This page shows what was measured, who it was measured in, and what that does not settle.
What Palbociclib does in the body
1 ); or o fulvestrant in patients with disease progression following endocrine therapy.
From the FDA-approved label: Palbociclib is an inhibitor of cyclin-dependent kinases (CDK) 4 and 6. Cyclin D1 and CDK4/6 are downstream of signaling pathways which lead to cellular proliferation. In vitro, palbociclib reduced cellular proliferation of estrogen receptor (ER)-positive breast cancer cell lines by blocking progression of the cell from G1 into S phase of the cell cycle. Treatment of breast cancer cell lines with the combination of palbociclib and antiestrogens leads to decreased retinoblastoma (Rb) protein phosphorylation resulting in reduced E2F expression and signaling, and increased growth arrest compared to treatment with each drug alone.
Why people take it. IBRANCE is a kinase inhibitor indicated: • for the treatment of adult patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer in combination with: o an aromatase inhibitor as initial endocrine-based therapy ( 1.1 ); or o fulvestrant in patients with disease progression following endocrine therapy.
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 · G9ZF61LE7G · read 2026-08-29
Where each sentence above came from
The use the label states, quoted from it. No plain-language version of this sentence has been written.
The use the label states, quoted from it. It is written for a clinician, not for a reader without medical training.
No statement of the main limit is recorded.
The four opening statements run to 175 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.
Objective response rate (ORR)
✗ The study did not show it
Who was studied
NCT02465060
How many people
6452
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
Invasive Disease Free Survival (iDFS)
✗ The study did not show it
Who was studied
NCT02513394
How many people
5796
Study design
Phase 3
Compared against
Not recorded for this study
Kind of result
Living longer, or avoiding a major event
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
Objective Response Rate defined as % of participants in a cohort with complete or partial response or with stable disease according to standard response criteria
✗ The study did not show it
Who was studied
NCT02693535
How many people
4200
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
Accrual of patients to ComboMATCH treatment trials
✗ The study did not show it
Who was studied
NCT05564377
How many people
2900
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 that are treated based on their molecular tumor profile
✗ The study did not show it
Who was studied
NCT02925234
How many people
1550
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
Proportion of Pediatric Patients Whose Advanced Tumors Have Pathway Alterations That Can be Targeted by Select Anti-cancer Drugs
✗ The study did not show it
Who was studied
NCT03155620
How many people
1377
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 eventEvidence recorded. Death, a heart attack, a stroke, a hospital stay.10 registered measures of this kind. 1 written-up study measured this and did not show a benefit.
□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.2 registered measures 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.
maximum observed plasma concentration
maximum plasma concentration
Meaningful
Things that change how a life goes, not only a number.
progression free survival at 12 weeks
progression free survival
progression free survival as assessed by the investigator
progression free survival in phase 2 cohort 2b
progression free survival at 6 months
1 year progression free survival
overall survival
invasive disease free survival
progression free survival at six months
without progression free survival events
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 (28)
response rates
recommended phase 2 dose and schedule
safety and tolerability
maximum tolerated dose and recommended phase 2 dose
2 year treatment discontinuation rate
part 1 change from baseline in vital signs
part 1 number of adverse events
phase i maximum tolerated dose
screen success rate
who experienced dose limiting toxicities
single dose apparent oral clearance
measurement of the proliferation marker ki67
adverse events
overall response rate
confirmed objective response in pf 06747775 200 qd group
grade 3 or 4 neutropenia
clinical benefit rate
clinical benefit rate by esr1 genotype
all grade neutrophil count decrease
objective response rate
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.
IBRANCE is a kinase inhibitor indicated: • for the treatment of adult patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer in combination with: o an aromatase inhibitor as initial endocrine-based therapy ( 1.1 ); or o fulvestrant in patients with disease progression following endocrine therapy.
Who is missing from the studies
Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What the label states about particular groups
On pediatric, the label states: “The safety and effectiveness of IBRANCE in pediatric patients have not been established.”
US prescribing information · fecbdd7d-b729-41b5-9872-231b8fe104ce · read 2026-08-30
On older people, the label states: “Of 444 patients who received IBRANCE in PALOMA-2, 181 patients (41%) were ≥65 years of age and 48 patients (11%) were ≥75 years of age.”
