This page shows what was measured, who it was measured in, and what that does not settle.
What Sapropterin does in the body
JAVYGTOR (sapropterin dihydrochloride) is indicated to reduce blood phenylalanine (Phe) levels in adult and pediatric patients one month of age and older with hyperphenylalaninemia (HPA) due to tetrahydrobiopterin-(BH4-) responsive Phenylketonuria (PKU).
Sapropterin dihydrochloride is a synthetic form of BH4, the cofactor for the enzyme phenylalanine hydroxylase (PAH). PAH hydroxylates Phe through an oxidative reaction to form tyrosine. In patients with PKU, PAH activity is absent or deficient. Treatment with BH4 can activate residual PAH enzyme activity, improve the normal oxidative metabolism of Phe, and decrease Phe levels in some patients.
Why people take it. JAVYGTOR (sapropterin dihydrochloride) is indicated to reduce blood phenylalanine (Phe) levels in adult and pediatric patients one month of age and older with hyperphenylalaninemia (HPA) due to tetrahydrobiopterin-(BH4-) responsive Phenylketonuria (PKU).
What happened in people
RNAWiki has not yet published a reviewed conclusion for this use.
§ A fixed RNAWiki sentence
Where this came from
Wording RNAWiki always uses, not a finding about this substance.
No reviewed claim names a result for any goal on this record.
No source is stored against this line.
The limit that matters most
Not recorded.
Where it acts
Not recorded.
Kind of result
No result is published, so no kind of result applies yet
Supervision
RNAWiki has not recorded a supervision or regulatory status for this substance.
What the registries record it as
The substance registry classes this as chemical.
FDA substance registry · EGX657432I · read 2026-08-29
Its recorded molecular formula is C9H15N5O3·2HCl, weighing 314.17.
US prescribing information · d9f3723f-bf7d-9a72-2ef9-41c5508d6ab4 · read 2026-08-30
Where each sentence above came from
The use the label states, quoted from it. No plain-language version of this sentence has been written.
The use the label states, quoted from it. It is written for a clinician, not for a reader without medical training.
No statement of the main limit is recorded.
The four opening statements run to 134 words.
Words this page uses
Four words worth knowing first
Chosen from what this page shows, with each one explained before the word it depends on.
Biomarker
A biomarker is a number from a test that stands in for something about health.
A picture of it, and where the picture fails
A biomarker is like a fuel gauge.
Where that stops being true. A gauge is wired to the tank. Many biomarkers are only loosely tied to health.
What people get wrong. A better number is read as a better life. Several medicines improved a number and helped nobody.
A measurable indicator used as a substitute for a clinical outcome of interest.
Stand-in result
A stand-in result is a number measured because the real result takes too long.
A picture of it, and where the picture fails
It is like judging a journey by the speedometer rather than by arriving.
Where that stops being true. Speed does predict arrival. Many stand-in results do not predict the real one.
What people get wrong. A stand-in result is often reported as the result itself.
A surrogate endpoint substituted for a clinical endpoint, valid only where the substitution has been shown to hold.
What happened in people◇Read from sources, not yet reviewed
What was measured, goal by goal
One row for each goal a registered study measured something for. One column for each kind of thing that could be measured.
Registered studies list 24 outcome measures that RNAWiki could read. A registered study says what someone planned to measure. It does not say what they found. 0 of the matched studies tested this substance, and 0 posted a result.
There is no single score. A strong test result and a weak life result are different facts.
Goals down the side, kinds of measurement across the top. Each cell says what kind of thing was registered, not what was found.
Goal
Life outcome
What a body can do
How a person feels
A test result
A step in the body
Harms
How long
Who was studied
Cholesterol
∅Nothing in the sources checkedNo registered study lists a life outcome for this goal.
∅Nothing in the sources checkedNo registered study lists a performance measure for this goal.
∅Nothing in the sources checkedNo registered study lists a symptom measure for this goal.
∅Nothing in the sources checkedNo registered study lists a test result for this goal.
∅Nothing in the sources checkedNo registered study lists a body-step measure for this goal.
—Not recordedHarms were not a registered measure for this goal.
—Not recordedNo finished study window is recorded.
…Waiting for a reviewerWho was studied is listed further down the page.
Which registered measures put each goal on this table
Cholesterol
lipid peroxidation
Sorted by fixed word lists, version v1. A name the rules do not recognise stays unsorted rather than moving to the nearest column.
