This page shows what was measured, who it was measured in, and what that does not settle.
What Fostamatinib does in the body
The fostamatinib metabolite R406 reduces antibody-mediated destruction of platelets.
From the FDA-approved label: Fostamatinib is a tyrosine kinase inhibitor with demonstrated activity against spleen tyrosine kinase (SYK). The major metabolite of fostamatinib, R406, inhibits signal transduction of Fc-activating receptors and B-cell receptor.
Why people take it. Thrombocytopenia
What happened in people
RNAWiki has not yet published a reviewed conclusion for this use.
§ A fixed RNAWiki sentence
Where this came from
Wording RNAWiki always uses, not a finding about this substance.
No reviewed claim names a result for any goal on this record.
No source is stored against this line.
The limit that matters most
Not recorded.
Where it acts
Not recorded.
Kind of result
No result is published, so no kind of result applies yet
Supervision
Professional supervision is normally required. A regulator classifies this substance in a way that restricts how it is supplied.
What the registries record it as
The substance registry classes this as chemical.
FDA substance registry · SQ8A3S5101 · read 2026-08-29
Its recorded molecular formula is C23H24FN6Na2O9P∙6H2O, weighing 732.52.
US prescribing information · 21149cc3-049b-43e2-b141-c9499160556c · read 2026-08-30
Where each sentence above came from
A person wrote this explanation into the record, with the studies named in the path below.
The recorded use, written for a reader without medical training. Not signed off.
No statement of the main limit is recorded.
The four opening statements run to 54 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.
Stand-in result
A stand-in result is a number measured because the real result takes too long.
A picture of it, and where the picture fails
It is like judging a journey by the speedometer rather than by arriving.
Where that stops being true. Speed does predict arrival. Many stand-in results do not predict the real one.
What people get wrong. A stand-in result is often reported as the result itself.
A surrogate endpoint substituted for a clinical endpoint, valid only where the substitution has been shown to hold.
Enzyme
An enzyme is a protein that speeds up one chemical change.
A picture of it, and where the picture fails
An enzyme is like a machine on a production line doing one cut.
Where that stops being true. A machine is switched on and off by a person. Enzymes are controlled by the cell.
What people get wrong. Enzymes are thought to be used up. They are not; they work again and again.
A catalytic protein that lowers the activation energy of a specific reaction.
Receptor
A receptor is a part of a cell that a signal fits into.
A picture of it, and where the picture fails
A receptor is like a lock waiting for one key.
Where that stops being true. A lock either opens or does not. A receptor can be half-triggered, or worn out.
What people get wrong. Fitting a receptor is read as causing a benefit. It causes a step, and nothing more.
A protein that binds a specific ligand and converts that binding into a cellular response.
Pathway
A pathway is a chain of steps inside a cell, each one setting off the next.
A picture of it, and where the picture fails
A pathway is like a row of dominoes.
Where that stops being true. Dominoes fall one way. Pathways loop back and can switch themselves off.
What people get wrong. Changing one step is read as changing the outcome. Other steps often absorb it.
An ordered series of molecular interactions producing a defined cellular change.
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.
Percentage of Patients Who Had at Least 1 Adverse Event in Any Category
✗ The study did not show it
Who was studied
NCT01242514
How many people
1917
Study design
Phase 3
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. No limitation is recorded for this study.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
openFDA Drugs@FDA · a recorded source, not a stored snapshot
openFDA NDC Directory · a recorded source, not a stored snapshot
openFDA SPL label · a recorded source, not a stored snapshot
PubChem PUG-REST · a recorded source, not a stored snapshot
Oxygen Free Days Through Day 28.
✗ The study did not show it
Who was studied
NCT04924660
How many people
1060
Study design
Phase 2/Phase 3
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. No limitation is recorded for this study.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
openFDA Drugs@FDA · a recorded source, not a stored snapshot
openFDA NDC Directory · a recorded source, not a stored snapshot
openFDA SPL label · a recorded source, not a stored snapshot
PubChem PUG-REST · a recorded source, not a stored snapshot
Proportion of Patients With ACR20 at Week 24, Comparison Between Fostamatinib and Placebo.
