This page shows what was measured, who it was measured in, and what that does not settle.
What Eteplirsen does in the body
Used for one genetic form of Duchenne muscular dystrophy.
The dystrophin gene is read like a sentence in three-letter words. A deletion can leave a stray letter that throws every following word out of alignment, so the cell gives up and makes nothing. Eteplirsen sticks over one exon so the cell skips it entirely, which realigns the rest of the sentence. The protein that comes out is shorter than normal but, in principle, still functional. The unresolved question is how much of it the drug actually produces.
What happened in people
After three and a half years, treated boys made less than 1% of the muscle protein found in a healthy person.
✓ Reviewed first-read answer
Where this came from
A person wrote this and a reviewer approved it against this exact record. It carries no effect size.
A reviewer approved this against this record. The reviewed-claim record carrying the exact population and effect size does not exist yet.
No source is stored against this line.
The limit that matters most
It has not been shown to help boys walk or function better.
Where it acts
Skeletal muscle fibre nucleus
Kind of result
A step measured inside a person
Supervision
Professional supervision is normally required. It is a prescription or clinician-administered medicine where it is approved.
What the registries record it as
The substance registry classes this as nucleicacid.
FDA substance registry · AIW6036FAS · read 2026-08-29
Where each sentence above came from
No recorded sentence describes the change this makes in a way that stands on its own. The page opens with what it is taken for instead, and the recorded explanation follows below.
Shown as the opening line on this page.
The limit a reviewer approved as the one that matters most here.
The four opening statements run to 110 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.
Protein
A protein is a folded chain your body builds to do a specific job.
A picture of it, and where the picture fails
A protein is like a tool bent into one shape for one task.
Where that stops being true. A tool keeps its shape. A protein can change shape and stop working.
What people get wrong. Protein in food and a protein in the body are related but not the same thing.
A polymer of amino acids folded into a defined structure that determines its function.
Gene
A gene is a stretch of instructions for building one protein.
A picture of it, and where the picture fails
A gene is like one page of a building plan.
Where that stops being true. A page is read the same way every time. A gene can be read more or less often.
What people get wrong. Having a gene is often read as having a trait. Whether it is used matters as much.
A segment of DNA that encodes a functional product, usually a protein.
Messenger RNA
Messenger RNA is a working copy of one gene, carried to where proteins are built.
A picture of it, and where the picture fails
It is like a photocopy of one plan page, taken to the workshop.
Where that stops being true. A photocopy lasts. This copy is destroyed soon after use, on purpose.
What people get wrong. It is often thought to change the gene. It is a copy, and it does not alter the original.
A single-stranded transcript of a gene that ribosomes translate into a protein.
Small interfering RNA
A small interfering RNA is a short piece that makes a cell destroy one working copy.
A picture of it, and where the picture fails
It is like a note telling the workshop to shred one plan page.
Where that stops being true. A note is read once. This keeps working for months after one injection.
What people get wrong. It is often described as gene editing. It leaves the gene untouched.
A short double-stranded RNA that directs the RNA-induced silencing complex to cleave a complementary transcript.
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.
