This page shows what was measured, who it was measured in, and what that does not settle.
What Elbasvir does in the body
Long-standing hepatitis C infection in two genetic forms.
Hepatitis C cannot copy itself in the open cytoplasm. It first folds the liver cell’s membranes into a sealed workshop, and one viral protein called NS5A is what holds that structure together and loads finished genomes into new virus particles. Elbasvir binds NS5A at concentrations measured in trillionths of a gram and stops it doing either job. It is always given fixed together with grazoprevir, which attacks a different viral protein, because hitting one target alone lets the virus escape.
What happened in people
Combined with grazoprevir, it cured about 95 in 100 untreated people and 99 in 100 with severe kidney disease.
✓ 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
Natural resistance changes cut cure sharply, so a resistance test is needed before treatment.
Where it acts
Hepatocyte cytoplasm — the membranous web of remodelled endoplasmic reticulum where NS5A holds the replication complex together
Kind of result
The kind of result is not recorded
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 · 632L571YDK · read 2026-08-29
Where each sentence above came from
The recorded explanation is written in label language rather than for a beginner. 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 109 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.
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.
Randomisation
Randomisation means chance decides who gets which treatment.
A picture of it, and where the picture fails
It is like a coin toss deciding the groups.
Where that stops being true. A coin toss is fair once. Fairness here comes from doing it for everyone.
What people get wrong. It is thought to make groups identical. It makes them similar on average, including on things nobody measured.
Allocation of participants to arms by a chance process, so that unmeasured factors are balanced in expectation.
Absolute difference
An absolute difference is how many more people in a hundred were affected.
A picture of it, and where the picture fails
It is like counting heads in two rooms of a hundred.
Where that stops being true. Heads are easy to count. Study results carry a margin of error too.
What people get wrong. It is confused with a percentage change, which can look far larger.
The arithmetic difference in event rates between arms.
Confidence interval
A confidence interval is the range the true answer is likely to sit in.
A picture of it, and where the picture fails
It is like a weather forecast giving a range rather than one number.
Where that stops being true. A forecast range covers tomorrow. This one covers what the study could resolve.
What people get wrong. The middle number is read as the answer. A range crossing zero means no change is still possible.
An interval estimate that would contain the true parameter in a stated proportion of repeated studies.
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.
Unquantifiable HCV RNA 12 weeks after the end of treatment in the immediate-treatment group
✓ The study showed what it set out to show
Who was studied
C-EDGE TREATMENT-NAIVE (NCT02105467)
How many people
421
Study design
Phase 3, randomised 3:1 to immediate or deferred therapy, blinded, placebo-controlled
Compared against
A dummy treatment
Kind of result
A number that stands in for health
What was found
95% (299/316; 95% CI 92 to 97), including 92% (144/157) in genotype 1a and 97% (68/70) with cirrhosis
Repeated elsewhere
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. The paper lists as limitations the absence of an active-comparator control and relatively few genotype 4 and 6 infections; genotype 6 SVR12 was 80% (8/10). All 13 virologic failures were associated with baseline NS5A polymorphisms or emergent variants.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral fixed-dose combination tablet with grazoprevir
Interval reported. 95% CI 92 to 97), including 92% (144/157) in genotype 1a and 97% (68/70) with cirrhosis
Written into the record, not signed off as a reviewed claim.
Sustained virologic response 12 weeks after treatment in genotype 1 with stage 4 or 5 chronic kidney disease
✓ The study showed what it set out to show
Who was studied
C-SURFER (NCT02092350)
How many people
235
Study design
Phase 3, randomised for safety against deferred treatment, observational for efficacy against a historical control
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
99% (115/116; 95% CI 95.3 to 100.0) against a historical control of 45% from interferon-based meta-analyses
Repeated elsewhere
Unreplicated
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. The efficacy comparison was explicitly non-randomised. The placebo-controlled randomisation was used for the safety endpoint only, so the 99% figure has no concurrent control.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral fixed-dose combination tablet with grazoprevir
Interval reported. 95% CI 95
Written into the record, not signed off as a reviewed claim.
SVR12 in genotype 1a patients with one or more baseline NS5A polymorphisms at M28, Q30, L31 or Y93
✗ The study did not show it
Who was studied
Veterans Administration NS5A cohort (postmarketing, cited in the label)
How many people
93
Study design
Retrospective observational cohort of the 16-week plus ribavirin rescue regimen
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
81% (75/93) overall, falling to 64% (18/28) in patients with polymorphisms at more than one position — against 100% (6/6) in the corresponding clinical trial dataset
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. Retrospective and uncontrolled. The label notes observational effectiveness data are subject to bias and confounding; the trial denominator it is being compared against is six patients.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral fixed-dose combination tablet with grazoprevir
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
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
Elbasvir
What a person takes: Oral fixed-dose combination tablet with grazoprevir.