✗ The study did not show it
Who was studied
NCT01197521
How many people
923
Study design
Phase 3
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. No limitation is recorded for this study.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
openFDA Drugs@FDA · a recorded source, not a stored snapshot
openFDA NDC Directory · a recorded source, not a stored snapshot
openFDA SPL label · a recorded source, not a stored snapshot
PubChem PUG-REST · a recorded source, not a stored snapshot
Proportion of Patients With ACR20 at Week 24, Comparison Between Fostamatinib and Placebo
✗ The study did not show it
Who was studied
NCT01197534
How many people
913
Study design
Phase 3
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. No limitation is recorded for this study.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
openFDA Drugs@FDA · a recorded source, not a stored snapshot
openFDA NDC Directory · a recorded source, not a stored snapshot
openFDA SPL label · a recorded source, not a stored snapshot
PubChem PUG-REST · a recorded source, not a stored snapshot
DAS28-CRP Score - Change From Baseline to Week 6 Compared to Placebo
✗ The study did not show it
Who was studied
NCT01264770
How many people
644
Study design
Phase 2
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. No limitation is recorded for this study.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
openFDA Drugs@FDA · a recorded source, not a stored snapshot
openFDA NDC Directory · a recorded source, not a stored snapshot
openFDA SPL label · a recorded source, not a stored snapshot
PubChem PUG-REST · a recorded source, not a stored snapshot
Percentage of Patients Who Had at Least 1 Treatment Emergent Adverse Event in Any Category
✗ The study did not show it
Who was studied
NCT00805467
How many people
624
Study design
Phase 2
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. No limitation is recorded for this study.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
openFDA Drugs@FDA · a recorded source, not a stored snapshot
openFDA NDC Directory · a recorded source, not a stored snapshot
openFDA SPL label · a recorded source, not a stored snapshot
PubChem PUG-REST · a recorded source, not a stored snapshot
What we know
RNAWiki holds 6 written-up human studies for this substance, each with the question it asked.
How we know it
Each card names the study, the number of people and what the study set out to measure.
What this does not prove
These summaries were written by a person and have not been signed off as reviewed claims.
Why it matters
A study that failed is as informative as one that worked, and both are here.
What we still do not know
No reviewed claim exists, so no exact population, effect size or interval is published yet.
What happened in people◇Read from sources, not yet reviewed
How close this is to real life
The top step is something a person would feel or care about. The bottom is a guess from software. Filled steps are where evidence exists for this substance.
□Living longer, or avoiding a major eventNo evidence recorded. Death, a heart attack, a stroke, a hospital stay.No registered study measures this.
□What a body can do day to dayNo evidence recorded. Walking, dressing, breathing, recovering.No registered study measures this.
□Measured performanceNo evidence recorded. How much was lifted, how far was run, how fast.No registered study measures this.
□Symptoms and quality of lifeNo evidence recorded. Pain, tiredness, mood, sleep, as the person rated it.No registered study measures this.
■A number that stands in for healthEvidence recorded. Cholesterol, blood sugar, bone density. A stand-in, not the thing itself.1 registered measure of this kind.
■A step measured inside a personEvidence recorded. Something measured in human tissue or human cells.A human record sits on the stored organism ladder.
■AnimalsEvidence recorded. Mice, rats, dogs. Useful for ideas, not proof about people.Stored records in Mouse. A result in animals says what to test next. It does not say what happens in people.
■Cells in a dishEvidence recorded. Cells or chemistry on a bench, far from a whole body.Stored mechanism abstracts describe steps measured in cells or tissue.
□A guess from softwareNo evidence recorded. Nobody measured it. RNAWiki never publishes one as a finding.RNAWiki stores no prediction for this record. Software can suggest a link. RNAWiki does not publish one as a finding.
Higher on these steps means closer to something a person would feel. It does not mean better done.
What it would be like to take◇Read from sources, not yet reviewed
Felt, measured, or meaningful
Three different things that get called the same word. Registered studies measured all three, and mixing them is how a blood test becomes a health claim.