Dystrophin production at week 24, with 6-minute walk distance versus placebo assessed alongside
✗ The study did not show it
Who was studied
Study 201/202 (NCT01396239 and NCT01540409)
How many people
12
Study design
Phase 2
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
No significant difference in 6-minute walk distance; baseline dystrophin unavailable so production could not be estimated
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. Four patients per arm at randomisation; the label notes crude adverse-event frequencies that may not reflect practice at this sample size
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Intravenous infusion of an uncharged phosphorodiamidate morpholino oligomer
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
EXONDYS 51 (eteplirsen) US prescribing information, DailyMed (https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=33bff678-7829-479e-9110-b8e33a0bc0aa) · a recorded source, not a stored snapshot
Change in muscle dystrophin protein by western blot at week 48
✓ The study showed what it set out to show
Who was studied
Study 301 biopsy study
How many people
13
Study design
Phase 3 (open label)
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
p=0.008
Repeated elsewhere
Partially Replicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
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 infusion of an uncharged phosphorodiamidate morpholino oligomer
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
EXONDYS 51 (eteplirsen) US prescribing information, DailyMed (https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=33bff678-7829-479e-9110-b8e33a0bc0aa) · a recorded source, not a stored snapshot
Change in 6-minute walk distance at week 96 versus a concurrent untreated cohort not amenable to exon 51 skipping
✗ The study did not show it
Who was studied
PROMOVI (NCT02255552)
How many people
109
Study design
Phase 3 (open label)
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Not reported as a significant concurrent comparison; the untreated cohort was judged an inappropriate control
Repeated elsewhere
Failed to Replicate
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. Only 15 of 30 untreated participants completed, against 78 of 79 treated participants
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Intravenous infusion of an uncharged phosphorodiamidate morpholino oligomer
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
EXONDYS 51 (eteplirsen) US prescribing information, DailyMed (https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=33bff678-7829-479e-9110-b8e33a0bc0aa) · a recorded source, not a stored snapshot
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 it changes in the body◇Read from sources, not yet reviewed
The path through the body
From what a person takes to what changes. A solid line is a step measured in people. A dashed line is a step nobody has measured that way.
Start
Eteplirsen
What a person takes: Intravenous infusion of an uncharged phosphorodiamidate morpholino oligomer.
The measurement behind this step
Single-dose vials diluted into saline and infused weekly over 35 to 60 minutes. No lipid carrier, no targeting ligand, and no chemical modification to improve muscle uptake.
Getting in
Weekly intravenous infusion
The drug goes in through a vein once a week, usually through a long-term line because the schedule never stops.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
Uncharged phosphorodiamidate morpholino oligomer given as an isotonic phosphate-buffered infusion. Plasma clearance is rapid and largely renal; most of an administered dose is excreted within hours.
EXONDYS 51 (eteplirsen) US prescribing information, DailyMed (https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=33bff678-7829-479e-9110-b8e33a0bc0aa) · a recorded source, not a stored snapshot
Only a small fraction of what is infused ever reaches the inside of a muscle cell nucleus.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
The neutral backbone that makes PMOs nuclease-resistant also denies them the protein-binding-driven uptake that charged phosphorothioates use. Uptake into mature myofibres is poor and is thought to depend partly on membrane damage in dystrophic muscle.
EXONDYS 51 (eteplirsen) US prescribing information, DailyMed (https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=33bff678-7829-479e-9110-b8e33a0bc0aa) · a recorded source, not a stored snapshot
It binds directly over the exon the cell is supposed to leave out, masking the signals that recruit it.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Watson-Crick pairing to a 30-nucleotide site within DMD exon 51, occluding an exonic splicing enhancer and preventing SR-protein-dependent exon definition.
EXONDYS 51 (eteplirsen) US prescribing information, DailyMed (https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=33bff678-7829-479e-9110-b8e33a0bc0aa) · a recorded source, not a stored snapshot
The spliceosome skips the exon and restores the reading frame
The cell splices exon 50 straight to exon 52, which puts the rest of the instructions back into alignment.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
Exon 51 is excluded from the mature transcript. In patients with deletions such as 48-50 or 52, exclusion restores an in-frame junction, allowing translation through to the C-terminal dystroglycan-binding domain.
EXONDYS 51 (eteplirsen) US prescribing information, DailyMed (https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=33bff678-7829-479e-9110-b8e33a0bc0aa) · a recorded source, not a stored snapshot
A shortened dystrophin appears at the sarcolemma, in trace amounts
Some internally shortened dystrophin does show up at the muscle membrane. The measured quantity is a fraction of one percent of normal.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Immunohistochemistry shows sarcolemmal localisation of the truncated isoform, and western blot quantifies it at 0.44 to 0.93 percent of healthy muscle. Whether that quantity restores the dystrophin-glycoprotein complex sufficiently to reduce contraction-induced injury is unresolved.