What each mark on this table means
∅ Nothing in the sources checked
No registered study lists a life outcome for this goal.
— Not recorded
Harms were not a registered measure for this goal.
… Waiting for a reviewer
Who was studied is listed further down the page.
What happened in people◇Read from sources, not yet reviewed
What happened in people
Each card is one study: the exact question it asked, who was in it, and whether it showed what it set out to show.
Evaluate the degree and frequency of response to Phenoptin™, as demonstrated by a reduction in blood Phe level among subjects with PKU who have elevated Phe levels
✗ The study did not show it
Who was studied
NCT00104260
How many people
700
Study design
Phase 2
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. No limitation is recorded for this study.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route.
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
openFDA Drugs@FDA · a recorded source, not a stored snapshot
openFDA NDC Directory · a recorded source, not a stored snapshot
Europe PMC · a recorded source, not a stored snapshot
ClinicalTrials.gov · a recorded source, not a stored snapshot
Change in Limb Blood Flow
✗ The study did not show it
Who was studied
NCT02966665
How many people
420
Study design
Phase 1
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. No limitation is recorded for this study.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route.
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
openFDA Drugs@FDA · a recorded source, not a stored snapshot
openFDA NDC Directory · a recorded source, not a stored snapshot
Europe PMC · a recorded source, not a stored snapshot
ClinicalTrials.gov · a recorded source, not a stored snapshot
Six-Minute Walk Distance 6-month change
✗ The study did not show it
Who was studied
NCT06686121
How many people
386
Study design
Phase 3
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. No limitation is recorded for this study.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route.
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
openFDA Drugs@FDA · a recorded source, not a stored snapshot
openFDA NDC Directory · a recorded source, not a stored snapshot
Europe PMC · a recorded source, not a stored snapshot
ClinicalTrials.gov · a recorded source, not a stored snapshot
acute radiation-induced proctitis (ARP) incidence
✗ The study did not show it
Who was studied
NCT05138887
How many people
366
Study design
Phase 2
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. No limitation is recorded for this study.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route.
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
openFDA Drugs@FDA · a recorded source, not a stored snapshot
openFDA NDC Directory · a recorded source, not a stored snapshot
Europe PMC · a recorded source, not a stored snapshot
ClinicalTrials.gov · a recorded source, not a stored snapshot
extended Glasgow Outcome Scale
✗ The study did not show it
Who was studied
NCT02794168
How many people
224
Study design
Phase 3
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. No limitation is recorded for this study.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route.
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
openFDA Drugs@FDA · a recorded source, not a stored snapshot
openFDA NDC Directory · a recorded source, not a stored snapshot
Europe PMC · a recorded source, not a stored snapshot
ClinicalTrials.gov · a recorded source, not a stored snapshot
Change in Attention-Deficit Hyperactivity Disorder Rating Scale-IV (ADHD-RS) / Adult ADHD Self-Report Scale (ASRS) Total Score From Baseline to Week 13
✗ The study did not show it
Who was studied
NCT01114737
How many people
206
Study design
Phase 3
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. No limitation is recorded for this study.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route.
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
openFDA Drugs@FDA · a recorded source, not a stored snapshot
openFDA NDC Directory · a recorded source, not a stored snapshot
Europe PMC · a recorded source, not a stored snapshot
ClinicalTrials.gov · a recorded source, not a stored snapshot
What we know
RNAWiki holds 6 written-up human studies for this substance, each with the question it asked.
How we know it
Each card names the study, the number of people and what the study set out to measure.
What this does not prove
These summaries were written by a person and have not been signed off as reviewed claims.
Why it matters
A study that failed is as informative as one that worked, and both are here.
What we still do not know
No reviewed claim exists, so no exact population, effect size or interval is published yet.
What happened in people◇Read from sources, not yet reviewed
How close this is to real life
The top step is something a person would feel or care about. The bottom is a guess from software. Filled steps are where evidence exists for this substance.
□Living longer, or avoiding a major eventNo evidence recorded. Death, a heart attack, a stroke, a hospital stay.No registered study measures this.
□What a body can do day to dayNo evidence recorded. Walking, dressing, breathing, recovering.No registered study measures this.
□Measured performanceNo evidence recorded. How much was lifted, how far was run, how fast.No registered study measures this.
■Symptoms and quality of lifeEvidence recorded. Pain, tiredness, mood, sleep, as the person rated it.3 registered measures of this kind.