Felt
Things a person could notice without a test.
No registered study measured anything of this kind.
Measured
Things only a test, a scale or a device shows.
blood pressure
Meaningful
Things that change how a life goes, not only a number.
No registered study measured anything of this kind.
A registered study says what someone planned to measure. It does not say what they found. A number moving is not the same as a life going better. The two are shown apart here.
Felt, but not shown to help. A person notices a change. No study showed it leads anywhere good.
Measured, but not felt. A number moves. The person notices nothing. Both can be true.
Measured, but not shown to matter. A number moves in the good direction. Nobody showed that lives went better.
Matters, but takes years. The result that counts may take longer than anyone would keep watching.
Names that fit none of the three (11)
american college of rheumatology 20 response at 6 months
response rate
objective response rate
pharmacokinetics of rosuvastatin measured by auc and cmax
pharmacokinetics of simvastatin measured by auc and cmax
adverse events
neutrophil count
platelet response
at least 1 serious adverse event
oxygen free days through day 28
minimum safe and biologically effective dose
These are harms, study-process measures, or names the rules did not recognise. They are shown rather than dropped.
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.
TAVALISSE is indicated for the treatment of thrombocytopenia in adult patients with chronic immune thrombocytopenia (ITP) who have had an insufficient response to a previous treatment. TAVALISSE is a kinase inhibitor indicated for the treatment of thrombocytopenia in adult patients with chronic immune thrombocytopenia (ITP) who have had an insufficient response to a previous treatment.
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: “Safety and effectiveness in pediatric patients have not been established.”
US prescribing information · 21149cc3-049b-43e2-b141-c9499160556c · read 2026-08-30
On older people, the label states: “Of the 102 patients with ITP who received TAVALISSE, 28 (27%) were 65 years of age and older, while 11 (11%) were 75 years of age and older.”
US prescribing information · 21149cc3-049b-43e2-b141-c9499160556c · read 2026-08-30
On people who are pregnant, the label states: “Risk Summary Based on findings from animal studies and the mechanism of action, TAVALISSE can cause fetal harm when administered to a pregnant woman [see Clinical Pharmacology (12.1) ].”
US prescribing information · 21149cc3-049b-43e2-b141-c9499160556c · read 2026-08-30
On people who are breastfeeding, the label states: “Risk Summary There are no data on the presence of fostamatinib and/or its metabolites in human milk, the effects on the breastfed child, or on milk production.”
US prescribing information · 21149cc3-049b-43e2-b141-c9499160556c · read 2026-08-30
Where the result stopped carrying
This is a scope explorer, not a diagnosis engine.
It shows who was studied so you can see whether people similar to you were included.
RNAWiki cannot tell whether a study fits you. It can show who was in it.
What it would be like to take◇Read from sources, not yet reviewed
Why it might seem to do nothing
A real effect and a noticed effect are different things. These are the recorded reasons the two come apart.
It was studied for a different goal
The studies measured something else entirely.
On this record: Some registered studies measured things that match no goal on this page.
It was studied in different people
The people in the studies were not much like the reader.
On this record: Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
The evidence may simply be wrong
Small early studies often do not hold up.
On this record: RNAWiki has not yet published a reviewed conclusion for this use.
Other reasons RNAWiki checked and found nothing for (10)
A different form was studied
The studied form is not the form on the shelf. Nothing in this record points to this reason.
There was nothing to correct
Where a level is already normal, topping it up may change nothing. Nothing in this record points to this reason.
Something else had to happen too
In the studies it was paired with training, a diet or another treatment. Nothing in this record points to this reason.
The change is too small to feel
A real change can still sit below what a person notices. Nothing in this record points to this reason.
Day-to-day swing hides it
Sleep, food, stress and time of day move most numbers more than this would. Nothing in this record points to this reason.
Not enough time yet
The studies ran longer than the person has waited. Nothing in this record points to this reason.
It was not taken as studied
Missed days change the result, and studies count them. Nothing in this record points to this reason.
Something else changed at the same time
Two changes at once cannot be told apart afterwards. Nothing in this record points to this reason.