EXONDYS 51 (eteplirsen) US prescribing information, DailyMed (https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=33bff678-7829-479e-9110-b8e33a0bc0aa) · a recorded source, not a stored snapshot
No suggested links are held for this record, so nothing is hidden from this path.
What we know
The record describes 5 steps from taking it to an effect in a person.
How we know it
Each step names the study behind it in the technical detail beside it.
What this does not prove
A change inside the body is a reason to look. It is not a result in a person.
Why it matters
A reader can see exactly where the chain stops being measured in people.
What we still do not know
No reviewed claim binds any of these steps to a named population.
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
People similar to this profile were included.
Boys and young men with a genetically confirmed DMD deletion amenable to exon 51 skipping, given weekly by intravenous infusion, usually on top of corticosteroids.
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: “EXONDYS 51 is indicated for the treatment of Duchenne muscular dystrophy (DMD) in patients who have a confirmed mutation of the DMD gene that is amenable to exon 51 skipping, including pediatric patients [see Clinical Studies ( 14 )] .”
US prescribing information · 33bff678-7829-479e-9110-b8e33a0bc0aa · read 2026-08-30
On older people, the label states: “DMD is largely a disease of children and young adults; therefore, there is no geriatric experience with EXONDYS 51.”
US prescribing information · 33bff678-7829-479e-9110-b8e33a0bc0aa · read 2026-08-30
On people who are pregnant, the label states: “Risk Summary There are no human or animal data available to assess the use of EXONDYS 51 during pregnancy.”
US prescribing information · 33bff678-7829-479e-9110-b8e33a0bc0aa · read 2026-08-30
On people who are breastfeeding, the label states: “Risk Summary There are no human or animal data to assess the effect of EXONDYS 51 on milk production, the presence of eteplirsen in milk, or the effects of EXONDYS 51 on the breastfed infant.”
US prescribing information · 33bff678-7829-479e-9110-b8e33a0bc0aa · read 2026-08-30
Where the result stopped carrying
The randomised 12-patient study showed no significant 6-minute walk separation
PROMOVI lost its concurrent control cohort to genotype-driven non-comparability
The EMA refused marketing authorisation in 2018 and confirmed the refusal on re-examination
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 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 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
Not established
❝ 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 infusion of an uncharged phosphorodiamidate morpholino oligomer
✎ 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. It is a prescription or clinician-administered medicine where it is approved.
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
The identity record classes it as ASO (Antisense Oligonucleotide).
No source is stored against this line.
What is in the pack
Single-dose vials diluted into saline and infused weekly over 35 to 60 minutes. No lipid carrier, no targeting ligand, and no chemical modification to improve muscle uptake.
✎ 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 take◇Read from sources, not yet reviewed
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.
·Worth asking a clinician aboutWritten into the record from the studies named on this page
The most common adverse reactions in the randomised study were balance disorder and vomiting, at crude frequencies from a 12-patient trial. Hypersensitivity reactions are labelled. The dominant real-world risks come from long-term central venous access rather than from the molecule.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
Where this came from
EXONDYS 51 (eteplirsen) US prescribing information, DailyMed (https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=33bff678-7829-479e-9110-b8e33a0bc0aa) · a recorded source, not a stored snapshot
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
Intravenous infusion of an uncharged phosphorodiamidate morpholino oligomer
✎ 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
No lipid carrier, no targeting ligand, and no chemical modification to improve muscle uptake.
✎ 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 which forms are sold and how they compare.
No source is stored against this line.
What is recorded as being sold
9 products list this as an active ingredient in the United States drug directory. 9 of them contain it and nothing else.
FDA National Drug Code directory · 52416-120 · read 2026-08-29
They are sold as injection and powder, taken intravenous.