■A number that stands in for healthEvidence recorded. Cholesterol, blood sugar, bone density. A stand-in, not the thing itself.5 registered measures of this kind.
■A step measured inside a personEvidence recorded. Something measured in human tissue or human cells.A human record sits on the stored organism ladder.
□AnimalsNo evidence recorded. Mice, rats, dogs. Useful for ideas, not proof about people.No animal record is stored.
□Cells in a dishNo evidence recorded. Cells or chemistry on a bench, far from a whole body.No cell or bench record is stored.
□A guess from softwareNo evidence recorded. Nobody measured it. RNAWiki never publishes one as a finding.RNAWiki stores no prediction for this record. Software can suggest a link. RNAWiki does not publish one as a finding.
Higher on these steps means closer to something a person would feel. It does not mean better done.
What it would be like to take◇Read from sources, not yet reviewed
Felt, measured, or meaningful
Three different things that get called the same word. Registered studies measured all three, and mixing them is how a blood test becomes a health claim.
Felt
Things a person could notice without a test.
behavior rating inventory of executive function
clinical global impression improvement scale
clinical global impression severity scale
Measured
Things only a test, a scale or a device shows.
bone mineral density at 12 months
c reactive protein
flow mediated dilation
bone mineral density
brachial artery flow mediated dilation
Meaningful
Things that change how a life goes, not only a number.
No registered study measured anything of this kind.
A registered study says what someone planned to measure. It does not say what they found. A number moving is not the same as a life going better. The two are shown apart here.
Felt, but not shown to help. A person notices a change. No study showed it leads anywhere good.
Measured, but not felt. A number moves. The person notices nothing. Both can be true.
Measured, but not shown to matter. A number moves in the good direction. Nobody showed that lives went better.
Matters, but takes years. The result that counts may take longer than anyone would keep watching.
Names that fit none of the three (16)
primary objective
adverse events
treatment emergent adverse events
clinical global impressions scale
gastric accommodation
resting muscle sympathetic nerve activity
lipid peroxidation
changes in hepatic venous pressure gradient
functional sympatholysis
vascular alpha 1 adrenergic responsiveness
exaggerated pressor responses during exercise
blood flow
endothelial function
changes in brain chemistry as measured by 1h mrs scans
nitric oxide bioavailability
objective response rate
These are harms, study-process measures, or names the rules did not recognise. They are shown rather than dropped.
What it would be like to take◇Read from sources, not yet reviewed
How long anything takes
Nine different lengths of time that get confused with each other. None of them is worked out from another.
Before anything is noticed.RNAWiki does not store this separately, and never works it out from another figure on this page.
Before a test result moves.RNAWiki does not store this separately, and never works it out from another figure on this page.
Before performance moves.RNAWiki does not store this separately, and never works it out from another figure on this page.
How long the result was watched.No finished study window is recorded for a study that tested this substance.
How long people took it.How long people actually took it is not stored. The study window is not the same thing.
How long people were followed.Follow-up length is not stored separately. It is never read off the study window, which would be a different thing.
How fast the body clears it. 6.7 hours hours
Read from the label, which states: “The mean elimination half-life in PKU patients was approximately 6.7 hours (range 3.9 to 17 hours), comparable with values seen in healthy subjects (range 3 to 5.3 hours).”
How long effects linger.RNAWiki does not store this separately, and never works it out from another figure on this page.
Beyond the studies. Nothing is recorded about the long term.
The longest finished study sets the edge of what anyone measured.
A study window is not how long people took it, and neither is how long they were followed. Where RNAWiki holds only one of the three, it shows one.
What is missing or unclear◇Read from sources, not yet reviewed
Were people like you studied?
RNAWiki cannot tell whether a study fits you. It can show who was in it, and where the result stops carrying.
Who was studied
No description of who was studied is recorded.
Who is missing from the studies
Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What the label states about particular groups
On pediatric, the label states: “The efficacy and safety of sapropterin dihydrochloride have not been established in neonates.”
US prescribing information · d9f3723f-bf7d-9a72-2ef9-41c5508d6ab4 · read 2026-08-30
On older people, the label states: “Clinical studies of sapropterin dihydrochloride in patients with PKU did not include patients aged 65 years and older.”