The product may not be what it says
Contents of a sold product are not always what the label states. Nothing in this record points to this reason.
No recorded reason
RNAWiki has nothing stored that would explain it. Nothing in this record points to this reason.
None of these is a reason to take more. Taking more is not a step this page ever suggests.
What it would be like to take◇Read from sources, not yet reviewed
What taking it involves
The recorded facts about getting hold of it and using it. Nothing here is a suggestion about what you should do.
How it is supplied
Prescription only
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Read from the recorded approval status.
No source is stored against this line.
Form and route
Oral
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form and route recorded on this substance.
No source is stored against this line.
Who oversees it
Professional supervision is normally required. A regulator classifies this substance in a way that restricts how it is supplied.
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Suppression classes recorded: S3.
No source is stored against this line.
What is in the pack
Sold as tablet, given by the oral route.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on how this is sold and what that means for what is in the pack.
No source is stored against this line.
Where it is registered
Regulatory records are listed in the technical disclosure at the foot of this page.
# Counted from records
Where this came from
A count of rows RNAWiki holds. It describes our records, not your body.
Register entries are stored per jurisdiction and shown with their dates.
No source is stored against this line.
Why people stop
Not recorded.
∅ Nothing recorded
Where this came from
RNAWiki holds nothing here and says so rather than guessing.
No record of why people stopped taking it is stored for this substance.
No source is stored against this line.
What it would be like to take∅Nothing found in the sources checked
What can go wrong
Sorted by where each line came from. A regulator's label and a report somebody sent in are not the same kind of fact.
∅Nothing found in the sources checked
No harm is recorded against this substance in the sources RNAWiki checked. Finding nothing is not the same as showing there is nothing.
The sources listed were searched and held nothing. That is not the same as nothing existing.
Reports sent to a regulator
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.
Fostamatinib appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 161 reaction mentions were counted. One report can name several reactions.
The recorded terms (10)
platelet count decreased — 53 reaction mentions
diarrhoea — 50 reaction mentions
blood pressure increased — 15 reaction mentions
hospitalisation — 13 reaction mentions
product dose omission issue — 9 reaction mentions
contusion — 8 reaction mentions
platelet count — 5 reaction mentions
splenectomy — 3 reaction mentions
taste disorder — 3 reaction mentions
allergy to immunoglobulin therapy — 2 reaction mentions
open-targets-adr · recorded 2026-06-24 · 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
Oral
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form used in the studies cited on this page.
No source is stored against this line.
What is sold
Not recorded.
∅ Nothing recorded
Where this came from
RNAWiki holds nothing here and says so rather than guessing.
Nothing further is recorded about which forms are sold.
No source is stored against this line.
What is recorded as being sold
4 products list this as an active ingredient in the United States drug directory. 4 of them contain it and nothing else.
FDA National Drug Code directory · 71332-002 · read 2026-08-29
They are sold as powder and tablet, taken oral.
FDA National Drug Code directory · 71332-002 · 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 · 21149cc3-049b-43e2-b141-c9499160556c · read 2026-08-29
Those labels are classed as human prescription drug.
US prescribing information · 21149cc3-049b-43e2-b141-c9499160556c · read 2026-08-29
TAVALISSE is oral at 3 DOSAGE FORMS AND STRENGTHS TAVALISSE is available as: 100 mg tablet: orange, film-coated, round, biconvex tablets debossed with "100" on one side and "R" on the reverse side. 150 mg tablet: orange, film-coated, oval,…, recorded as fda label in effect 2025-11-05 in the United States.
US prescribing information · 21149cc3-049b-43e2-b141-c9499160556c · read 2026-08-30
Evidence carries across two names for one substance. It does not carry across a salt, a mirror form or a mixture.
What it would be like to take◇Read from sources, not yet reviewed
What you could measure
This one is decided with a clinician, so this section holds questions to ask rather than a plan to run.
Self-experiment planning is not offered for a prescription or clinician-supervised medicine. The questions below are for a clinician or pharmacist.
Questions worth asking
Which of the trials of Fostamatinib studied people like me?
What was measured, and for how long?
