This page shows what was measured, who it was measured in, and what that does not settle.
What Romiplostim does in the body
A weekly injection that tells the bone marrow to make more platelets — and, separately, the drug stockpiled to keep people alive after a radiation accident
The bone marrow decides how many platelets to make based on a hormone signal. Romiplostim is a manufactured protein in two parts: a stalk borrowed from an antibody, which keeps it in the bloodstream for days, and a short peptide that was designed from scratch to fit the hormone’s receptor. It has no resemblance to the real hormone, which is the point — an earlier attempt that did resemble it taught some patients’ immune systems to attack their own hormone. Injected weekly under the skin, it tells the marrow to build more platelet-producing cells.
What happened in people
Durable platelet response in 16 of 42 splenectomised patients against 0 of 21 on placebo, and 25 of 41 non-splenectomised against 1 of 21
✎ 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 recorded finding that sits closest to something a person would notice. Written into the record, not signed off, and it carries no population or interval.
Romiplostim in splenectomised patients with chronic immune thrombocytopenic purpura (NCT00102323) · a recorded source, not a stored snapshot
The limit that matters most
That a survival benefit in 80 irradiated monkeys transfers to adults, children and term neonates exposed to radiation — licensed as a survival claim with no human efficacy data of any kind
Where it acts
Bone marrow — the megakaryocyte and its progenitors
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 protein.
FDA substance registry · GN5XU2DXKV · 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.
A limit recorded against this substance. Not signed off as a reviewed claim.
The four opening statements run to 144 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.
Durable platelet response: a count of at least 50 × 10⁹/L during six or more of the last eight weeks of treatment
✓ The study showed what it set out to show
Who was studied
NCT00102336 and NCT00102323 — parallel phase 3 trials in chronic immune thrombocytopenia
How many people
125
Study design
Two parallel double-blind placebo-controlled randomised trials, 24 weeks
Compared against
A dummy treatment
Kind of result
A number that stands in for health
What was found
Splenectomised: 16 of 42 versus 0 of 21, difference 38% (95% CI 23.4 to 52.8), p = 0.0013. Non-splenectomised: 25 of 41 versus 1 of 21, difference 56% (95% CI 38.7 to 73.7), p < 0.0001
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 endpoint is a platelet count sustained over eight weeks, not a bleeding outcome. Twenty-four weeks of exposure in 125 patients cannot address the marrow fibrosis or immunogenicity questions the molecule raises.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Weekly subcutaneous injection, reconstituted from a lyophilised powder
Interval reported. 95% CI 23
Written into the record, not signed off as a reviewed claim.
Romiplostim in splenectomised patients with chronic immune thrombocytopenic purpura (NCT00102323) · a recorded source, not a stored snapshot
Romiplostim in non-splenectomised patients with chronic immune thrombocytopenic purpura (NCT00102336) · a recorded source, not a stored snapshot
Incidence of treatment failure and incidence of splenectomy
✓ The study showed what it set out to show
Who was studied
NCT00415532 — romiplostim versus standard of care in immune thrombocytopenia
How many people
234
Study design
Open-label randomised trial over 52 weeks
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Treatment failure 11% versus 30%, odds ratio 0.31 (95% CI 0.15 to 0.61), p < 0.001; splenectomy 9% versus 36%, odds ratio 0.17 (95% CI 0.08 to 0.35), p < 0.001
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. Open-label, and splenectomy is a decision made by an unblinded clinician who knows which arm the patient is in. Serious adverse events were nonetheless lower on romiplostim, 23% versus 37%.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Weekly subcutaneous injection, reconstituted from a lyophilised powder
Interval reported. 95% CI 0
Written into the record, not signed off as a reviewed claim.