The measurement behind this step
One tablet once daily, with or without food. Elbasvir is not sold separately. Duration is 12 or 16 weeks depending on genotype, prior treatment and, in genotype 1a, the result of a baseline NS5A resistance test; ribavirin is added in defined populations.
Getting in
Two tests, then one tablet a day
Before the first dose, everyone is tested for hepatitis B and, in genotype 1a, for resistance changes in the virus. Those results decide the length of the course.
╌╌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
Fixed-dose combination of 50 mg elbasvir with 100 mg grazoprevir, one tablet once daily with or without food. Testing for NS5A resistance-associated polymorphisms at positions 28, 30, 31 and 93 is recommended in genotype 1a; their presence changes the regimen to 16 weeks with ribavirin.
The drug is taken up by liver cells and leaves in bile rather than urine, which is why it can be used when the kidneys have failed.
╌╌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
Hepatic uptake with biliary elimination and negligible renal clearance, which is the pharmacological basis for the stage 4 and 5 chronic kidney disease result in C-SURFER. Elbasvir is a substrate of P-glycoprotein.
NS5A does not cut or copy anything. It organises. Elbasvir sticks to it at trillionths of a gram per litre.
╌╌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
EC50 of 4 pM against genotype 1a, 3 pM against 1b and 0.3 pM against genotype 4 in full-length replicons. NS5A has no catalytic site, so the binding surface is a protein-protein interface at domain I rather than an enzyme active site.
The membrane compartment where the virus copies itself is never properly built, and the genomes already made are never loaded into new particles.
╌╌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
NS5A is required both for replication complex formation on the membranous web and for virion assembly through its domain III interaction with core protein. Inhibiting it blocks both, which is why NS5A inhibitors clear serum viral RNA faster in the first days of treatment than any other class.
Naturally occurring variations at four positions in NS5A cut the cure rate in genotype 1a from 98% to 70%. That is why the test exists.
╌╌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
Baseline polymorphisms at M28, Q30, L31 or Y93 reduced 12-week SVR12 from 98% (441/450) to 70% (39/56) in genotype 1a. Against clinical isolates of subtype 4b, median EC50 was 3,600 pM against 0.2 pM for subtype 4a.
No suggested links are held for this record, so nothing is hidden from this path.
What we know
The record describes 6 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.
Adults and children aged 12 and over with genotype 1 or 4. Not for genotypes 2, 3, 5 or 6. Contraindicated in anyone with moderate or severe liver impairment or a history of hepatic decompensation.
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.
Where the result stopped carrying
Naturally occurring NS5A polymorphisms at four positions cost 28 percentage points of cure rate in genotype 1a, which is why a pre-treatment resistance test is recommended
The rescue regimen fell to 64% in patients carrying polymorphisms at more than one position in the Veterans Administration cohort
Genotype 4b isolates showed a median EC50 ten thousand times higher than genotype 4a
Genotype 6 SVR12 was 80% (8/10) in C-EDGE, and the label covers only genotypes 1 and 4
Contraindicated in Child-Pugh B or C liver disease and in any history of hepatic decompensation, on account of its protease-inhibitor partner
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.
There was nothing to correct
Where a level is already normal, topping it up may change nothing.
On this record: The only current hepatitis C regimen whose label recommends baseline resistance testing before treatment
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)
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.
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
Oral fixed-dose combination tablet with grazoprevir
✎ 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
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
One tablet once daily, with or without food. Elbasvir is not sold separately. Duration is 12 or 16 weeks depending on genotype, prior treatment and, in genotype 1a, the result of a baseline NS5A resistance test; ribavirin is added in defined populations.
✎ 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
Boxed warning for hepatitis B virus reactivation, which has caused fulminant hepatitis, hepatic failure and death, including in patients whose hepatitis B was considered resolved — so both HBsAg and anti-HBc must be checked before treatment. Contraindicated in Child-Pugh B or C hepatic impairment, in any history of hepatic decompensation, with OATP1B1/3 inhibitors, with strong CYP3A inducers and with efavirenz. Around 1% of subjects had ALT rise from normal to more than five times the upper limit of normal, generally at or after week 8, with higher rates in women (2%), Asian patients (2%) and those aged 65 or older (2%); this is attributed to grazoprevir exposure and drives the requirement for liver testing before treatment and at week 8. Serious adverse events in C-EDGE were 2.8% on active treatment against 2.9% on placebo.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
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
Oral fixed-dose combination tablet with grazoprevir
✎ 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
Elbasvir is not sold separately. Duration is 12 or 16 weeks depending on genotype, prior treatment and, in genotype 1a, the result of a baseline NS5A resistance test; ribavirin is added in defined populations.