Was the result a laboratory value or a health outcome?
What would we watch for, and when would we stop?
Tracking can show whether something changed for you. It cannot show what caused it.
RNAWiki records evidence. It does not say whether this substance is right for you.
What is missing or unclear◇Read from sources, not yet reviewed
What nobody knows yet
Open questions, each with why it is open and what would close it.
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 Fostamatinib are recorded. Results from one form may not transfer to another.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Mechanism not reviewed
No reviewed mechanism story exists for this substance.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
What happened in people◇Read from sources, not yet reviewed
Check any of this yourself
Every line above traced back to the study it came from. This is the technical layer, and the vocabulary changes here.
Where else this substance is registered
FDA substance identifier (UNII)
SQ8A3S5101
RxNorm concept
2044922
Checks this page had to pass
✓ Passed
Identity resolved
no open identity hold
✓ Passed
No unresolved merge across substance families
no quarantine open
✓ Passed
Every public sentence names a source
The opening statement carries the origin: Written into the record, not signed off.
✗ Not passed
Trial roles classified for highlighted evidence
No registered study is classified as testing this substance.
✓ Passed
No internal keys in reader text
enforced by the copy-contract test over the rendered page
✓ Passed
Safety mode resolved
Suppression classes recorded: S3.
✓ Passed
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
2 approved applications cover products containing this substance. The earliest was NDA209299, approved 20180417 to RIGEL PHARMS.
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.
The path through the body — found nothing in the sources checked.
How long anything takes — found nothing in the sources checked.
What it may clash with — found nothing in the sources checked.
Other ways to the same goal — found nothing in the sources checked.
Claims that go past the evidence — found nothing in the sources checked.
What changed on this page — found nothing in the sources checked.
The record as stored
The full record, for auditing
Everything above is built from what is below. This layer keeps the technical vocabulary, record identifiers and every stored row, so a reader who wants to check the page can.
Recorded evidence blocks (11)
Q2
What did Fostamatinib's largest trial (1917 people) and its longest (6.4 years) measure?
1917 people in Fostamatinib's largest registered study, 6.4 years in its longest registered window, measuring To investigate whether the plasma concentration-time profiles and resulting PK parameters of digoxin are altered during steady-state fostamatinib administration. Digoxin AUCss and Cmaxss will be… ClinicalTrials.gov · 2026-09-01
27 phase2, 20 phase1, 13 phase3, 5 na or unstated; NCT03991780; 2025-10-15; no ageing endpoint recorded. Last human test completed 2024, NCT05030675.
Interpretation These counts include studies where Fostamatinib was a comparison treatment, a background treatment or an exposure in an observational study, and the longest window may be a planned end date. Trial roles have not yet been classified for this record.
Show the evidence
phase2
27
phase1
20
phase3
13
na or unstated
5
Last recorded human testNCT05030675
2024-08-08
recorded 2026-09-01 · last checked 2026-09-04
Q3
From mouse to human: where has Fostamatinib shown biomarker?
Interpretation To investigate whether the plasma concentration-time profiles and resulting PK parameters of digoxin are altered during steady-state fostamatinib… — the recorded outcome words.
Show the evidence
mouse
mechanism-only
humanNCT01355354
biomarker; To investigate whether the plasma concentration-time profiles and resulting PK parameters of digoxin are altered during steady-state fostamatinib administration. Digoxin AUCss and Cmaxss will be measured; 60
recorded 2026-09-01 · last checked 2026-09-04
Q4
12 of Fostamatinib's trials stopped: safety, accrual/recruitment, funding/business, other?
safety (1), accrual/recruitment (4), funding/business (1) and other (6): Fostamatinib's stop wording, clustered. ClinicalTrials.gov · 2026-09-01
"Study was withdrawn for business reasons before study start."; 12 of 60 registered studies
Show the evidence
Trial
NCT00752999
withdrawn; "Study was withdrawn for business reasons before study start."
NCT00805467
terminated; "AZ decision to discontinue fostamatinib development in RA; rights to fostamatinib returned to Rigel Pharmaceuticals."