US prescribing information · fecbdd7d-b729-41b5-9872-231b8fe104ce · read 2026-08-30
On people who are pregnant, the label states: “Risk Summary Based on findings from animal studies and its mechanism of action, IBRANCE can cause fetal harm when administered to a pregnant woman [see Clinical Pharmacology (12.1) ] .”
US prescribing information · fecbdd7d-b729-41b5-9872-231b8fe104ce · read 2026-08-30
On people who are breastfeeding, the label states: “Risk Summary There is no information regarding the presence of palbociclib in human milk, its effects on milk production, or the breastfed infant.”
US prescribing information · fecbdd7d-b729-41b5-9872-231b8fe104ce · read 2026-08-30
On people with reduced liver function, the label states: “No dose adjustment is required in patients with mild or moderate hepatic impairment (Child-Pugh classes A and B).”
US prescribing information · fecbdd7d-b729-41b5-9872-231b8fe104ce · read 2026-08-30
On people with reduced kidney function, the label states: “No dose adjustment is required in patients with mild, moderate, or severe renal impairment (CrCl >15 mL/min).”
US prescribing information · fecbdd7d-b729-41b5-9872-231b8fe104ce · 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: S1, S3, S4.
No source is stored against this line.
What is in the pack
Sold as tablet, capsule, tablet, film coated, 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.
Palbociclib appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 23252 reaction mentions were counted. One report can name several reactions.
The recorded terms (10)
fatigue — 4560 reaction mentions
white blood cell count decreased — 3283 reaction mentions
neoplasm progression — 2931 reaction mentions
neutropenia — 2834 reaction mentions
nausea — 2582 reaction mentions
alopecia — 1925 reaction mentions
diarrhoea — 1923 reaction mentions
disease progression — 1152 reaction mentions
decreased appetite — 1065 reaction mentions
stomatitis — 997 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
25 products list this as an active ingredient in the United States drug directory. 25 of them contain it and nothing else.
FDA National Drug Code directory · 60715-0188 · read 2026-08-29
They are sold as capsule, crystal, powder and tablet, film coated, taken oral.
FDA National Drug Code directory · 60715-0188 · read 2026-08-29
The regulator's established pharmacologic class for it is cytochrome p450 3a inhibitors [moa], kinase inhibitor [epc] and kinase inhibitors [moa].
FDA National Drug Code directory · 60715-0188 · read 2026-08-29
3 published labels name it as an active ingredient. 3 of them describe this substance alone, which is where its own label text on this page comes from.
US prescribing information · fecbdd7d-b729-41b5-9872-231b8fe104ce · read 2026-08-29
Those labels are classed as human prescription drug.
US prescribing information · fecbdd7d-b729-41b5-9872-231b8fe104ce · read 2026-08-29
Ibrance is oral at 3 DOSAGE FORMS AND STRENGTHS 125 mg tablets: Oval, light purple, film-coated tablets debossed with "Pfizer" on one side and "PBC 125" on the other side. 100 mg tablets: Oval, green, film-coated tablets debossed with "Pf…, recorded as fda label in effect 2026-07-02 in the United States.
US prescribing information · fecbdd7d-b729-41b5-9872-231b8fe104ce · 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 Palbociclib 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 Palbociclib 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.
How many documents were read
3 documents were read for this substance.
RNAWiki source record
3 of them state the same bioavailability, and they agree.
RNAWiki source record
3 of them state the same volumeOfDistribution, and they agree.
RNAWiki source record
Where else this substance is registered
FDA substance identifier (UNII)
G9ZF61LE7G
RxNorm concept
2284102
Checks this page had to pass
✓ Passed
Identity resolved
no open identity hold
✓ Passed
No unresolved merge across substance families
no quarantine open
✓ Passed
Every public sentence names a source
The opening statement carries the origin: Quoted from a stored source.
✗ Not passed
Trial roles classified for highlighted evidence
No registered study is classified as testing this substance.
✓ Passed
No internal keys in reader text
enforced by the copy-contract test over the rendered page
✓ Passed
Safety mode resolved
Suppression classes recorded: S1, S3, S4.
✓ 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
13 approved applications cover products containing this substance. The earliest was NDA207103, approved 20150203 to PFIZER.
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 (13)
Q2
What did Palbociclib's largest trial (6452 people) and its longest (18 years) measure?
