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Tividenofusp alfa

  • Biologic
  • Still being tested
  • Identity checked
  • Sources last checked 2026-09-04

This page shows what was measured, who it was measured in, and what that does not settle.

What Tividenofusp alfa does in the body

AVLAYAH is indicated for the treatment of neurologic manifestations of Hunter syndrome (Mucopolysaccharidosis type II, MPS II) when initiated in presymptomatic or symptomatic pediatric patients weighing at least 5 kg prior to advanced neurologic impairment.

From the FDA-approved label: Hunter syndrome is an inherited X-linked recessive lysosomal storage disease caused by a deficiency of iduronate-2-sulfatase (IDS), a lysosomal enzyme, that degrades heparan sulfate (HS) and dermatan sulfate (DS), the two primary glycosominoglycans (GAGs) in the lysosome. Insufficiency or absence of IDS leads to accumulation of GAGs, including HS and DS, and subsequent lysosome dysfunction in multiple organs and tissues, including the central nervous system (CNS). Tividenofusp alfa-eknm provides an exogenous source of IDS.

Why people take it. AVLAYAH is indicated for the treatment of neurologic manifestations of Hunter syndrome (Mucopolysaccharidosis type II, MPS II) when initiated in presymptomatic or symptomatic pediatric patients weighing at least 5 kg prior to advanced neurologic impairment.

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
Professional supervision is normally required. A regulator classifies this substance in a way that restricts how it is supplied.

What the registries record it as

  • The substance registry classes this as protein.

    FDA substance registry · QLD7UJN8CF · read 2026-08-29

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 159 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.

Placebo

A placebo is a dummy treatment given so the real one can be compared with it.

A picture of it, and where the picture fails

A placebo is like a blank control in an experiment.

Where that stops being true. A blank does nothing. People given a placebo often do get better.

What people get wrong. A placebo effect is read as imaginary. The improvement is measured and real.

An inactive intervention matched in appearance to the test intervention, used to control for non-specific effects.

Comparator

A comparator is whatever the treatment was measured against.

A picture of it, and where the picture fails

It is like the other runner in a race.

Where that stops being true. A race has one winner. A study can show both arms improved.

What people get wrong. Results are read without asking what the other group got. Beating nothing is not beating a treatment.

The control condition against which the experimental intervention is assessed.

What happened in peopleRead 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.

Incidence and intensity of treatment-emergent adverse events (TEAEs)

The study did not show it

Who was studied
NCT06075537
How many people
99
Study design
Phase 2/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. Intravenous

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • openFDA NDC Directory · a recorded source, not a stored snapshot
  • openFDA SPL label · a recorded source, not a stored snapshot
  • FDA label (openFDA SPL) · a recorded source, not a stored snapshot

Percent change from baseline in cerebrospinal fluid (CSF) heparan sulfate (HS) concentration (Cohort A)

The study did not show it

Who was studied
NCT05371613
How many people
63
Study design
Phase 2/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. Intravenous

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • openFDA NDC Directory · a recorded source, not a stored snapshot
  • openFDA SPL label · a recorded source, not a stored snapshot
  • FDA label (openFDA SPL) · a recorded source, not a stored snapshot

Incidence and severity of treatment-emergent adverse events (TEAEs)

The study did not show it

Who was studied
NCT04251026
How many people
47
Study design
Phase 1/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. Intravenous

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • openFDA NDC Directory · a recorded source, not a stored snapshot
  • openFDA SPL label · a recorded source, not a stored snapshot
  • FDA label (openFDA SPL) · a recorded source, not a stored snapshot
What we know
RNAWiki holds 3 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 is missing or unclearRead 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

People similar to this profile were included.

  • AVLAYAH is indicated for the treatment of neurologic manifestations of Hunter syndrome (Mucopolysaccharidosis type II, MPS II) when initiated in presymptomatic or symptomatic pediatric patients weighing at least 5 kg prior to advanced neurologic impairment. This indication is approved under accelerated approval based on the reduction of cerebrospinal fluid heparan sulfate [see Clinical Studies (14) ].

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 safety and effectiveness of AVLAYAH have not been established in pediatric patients weighing less than 5 kg.”

    US prescribing information · 014d92c1-b643-4680-8ca6-f0b3307da915 · read 2026-08-30

  • On older people, the label states: “Clinical trials of AVLAYAH in patients with Hunter syndrome did not include patients 65 years of age or older.”

