:
Baseline, 8 weeks, and 16 weeks

No measurements were reported for this outcome.

Adverse events

Collected over Adverse events were monitored for the length of the study, i.e., 16 weeks.. Non-serious events are listed at a 5% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
Sapropterin—2/23 (8.7%)10/23 (43.5%)
Placebo—1/23 (4.3%)14/23 (60.9%)
Most frequent serious events
Most frequent serious events
EventSapropterinPlacebo
transient viral rashSkin and subcutaneous tissue disorders2/230/23
seizure disorderNervous system disorders0/231/23
Most frequent other events
Most frequent other events
EventSapropterinPlacebo
irritablityPsychiatric disorders5/234/23
difficulty sleepingNervous system disorders2/234/23
Change in Bowel HabitsGastrointestinal disorders0/234/23
repetitive behaviorsNervous system disorders1/232/23
hyperactivityNervous system disorders2/231/23

Baseline characteristics

Age, Categorical
Age, Categorical(Participants)SapropterinPlaceboTotal
<=18 years232346
Between 18 and 65 years000
>=65 years000
Age, Continuous
Age, Continuous(years)SapropterinPlaceboTotal
Mean5 ± 15 ± 15 ± 1
Sex: Female, Male
Sex: Female, Male(Participants)SapropterinPlaceboTotal
Female358
Male201838
Region of Enrollment
Region of Enrollment(participants)SapropterinPlaceboTotal
United States232346
08

Study locations

1 site
  • The Children's Health Council
    Palo Alto, California 94304, United States
09

References and documents

Publications

  • Klaiman C, Huffman L, Masaki L, Elliott GR. Tetrahydrobiopterin as a treatment for autism spectrum disorders: a double-blind, placebo-controlled trial. J Child Adolesc Psychopharmacol. 2013 Jun;23(5):320-8. doi: 10.1089/cap.2012.0127. PubMed 23782126 ↗
10

Timeline

Tracking since Sep 25, 2026
Not marked actual or estimatedDates not marked actual or estimated

The record gives a start of Mar 2009, a primary completion of Aug 2011 and a completion of Oct 2011. It does not say whether these dates are actual or estimated.

Results were first posted in Feb 2014, 2 years 6 months after primary completion.

How these figures are worked out, and which studies are left out of them.

Registered
Feb 20, 2009
First posted
Feb 24, 2009
Start
Mar 2009
Primary completionActual
Aug 2011
CompletionActual
Oct 2011
Results first posted
Feb 28, 2014
Last update
May 1, 2018
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on May 1, 2018, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
11

Registry details

Key details

Study ID
NCT00850070
Lead sponsor
The Children's Health Council
Responsible party
Glen R. Elliott (Chief Psychiatrist and Medical Director, The Children's Health Council) — Principal investigator
First posted
Feb 24, 2009
Start date
Mar 2009
Primary completion
Aug 2011
Completion
Oct 2011
Results posted
Feb 28, 2014
Last update
May 1, 2018

Study contacts

Glen R Elliott, Ph.D., M.D.
principal investigator · The Children's Health Council

Oversight

Data monitoring committee
Yes
View the source record on ClinicalTrials.gov ↗

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