6452 people in Palbociclib's largest registered study, 18 years in its longest registered window, measuring Progression-free survival time (PFS). ClinicalTrials.gov · 2026-09-01
150 phase2, 102 phase1, 32 phase3, 28 na or unstated, 5 early phase1, 5 na, 5 phase4; NCT05725200; 2040-12-31; no ageing endpoint recorded. Last human test completed 2026, NCT06570031.
Interpretation These counts include studies where Palbociclib 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
150
phase1
102
phase3
32
na or unstated
28
early phase1
5
na
5
2 more recorded rows
phase4
5
Last recorded human testNCT06570031
2026-04-30
recorded 2026-09-01 · last checked 2026-09-04
Q3
From mouse to human: where has Palbociclib shown lifespan?
Interpretation Progression-free survival time (PFS) — the recorded outcome words.
Show the evidence
mouse
mechanism-only
humanNCT02664935
lifespan; Progression-free survival time (PFS); 288
recorded 2026-09-01 · last checked 2026-09-04
Q4
37 of Palbociclib's trials stopped: safety, futility/efficacy, accrual/recruitment, funding/business, other?
safety (5), futility/efficacy (2), accrual/recruitment (13), funding/business (8) and other (9): Palbociclib's stop wording, clustered. ClinicalTrials.gov · 2026-09-01
"The Sponsor decided to halt the development of GDC-0810, but not due to any safety concerns."; 37 of 288 registered studies
Show the evidence
Trial
NCT01823835
terminated; "The Sponsor decided to halt the development of GDC-0810, but not due to any safety concerns."
NCT02030483
terminated; "The company providing one of the study drugs withdrew its support due to low enrollment. Therefore, we had to close the study due to lack of funding."
NCT02255461
terminated; "Data for the primary objectives is complete and the MTD identified in Stratum II."
NCT02334527
terminated; "Data from first 12 subjects-primary endpoint not met. Data analysis underway."
NCT02349633
terminated; "The study was ended for strategic reasons and changes in the external environment. The safety profile and risk benefit ratio for PF-0674775 remained unchanged."
NCT02774681
terminated; "Slow accrual"
14 further recorded trials
NCT02907918
terminated; "Futility"
NCT03065062
suspended; "Funding and drug supply to continue the study are pending."
NCT03065387
terminated; "\<75% participation"
NCT03123744
withdrawn; "No study funding available."
NCT03128619
terminated; "Insufficient accrual"
NCT03220178
terminated; "Due to COVID-19 pandemic, study cannot be finished in planned timeframe."
NCT03284957
terminated; "Sponsor decision to prematurely stop the study, not linked to any safety concern."
NCT03322215
terminated; "Slow accrual"
NCT03377101
withdrawn; "change in study design."
NCT03386929
terminated; "The SPRING trial had to be early terminated at the end of the Phase 1 portion of the study due to the absence of funding necessary for the performance of the Phase 2."
NCT03515200
terminated; "Due to departure of PI from St. Jude"
NCT03535506
terminated; "lack of accrual"
NCT03709082
terminated; "Low accrual"
NCT03878524
terminated; "Low accrual"
recorded 2026-09-01 · last checked 2026-09-04
Q5
Human studies of Palbociclib used Palbociclib 200mg — over how long?
9 recorded entries; human; also "Palbociclib 200mg", "Palbociclib 125mg", "Palbociclib 75mg"
Show the evidence
human
NCT01209598
Palbociclib 200mg
NCT01209598
Palbociclib 125mg
NCT02059330
Palbociclib 75mg
NCT02059330
Palbociclib 100mg
NCT02334800
Palbociclib 75 mg Capsule
NCT04920708
Palbociclib 75mg-125mg
3 more recorded rows
humanNCT05691400
Palbociclib 125Mg Tab
humanNCT06654297
Palbociclib(100mg)
humanNCT06654297
Palbociclib(125mg)
recorded 2026-09-01 · last checked 2026-09-04
Q6
Which of 1 year progression free survival, 2 year treatment discontinuation rate and adverse events did Palbociclib's trials measure?
1 year progression free survival, 2 year treatment discontinuation rate and adverse events lead 40 outcome terms across Palbociclib's trials. ClinicalTrials.gov · 2026-09-01
recommended phase 2 dose and schedule, progression free survival as assessed by the investigator, maximum observed plasma concentration, safety and tolerability, maximum tolerated dose and recommended phase 2 dose and 2 year treatment discontinuation rate follow.