Romiplostim in splenectomised patients with chronic immune thrombocytopenic purpura (NCT00102323) · a recorded source, not a stored snapshot
Romiplostim in non-splenectomised patients with chronic immune thrombocytopenic purpura (NCT00102336) · a recorded source, not a stored snapshot
Sixty-day survival after 6.8 Gy total body irradiation
✓ The study showed what it set out to show
Who was studied
Rhesus macaque total body irradiation study — the sole efficacy evidence for the radiation indication
How many people
80
Study design
Randomised blinded placebo-controlled non-human primate study under the FDA Animal Rule
Compared against
A dummy treatment
Kind of result
Living longer, or avoiding a major event
What was found
72.5% (29 of 40) versus 32.5% (13 of 40), one-sided p = 0.0002
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. No human has been treated for this indication in a trial and none ever will be. The human dose of 10 micrograms per kilogram comes from population modelling and simulation, and the paediatric and neonatal dose is extrapolated from immune thrombocytopenia data.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Weekly subcutaneous injection, reconstituted from a lyophilised powder
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Romiplostim in splenectomised patients with chronic immune thrombocytopenic purpura (NCT00102323) · a recorded source, not a stored snapshot
Romiplostim in non-splenectomised patients with chronic immune thrombocytopenic purpura (NCT00102336) · a recorded source, not a stored snapshot
Platelet response and safety, with progression to acute myelogenous leukaemia and overall survival followed for five years
✗ The study did not show it
Who was studied
Randomised trial in low and intermediate-1 risk myelodysplastic syndrome
How many people
250
Study design
Randomised double-blind placebo-controlled trial, terminated early, with 5-year long-term follow-up
Compared against
A dummy treatment
Kind of result
Living longer, or avoiding a major event
What was found
Progression to acute myelogenous leukaemia at 58 weeks 6.0% versus 4.8%, hazard ratio 1.20 (95% CI 0.38 to 3.84); at 5 years 11.9% versus 11.0%, hazard ratio 1.06 (95% CI 0.48 to 2.33); death 55.7% versus 54.2%, hazard ratio 1.03 (95% CI 0.72 to 1.47)
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. Terminated on an interim leukaemia signal that did not persist. The limitation of use excluding myelodysplastic syndrome remains on the label despite five-year hazard ratios centred on one.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Weekly subcutaneous injection, reconstituted from a lyophilised powder
Interval reported. 95% CI 0
Written into the record, not signed off as a reviewed claim.
Romiplostim in splenectomised patients with chronic immune thrombocytopenic purpura (NCT00102323) · a recorded source, not a stored snapshot
Romiplostim in non-splenectomised patients with chronic immune thrombocytopenic purpura (NCT00102336) · a recorded source, not a stored snapshot
What we know
RNAWiki holds 4 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
Romiplostim
What a person takes: Weekly subcutaneous injection, reconstituted from a lyophilised powder.
The measurement behind this step
Supplied as 125, 250 or 500 microgram single-dose vials reconstituted with sterile water for injection to 500 micrograms per millilitre and given as a small weekly subcutaneous injection, with the dose titrated to platelet count. For acute radiation exposure the label describes a single 10 microgram per kilogram subcutaneous dose. There is no oral route: it is a protein and would not survive the gut.
Getting in
A weekly injection under the skin
Given once a week as a small subcutaneous injection, reconstituted from a powder. Weekly rather than daily because the antibody stalk keeps it in circulation.
╌╌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
Supplied as 125, 250 or 500 microgram single-dose lyophilised vials reconstituted with sterile water to 500 micrograms per millilitre. The IgG1 Fc domain engages neonatal Fc receptor recycling, which is what converts a short synthetic peptide into a once-weekly drug.
Romiplostim in splenectomised patients with chronic immune thrombocytopenic purpura (NCT00102323) · a recorded source, not a stored snapshot
Reaching the cell
It travels to the bone marrow and stays outside the cell
Its target sits on the outside surface of marrow cells, so the protein never has to get inside anything. It docks from the bloodstream.
╌╌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
Unlike the small-molecule agonists in the same class, the peptibody binds the extracellular domain of c-Mpl. That difference in binding site is why it competes with endogenous thrombopoietin where eltrombopag does not, and why the two classes are pharmacologically additive rather than redundant only in one direction.
Romiplostim in splenectomised patients with chronic immune thrombocytopenic purpura (NCT00102323) · a recorded source, not a stored snapshot
What it acts on
A peptide that resembles nothing in nature fits the hormone’s socket
The business end is a short peptide designed from scratch. It has no similarity to the natural hormone whatsoever, yet it fits the same receptor and switches it on the same way.
╌╌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
Each of the two identical subunits carries an IgG1 Fc domain linked at its C-terminus to a peptide containing two thrombopoietin receptor-binding domains, giving four binding domains per molecule. The label records both facts side by side: no amino acid sequence homology to endogenous thrombopoietin, and activation by a mechanism analogous to it.