FDA National Drug Code directory · 52416-120 · read 2026-08-29
The regulator's established pharmacologic class for it is antisense oligonucleotide [epc], antisense [cs] and oligonucleotides.
FDA National Drug Code directory · 52416-120 · 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 · 33bff678-7829-479e-9110-b8e33a0bc0aa · read 2026-08-29
Those labels are classed as human prescription drug.
US prescribing information · 33bff678-7829-479e-9110-b8e33a0bc0aa · read 2026-08-29
Exondys 51 is intravenous at 3 DOSAGE FORMS AND STRENGTHS EXONDYS 51 is a clear and colorless solution that may have some opalescence, and may contain white to off-white amorphous particles, and is available as follows: Injection: 100 mg/2 mL (50 m…, recorded as fda label in effect 2025-08-13 in the United States.
US prescribing information · 33bff678-7829-479e-9110-b8e33a0bc0aa · 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.
Self-experiment planning is not offered for a prescription or clinician-supervised medicine. The questions below are for a clinician or pharmacist.
Questions worth asking
Which of the trials of Eteplirsen 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
Claims that go past the evidence
Things said about this substance that sound reasonable, and the exact step that is missing between the evidence and the claim.
✗Goes past the evidence
That this quantity of dystrophin slows loss of ambulation; the label states clinical benefit has not been established
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That the 6-minute walk comparisons against external natural-history cohorts are equivalent to randomised evidence
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That survival is extended, which rests on a non-randomised comparison with historical controls
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
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 Eteplirsen 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.
Every line above can be traced to the study named beside it. Follow the link and read it.
Dystrophin reached 0.93 percent of normal after 180 weeks
In plain words
Eleven boys had a muscle biopsy after three and a half years of treatment. Their average dystrophin was under one percent of a healthy person.
What was measured
Mean dystrophin 0.93 percent of normal at week 180, n=11
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Study 2, the open-label extension of the 12-patient randomised study, biopsied 11 patients at week 180. The label records an average dystrophin protein level of 0.93 percent of the level in healthy subjects, measured by Sarepta western blot. Baseline dystrophin was not available for Study 1 patients, so the increase attributable to treatment could not be estimated from that study.
Written into the record, not signed off as a reviewed claim
Study 3: dystrophin rose from 0.16 to 0.44 percent of normal, median change 0.1 percent
In plain words
In the only study with before-and-after biopsies, the average went from 0.16 percent to 0.44 percent. The median boy gained 0.1 percent.
What was measured
Dystrophin 0.16 percent to 0.44 percent of normal at 48 weeks, p=0.008
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Thirteen patients were treated open-label for 48 weeks with biopsies at baseline and week 48. In the 12 evaluable patients the mean was 0.16 +/- 0.12 percent before and 0.44 +/- 0.43 percent after, p=0.008. The distribution is what matters: individual changes ranged from -0.07 to +1.33 percent, and the median change was 0.1 percent.
Source
EXONDYS 51 US prescribing information, section 14, Table 2
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
verified
Review state
Written into the record, not signed off as a reviewed claim
Sub-1-percent dystrophin is read as clinical benefit, and the label says otherwise
In plain words
The drug was approved because it raises dystrophin, not because it was shown to help boys walk. The prescribing information states this in plain words.
What was measured
That an increase to roughly 0.4 to 0.9 percent of normal dystrophin slows Duchenne muscular dystrophy
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Accelerated approval rested on dystrophin as a surrogate reasonably likely to predict benefit. The label states that a clinical benefit of EXONDYS 51, including improved motor function, has not been established, and that Study 2 failed to provide evidence of a clinical benefit compared with the external control group. Whether 0.44 percent of normal dystrophin is above any therapeutic threshold has never been established; Becker muscular dystrophy phenotypes are typically associated with levels an order of magnitude higher.