Show the evidence
response rates
1
progression free survival at 12 weeks
1
progression free survival
1
recommended phase 2 dose and schedule
1
progression free survival as assessed by the investigator
1
maximum observed plasma concentration
1
14 more recorded rows
safety and tolerability
1
maximum tolerated dose and recommended phase 2 dose
1
2 year treatment discontinuation rate
1
part 1 change from baseline in vital signs
1
part 1 number of adverse events
1
phase i maximum tolerated dose
1
screen success rate
1
who experienced dose limiting toxicities
1
single dose apparent oral clearance
1
measurement of the proliferation marker ki67
1
adverse events
1
overall response rate
1
maximum plasma concentration
1
confirmed objective response in pf 06747775 200 qd group
1
recorded 2026-09-01 · last checked 2026-09-04
Q7
Which of Palbociclib's 112 ongoing trials reports first?
Recommended phase II dose of the combination of ibrutinib and palbociclib; Objective response rate (ORR); latest 2040-12-31
Show the evidence
Trial
NCT02159755
"Ibrutinib and Palbociclib in Treating Patients With Previously Treated Mantle Cell Lymphoma"; n 28; "Recommended phase II dose of the combination of ibrutinib and palbociclib"; 2027-04-30
NCT02465060
"Targeted Therapy Directed by Genetic Testing in Treating Patients With Advanced Refractory Solid Tumors, Lymphomas, or Multiple Myeloma (The MATCH Screening Trial)"; n 6452; "Objective response rate (ORR)"; 2026-12-31
"Neoadjuvant Response-guided Treatment of Slowly Proliferating Hormone Receptor Positive Tumors"; n 10; "Clinical and Radiological Response"; 2029-02
NCT02603679
"Neoadjuvant Response-guided Treatment of Luminal B-type Tumors and Luminal A-type Tumors With Node Metastases"; n 181; "Radiological Objective Response Rate after Completion of the First 12-week Period of Primary Medical Treatment"; 2031-12-31
NCT02605486
"Palbociclib in Combination With Bicalutamide for the Treatment of AR(+) Metastatic Breast Cancer (MBC)"; n 46; "recommended phase II dose (RP2D) (phase I)"; 2026-11
14 further recorded trials
NCT02738866
"Palbociclib With Fulvestrant for Metastatic Breast Cancer After Treatment With Palbociclib and an Aromatase Inhibitor"; n 60; "Progression-free survival"; 2026-12
NCT02764541
"Palbociclib and Endocrine Therapy for LObular Breast Cancer Preoperative Study (PELOPS)"; n 195; "Difference in Anti-proliferative Activity of Patients Given Letrozole Versus Tamoxifen During the Window Phase"; 2031-04
NCT02778685
"Pembrolizumab, Endocrine Therapy, and Palbociclib in Treating Postmenopausal Patients With Newly Diagnosed Metastatic Stage IV Estrogen Receptor Positive Breast Cancer"; n 47; "Response Rate (Complete Response or Partial Response)"; 2026-03-30
NCT02896335
"Palbociclib and Pembrolizumab In Central Nervous System Metastases"; n 45; "Intracranial Clinical Benefit Rate (Cohort 1)"; 2029-09-01
NCT02905318
"Palbociclib in Patients With Metastatic Castration-Resistant Prostate Cancer"; n 19; "Clinical benefit rate estimated by proportion of evaluable patients who had CR, PR or SD as their best response to treatment"; 2026-12-30
NCT02925234
"The Drug Rediscovery Protocol (DRUP Trial)"; n 1550; "Percentage of patients that are treated based on their molecular tumor profile"; 2027-12
NCT02942355
"Trial of Anastrozole and Palbociclib in Metastatic HER2-Negative Breast Cancer"; n 40; "Number of participants with neutropenia that leads to permanent treatment discontinuation"; 2028-06-30
NCT02947685
"Randomized, Open Label, Clinical Study of the Targeted Therapy, Palbociclib, to Treat Metastatic Breast Cancer"; n 518; "Progression-free Survival (PFS) as Assessed by Investigator"; 2026-07-31
NCT03006172