Romiplostim in splenectomised patients with chronic immune thrombocytopenic purpura (NCT00102323) · a recorded source, not a stored snapshot
The change it makes
The receptor pairs up and the growth signal fires
The receptor only works when two copies are brought together. With four binding sites per molecule, the drug does exactly that, and the cell reads it as an instruction to make platelets.
╌╌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
Receptor dimerisation activates the associated JAK2 and downstream STAT5 signalling, driving proliferation and maturation of megakaryocytic progenitors. Multivalency is the design principle: a monovalent peptide would occupy the receptor without dimerising it, and would be an antagonist rather than an agonist.
Romiplostim in splenectomised patients with chronic immune thrombocytopenic purpura (NCT00102323) · a recorded source, not a stored snapshot
What that does for a person
The platelet count rises, and other treatments can be reduced
Counts climb into the safe range and stay there with weekly dosing. In the pivotal trials most patients were able to cut back or stop the steroids and other drugs they had been on.
──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
Durable platelet response in 38 and 56 percentage points more patients than placebo across the two pivotal trials, with 20 of 23 romiplostim patients reducing or discontinuing concurrent therapy against 6 of 16 on placebo. Against standard of care over 52 weeks, treatment failure 11% against 30% and splenectomy 9% against 36%.
Romiplostim in splenectomised patients with chronic immune thrombocytopenic purpura (NCT00102323) · a recorded source, not a stored snapshot
What that does for a person
Stop it, and the count can fall below where it started
This is a continuous stimulus, not a cure. After stopping, thrombocytopenia can return worse than before treatment, and years of driving the marrow can leave fibre behind.
──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
The label warns that following discontinuation, thrombocytopenia and bleeding risk may develop that are worse than before treatment. Reticulin progression of two or more grades or to grade 4 was reported in 7% of 131 evaluable adults biopsied over up to three years, with collagen in 2% of 132 — one of whom had no detectable collagen 12 weeks after stopping.
Romiplostim in splenectomised patients with chronic immune thrombocytopenic purpura (NCT00102323) · 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 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 with chronic immune thrombocytopenia who have failed earlier lines. It is also held in national stockpiles for use after a radiological or nuclear incident, an indication no human has ever been treated for in a trial.
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 pharmacokinetics of romiplostim have been evaluated in pediatric patients 1 year and older with ITP [ see Clinical Pharmacology ( 12.3 ) ] .”
US prescribing information · c45f9a58-37c1-4f76-8e36-97d38c577037 · read 2026-08-30
On older people, the label states: “Of the 271 patients who received Nplate in ITP clinical studies, 55 (20%) were age 65 and over, and 27 (10%) were 75 and over.”
US prescribing information · c45f9a58-37c1-4f76-8e36-97d38c577037 · read 2026-08-30
On people who are pregnant, the label states: “Risk Summary Based on findings from animal reproduction studies, Nplate may cause fetal harm when administered to a pregnant woman.”
US prescribing information · c45f9a58-37c1-4f76-8e36-97d38c577037 · read 2026-08-30
On people who are breastfeeding, the label states: “Risk Summary There is no information regarding the presence of romiplostim in human milk, the effects on the breastfed child, or the effects on milk production.”
US prescribing information · c45f9a58-37c1-4f76-8e36-97d38c577037 · read 2026-08-30
Where the result stopped carrying
The myelodysplastic syndrome trial was terminated early for excess acute myelogenous leukaemia, on a hazard ratio of 1.20 with a confidence interval from 0.38 to 3.84
Bone marrow reticulin progressed in 7% of adults biopsied over up to three years, and in 47.2% of children in the second-year cohort, with a maximum grade of 2 and no collagen
Discontinuation can leave thrombocytopenia worse than before treatment, which the label warns about explicitly
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
Given by a clinician
❝ 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
Weekly subcutaneous injection, reconstituted from a lyophilised powder
✎ 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
Supplied as 125, 250 or 500 microgram single-dose vials reconstituted with sterile water for injection to 500 micrograms per millilitre and given as a small weekly subcutaneous injection, with the dose titrated to platelet count.
✎ 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. The rest of the recorded wording: For acute radiation exposure the label describes a single 10 microgram per kilogram subcutaneous dose. There is no oral route: it is a protein and would not survive the gut.
