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Open-Label Extension Study of Kuvan for Autism

Kuvan® (Sapropterin) as a Treatment for Autistic Disorder: An Open Label Extension Protocol

Status
Completed
Phases
Phase 2Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT00943579
Enrollment
41
Registered
2009-07-22
Start date
2009-08-31
Completion date
2012-03-31
Last updated
2018-05-02

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

Conditions

Autistic Disorder

Keywords

autism, autistic disorder, tetrahydrobiopterin, sapropterin, treatment

Brief summary

This is an open-label extension study available only to subjects who completed an earlier double-blind, placebo-controlled study of sapropterin in children with autism.

Detailed description

This is an open-label extension study available only to subjects who completed an earlier double-blind, placebo-controlled study of sapropterin in children with autism. During this protocol, all subjects will be receiving brand-name Kuvan 20 mg/kg/day for 16 weeks; subject who complete the first 16 weeks will have the option of continuing on Kuvan at the same dose for up to 90 days after the last subject has completed the first 16 weeks of this protocol. The purpose of the study primarily is to gather additional information on safety and efficacy in this population.

Interventions

Brand-name Kuvan® (sapropterin) will be administered to all subjects at a dose of 20 mg/kg/day for 16 weeks.

Sponsors

BioMarin Pharmaceutical
CollaboratorINDUSTRY
The Children's Health Council
Lead SponsorOTHER

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE

Eligibility

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

Inclusion criteria

* All subjects must have completed earlier trial, CHC 0901 (NCT00850070) * Parents must be willing and able to sign informed consent

Exclusion criteria

* Child failed to complete CHC 0901 (NCT00850070)

Design outcomes

Primary

MeasureTime frameDescription
Clinical Global Impressions Scale16 weeksThis 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 (1) very much improved, (2) much improved, (3) minimally improved (4) no change, (5) minimally worse, (6) much worse and (7) very much worse. Chi-square analyses were used to assess change in CHI-I scores (by group, post-test)Mixed-effects regression models 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. The mixed-effects models accounted for each participant's outcome data at each time point. The mixed-effects regression model is robust to data dependency that occurs with the repeated assessments of individuals over time & can handle missing data. 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
Children's Yale Brown Obsessive Compulsive ScaleWeeks 8 & 16The 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.
Parental Global AssessmentWeeks 8 & 16this is a measure of parents impression of improvement.
Preschool Language Scale, 4th Edition (PLS-4)Weeks baseline (week 16 from CHC-0901), 8 and 16. Primary outcome assessment looked at change between baseline (week 16 from CHC-0901 and week 16 of CHC-0902).Measures expressive & receptive language and total scores in ages 0 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 raw scores indicate better language skills. 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. The mixed-effects models accounted for each participant's outcome data at each time point. We used random intercept & trend modeling that accounts for each individual's initial level of symptom severity/functioning & rate of change/time
Vineland Adaptive Behavior Scale, 2nd EditionWeeks baseline (week 16 from CHC-0901), 8 and 16. Primary outcome assessment looked at change between baseline (week 16 from CHC-0901 and week 16 of CHC-0902).The Vineland-2 is semi-structured interview designed to communication, 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. The scales generate raw or sum, V-, and age-equivalent scores; raw scores were selected for use in this study. Higher subscale scores indicate more skills. Raw scores can range from 0 to 766 for the overall adaptive behavior composite. Subscales are combined to form the overall Adaptive Behavior Composite, which is essentially a weighted average of the various subscales combined.
Aberrant Behavior Checklist (ABC)Weeks baseline (week 16 from CHC-0901), 8 and 16. Primary outcome assessment looked at change between baseline (week 16 from CHC-0901 and week 16 of CHC-0902).This is a 58-item informant-based, factor-analyzed scale comprised of a total scale and 5 subscales that generate raw scores. Scores based on a likert scale ranging from 0-3 where 0 is not a problem to 3 where the problem is severe. Subscales include: Irritability, Social Withdrawal, Stereotypic Behaviors, Hyperactivity and Inappropriate Speech. Total maximum score is 174. Higher subscale scores indicate more symptoms. Scores are totaled to compute subscale scores. 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. The mixed-effects models accounted for each participant's outcome data at each time point. We used random intercept and trend modeling that accounts for each individual's initial level of symptom severity/functioning and rate of change/time
Adverse Events ReportingCummulative throughout studyThis is not a standardized measure but instead a set of questions, both closed and open ended, asked of families about their child's response to the medication. Used for determining whether treatment needed to be discontinued.
Connor's Preschool ADHD QuestionnaireWeeks 8 & 16This is a measure of behavioral symptomatology in children 2-6 years of age. The ADHD scale is one subdomain.

Countries

United States

Participant flow

Recruitment details

Recruitment spanned from 08/09 - 10/11. Only individuals who completed 0901 (NCT00850070) were eligible to participate in this study thus recruitment was restricted to those already enrolled in that trial. When participants were at their 12-week visit for 0901 (NCT00850070) they were asked if they wanted to continue in the open label extension.

Pre-assignment details

All participants who consented went straight from the randomized control trial in 0901 (NCT00850070) to entering this trial. No washout period was needed. No participants were excluded who had completed the previous trial.