US prescribing information · d9f3723f-bf7d-9a72-2ef9-41c5508d6ab4 · read 2026-08-30
On people who are pregnant, the label states: “Risk Summary Available data from pregnancy safety studies, pharmacovigilance, and published case reportswith sapropterin use during pregnancy have not identified a drug-associated risk of major birthdefects, miscarriage, or adverse maternal or fetal outcomes (see Data).”
US prescribing information · d9f3723f-bf7d-9a72-2ef9-41c5508d6ab4 · read 2026-08-30
On people who are breastfeeding, the label states: “Risk Summary There are insufficient data to assess the presence of sapropterin in human milk and no data on the effects on milk production.”
US prescribing information · d9f3723f-bf7d-9a72-2ef9-41c5508d6ab4 · read 2026-08-30
Where the result stopped carrying
This is a scope explorer, not a diagnosis engine.
It shows who was studied so you can see whether people similar to you were included.
RNAWiki cannot tell whether a study fits you. It can show who was in it.
What it would be like to take◇Read from sources, not yet reviewed
Why it might seem to do nothing
A real effect and a noticed effect are different things. These are the recorded reasons the two come apart.
It was studied for a different goal
The studies measured something else entirely.
On this record: Some registered studies measured things that match no goal on this page.
It was studied in different people
The people in the studies were not much like the reader.
On this record: Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
The evidence may simply be wrong
Small early studies often do not hold up.
On this record: RNAWiki has not yet published a reviewed conclusion for this use.
Other reasons RNAWiki checked and found nothing for (10)
A different form was studied
The studied form is not the form on the shelf. Nothing in this record points to this reason.
There was nothing to correct
Where a level is already normal, topping it up may change nothing. Nothing in this record points to this reason.
Something else had to happen too
In the studies it was paired with training, a diet or another treatment. Nothing in this record points to this reason.
The change is too small to feel
A real change can still sit below what a person notices. Nothing in this record points to this reason.
Day-to-day swing hides it
Sleep, food, stress and time of day move most numbers more than this would. Nothing in this record points to this reason.
Not enough time yet
The studies ran longer than the person has waited. Nothing in this record points to this reason.
It was not taken as studied
Missed days change the result, and studies count them. Nothing in this record points to this reason.
Something else changed at the same time
Two changes at once cannot be told apart afterwards. Nothing in this record points to this reason.
The product may not be what it says
Contents of a sold product are not always what the label states. Nothing in this record points to this reason.
No recorded reason
RNAWiki has nothing stored that would explain it. Nothing in this record points to this reason.
None of these is a reason to take more. Taking more is not a step this page ever suggests.
What it would be like to take◇Read from sources, not yet reviewed
What taking it involves
The recorded facts about getting hold of it and using it. Nothing here is a suggestion about what you should do.
How it is supplied
Prescription only
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Read from the recorded approval status.
No source is stored against this line.
Form and route
Not recorded.
∅ Nothing recorded
Where this came from
RNAWiki holds nothing here and says so rather than guessing.
No form or route is recorded.
No source is stored against this line.
Who oversees it
RNAWiki has not recorded a supervision or regulatory status for this substance.
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
No register row and no identity class settled the question.
No source is stored against this line.
What is in the pack
Not recorded.
∅ Nothing recorded
Where this came from
RNAWiki holds nothing here and says so rather than guessing.
Nothing is recorded about product quality.
No source is stored against this line.
Where it is registered
Regulatory records are listed in the technical disclosure at the foot of this page.
# Counted from records
Where this came from
A count of rows RNAWiki holds. It describes our records, not your body.
Register entries are stored per jurisdiction and shown with their dates.
No source is stored against this line.
Why people stop
Not recorded.
∅ Nothing recorded
Where this came from
RNAWiki holds nothing here and says so rather than guessing.
No record of why people stopped taking it is stored for this substance.
No source is stored against this line.
What it would be like to take∅Nothing found in the sources checked
What can go wrong
Sorted by where each line came from. A regulator's label and a report somebody sent in are not the same kind of fact.
∅Nothing found in the sources checked
No harm is recorded against this substance in the sources RNAWiki checked. Finding nothing is not the same as showing there is nothing.
The sources listed were searched and held nothing. That is not the same as nothing existing.
Over a long time. No completed tested study window is recorded, so long-term effects are not established by the registry record.
Groups the studies covered thinly. Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What is missing or unclear◇Read from sources, not yet reviewed
Does the exact form matter?
Evidence belongs to the exact thing that was tested. A different salt, a different mixture or a different preparation is a different question.