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
No boxed warning. The label warns that in some patients with myelodysplastic syndrome the drug increases blast cell counts and the risk of progression to acute myelogenous leukaemia, and excludes that population from the licence. Thrombotic and thromboembolic complications can follow increases in platelet count, and portal vein thrombosis has been reported in chronic liver disease. Severe thrombocytopenia may persist because of neutralising antibodies or other causes. Bone marrow reticulin formation and collagen fibrosis can develop and may improve after stopping. After discontinuation, thrombocytopenia and bleeding risk may be worse than before treatment started. The label states explicitly that the drug should not be used in an attempt to normalise platelet counts.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
Romiplostim in splenectomised patients with chronic immune thrombocytopenic purpura (NCT00102323) · 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
Weekly subcutaneous injection, reconstituted from a lyophilised powder
✎ 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
For acute radiation exposure the label describes a single 10 microgram per kilogram subcutaneous dose. There is no oral route: it is a protein and would not survive the gut.
✎ 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
6 products list this as an active ingredient in the United States drug directory. 6 of them contain it and nothing else.
FDA National Drug Code directory · 68225-050 · read 2026-08-29
They are sold as injection, powder, lyophilized, for solution, taken subcutaneous.
FDA National Drug Code directory · 68225-050 · read 2026-08-29
The regulator's established pharmacologic class for it is increased megakaryocyte maturation [pe], increased platelet production [pe] and thrombopoietin receptor agonist [epc].
FDA National Drug Code directory · 68225-050 · 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 · c45f9a58-37c1-4f76-8e36-97d38c577037 · read 2026-08-29
Those labels are classed as human prescription drug.
US prescribing information · c45f9a58-37c1-4f76-8e36-97d38c577037 · read 2026-08-29
Nplate is subcutaneous at 3 DOSAGE FORMS AND STRENGTHS For injection: 125 mcg, 250 mcg or 500 mcg of Nplate as a sterile, lyophilized, solid white powder in single-dose vials., recorded as fda label in effect 2026-06-23 in the United States.
US prescribing information · c45f9a58-37c1-4f76-8e36-97d38c577037 · 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 Romiplostim 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 a survival benefit in 80 irradiated monkeys transfers to adults, children and term neonates exposed to radiation — licensed as a survival claim with no human efficacy data of any kind
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 human dose is correct, when it was chosen by population modelling to reproduce an animal platelet response rather than tested
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 sequence dissimilarity from thrombopoietin guarantees no cross-reactive neutralising antibody over years of use
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 myelodysplastic syndrome exclusion still reflects the evidence, when five-year hazard ratios for leukaemia progression and death both sit at approximately one
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 Romiplostim 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.
Durable platelet responses where placebo produced almost none
In plain words
In two parallel trials, 16 of 42 patients who had had their spleen removed achieved a durable platelet response against none of 21 on placebo, and 25 of 41 who had not against one of 21.
What was measured
Durable platelet response, defined as a count of at least 50 × 10⁹/L in six or more of the last eight treatment weeks
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Kuter et al. ran two parallel double-blind randomised trials in 63 splenectomised and 62 non-splenectomised patients with immune thrombocytopenia and a mean of three platelet counts at or below 30 × 10⁹/L, randomised 2:1 to weekly subcutaneous romiplostim or placebo for 24 weeks, with doses adjusted to maintain counts between 50 and 200 × 10⁹/L. Durable platelet response — a count of at least 50 × 10⁹/L during six or more of the last eight weeks — was achieved by 16 of 42 splenectomised patients against 0 of 21 (difference 38%, 95% CI 23.4 to 52.8, p=0.0013) and by 25 of 41 non-splenectomised patients against 1 of 21 (difference 56%, 95% CI 38.7 to 73.7, p<0.0001). Overall platelet response was 79% and 88% against 0% and 14%. Concurrent therapy was reduced or stopped by 20 of 23 patients on romiplostim against 6 of 16 on placebo. No antibodies against romiplostim or thrombopoietin were detected.
Written into the record, not signed off as a reviewed claim
It cut splenectomy from more than a third to under one in ten
In plain words
In a 234-patient open trial against whatever the treating doctor would otherwise have used, 9% of the romiplostim group had their spleen removed against 36% of the standard-care group. Bleeding events and transfusions were also lower.