✎ 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
4 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 · 50473-0097 · read 2026-08-29
They are sold as powder and tablet, film coated, taken oral.
FDA National Drug Code directory · 50473-0097 · read 2026-08-29
1 published label names it as an active ingredient. None of them describes this substance alone, so no label text on this page can be attributed to it rather than to a combination.
US prescribing information · 164dc02a-9180-426a-b8b5-04ab39d2bbd4 · read 2026-08-29
Those labels are classed as human prescription drug.
US prescribing information · 164dc02a-9180-426a-b8b5-04ab39d2bbd4 · read 2026-08-29
ZEPATIER is oral at 3 DOSAGE FORMS AND STRENGTHS ZEPATIER is available as a beige-colored, oval-shaped, film-coated tablet debossed with "770" on one side and plain on the other., recorded as fda label in effect 2026-03-13 in the United States.
US prescribing information · 164dc02a-9180-426a-b8b5-04ab39d2bbd4 · 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 Elbasvir 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 the 16-week plus ribavirin rescue restores full efficacy — 100% of six patients in trial against 81% of ninety-three in a postmarketing cohort
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 99% kidney-disease result was established against a concurrent control; the comparator was a 45% historical rate from interferon studies
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 an indication covering "genotype 4" implies uniform activity across genotype 4; subtype 4b differs from 4a by four orders of magnitude in the label’s own table
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 curing hepatitis C in advanced kidney disease reduces death or graft failure, the stated rationale for C-SURFER and not its endpoint
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.
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 Elbasvir 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.
C-EDGE: 95% cured in 316 previously untreated patients, against a placebo arm
In plain words
A randomised, blinded, placebo-controlled trial of 421 people found 95% of those treated were cured, including 97% of those who already had cirrhosis. Serious side effects occurred at the same rate on the drug as on placebo.
What was measured
Sustained virologic response at 12 weeks, against a concurrent blinded placebo arm
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
C-EDGE TREATMENT-NAIVE randomised 421 cirrhotic and non-cirrhotic treatment-naive adults with genotype 1, 4 or 6 infection 3:1 to immediate or deferred fixed-dose grazoprevir 100 mg with elbasvir 50 mg for 12 weeks, blinded and placebo-controlled, at 60 centres. Of 316 receiving immediate treatment, 299 (95%, 95% CI 92 to 97) achieved SVR12: 92% (144/157) in genotype 1a, 97% (68/70) with cirrhosis, 94% (231/246) without cirrhosis, and 80% (8/10) in genotype 6. Virologic failure occurred in 13 patients (4%) — one breakthrough and twelve relapses — and was associated with baseline NS5A polymorphisms and emergent NS3 or NS5A variants. Serious adverse events occurred in 2.8% on active treatment and 2.9% on placebo, none considered drug related.
Written into the record, not signed off as a reviewed claim
The label’s own numbers: 98% without baseline polymorphisms, 70% with them
In plain words
In genotype 1a, cure rates depended heavily on changes the virus already carried before treatment. Without them, 441 of 450 patients were cured. With them, 39 of 56 — a drop of 28 points.
What was measured
SVR12 in genotype 1a by baseline NS5A polymorphism status: 98% (441/450) against 70% (39/56)
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
Table 12 of the prescribing information reports SVR12 in genotype 1a-infected subjects on the 12-week regimen as 98% (441/450) without any baseline NS5A polymorphism at M28, Q30, L31 or Y93, against 70% (39/56) with one or more. Genotype 1b was far less affected: 94% (48/51) with polymorphisms against 99% (247/248) without. In genotype 1a the NS3 Q80K polymorphism, which defeated an earlier protease inhibitor, did not affect response, so the vulnerability is specific to the NS5A component. This is the reason the dosing section recommends testing for NS5A resistance-associated polymorphisms in genotype 1a before treatment — a requirement no other current hepatitis C regimen carries.
Source
ZEPATIER United States prescribing information, Microbiology 12.4, Table 12, and Dosage and Administration 2.1 (NDA 208261)
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
caution
Review state
Written into the record, not signed off as a reviewed claim
The rescue regimen was validated in six patients and then tested in ninety-three
In plain words
For patients carrying those changes, the label prescribes a longer course with ribavirin. In the trials that worked in six out of six people. In a later cohort of ninety-three real patients it worked in 81%, and in those with more than one change, 64%.