NCT01242514
terminated; "AZ decision to discontinue fostamatinib development in RA; rights to fostamatinib returned to Rigel Pharmaceuticals."
NCT01569074
terminated; "AZ decision to discontinue fostamatinib development in RA; rights to fostamatinib returned to Rigel Pharmaceuticals."
NCT01640054
terminated; "AZ decision to discontinue fostamatinib development in RA; rights to fostamatinib returned to Rigel Pharmaceuticals."
NCT02092961
terminated; "AZ decision to discontinue fostamatinib development in RA; rights to fostamatinib returned to Rigel Pharmaceuticals."
6 further recorded trials
NCT02433236
withdrawn; "Study withdrawn prior to enrollment of first subject"
NCT04543279
terminated; "Low accrual"
NCT04904276
terminated; "met minimum enrollment goal, however, enrollment was slow due to the pandemic, therefore, the study was terminated"
NCT05502783
terminated; "Clinical trial was halted prematurely due to low enrollment"
NCT05509582
withdrawn; "No responders in parent protocol 000758; this follow-on protocol not activated and PI leaving NIH"
NCT05593770
terminated; "Following a meeting of the DSMB on 20th September 2023, the recommendation was made to the sponsor on 26th September 2023 that the Fostamatinib arm of the trial ceases enrolment and study medication is discontinued immediately."
recorded 2026-09-01 · last checked 2026-09-04
Q5
Human studies of Fostamatinib used Fostamatinib 100mg — over how long?
9 recorded entries; human; tablet; also "Fostamatinib 100mg", "Fostamatinib 200mg", "Fostamatinib 150 mg"
Show the evidence
human
NCT01608542
Fostamatinib 100mg
NCT01608542
Fostamatinib 200mg
NCT02112838
Fostamatinib 150 mg
NCT02112838
Fostamatinib 100 mg
NCT02433236
tablet; Fostamatinib Disodium tablet 100 mg
NCT02433236
tablet; Fostamatinib Disodium tablet 150 mg
3 more recorded rows
humanNCT02612558
Fostamatinib 150 mg bid
humanNCT03363334
Fostamatinib disodium 100 mg
humanNCT03363334
Fostamatinib disodium 150 mg
recorded 2026-09-01 · last checked 2026-09-04
Q6
Which of adverse events, american college of rheumatology 20 response at 6 months and at least 1 serious adverse event did Fostamatinib's trials measure?
adverse events, american college of rheumatology 20 response at 6 months and at least 1 serious adverse event lead 12 outcome terms across Fostamatinib's trials. ClinicalTrials.gov · 2026-09-01
Interpretation pharmacokinetics of rosuvastatin measured by auc and cmax, pharmacokinetics of simvastatin measured by auc and cmax, adverse events, blood pressure, neutrophil count and platelet response follow.
Show the evidence
american college of rheumatology 20 response at 6 months
1
response rate
1
objective response rate
1
pharmacokinetics of rosuvastatin measured by auc and cmax
1
pharmacokinetics of simvastatin measured by auc and cmax
1
adverse events
1
6 more recorded rows
blood pressure
1
neutrophil count
1
platelet response
1
at least 1 serious adverse event
1
oxygen free days through day 28
1
minimum safe and biologically effective dose
1
recorded 2026-09-01 · last checked 2026-09-04
Q7
Which of Fostamatinib's 7 ongoing trials reports first?