What was measured
Incidence of treatment failure and of splenectomy over 52 weeks
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
This open-label 52-week trial randomised 234 non-splenectomised adults with immune thrombocytopenia to standard of care (77) or weekly subcutaneous romiplostim (157), with co-primary endpoints of treatment failure and splenectomy. Platelet response rate was 2.3 times that of standard care (95% CI 2.0 to 2.6, p<0.001). Treatment failure occurred in 18 of 157 (11%) against 23 of 77 (30%), odds ratio 0.31 (95% CI 0.15 to 0.61, p<0.001). Splenectomy was performed in 14 of 157 (9%) against 28 of 77 (36%), odds ratio 0.17 (95% CI 0.08 to 0.35, p<0.001). The romiplostim group had fewer bleeding events, fewer transfusions and greater quality-of-life improvement, and serious adverse events in 23% against 37%. The trial was open-label, and splenectomy is a decision an unblinded clinician makes, which is a real limitation on an otherwise unusually patient-centred endpoint.
Written into the record, not signed off as a reviewed claim
The radiation survival claim rests on eighty monkeys
In plain words
Nplate is licensed to increase survival after radiation exposure. No human has ever been treated in a trial for it. The evidence is forty irradiated rhesus monkeys given the drug and forty given saline.
What was measured
Sixty-day survival in rhesus monkeys after 6.8 Gy total body irradiation, 72.5% against 32.5%
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The label states plainly that efficacy studies could not be conducted in humans with acute radiation syndrome for ethical and feasibility reasons, and that approval was based on animal efficacy studies, the effect on platelet count in healthy human volunteers, and data from immune thrombocytopenia patients. In the pivotal study, rhesus monkeys were randomised to control (n=40) or treatment (n=40) and exposed to 6.8 Gy total body irradiation, a dose lethal to 70% of animals by 60 days. A single subcutaneous dose was given 24 hours after irradiation alongside full supportive medical management. Sixty-day survival was 72.5% (29 of 40) against 32.5% (13 of 40), one-sided p=0.0002. The human dose of 10 micrograms per kilogram is derived from population modelling and simulation aimed at producing a platelet response similar to that seen in the animals, and the paediatric dose including term neonates is extrapolated from immune thrombocytopenia data. This is the Animal Rule working as designed, and it is also the largest inferential leap on any page in this group.
Source
Nplate (romiplostim) prescribing information, section 14.3 Patients with Hematopoietic Syndrome of Acute Radiation Syndrome
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
A leukaemia signal stopped a trial, and five years later it was gone
In plain words
A trial in myelodysplastic syndrome was terminated because more patients on romiplostim progressed to acute leukaemia. With five years of follow-up the difference had disappeared — and the exclusion stayed on the label anyway.
What was measured
Progression to acute myelogenous leukaemia and overall survival at 58 weeks and at 5 years in low and intermediate-1 risk myelodysplastic syndrome
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
A randomised, double-blind, placebo-controlled trial in adults with severe thrombocytopenia and IPSS low or intermediate-1 risk myelodysplastic syndrome randomised 167 to romiplostim and 83 to placebo, and was terminated because of more cases of acute myelogenous leukaemia in the romiplostim arm. During the 58-week study period, progression to acute myelogenous leukaemia occurred in 10 of 167 (6.0%) against 4 of 83 (4.8%), hazard ratio 1.20 (95% CI 0.38 to 3.84). Of 250 patients, 210 entered the five-year follow-up phase: progression occurred in 20 of 168 (11.9%) against 9 of 82 (11.0%), hazard ratio 1.06 (95% CI 0.48 to 2.33), and death in 93 of 167 (55.7%) against 45 of 83 (54.2%), hazard ratio 1.03 (95% CI 0.72 to 1.47). The limitation of use excluding myelodysplastic syndrome remains on the label. Whether that is appropriate caution or a decision the long-term data no longer support is a live question, and the contrast with eltrombopag — where the leukaemia hazard ratio was 2.66 with a confidence interval excluding one — is the reason it matters.
Source
Nplate (romiplostim) prescribing information, section 5.1 Risk of Progression of Myelodysplastic Syndromes to Acute Myelogenous Leukemia, and section 1 Limitations of Use
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
Driving the marrow for years leaves fibre behind in some patients
In plain words
A study that biopsied the bone marrow of patients on romiplostim for up to three years found reticulin fibre had progressed in 7% of them, and 2% had developed collagen — the more serious kind of scarring.