    US prescribing information · 014d92c1-b643-4680-8ca6-f0b3307da915 · read 2026-08-30

  • On people who are pregnant, the label states: “Risk Summary There are no available data on the use of AVLAYAH during pregnancy to evaluate for a drug-associated risk of major birth defects, miscarriage, or other adverse maternal or fetal outcomes.”

    US prescribing information · 014d92c1-b643-4680-8ca6-f0b3307da915 · read 2026-08-30

  • On people who are breastfeeding, the label states: “Risk Summary There are no data on the presence of tividenofusp alfa-eknm in either human or animal milk, the effects on the breastfed infant, or the effects on milk production.”

    US prescribing information · 014d92c1-b643-4680-8ca6-f0b3307da915 · 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 takeRead 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 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 (11)
It was studied for a different goal
The studies measured something else entirely. Nothing in this record points to this reason.
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 takeRead 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

Still being tested

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

Intravenous

Source-linked record

Where this came from

A person wrote this into the record with the study named beside it. No reviewer has signed it off.

The form and route recorded on this substance.

No source is stored against this line.

Who oversees it

Professional supervision is normally required. A regulator classifies this substance in a way that restricts how it is supplied.

Quoted from a source

Where this came from

Copied from a source RNAWiki stored, with the source named.

Suppression classes recorded: S7.

No source is stored against this line.

What is in the pack

Sold as injection, powder, lyophilized, for solution, given by the intravenous route.

Source-linked record

Where this came from

A person wrote this into the record with the study named beside it. No reviewer has signed it off.

Recorded notes on how this is sold and what that means for what is in the pack.

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 takeNothing 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 unclearRead 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

Intravenous

Source-linked record

Where this came from

A person wrote this into the record with the study named beside it. No reviewer has signed it off.

The form used in the studies cited on this page.

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

  • 2 products list this as an active ingredient in the United States drug directory. 2 of them contain it and nothing else.

    FDA National Drug Code directory · 49187-5002 · read 2026-08-29

  • They are sold as injection, powder, lyophilized, for solution and solution, taken intravenous.

    FDA National Drug Code directory · 49187-5002 · read 2026-08-29

  • 1 published label names it as an active ingredient. 1 of them describe this substance alone, which is where its own label text on this page comes from.

    US prescribing information · 014d92c1-b643-4680-8ca6-f0b3307da915 · read 2026-08-29

  • Those labels are classed as human prescription drug.

    US prescribing information · 014d92c1-b643-4680-8ca6-f0b3307da915 · read 2026-08-29

  • AVLAYAH is intravenous at 3 DOSAGE FORMS AND STRENGTHS For injection: 150 mg of tividenofusp alfa-eknm as a white to off-white lyophilized powder with a cake-like appearance in a single-dose vial for reconstitution and further dilution., recorded as fda label in effect 2026-03-20 in the United States.

    US prescribing information · 014d92c1-b643-4680-8ca6-f0b3307da915 · 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 takeRead 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.

Self-experiment planning is not offered for a prescription or clinician-supervised medicine, investigational agent. The questions below are for a clinician or pharmacist.

Questions worth asking

  • Which of the trials of Tividenofusp alfa 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 unclearRead 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 Tividenofusp alfa 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 peopleRead 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)
QLD7UJN8CF
CAS registry number
2641020-57-5
WHO international nonproprietary name list entry
12197
EMA substance identifier
100000181784

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

  • Passed

    Safety mode resolved

    Suppression classes recorded: S7.

  • Passed

    Canonical metadata present

    slug and display name present

What is missing or unclearRead from sources, not yet reviewed

How this medicine reached us

Kept near the foot of the page. A historical event moves up only when it changes something about this substance today.

What the approval register records

  • The earliest marketing start date recorded for a listed product is 20260324.

    FDA National Drug Code directory · 49187-5002 · read 2026-08-29

What is missing or unclearRead 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

9 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.

  • What was measured, goal by goal — found nothing in the sources checked.
  • How close this is to real life — found nothing in the sources checked.
  • The path through the body — found nothing in the sources checked.
  • Felt, measured, or meaningful — found nothing in the sources checked.
  • How long anything takes — 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.
  • 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 (3)

On the Tividenofusp alfa label: indicated for what?

"AVLAYAH is indicated for the treatment of neurologic manifestations of Hunter syndrome (Mucopolysaccharidosis type II, MPS II) when initiated in presymptomatic or symptomatic pediatric patients weighing at least 5 kg prior to advanced neurologic impairment. This indication is approved under accelerated approval based…": indications and usage on Tividenofusp alfa's label. DailyMed label · 014d92c1-b643-4680-8ca6-f0b3307da915 · 2026-03-20

3 registered trials of Tividenofusp alfa — at which phases?