"To Evaluate the Safety, Tolerability, and Pharmacokinetics of Inavolisib Single Agent in Participants With Solid Tumors and in Combination With Endocrine and Targeted Therapies in Participants With Breast Cancer"; n 200; "Stage 1: Percentage of Participants With Dose Limiting Toxicities"; 2026-12-31
NCT03132454
"Palbociclib and Sorafenib, Decitabine, or Dexamethasone in Treating Patients With Recurrent or Refractory Leukemia"; n 32; "Maximum tolerated dose (MTD) as determined by dose limiting toxicity (DLT)"; 2027-12-31
NCT03147287
"Palbociclib After CDK and Endocrine Therapy (PACE)"; n 220; "Progression-Free Survival (PFS), According to RECIST v1.1 Criteria (Investigator Assessment)"; 2026-06-30
NCT03155620
"Targeted Therapy Directed by Genetic Testing in Treating Pediatric Patients With Relapsed or Refractory Advanced Solid Tumors, Non-Hodgkin Lymphomas, or Histiocytic Disorders (The Pediatric MATCH Screening Trial)"; n 1377; "Proportion of Pediatric Patients Whose Advanced Tumors Have Pathway Alterations That Can be Targeted by Select Anti-cancer Drugs"; 2027-01-06
NCT03297606
"Canadian Profiling and Targeted Agent Utilization Trial (CAPTUR)"; n 720; "Objective response rate defined as the number of patients with complete response or partial response"; 2027-01-31
NCT03304080
"Anastrozole, Palbociclib, Trastuzumab and Pertuzumab in HR-positive, HER2-positive Metastatic Breast"; n 44; "Dose-Limiting Toxicity (DLT)"; 2027-12-31
recorded 2026-09-01 · last checked 2026-09-04
Q8
Which running trial of Palbociclib could settle lifespan?
NCT03709680 measures Phase 2 open-label, randomized: Event-free survival (EFS) based on Investigator assessment., reading out 2025-10-18.
31 open trials; n 128; "Study Of Palbociclib Combined With Chemotherapy In Pediatric Patients With Recurrent/Refractory Solid Tumors"
Show the evidence
Trial
NCT03709680
"Study Of Palbociclib Combined With Chemotherapy In Pediatric Patients With Recurrent/Refractory Solid Tumors"; n 128; "Phase 2 open-label, randomized: Event-free survival (EFS) based on Investigator assessment."; 2025-10-18
NCT03147287
"Palbociclib After CDK and Endocrine Therapy (PACE)"; n 220; "Progression-Free Survival (PFS), According to RECIST v1.1 Criteria (Investigator Assessment)"; 2026-06-30
NCT02947685
"Randomized, Open Label, Clinical Study of the Targeted Therapy, Palbociclib, to Treat Metastatic Breast Cancer"; n 518; "Progression-free Survival (PFS) as Assessed by Investigator"; 2026-07-31
NCT03478514
"Phase II Palbociclib +Ibrutinib in Mantle Cell Lymphoma"; n 39; "Progression free survival"; 2026-08-30
NCT06338644
"Palbociclib in Metastatic Breast Cancer: Gene Polymorphism-based Study in Egyptian Patients."; n 100; "1-year Progression free survival (PFS)"; 2026-09-01
NCT02738866
"Palbociclib With Fulvestrant for Metastatic Breast Cancer After Treatment With Palbociclib and an Aromatase Inhibitor"; n 60; "Progression-free survival"; 2026-12
14 further recorded trials
NCT04605562
"Umbrella Biomarker-Guided Therapy in NPC"; n 206; "Failure-free survival (FFS)"; 2026-12
NCT06495164
"A Real-life Study to Understand the Use and Effects of Palbociclib in US Patients With Breast Cancer"; n 1; "Overall Survival (OS)"; 2026-12-30
NCT05501886
"Gedatolisib Plus Fulvestrant With or Without Palbociclib vs Standard-of-Care for the Treatment of Patients With Advanced or Metastatic HR+/HER2- Breast Cancer (VIKTORIA-1)"; n 701; "Progression Free Survival (PFS) in Patients with PIK3CA WT and PIK3CA MT Breast Cancer"; 2026-12-31
NCT06478927
"Backline Treatment of Advanced Hepatocellular Carcinoma With Palbociclib"; n 22; "Progression-free survival (PFS)"; 2027-01-15
NCT06126276
"Testing the Use of Neratinib or the Combination of Neratinib and Palbociclib Targeted Treatment for HER2+ Solid Tumors (A ComboMATCH Treatment Trial)"; n 70; "Progression free survival"; 2027-02-20
NCT05694871