What was measured
Progression of bone marrow reticulin formation and incidence of collagen fibrosis on the modified Bauermeister scale
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
An open-label trial prospectively evaluated changes in bone marrow reticulin and collagen in adults with immune thrombocytopenia treated weekly for up to three years, with biopsies at year 1, 2 or 3 by cohort against baseline, graded on the modified Bauermeister scale. Of 169 patients enrolled, 132 were evaluable for collagen and 131 for reticulin. Progression of reticulin formation, defined as an increase of two or more grades or an increase to grade 4, was reported in 9 of 131 (7%). Grade 4 findings indicating collagen developed in 2 of 132 (2%), both in the three-year cohort, and one of those had no detectable collagen on repeat testing 12 weeks after stopping the drug. In children, increased reticulin was reported in 18.5% at year 1 and 47.2% at year 2, with a maximum grade of 2 and no collagen fibrosis. Separately, one patient with immune thrombocytopenia and haemolytic anaemia developed marrow fibrosis with collagen during therapy in an earlier trial.
Source
Nplate (romiplostim) prescribing information, section 6.1, Bone Marrow Reticulin Formation and Collagen Fibrosis
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 molecule was designed to look nothing like the hormone it imitates
In plain words
Earlier engineered versions of thrombopoietin taught some patients’ immune systems to attack their own hormone, leaving them worse off than before. Romiplostim shares no sequence with it at all, which is a design decision made from that failure.
What was measured
That sequence dissimilarity guarantees no cross-reactive immune response over years of use — a design rationale supported by trial-length data rather than by long-term surveillance
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The label states that romiplostim has no amino acid sequence homology to endogenous thrombopoietin, while increasing platelet production through binding and activation of the same receptor by a mechanism it describes as analogous. In the pivotal trials no antibodies against romiplostim or thrombopoietin were detected. The label nonetheless warns that severe thrombocytopenia may persist during treatment because of neutralising antibodies or other causes. Absence of detected antibodies in trials of 125 patients over 24 weeks is a much weaker statement than absence of the risk, and the failure mode being guarded against — a neutralising antibody that cross-reacts with the patient’s own hormone — is one that appears late and in small numbers.
Source
Nplate (romiplostim) prescribing information, sections 11 Description, 12.1 Mechanism of Action and 5.3 Lack of Response or Loss of Response to Nplate
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
Where else this substance is registered
FDA substance identifier (UNII)
GN5XU2DXKV
RxNorm concept
1728092
Checks this page had to pass
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Identity resolved
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No unresolved merge across substance families
no quarantine open
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Every public sentence names a source
The opening statement carries the origin: Written into the record, not signed off.
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Trial roles classified for highlighted evidence
No registered study is classified as testing this substance.
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enforced by the copy-contract test over the rendered page
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Safety mode resolved
No register row and no identity class settled the question.
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Canonical metadata present
slug and display name present
What is missing or unclear◇Read 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
1 approved application covers products containing this substance. The earliest was BLA125268, approved 20080822 to AMGEN.
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
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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.
A synthetic peptide grafted onto an antibody stalk that switches on the platelet receptor without resembling the hormone that normally does, producing durable platelet responses in 38 to 56 percentage points more patients than placebo and cutting splenectomy from 36% to 9% — and separately carrying a licensed claim to increase survival after radiation exposure that rests entirely on eighty irradiated rhesus monkeys, because the human trial can never be done.
Recorded evidence blocks (8)
Q1
On the Romiplostim label: indicated for what?
"Nplate is a thrombopoietin receptor agonist indicated for the treatment of thrombocytopenia in: Adult patients with immune thrombocytopenia (ITP) who have had an insufficient response to corticosteroids, immunoglobulins, or splenectomy. ( 1.1 ) Pediatric patients 1 year of age and older with ITP for at least 6 months…": indications and usage on Romiplostim's label. DailyMed label · c45f9a58-37c1-4f76-8e36-97d38c577037 · 2026-06-23
Q2
74 registered trials of Romiplostim — at which phases?