Participants by arm

ArmCount
Kuvan Following Placebo
Kuvan® (sapropterin) will be administered to all subjects at 20 mg/kg/day for 16 weeks. Participants in this arm received Kuvan following the randomized control trial in which they were on placebo.
21
Kuvan Following Active Treatment
Kuvan® (sapropterin) will be administered to all subjects at 20 mg/kg/day for 16 weeks. Participants in this arm received Kuvan following the randomized control trial in which they were on active medication.
20
Total41

Withdrawals & dropouts

PeriodReasonFG000FG001
Overall StudyAdverse Event43
Overall StudyLack of Efficacy22

Baseline characteristics

CharacteristicKuvan Following Active TreatmentKuvan Following PlaceboTotal
Age, Categorical
<=18 years
20 Participants21 Participants41 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
20 participants21 participants41 participants
Sex: Female, Male
Female
5 Participants5 Participants10 Participants
Sex: Female, Male
Male
15 Participants16 Participants31 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
deaths
Total, all-cause mortality
— / —— / —
other
Total, other adverse events
14 / 2113 / 20
serious
Total, serious adverse events
0 / 210 / 20

Outcome results

Primary

Clinical Global Impressions 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 (1) very much improved, (2) much improved, (3) minimally improved (4) no change, (5) minimally worse, (6) much worse and (7) very much worse. Chi-square analyses were used to assess change in CHI-I scores (by group, post-test)Mixed-effects regression models 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. The mixed-effects models accounted for each participant's outcome data at each time point. The mixed-effects regression model is robust to data dependency that occurs with the repeated assessments of individuals over time & can handle missing data. 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: 16 weeks

Population: The number of participants analyzed included those who completed the open label extension of this study.

ArmMeasureValue (NUMBER)
Kuvan Following PlaceboClinical Global Impressions Scale3 # participants much - very much improved
Kuvan Following Active TreatmentClinical Global Impressions Scale3 # participants much - very much improved
Comparison: Chi-square analyses were used to assess CGI-I scores. there were no transformations.p-value: >0.05Chi-squared
Secondary

Aberrant Behavior Checklist (ABC)

This is a 58-item informant-based, factor-analyzed scale comprised of a total scale and 5 subscales that generate raw scores. Scores based on a likert scale ranging from 0-3 where 0 is not a problem to 3 where the problem is severe. Subscales include: Irritability, Social Withdrawal, Stereotypic Behaviors, Hyperactivity and Inappropriate Speech. Total maximum score is 174. Higher subscale scores indicate more symptoms. Scores are totaled to compute subscale scores. 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. The mixed-effects models accounted for each participant's outcome data at each time point. 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: Weeks baseline (week 16 from CHC-0901), 8 and 16. Primary outcome assessment looked at change between baseline (week 16 from CHC-0901 and week 16 of CHC-0902).

Population: all participants who completed the open label extension were analyzed.

ArmMeasureValue (MEAN)Dispersion
Kuvan Following PlaceboAberrant Behavior Checklist (ABC)16.84 units on a scaleStandard Error 1.68
Kuvan Following Active TreatmentAberrant Behavior Checklist (ABC)9.70 units on a scaleStandard Error 1.73
Secondary

Adverse Events Reporting

This is not a standardized measure but instead a set of questions, both closed and open ended, asked of families about their child's response to the medication. Used for determining whether treatment needed to be discontinued.

Time frame: Cummulative throughout study

Population: Data were not specifically analyzed but used instead to determine whether treatment needed to be discontinued. 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

Children's Yale Brown Obsessive Compulsive Scale

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: Weeks 8 & 16

Population: The data was not analyzed secondary to lack of significant findings in primary outcome measures and limited data collected on this measure. 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

This is a measure of behavioral symptomatology in children 2-6 years of age. The ADHD scale is one subdomain.

Time frame: Weeks 8 & 16

Population: Data was not analyzed secondary to lack of significant findings in primary outcome measure and reduced number of completed questionnaires. 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

Parental Global Assessment

this is a measure of parents impression of improvement.

Time frame: Weeks 8 & 16

Population: the data were not analyzed secondary to lack of findings in primary outcome measure as well as the nature of an open label study. 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, 4th Edition (PLS-4)

Measures expressive & receptive language and total scores in ages 0 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 raw scores indicate better language skills. 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. The mixed-effects models accounted for each participant's outcome data at each time point. We used random intercept & trend modeling that accounts for each individual's initial level of symptom severity/functioning & rate of change/time

Time frame: Weeks baseline (week 16 from CHC-0901), 8 and 16. Primary outcome assessment looked at change between baseline (week 16 from CHC-0901 and week 16 of CHC-0902).

Population: All participants completed the open label extension were analyzed in the study.

ArmMeasureValue (MEAN)Dispersion
Kuvan Following PlaceboPreschool Language Scale, 4th Edition (PLS-4)57.24 units on a scaleStandard Error 5.48
Kuvan Following Active TreatmentPreschool Language Scale, 4th Edition (PLS-4)77.83 units on a scaleStandard Error 5.27
Secondary

Vineland Adaptive Behavior Scale, 2nd Edition

The Vineland-2 is semi-structured interview designed to communication, 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. The scales generate raw or sum, V-, and age-equivalent scores; raw scores were selected for use in this study. Higher subscale scores indicate more skills. Raw scores can range from 0 to 766 for the overall adaptive behavior composite. Subscales are combined to form the overall Adaptive Behavior Composite, which is essentially a weighted average of the various subscales combined.

Time frame: Weeks baseline (week 16 from CHC-0901), 8 and 16. Primary outcome assessment looked at change between baseline (week 16 from CHC-0901 and week 16 of CHC-0902).

Population: All participants who completed the open label extension were analyzed.

ArmMeasureValue (MEAN)Dispersion
Kuvan Following PlaceboVineland Adaptive Behavior Scale, 2nd Edition275 units on a scaleStandard Error 10.77
Kuvan Following Active TreatmentVineland Adaptive Behavior Scale, 2nd Edition321 units on a scaleStandard Error 10.78

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026