The form that was studied
Not recorded.
∅ Nothing recorded
Where this came from
RNAWiki holds nothing here and says so rather than guessing.
The exact form studied is not recorded.
No source is stored against this line.
What is sold
Not recorded.
∅ Nothing recorded
Where this came from
RNAWiki holds nothing here and says so rather than guessing.
Nothing further is recorded about which forms are sold.
No source is stored against this line.
What is recorded as being sold
JAVYGTOR is oral at 3 DOSAGE FORMS AND STRENGTHS JAVYGTOR tablets are for oral use., recorded as fda label in effect 2024-10-21 in the United States.
US prescribing information · d9f3723f-bf7d-9a72-2ef9-41c5508d6ab4 · read 2026-08-30
Evidence carries across two names for one substance. It does not carry across a salt, a mirror form or a mixture.
What it would be like to take◇Read from sources, not yet reviewed
What you could measure
This one is decided with a clinician, so this section holds questions to ask rather than a plan to run.
RNAWiki could not confidently classify this substance, so no self-experiment plan is offered.
Questions worth asking
Which of the trials of Sapropterin studied people like me?
What was measured, and for how long?
Was the result a laboratory value or a health outcome?
What would we watch for, and when would we stop?
Tracking can show whether something changed for you. It cannot show what caused it.
RNAWiki records evidence. It does not say whether this substance is right for you.
What is missing or unclear◇Read from sources, not yet reviewed
What nobody knows yet
Open questions, each with why it is open and what would close it.
How much did people take in the studies?
The sources RNAWiki checked hold nothing for this field.
Why it matters. A result belongs to an amount. Without the amount the result floats free.
What would answer it
A stored source that records it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing populations
Which groups were under-represented in the studies has not been recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing long-term data
No completed tested study window is recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
No reviewed conclusion
RNAWiki has not yet published a reviewed conclusion for this use.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing interaction studies
No interaction was found in the registers checked. Not finding one is not the same as showing there is none.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Formulation uncertainty
Several salts, forms or products of Sapropterin are recorded. Results from one form may not transfer to another.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Mechanism not reviewed
No reviewed mechanism story exists for this substance.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
What happened in people◇Read from sources, not yet reviewed
Check any of this yourself
Every line above traced back to the study it came from. This is the technical layer, and the vocabulary changes here.
Where else this substance is registered
FDA substance identifier (UNII)
EGX657432I
CAS registry number
62989-33-7
PubChem compound
135398654
ChEMBL
CHEMBL1201774
ChEBI
59560
WHO international nonproprietary name list entry
6553
RxNorm concept
753340
EMA substance identifier
100000084074
DrugBank
DB00360
Checks this page had to pass
✓ Passed
Identity resolved
no open identity hold
✓ Passed
No unresolved merge across substance families
no quarantine open
✓ Passed
Every public sentence names a source
The opening statement carries the origin: Quoted from a stored source.
✗ Not passed
Trial roles classified for highlighted evidence
No registered study is classified as testing this substance.
✓ Passed
No internal keys in reader text
enforced by the copy-contract test over the rendered page
✗ Not passed
Safety mode resolved
No register row and no identity class settled the question.
✓ Passed
Canonical metadata present
slug and display name present
What is missing or unclear◇Read from sources, not yet reviewed
What to learn next
Ordered by what would most change how you read this page, starting with what is easiest to misunderstand.
This order is fixed in code and does not count clicks or time on the page.
What is not here
6 questions this page could not answer
These sections were prepared and left out because there was nothing to put in them. They are listed rather than hidden, so the gaps in this record are visible.
The path through the body — found nothing in the sources checked.
What it may clash with — found nothing in the sources checked.
Other ways to the same goal — found nothing in the sources checked.
Claims that go past the evidence — found nothing in the sources checked.
How this medicine reached us — found nothing in the sources checked.
What changed on this page — found nothing in the sources checked.
The record as stored
The full record, for auditing
Everything above is built from what is below. This layer keeps the technical vocabulary, record identifiers and every stored row, so a reader who wants to check the page can.
Recorded evidence blocks (11)
Q1
What did Sapropterin's largest trial (1887 people) and its longest (12 years) measure?