What was measured
That extending to 16 weeks with ribavirin restores full efficacy in genotype 1a patients with baseline NS5A polymorphisms — 100% of six in trial, 81% of ninety-three in practice
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The 16-week regimen with ribavirin achieved SVR12 in 100% (6/6) of genotype 1a subjects with baseline NS5A polymorphisms in the clinical trial dataset, and 100% (49/49) of those without. In postmarketing observational data the same regimen achieved 93% (27/29) in Protocol 095, and 81% (75/93) in a retrospective Veterans Administration cohort — falling to 64% (18/28) in patients with polymorphisms at more than one of the four positions. Within the VA cohort, single polymorphisms at M28, Q30, L31 and Y93 gave 94%, 100%, 84% and 81%. The label states that effectiveness in observational studies is subject to bias and confounding, which is true; it is also true that a six-patient trial denominator is a thin basis for the strategy that rescues the population the primary regimen fails.
Source
ZEPATIER United States prescribing information, Microbiology 12.4, clinical trial data and postmarketing observational studies including Protocol 095 and the VA NS5A cohort (NDA 208261)
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
contested
Review state
Written into the record, not signed off as a reviewed claim
Genotype 4b: a ten-thousandfold potency gap inside an approved genotype
In plain words
Against the reference genotype 4 virus, elbasvir is one of the most potent antivirals ever measured. Against clinical isolates of one subtype of genotype 4, it is roughly ten thousand times weaker.
What was measured
Median elbasvir EC50 by genotype 4 subtype: 0.2 pM (4a), 0.45 pM (4d), 3,600 pM (4b)
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
Against chimeric replicons encoding NS5A from clinical isolates, median EC50 values were 5 pM for genotype 1a (range 3 to 9, N=5), 9 pM for 1b (5 to 10, N=4), 0.2 pM for 4a (N=2), 0.45 pM for 4d (N=2), 1.9 pM for 4f, 0.6 pM for 4m and 0.5 pM for 4q — and 3,600 pM for genotype 4b, with a range of 17 to 34,000 pM across three isolates. The full-length laboratory genotype 4 replicon reads 0.3 pM. The label indication covers genotype 4 without subtype qualification. The number of genotype 4 patients in the registrational programme was small: C-EDGE enrolled 91% genotype 1 and the pooled genotype 4 phylogenetic analysis covered 71 subjects, and the paper itself lists relatively few genotype 4 and 6 infections as a limitation.
Source
ZEPATIER United States prescribing information, Microbiology 12.4, antiviral activity against chimeric replicons (NDA 208261)
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
caution
Review state
Written into the record, not signed off as a reviewed claim
C-SURFER: 99% cured in stage 4 and 5 kidney disease
In plain words
A hundred and sixteen people with failing kidneys or on dialysis were treated and 115 were cured. Before this, the comparison was a 45% response rate from interferon.
What was measured
Sustained virologic response at 12 weeks in stage 4 or 5 chronic kidney disease
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
C-SURFER enrolled patients with genotype 1 hepatitis C and stage 4 or 5 chronic kidney disease, randomising 224 to immediate (n=111) or deferred (n=113) grazoprevir 100 mg with elbasvir 50 mg for 12 weeks, plus 11 in an intensive pharmacokinetic cohort. SVR12 in the combined immediate treatment and pharmacokinetic population was 99% (115/116; 95% CI 95.3 to 100.0), with one relapse. No patient in that group discontinued for an adverse event, against five (4%) in the deferred group. The most common events — headache, nausea, fatigue — occurred at similar frequencies on active drug and placebo.
Written into the record, not signed off as a reviewed claim
C-SURFER randomised for safety and compared efficacy against a historical control
In plain words
The kidney trial did have a placebo group, but it was not used to judge whether the drug worked. The cure rate was compared instead against a 45% figure taken from older interferon studies.
What was measured
That the 99% cure rate in advanced kidney disease was established against a concurrent control — the concurrent control existed and was used for safety, not efficacy
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The paper describes itself as a phase 3 randomised study of safety and observational study of efficacy. The primary efficacy outcome was a non-randomised comparison of SVR12 in the combined immediate-treatment and pharmacokinetic populations against a historical control of 45%, derived from meta-analyses of interferon-based regimens in haemodialysis patients. The randomised comparison between immediate and deferred groups was the primary safety outcome. This is a defensible design and it is not the same thing as a randomised efficacy result: the 99% figure has no concurrent control, and the 45% comparator comes from a different era, a different drug class and a different population.
Written into the record, not signed off as a reviewed claim
Two genotypes out of six, and the field moved past that
In plain words
This regimen treats genotypes 1 and 4 only. Within two years of its launch, two combinations that treat all six and need no resistance test were approved.