Registered studies posting no result
46 of 74
74 registered studies of Romiplostim: 39 phase2, 22 phase3, 9 phase1, 6 phase4, 5 na or unstated, 2 early phase1, 2 na. CLINICALTRIALS_SNAPSHOT · 2026-09-01
75 with a PubMed record
Show the evidence
phase2
39
phase3
22
phase1
9
phase4
6
na or unstated
5
early phase1
2
8 more recorded rows
na
2
completed
47
unknown
9
recruiting
6
terminated
5
withdrawn
3
active not recruiting
2
not yet recruiting
2
recorded 2026-09-01 · last checked 2026-09-04
Q3
8 of Romiplostim's trials stopped: futility/efficacy, accrual/recruitment, funding/business, other?
futility/efficacy (1), accrual/recruitment (2), funding/business (1) and other (4): Romiplostim's stop wording, clustered. CLINICALTRIALS_SNAPSHOT · 2026-09-01
"Approval of several new agents for the treatment of HCV infection would mitigate the future need for interferon HCV treatment"; 8 of 74 registered studies
Show the evidence
Trial
NCT01153919
terminated; "Approval of several new agents for the treatment of HCV infection would mitigate the future need for interferon HCV treatment"
NCT01676961
terminated; "PI left the institution"
NCT02227576
terminated; "Study halted for efficacy following the results of the interim analysis provided for in the protocol on 20 patients."
NCT03343847
withdrawn; "Study was not feasible"
NCT03622931
terminated; "due to lack of recruitment"
NCT04671901
terminated; "Lack of accrual"
2 further recorded trials
NCT04933942
withdrawn; "Amgen withdrew interest in providing further financial support"
NCT05323617
withdrawn; "Operational"
recorded 2026-09-01 · last checked 2026-09-04
Q4
Romiplostim's half-life is 7 to 50 hours — which schedules were studied?
7 to 50 hours, the half-life Romiplostim's label states: "Patients with Immune Thrombocytopenia (ITP) In the long-term extension study in adult patients with ITP receiving weekly treatment of Nplate subcutaneously, the pharmacokinetics of romiplostim over the dose range of 3 to 15 mcg/kg indicated that peak serum concentrations of romiplostim were observed about 7 to 50…" DailyMed label · c45f9a58-37c1-4f76-8e36-97d38c577037 · 2026-06-23
Show the evidence
half lifepharmacokinetics
7 to 50 hours; Patients with Immune Thrombocytopenia (ITP) In the long-term extension study in adult patients with ITP receiving weekly treatment of Nplate subcutaneously, the pharmacokinetics of romiplostim over the dose range of 3 to 15 mcg/kg indicated that peak serum concentrations of romiplostim were observed about 7 to 50 hours post dose (median: 14 hours) with half-life values ranging from 1 to 34 days…
recorded 2026-06-23 · last checked 2026-09-04
Q5
Which 19 trials of Romiplostim posted no result?
Posted no result
19 of 19 completed trials
Registrations
NCT00305435, NCT00102323, NCT00102336, NCT01236014, NCT01439321 and NCT01516619, and 13 more
Completion dates
oldest 2006-11; newest 2024-04-03
Show the evidence
Trial
NCT00305435
2006-11
NCT00102323
2007-03-01
NCT00102336
2007-04-01
NCT01236014
2009-10
NCT01439321
2011-06
NCT01516619
2012-11
13 further recorded trials
NCT01971684
2017-04
NCT02868099
2017-06
NCT02868060
2017-08
NCT01980030
2018-11
NCT02760251
2020-03
NCT04350164
2020-06
NCT02773290
2020-07-28
NCT03957694
2021-05-26
NCT02046291
2021-06-01
NCT04095936
2021-10-29
NCT05220878
2023-10-19
NCT04478227
2024-01-18
NCT05492409
2024-04-03
Q6
At the median, Romiplostim's trials enrolled 44.5 people — anything larger?
Median enrolment
44.5
Largest enrolment
467
Registered trials counted
74
Q7
What do 4158 spontaneous reports say about Romiplostim — 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.
Romiplostim appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 4158 reaction mentions were counted: platelet count decreased 1012; therapeutic response decreased 797; platelet count abnormal 632; thrombocytopenia 547. FAERS via Open Targets · CHEMBL1201832 · 2026-06-24
Show the evidence
platelet count decreased
1012
therapeutic response decreased
797
platelet count abnormal
632
thrombocytopenia
547
hospitalisation
213
platelet count increased
210
4 more recorded rows
thrombocytosis
201
haemorrhage
193
deep vein thrombosis
180
pulmonary embolism
173
recorded 2026-06-24 · last checked 2026-09-04
Q8
Which 10 reactions does Romiplostim's label not list?
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
✓ canonical metadata passed: slug and display name present
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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.