1887 people in Sapropterin's largest registered study, 12 years in its longest registered window, measuring Area Under the Curve (AUC0-12hrs) of Plasma BH4 Concentration. ClinicalTrials.gov · 2026-09-01
22 phase2, 10 na or unstated, 10 phase3, 9 na, 9 phase1, 4 phase4, 2 early phase1; NCT00778206; 2021-01-29. Last human test completed 2025, NCT03136029.
Interpretation These counts include studies where Sapropterin was a comparison treatment, a background treatment or an exposure in an observational study, and the longest window may be a planned end date. Trial roles have not yet been classified for this record.
Show the evidence
phase2
22
na or unstated
10
phase3
10
na
9
phase1
9
phase4
4
2 more recorded rows
early phase1
2
Last recorded human testNCT03136029
2025-07-31
recorded 2026-09-01 · last checked 2026-09-04
Q2
Sapropterin was tested only in human — what did it show?
"Too few participants recruited within timeframe"; 8 of 60 registered studies
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Trial
NCT00827762
terminated; "Too few participants recruited within timeframe"
NCT00935753
withdrawn; "Contractual issues"
NCT01395394
terminated; "Difficulty with recruitment and agreed with Sponsor to report completed data as case reports"
NCT01412437
withdrawn; "poor recruitment"
NCT01806051
terminated; "Participants found the study procedures to be too cumbersome and no longer wanted to participate"
NCT01977820
terminated; "Recruitment challenges"
2 further recorded trials
NCT03493412
withdrawn; "discontinued due to change in operating plans prior to study initiation and enrollment"
NCT04054973
withdrawn; "Study was unable to be started due to unavailability of study medication."
recorded 2026-09-01 · last checked 2026-09-04
Q4
Sapropterin's half-life is 6.7 hours — which schedules were studied?
6.7 hours, the half-life Sapropterin's label states. openfda-label · c4d92cce-e899-4f14-b19c-5e17f9922215 · 2026-08-30
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half life
6.7 hours hours; The mean elimination half-life in PKU patients was approximately 6.7 hours (range 3.9 to 17 hours), comparable with values seen in healthy subjects (range 3 to 5.3 hours).
metabolism
Apparent Plasma Clearance by Age Parameter 0 to <1yr Evaluated at 20 mg/kg per day dose (N=10) 1 to <6 yr (N=57) 6 to <12 yr Evaluated at 5, 10, or 20 mg/kg per day doses (N=23) 12 to <18 yr (N=24) ≥18 yr (N=42) CL/F (L/hr/kg) Mean ± SD (Median) 81.5 ± 92.4 (53.6) 50.7 ± 20.1 (48.4) 51.7 ± 21.9 (47.4) 39.2 ± 9.3 (38.3) 37.9 ± 20.2 (31.8) Metabolism Sapropterin is a synthetic form of…
recorded 2026-08-30 · last checked 2026-09-04
Q5
Could one person measure Sapropterin's effect on primary objective?
Primary objective: measured in Sapropterin's trials.
Interpretation primary objective is the recorded endpoint.
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biomarkers
primary objective; 2026-09-01
adverse events; 2026-09-01
treatment emergent adverse events; 2026-09-01
bone mineral density at 12 months; 2026-09-01
behavior rating inventory of executive function; 2026-09-01
clinical global impression improvement scale; 2026-09-01
14 more recorded rows
biomarkers
clinical global impression severity scale; 2026-09-01
0; NCT00935753; PHASE2/PHASE3; the smallest recorded human enrolment at or below 30; the registry states no direction of its result; WITHDRAWN
Q6
Which of adverse events, behavior rating inventory of executive function and blood flow did Sapropterin's trials measure?
adverse events, behavior rating inventory of executive function and blood flow lead 24 outcome terms across Sapropterin's trials. ClinicalTrials.gov · 2026-09-01
bone mineral density at 12 months, behavior rating inventory of executive function, clinical global impression improvement scale, clinical global impression severity scale, clinical global impressions scale and gastric accommodation follow.
Show the evidence
primary objective
1
adverse events
1
treatment emergent adverse events
1
bone mineral density at 12 months
1
behavior rating inventory of executive function
1
clinical global impression improvement scale
1
14 more recorded rows
clinical global impression severity scale
1
clinical global impressions scale
1
gastric accommodation
1
resting muscle sympathetic nerve activity
1
lipid peroxidation
1
c reactive protein
1
flow mediated dilation
1
changes in hepatic venous pressure gradient
1
bone mineral density
1
brachial artery flow mediated dilation
1
functional sympatholysis
1
vascular alpha 1 adrenergic responsiveness
1
exaggerated pressor responses during exercise
1
blood flow
1
recorded 2026-09-01 · last checked 2026-09-04
Q7
Which of Sapropterin's 5 ongoing trials reports first?