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 indication covers chronic hepatitis C genotype 1 or 4 in patients aged 12 and over. Sofosbuvir/velpatasvir was approved in June 2016 and glecaprevir/pibrentasvir in August 2017, both covering genotypes 1 through 6 with no pre-treatment resistance testing requirement. The clinical case for elbasvir with grazoprevir narrowed to advanced kidney disease, where its C-SURFER result is strong — and where glecaprevir with pibrentasvir subsequently produced 98% in EXPEDITION-4 across all six genotypes.
Source
ZEPATIER United States prescribing information, Indications and Usage 1 (NDA 208261)
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
caution
Review state
Written into the record, not signed off as a reviewed claim
Every endpoint is a blood test twelve weeks after the last tablet
In plain words
C-EDGE and C-SURFER measured virus in blood. Neither counted deaths, cancers, transplants or dialysis outcomes.
What was measured
That curing hepatitis C in advanced kidney disease reduces death or graft failure — the stated reason for running C-SURFER, and not something C-SURFER measured
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The 2017 Cochrane review of 138 randomised direct-acting antiviral trials in 25,232 participants found no usable randomised evidence on hepatitis C-related morbidity or hepatocellular carcinoma, and mortality data from only 11 trials. C-SURFER makes the gap concrete: the population is defined by stage 4 or 5 kidney disease, the trial’s own rationale cites increased risk of death and renal graft failure, and the endpoint measured was viral RNA at twelve weeks.
This order is fixed in code and does not count clicks or time on the page.
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 NS5A inhibitor of picomolar potency — 4 pM against genotype 1a and 0.3 pM against genotype 4 — that cured 95% of 316 previously untreated patients in C-EDGE and 99% of 116 with stage 4 or 5 kidney disease in C-SURFER, but whose own label reports 98% cure in genotype 1a without baseline NS5A polymorphisms against 70% with them, which is why it is the one modern hepatitis C drug that asks for a resistance test before the first tablet.
Recorded evidence blocks (6)
Q1
42 registered trials of Elbasvir — at which phases?
"Insufficient study participants enrolled"; 10 of 42 registered studies
Show the evidence
Trial
NCT02895958
terminated; "Insufficient study participants enrolled"
NCT02940691
terminated; "Poor recruitment due to new treatments becoming available."
NCT03026023
withdrawn; "moved forward with another protocol utilizing pan genotypic treatment once it became commercially available and FDA approved"
NCT03093740
withdrawn; "Withdrew IRB application, never approved and no subjects enrolled"
NCT03105349
withdrawn; "No availability of investigational medication."
NCT03143998
withdrawn; "Business reasons"
4 further recorded trials
NCT03221582
terminated; "Site unable to recruit the agreed upon number of participants"
NCT03723824
terminated; "COV-19 pandemic"
NCT03791814
withdrawn; "The study was stopped due to difficulty in identifying potential patients."
NCT03797066
terminated; "Changing parameters in HCV management, resulted in poor recruitment; additionally onset of SARS CoV2 resulted in the cessation of all mobile clinical services."
recorded 2026-09-01 · last checked 2026-09-04
Q3
Human studies of Elbasvir used Elbasvir 50 mg/d 8 weeks — over how long?
Human studies of Elbasvir used "Elbasvir 50 mg/d 8 weeks". ClinicalTrials.gov · 2026-09-01
NCT02333292, NCT03186365, NCT03706222, NCT04047680 and NCT04048850
Completion dates
oldest 2017-06-30; newest 2022-09-09
Show the evidence
Trial
NCT02333292
2017-06-30
NCT03186365
2018-09-19
NCT03706222
2019-02-25
NCT04047680
2019-06
NCT04048850
2022-09-09
Q5
At the median, Elbasvir's trials enrolled 44 people — anything larger?
Median enrolment
44
Largest enrolment
1275
Registered trials counted
42
Q6
What do 1606 spontaneous reports say about Elbasvir — 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.
Elbasvir appears in spontaneous reports to regulators. Across the 9 most-reported reaction terms, 1606 reaction mentions were counted: fatigue 577; headache 435; nausea 270; diarrhoea 138. FAERS via Open Targets · CHEMBL3039514 · 2026-06-24
Show the evidence
fatigue
577
headache
435
nausea
270
diarrhoea
138
insomnia
133
hepatitis c
43
3 more recorded rows
pancreas transplant rejection
7
drug hypersensitivity
2
hypotension
1
recorded 2026-06-24 · last checked 2026-09-04
Where it is registeredIdentifiers, relations and other names
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
✗ 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
✓ 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.