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Sapropterin as a Treatment for Autistic Disorder

Sapropterin as a Treatment for Autistic Disorder: A Phase II Randomized, Double-Blind, Placebo-Controlled Trial

Status
Completed
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT00850070
Enrollment
46
Registered
2009-02-24
Start date
2009-03-31
Completion date
2011-10-31
Last updated
2018-05-01

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Autistic Disorder

Keywords

autism

Brief 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.

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.

Interventions

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

DRUGPlacebo

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

Sponsors

BioMarin Pharmaceutical
CollaboratorINDUSTRY
The Children's Health Council
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Eligibility

Sex/Gender
ALL
Age
3 Years to 6 Years
Healthy volunteers
No

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

* 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

Design outcomes

Primary

MeasureTime frameDescription
Clinical Global Impression -- Improvement (CGI-I) ScaleWeekly for 4 weeks, then monthly, with 16-week end point. Primary outcome assessment used two time points, baseline and 16 weeks.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
Clinical Global Impression -- Severity (CGI-S) ScaleBaseline, 8 weeks, and 16 weeks. Primary outcome assessment used 2 time points, baseline and 16 weeks.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

Secondary

MeasureTime frameDescription
Vineland Adaptive Behavior Scale-II.Primary outcome assessment used two time points, baseline and 16 weeks.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.
Children's Yale Brown Obsessive Compulsive Scale (C-YBOCS)Baseline, 8 weeks, and 16 weeksThe 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.
Connor's Preschool ADHD QuestionnaireBaseline, 8 weeks, and 16 weeksConners Early Childhood, addresses child behavior for ages 2 years to 6 years with a variety of scales, including an ADHD subdomain.
Preschool Language Scale-Fourth Edition (PLS-4). Assesses Expressive and Receptive Language Skills in Ages Birth Through 6 Years, 11 Months.Primary outcome assessment examined the difference in scores between baseline and week 16.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.
Aberrant Behavior Checklist (ABC) - Inappropriate SpeechPrimary outcome assessment used two time points, baseline and 16 weeks.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.
Social Responsiveness Scale (SRS)Primary outcome assessment used two time points, baseline and 16 weeks.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.
Adverse Events ScaleEvery 1-2 weeks for 16 weeksThis was not a standardized scale but a set of questions that was asked of each family - some standard and others open ended.
Parent Global Assessment (PGA) ScaleBaseline, 8 weeks, and 16 weeksThis is a measure where parents rate their impression of their child's improvement, in a global manner.

Countries

United States

Participant flow

Recruitment details

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.

Pre-assignment details

Few participants were excluded. Most common exclusions were failure to meet inclusion criteria, mostly absence of an autism diagnosis or cognitive functioning below the required minimum.

Participants by arm

ArmCount
Sapropterin
tetrahydrobiopterin (BH4)
23
Placebo
sugar pill
23
Total46

Withdrawals & dropouts

PeriodReasonFG000FG001
Overall StudyAdverse Event20
Overall StudyLack of Efficacy11

Baseline characteristics

CharacteristicPlaceboSapropterinTotal
Age, Categorical
<=18 years
23 Participants23 Participants46 Participants
Age, Categorical
>=65 years
0 Participants0 Participants0 Participants
Age, Categorical
Between 18 and 65 years
0 Participants0 Participants0 Participants
Age, Continuous5 years
STANDARD_DEVIATION 1
5 years
STANDARD_DEVIATION 1
5 years
STANDARD_DEVIATION 1
Region of Enrollment
United States
23 participants23 participants46 participants
Sex: Female, Male
Female
5 Participants3 Participants8 Participants
Sex: Female, Male
Male
18 Participants20 Participants38 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
deaths
Total, all-cause mortality
— / —— / —
other
Total, other adverse events
10 / 2314 / 23
serious
Total, serious adverse events
2 / 231 / 23

Outcome results

Primary

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.

Population: This was an Intent-to-Treat Analysis with Last Observation Carried Forward.Analyses looked at percentage of children who improved (showing much or very much improved ratings) at 16-week time frame.

ArmMeasureValue (NUMBER)
SapropterinClinical Global Impression -- Improvement (CGI-I) Scale5 participants
PlaceboClinical Global Impression -- Improvement (CGI-I) Scale3 participants
Comparison: Chi-square analyses were used to assess CGI-I scores. There were no transformations.p-value: <0.35Chi-squared
Primary

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.

Population: This was an Intent-to-Treat Analysis with Last Observation Carried Forward.Analyses looked at number of children who improved (from markedly, severely or extremely ill to markedly, mildly or no illness) at 16-week time frame.

ArmMeasureValue (NUMBER)
SapropterinClinical Global Impression -- Severity (CGI-S) Scale3 participants
PlaceboClinical Global Impression -- Severity (CGI-S) Scale1 participants
p-value: <0.06Chi-squared
Secondary

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.

Population: Intent to treat analysis

ArmMeasureValue (MEAN)Dispersion
SapropterinAberrant Behavior Checklist (ABC) - Inappropriate Speech2.6 units on a scaleStandard Deviation 1.9
PlaceboAberrant Behavior Checklist (ABC) - Inappropriate Speech3.9 units on a scaleStandard Deviation 3.6
p-value: 0.05Mixed Models Analysis
Secondary

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

Population: We did not specifically analyze this data but instead use it as a guide to determine if a drug should be discontinued for a particular child.

Secondary

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

Population: The data was not analyzed secondary to lack of significant findings in the primary outcome measure. Also, limited data collected secondary to the age range of the children we saw.The data cannot now be provided as the research team has since disbanded and it is not possible to reanalyze the data at this time.

Secondary

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

Population: Data was not analyzed secondary to lack of significant findings in primary outcome measures and limited data collected on this instrument. The data cannot now be provided as the research team has since disbanded and it is not possible to reanalyze the data at this time.

Secondary

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

Population: Data was not analyzed secondary to lack of significant findings in primary outcome measures and limited data collected on this instrument. The data cannot now be provided as the research team has since disbanded and it is not possible to reanalyze the data at this time.

Secondary

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.

Population: Intent-to-treat analysis; all subjects included. Difference in scores between baseline and 16 weeks was used as treatment outcome.

ArmMeasureValue (MEAN)Dispersion
SapropterinPreschool Language Scale-Fourth Edition (PLS-4). Assesses Expressive and Receptive Language Skills in Ages Birth Through 6 Years, 11 Months.84 units on a scaleStandard Deviation 29
PlaceboPreschool Language Scale-Fourth Edition (PLS-4). Assesses Expressive and Receptive Language Skills in Ages Birth Through 6 Years, 11 Months.60 units on a scaleStandard Deviation 25
Secondary

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.

Population: Intent-to-treat analysis; all subjects included. Includes mean at 16-week outcome.

ArmMeasureValue (MEAN)Dispersion
SapropterinSocial Responsiveness Scale (SRS)76.7 units on a scaleStandard Deviation 10.9
PlaceboSocial Responsiveness Scale (SRS)83.2 units on a scaleStandard Deviation 10.4
Secondary

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.

Population: Intent-to-treat analysis; all subjects included. Includes mean at 16-week outcome.

ArmMeasureValue (MEAN)Dispersion
SapropterinVineland Adaptive Behavior Scale-II.344.76 units on a scaleStandard Deviation 50
PlaceboVineland Adaptive Behavior Scale-II.294.9 units on a scaleStandard Deviation 70.1

Source: ClinicalTrials.gov · Data processed: Mar 10, 2026