Written into the record, not signed off as a reviewed claim
The FDA review division rejected it; the Center Director approved it anyway
In plain words
The reviewers who assessed the application said no. The head of the drugs centre overruled them, and the Commissioner let that stand.
What was measured
Not recorded
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The clinical reviewer and the Office of Drug Evaluation I director recommended against approval, as did the agency acting chief scientist. The CDER Center Director concluded that the dystrophin increase was reasonably likely to predict benefit and approved under the accelerated pathway in September 2016; the Commissioner declined to overturn that decision on formal dispute. The Center Director decisional memorandum is a public document and the disagreement is on the record.
Written into the record, not signed off as a reviewed claim
The confirmatory trial lost its control group
In plain words
PROMOVI was meant to compare treated boys against untreated boys. The untreated group turned out not to be comparable, so the comparison was made against historical data instead.
What was measured
Not recorded
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
PROMOVI (NCT02255552) enrolled 79 eteplirsen-treated patients amenable to exon 51 skipping and 30 untreated patients who were not amenable. Only 15 of 30 untreated patients completed. The publication states the cohort was an inappropriate control because of genotype-driven differences in clinical trajectory, and functional comparisons were made post hoc against external natural-history controls instead.
Written into the record, not signed off as a reviewed claim
The European Medicines Agency refused authorisation twice
In plain words
Europe looked at the same dossier and said the evidence did not support approval, then said it again on re-examination.
What was measured
Not recorded
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
The CHMP adopted a negative opinion on 31 May 2018 and confirmed the refusal on re-examination on 20 September 2018. Eteplirsen has therefore never been authorised in the European Union, which makes the transatlantic split on identical data one of the clearest natural experiments in surrogate-endpoint regulation.
Source
European Medicines Agency, Exondys refusal of marketing authorisation
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
verified
Review state
Written into the record, not signed off as a reviewed claim
Long-term survival benefit rests on external comparison, not randomisation
In plain words
A study reported that treated boys lived longer than historical controls. Nobody was randomised, so the two groups may have differed in ways nobody measured.
What was measured
That eteplirsen extends survival in Duchenne muscular dystrophy
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
An 8-year follow-up analysis compared survival in eteplirsen-treated patients against natural-history controls. Treated patients were, by construction, those whose families obtained and stayed on an expensive weekly infusion, which is correlated with access to specialist care, ventilatory support and cardiac management. That confounding is not removable by matching on the covariates that were recorded.
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What is not here
7 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.
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.
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.
The older medicine-wide conclusion held in this record
Written for a clinical reader, and about the medicine as a whole rather than about one indication, population and set of trials. RNAWiki does not treat it as a programme conclusion and no reviewer has signed it off in that form. It is here word for word because it is what the record holds.
An uncharged 30-mer morpholino that makes muscle cells skip a broken exon and produce a shortened dystrophin; after 180 weeks of treatment the measured dystrophin level was 0.93 percent of normal, and the FDA label states that clinical benefit has not been established.
Recorded evidence blocks (8)
Q1
On the Eteplirsen label: indicated for what?
"EXONDYS 51 is indicated for the treatment of Duchenne muscular dystrophy (DMD) in patients who have a confirmed mutation of the DMD gene that is amenable to exon 51 skipping. This indication is approved under accelerated approval based on an increase in dystrophin in skeletal muscle observed in some patients treated…": indications and usage on Eteplirsen's label. DailyMed label · 33bff678-7829-479e-9110-b8e33a0bc0aa · 2025-08-13
Q2
12 registered trials of Eteplirsen — at which phases?
"Participants were either transitioned to a post-trial access program or another Sarepta study, or they declined further treatment. There are no safety concerns with Eteplirsen."; 1 of 12 registered studies
Show the evidence
TrialNCT03985878
terminated; "Participants were either transitioned to a post-trial access program or another Sarepta study, or they declined further treatment. There are no safety concerns with Eteplirsen."
recorded 2026-09-01 · last checked 2026-09-04
Q4
Eteplirsen's half-life is 3 to 4 hours — which schedules were studied?