Change in functional sympatholysis; Nitric Oxide bioavailability; latest 2030-06-01
Show the evidence
Trial
NCT02947750
"Neurovascular Transduction During Exercise in Chronic Kidney Disease"; n 150; "Change in functional sympatholysis"; 2027-04-30
NCT04800692
"The Effects of ATLAS Therapy on Nitric Oxide Bioavailability in Patients With Intermittent Claudication"; n 10; "Nitric Oxide bioavailability"; 2027-12
NCT07255599
"Evaluation of BH4 Responsiveness in Our PKU Patients"; n 20; "• Serum phenylealanine level in patients after given tetrahydrobiopterin"; 2026-09-01
NCT07574034
"A Single Patient Study of Sapropterin for Multisystem Smooth Muscle Dysfunction Syndrome"; n 1; "Crossing of percentile of growth"; 2030-06-01
NCT07728032
"Impact Of A Phe-Restricted Diet On Gut Health In Children With PKU"; n 148; "Faecal gut microbiota taxonomic composition assessed by shotgun metagenomic sequencing"; 2026-12
recorded 2026-09-01 · last checked 2026-09-04
Q8
Which 13 trials of Sapropterin posted no result?
Posted no result
13 of 13 completed trials
Registrations
NCT00104260, NCT00225615, NCT00435331, NCT00789568, NCT00964236 and NCT01456286, and 7 more
Completion dates
oldest 2005-11; newest 2023-01-04
Show the evidence
Trial
NCT00104260
2005-11
NCT00225615
2006-06
NCT00435331
2008-10
NCT00789568
2009-10
NCT00964236
2011-08
NCT01456286
2013-10
7 further recorded trials
NCT01274026
2013-12
NCT02042196
2016-05-02
NCT00730080
2018-05
NCT03864029
2018-07-25
NCT03820804
2019-09-10
NCT00778206
2021-01-29
NCT01965912
2023-01-04
Q9
At the median, Sapropterin's trials enrolled 28 people — anything larger?
Median enrolment
28
Largest enrolment
1887
Registered trials counted
59
Q10
Sapropterin and BCRP, CYP1A2 and MATE1: shared by which compounds?
BCRP, CYP1A2 and MATE1 appear in Sapropterin's recorded interaction sentences, 1 in all. openfda-label+europepmc · 2026-08-30
Interpretation pharmacokinetics
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CYP1A2pharmacokinetics
In vitro Studies Where Drug Interaction Potential Was Not Further Evaluated Clinically The potential for sapropterin to induce or inhibit cytochrome P450 enzymes was evaluated in in vitro studies which showed sapropterin did not inhibit CYP 1A2, 2B6, 2C8, 2C9, 2C19, 2D6, or 3A4/5, nor induce CYP 1A2, 2B6, or 3A4/5.
recorded 2026-08-30 · last checked 2026-09-04
Q11
Was Sapropterin studied with exercise?
exercise is named in Sapropterin's label sentences: "Under baseline conditions, there was no significant difference in MSNA responses between the groups; however, when the BP response during exercise was equalized between the groups using nitroprusside, the 6R-BH4-treated group had a significantly lower MSNA response during RHG 20% (6R-BH4 vs.…" openfda-label+europepmc · 2026-08-30
1 recorded statement; exercise
Show the evidence
exercise
Under baseline conditions, there was no significant difference in MSNA responses between the groups; however, when the BP response during exercise was equalized between the groups using nitroprusside, the 6R-BH4-treated group had a significantly lower MSNA response during RHG 20% (6R-BH4 vs. placebo, +12 ± 1 vs. +21 ± 2 bursts/min, P = 0.004) but not during SHG 30%.
recorded 2026-08-30 · last checked 2026-09-04
Where it is registeredIdentifiers, relations and other names
ChEMBL ATC CC BY-SA · ClinicalTrials.gov — US Government work · Europe PMC — metadata only, under the recorded legal gate · derived from this page's own recorded fields; no external licence · mixed register set; per-register licences in docs/specs/corpus-20k-sources.md · openFDA / DailyMed — US Government work
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✓ public claims reviewed: 0 reviewed claim(s); drafts are never rendered
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