Histological changes of antibody mediated rejection assessed by a histopathologist; Adverse Events; latest 2029-07-01
Show the evidence
Trial
NCT03991780
"Fostamatinib in the Treatment of Chronic Active Antibody Mediated Rejection"; n 8; "Histological changes of antibody mediated rejection assessed by a histopathologist"; 2025-10-15
NCT04138927
"A Phase 3 Open Label Extension Study of Fostamatinib Disodium in the Treatment of Warm Antibody Autoimmune Hemolytic Anemia"; n 90; "Adverse Events"; 2024-04
NCT05904093
"Study to Evaluate the Safety and Tolerability of Escalating Doses of Fostamatinib in Subjects With Stable Sickle Cell Disease"; n 25; "The number of type, incidence, severity and relationship to study treatment of adverse events and serious adverse events"; 2027-05-14
NCT06233110
"Ruxolitinib Plus Fostamatinib for Steroid Refractory cGvHD"; n 30; "Minimum safe and biologically effective dose"; 2029-07-01
NCT06564207
"Fostamatinib for Treating Acute Respiratory Distress Syndrome (ARDS) in Hospitalized Adults"; n 40; "Cumulative Incidence of Serious Adverse Events (SAEs) Through Day 30"; 2027-10-31
NCT06757257
"Special Drug Use-results Survey for Long-term Use (Fostamatinib)"; n 149; "Adverse events"; 2028-09-30
1 further recorded trialNCT06948097
"Syk Inhibition in MItigating Lung Allograft Rejection (SIMILAR): A Trial to Evaluate the Safety and Tolerability of Fostamatinib in Lung Transplant Patients With Donor-Specific Antibodies"; n 30; "Study Drug Discontinuation Rate."; 2028-07-14
recorded 2026-09-01 · last checked 2026-09-04
Q8
Which 21 trials of Fostamatinib posted no result?
Posted no result
21 of 21 completed trials
Registrations
NCT00326339, NCT01208155, NCT01309854, NCT01311622, NCT01222455 and NCT01245790, and 15 more
Completion dates
oldest 2007-12; newest 2024-08-08
Show the evidence
Trial
NCT00326339
2007-12
NCT01208155
2010-11
NCT01309854
2011-05
NCT01311622
2011-05
NCT01222455
2011-06
NCT01245790
2011-06
14 further recorded trials
NCT01336218
2011-07
NCT01355354
2011-09
NCT01387308
2011-10
NCT01276262
2011-11
NCT01598571
2012-08
NCT01608542
2012-08
NCT01725230
2013-01
NCT02612558
2019-12
NCT02611063
2022-02-22
NCT04629703
2022-09-05
NCT05040698
2023-01-27
NCT06071520
2023-06-30
NCT04581954
2023-09-02
NCT05613296
2024-05-31
Q9
At the median, Fostamatinib's trials enrolled 37 people — anything larger?
Median enrolment
37
Largest enrolment
1917
Registered trials counted
59
Q10
What do 161 spontaneous reports say about Fostamatinib — 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.
Fostamatinib appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 161 reaction mentions were counted: platelet count decreased 53; diarrhoea 50; blood pressure increased 15; hospitalisation 13. open-targets-adr · CHEMBL2103830 · 2026-06-24
Show the evidence
platelet count decreased
53
diarrhoea
50
blood pressure increased
15
hospitalisation
13
product dose omission issue
9
contusion
8
4 more recorded rows
platelet count
5
splenectomy
3
taste disorder
3
allergy to immunoglobulin therapy
2
recorded 2026-06-24 · last checked 2026-09-04
Q11
Fostamatinib and CYP3A4, BCRP and P-GP: shared by which compounds?
CYP3A4, BCRP and P-GP appear in Fostamatinib's recorded interaction sentences, 10 in all. openfda-label+europepmc · 2026-08-30
Interpretation pharmacokinetics
Show the evidence
CYP2C8
pharmacokinetics
Drug Interaction Studies Clinical Pharmacology Studies No significant interactions were seen with concomitant use of TAVALISSE with the following drugs: methotrexate (OAT1/3 transporters), midazolam (CYP3A4 substrate), microgynon (ethinyl estradiol and levonorgestrel), warfarin, pioglitazone (CYP2C8 substrate) and ranitidine (H2-antagonist that increases gastric pH).
pharmacokinetics
R406 can inhibit CYP3A4 and BCRP, and can induce CYP2C8 activity.