3 to 4 hours; Elimination half-life (t 1/2 ) of eteplirsen was 3 to 4 hours.
tmaxpharmacokinetics
1.1 to 1.2 hours; Following single or multiple intravenous infusions of EXONDYS 51, the peak plasma concentrations (C max ) of eteplirsen occurred near the end of infusion (i.e., 1.1 to 1.2 hours across a dose range of 0.5 mg/kg/week to 50 mg/kg/week).
metabolismpharmacokinetics
Metabolism Eteplirsen did not appear to be metabolized by hepatic microsomes of any species tested, including humans.
recorded 2025-08-13 · last checked 2026-09-04
Q5
At the median, Eteplirsen's trials enrolled 17 people — anything larger?
Median enrolment
17
Largest enrolment
300
Registered trials counted
12
Q6
What do 350 spontaneous reports say about Eteplirsen — and not say?
These are reports people sent to a regulator. They do not show the medicine caused the reaction. Nobody counted how many people took the medicine and reported nothing. The same event can be reported more than once, and many reports are incomplete. News coverage, lawsuits and new warnings change how often people report. A count is not a rate and not a risk.
Eteplirsen appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 350 reaction mentions were counted: product dose omission issue 199; poor venous access 62; exposure to sars-cov-2 24; cough 20. FAERS via Open Targets · CHEMBL2108278 · 2026-06-24
Show the evidence
product dose omission issue
199
poor venous access
62
exposure to sars-cov-2
24
cough
20
influenza
11
flushing
10
4 more recorded rows
femur fracture
7
infusion site extravasation
7
lower limb fracture
5
product distribution issue
5
recorded 2026-06-24 · last checked 2026-09-04
Q7
Which 10 reactions does Eteplirsen's label not list?
Drug Interaction Studies In vitro data showed that eteplirsen did not significantly inhibit CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, or CYP3A4/5.
pharmacokinetics
Eteplirsen did not induce CYP2B6 or CYP3A4, and induction of CYP1A2 was substantially less than the prototypical inducer, omeprazole.
pharmacokinetics
Eteplirsen was not a substrate nor did it have any major inhibitory potential for any of the key human transporters tested (OAT1, OAT3, OCT1, OCT2, OATP1B1, OATP1B3, P-gp, BCRP, MRP2 and BSEP).
pharmacokinetics
Based on in vitro data on plasma protein binding, CYP or drug transporter interactions, and microsomal metabolism, eteplirsen is expected to have a low potential for drug-drug interactions in humans.
clinical_pharmacology
Drug Interaction Studies In vitro data showed that eteplirsen did not significantly inhibit CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, or CYP3A4/5.
clinical_pharmacology
Eteplirsen did not induce CYP2B6 or CYP3A4, and induction of CYP1A2 was substantially less than the prototypical inducer, omeprazole.
2 more recorded rows
Interaction statementclinical_pharmacology
Eteplirsen was not a substrate nor did it have any major inhibitory potential for any of the key human transporters tested (OAT1, OAT3, OCT1, OCT2, OATP1B1, OATP1B3, P-gp, BCRP, MRP2 and BSEP).
Interaction statementclinical_pharmacology
Based on in vitro data on plasma protein binding, CYP or drug transporter interactions, and microsomal metabolism, eteplirsen is expected to have a low potential for drug-drug interactions in humans.
ChEMBL 37 — CC BY-SA 3.0 Unported · ChEMBL ATC CC BY-SA · ClinicalTrials.gov — US Government work · Open Targets 26.06 — CC0 · mixed register set; per-register licences in docs/specs/corpus-20k-sources.md · openFDA / DailyMed — US Government work
✗ 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: 5 source rows
✓ no critical contamination: no quarantine open
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