Registered studies posting no result
3 of 3

3 registered studies of Tividenofusp alfa: 3 phase2, 2 phase3, 1 phase1. CLINICALTRIALS_SNAPSHOT · 2026-09-01

1 with a PubMed record

Show the evidence
  • phase2
    3
  • phase3
    2
  • phase1
    1
  • active not recruiting
    1
  • enrolling by invitation
    1
  • recruiting
    1

recorded 2026-09-01 · last checked 2026-09-04

At the median, Tividenofusp alfa's trials enrolled 63 people — anything larger?

Median enrolment
63
Largest enrolment
99
Registered trials counted
3
Where it is registered
Identifiers, relations and other names

The exact record

ChEMBL id
CHEMBL4594537
CAS number
2641020-57-5
Also called
Dnl-310, Dnl310, Etv:ids, DNL-310, RECOMBINANT IDURONATE 2-SULFATASE, ENZYME TRANSPORT VEHICLE SPECIFIC FOR THE TRANSFERRIN RECEPTOR FUSED TO IDURONATE 2-SULFATASE, Iduronate-2-sulfatase (human) fusion protein with immunoglobulin Fcab, anti-(human type 1 transferrin receptor) (synthetic human γ1-chain 2), (536→6′),(539→9′)-bis(disulfide) with immunoglobulin Fcab anti-(human type 1 transferrin receptor) (synthetic human γ1-chain 1), TIVIDENOFUSP ALFA [USAN], human iduronate 2-sulfatase (IDS, α- L-iduronate sulfate sulfatase, EC:3.1.6.13) pro-protein (1-525), fused via the peptide linker 526 GGGGS 530 to a human immunoglobulin G1 C-terminal Fc fragment (531-757) variant (L 544>A, L 545>A, T 676>S, L 678>A, Y 717 V), disulfide bridged to an engineered human immunoglobulin G1 anti-(human type 1 transferrin receptor (TfR1)) C-terminal Fc fragment (1'-227'), variant (L 14' >A, L 15' >A, T146' >W, N 164' >Y, Q 166' >T, P 167' >E, E 168' >W, N 169' >A, D 193' >T, S 195' >E, R 196' >E, N201' >F), heterodimer, produced in Chinese hamster ovary (CHO) cells, glycoform alfa (human iduronate 2-sulfatase (IDS, α-L-iduronate sulfate sulfatase, idursulfase, EC:3.1.6.13, UniProt:P22304), pro-protein (1-525), fused via the peptidic linker G4 S (526-530) with a human immunoglobulin G1 hinge-CH2-CH3 Fc fragment [Homo sapiens IGHG1*01 (531-757) (hinge (531-540, N-terminal hinge residues EPKSC deleted), CH2L 544>A, L 545>A (541-650), CH3 T676>S, L 678>A, Y 717 >V(651-755), CHS (756-757))], (536-6':539-9')-bisdisulfide with a human immunoglobulin G1 hinge-CH2-CH3 Fc fragment [Homo sapiens IGHG1*01 (1'-227') (hinge (1-10), CH2 L 14' >A, L 15' >A (11-120), CH3 T146' >W, N 164' >Y, Q166' >T, P 167' >E, E 168' >W, N 169' >A, D193' >T, S 195' >E, R 196' >E, N 201' >F engineered for binding to the human type 1 transferrin receptor (TfR1) (121-225), CHS (226-227))], produced in Chinese hamster ovary (CHO) cells, glycoform alfa), tividenofusp alfa [INN]
Trade name
Avlayah
Salt form
TIVIDENOFUSP ALFA-EKNM
Sources (4)

Sources

ClinicalTrials.gov — US Government work · mixed register set; per-register licences in docs/specs/corpus-20k-sources.md · openFDA / DailyMed — US Government work

How these records are assembled · Which registers were checked

Index-quality checks
  • identity passed: no open identity hold
  • required summary fields resolved: 4 required field(s) not terminal: Why people use it, Best-supported result, Biggest unanswered question, Human evidence
  • public claims reviewed: 0 reviewed claim(s); drafts are never rendered
  • source coverage passed: 4 source rows
  • no critical contamination: no quarantine open
  • canonical metadata passed: slug and display name present
  • no raw internal fields: enforced by the copy-contract test over the rendered page

This is a record of evidence. It is not medical advice, and it does not say this substance suits you. Nothing here says any substance on RNAWiki is appropriate for a child.