CYP3A4
pharmacokinetics
R406 is extensively metabolized, primarily through pathways of CYP450-mediated oxidation (by CYP3A4) and glucuronidation (by UDP glucuronosyltransferase [UGT]1A9).
pharmacokinetics
Drug Interaction Studies Clinical Pharmacology Studies No significant interactions were seen with concomitant use of TAVALISSE with the following drugs: methotrexate (OAT1/3 transporters), midazolam (CYP3A4 substrate), microgynon (ethinyl estradiol and levonorgestrel), warfarin, pioglitazone (CYP2C8 substrate) and ranitidine (H2-antagonist that increases gastric pH).
pharmacokinetics
CYP3A4 and UGT1A9 are involved in the metabolism of R406.
pharmacokinetics
R406 can inhibit CYP3A4 and BCRP, and can induce CYP2C8 activity.
pharmacokinetics
CYP3A4 inducer : Concomitant use of rifampicin (600 mg once daily for 8 days) with a single dose of 150 mg TAVALISSE decreased R406 AUC by 75% and C max by 59% .
pharmacokinetics
Effect of Other Drugs on TAVALISSE Strong CYP3A4 inhibitor : Concomitant use of ketoconazole (200 mg twice daily for 3.5 days) with a single dose of 80 mg TAVALISSE (0.53 times the 150 mg dosage) increased R406 AUC by 102% and C max by 37%.
2 more recorded rows
CYP3A4pharmacokinetics
Moderate CYP3A4 Inhibitor : Concomitant use of verapamil (80 mg three times daily for 4 days) with a single dose of 150 mg TAVALISSE increased R406 AUC by 39% and C max by 6% .
CYP3A4pharmacokinetics
Effect of TAVALISSE on Other Drugs CYP3A4 substrate: Concomitant use of simvastatin (single dose 40 mg) with 100 mg twice daily TAVALISSE increased simvastatin AUC by 64% and C max by 113% and simvastatin acid AUC by 64% and C max by 83%.
recorded 2026-08-30 · last checked 2026-09-04
Q12
What is recorded about Fostamatinib and autophagy?
"Autophagy modulators include several highly promiscuous drugs (e.g., artenimol and olanzapine acting as activators, fostamatinib as an inhibitor, or melatonin as a dual-modulator) as well as selected drugs that uniquely target specific proteins (~30% of modulators)." — where Fostamatinib and autophagy appear together. Europe PMC · pathway abstract search · 2021-12-02
"Autophagy modulators include several highly promiscuous drugs (e.g., artenimol and olanzapine acting as activators, fostamatinib as an inhibitor, or melatonin as a dual-modulator) as well as selected drugs that uniquely target specific proteins (~30% of modulators)."
"Autophagy modulators include several highly promiscuous drugs (e.g. artenimol and olanzapine acting as activator, fostamatinib as inhibitor, or melatonin as dual-modulator), as well as selected drugs uniquely targeting specific proteins (∼30% of modulators)."
mTORPMID 34943039
"The mTOR inhibitor everolimus, the α1-adrenergic receptor antagonist doxazosin, and the Syk inhibitor fostamatinib significantly increased the viability of CF submucosal gland cells under strong oxidative stress pressure."
autophagyPMID 30733195
"Genetic knockout of autophagy-related 7 (ATG7) or pharmacologic inhibition of SYK activity with fostamatinib, a clinically approved inhibitor of SYK, prevented P-body clearance and MET, inhibiting metastatic tumor outgrowth."
mTOR
PMID 30204521
"Areas covered: The following targeted therapies are illustrated: drugs acting on CD20 (rituximab, alone or in association with bendamustine and fludarabine) and CD52 (alemtuzumab), B cell receptor and proteasome inhibitors (ibrutinib, bortezomib), complement inhibitors (eculizumab, BIVV009, APL-2), and other drugs targeting T lymphocytes (subcutaneous IL-2, belimumab, and mTOR inhibitors), IgG…"
PMID 21239804
"The mTOR inhibitors temsirolimus and everolimus have demonstrated antitumor activity in all types of lymphoma, the Syk inhibitor fostamatinib has activity in diffuse large B-cell lymphoma and chronic lymphocytic leukemia, and the PKC-β inhibitor enzastaurin is being used as consolidation therapy after remission in diffuse large B-cell lymphoma."
recorded 2021-12-02 · last checked 2026-09-04
Where it is registeredIdentifiers, relations and other names
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