"Testing the Addition of Cemiplimab to Palbociclib for the Treatment of Advanced Dedifferentiated Liposarcoma"; n 77; "Progression-free survival (PFS)"; 2027-05-31
NCT04920708
"Fulvestrant, Ipatasertib and CDK4/6 Inhibition in Metastatic ER+/HER2- Breast Cancer Patients Without ctDNA Suppression"; n 57; "Assess progression free survival (PFS)"; 2027-06
NCT04546009
"A Study Evaluating the Efficacy and Safety of Giredestrant Combined With Palbociclib Compared With Letrozole Combined With Palbociclib in Participants With Estrogen Receptor-Positive, HER2-Negative Locally Advanced or Metastatic Breast Cancer (persevERA Breast Cancer)"; n 992; "Progression-Free Survival (PFS), as Determined by the Investigator According to RECIST v1.1"; 2027-07-31
NCT03870919
"Locoregional Treatment and Palbociclib in de Novo, Treatment Naive, Stage IV ER+, HER2- Breast Cancer Patients"; n 200; "Overall survival rate in patients receiving the letrozole plus palbociclib combination plus locoregional treatment"; 2027-10-23
NCT04191499
"A Study Evaluating the Efficacy and Safety of Inavolisib + Palbociclib + Fulvestrant vs Placebo + Palbociclib + Fulvestrant in Participants With PIK3CA-Mutant, Hormone Receptor-Positive, HER2-Negative, Locally Advanced or Metastatic Breast Cancer"; n 325; "Progression-Free Survival (PFS)"; 2027-11-15
NCT04966481
"Palbociclib and Cetuximab Versus Cetuximab Monotherapy for Patients With CDKN2A-altered, HPV-unrelated Head and Neck Squamous Cell Carcinoma Who Experienced Disease Progression on a PD-1/L1 Inhibitor"; n 81; "Overall survival (OS)"; 2028-02-28
NCT05554367
"Palbociclib and Binimetinib in RAS-Mutant Cancers, A ComboMATCH Treatment Trial"; n 199; "Progression free survival (PFS) (Cohort 1)"; 2028-08-26
NCT04964934
"Phase III Study to Assess AZD9833+ CDK4/6 Inhibitor in HR+/HER2-MBC With Detectable ESR1m Before Progression (SERENA-6)"; n 315; "Progression-free survival (PFS) assessed by the Investigator as defined by response evaluation criteria in solid tumors (RECIST version 1.1)"; 2028-09-01
NCT04563507
"Combined Immunotherapies in Metastatic ER+ Breast Cancer"; n 102; "Progression free survival (PFS) will be measured"; 2028-10-31
Q9
Which 44 trials of Palbociclib posted no result?
Posted no result
44 of 44 completed trials
Registrations
NCT01953731, NCT02041273, NCT02059330, NCT02085538, NCT02065063 and NCT03285568, and 38 more
Completion dates
oldest 2014-01; newest 2024-09-02
Show the evidence
Trial
NCT01953731
2014-01
NCT02041273
2014-03
NCT02059330
2014-06
NCT02085538
2016-05
NCT02065063
2016-06-23
NCT03285568
2016-12-30
14 further recorded trials
NCT02549430
2017-02-09
NCT03220191
2017-09-26
NCT02806648
2018-01
NCT04109261
2019-09-01
NCT02530424
2019-11
NCT04524728
2020-06
NCT05141240
2020-06-15
NCT05153135
2020-07-31
NCT02400567
2020-09
NCT03184090
2020-10-27
NCT03628066
2021-01-30
NCT02022982
2021-06-30
NCT03447132
2021-07-20
NCT03965845
2021-09-24
Q10
At the median, Palbociclib's trials enrolled 71 people — anything larger?
Median enrolment
71
Largest enrolment
6452
Registered trials counted
287
Q11
What do 23252 spontaneous reports say about Palbociclib — 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.
Palbociclib appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 23252 reaction mentions were counted: fatigue 4560; white blood cell count decreased 3283; neoplasm progression 2931; neutropenia 2834. open-targets-adr · CHEMBL189963 · 2026-06-24
Show the evidence
fatigue
4560
white blood cell count decreased
3283
neoplasm progression
2931
neutropenia
2834
nausea
2582
alopecia
1925
4 more recorded rows
diarrhoea
1923
disease progression
1152
decreased appetite
1065
stomatitis
997
recorded 2026-06-24 · last checked 2026-09-04
Q12
Palbociclib and BCRP, P-GP and CYP1A2: shared by which compounds?
BCRP, P-GP and CYP1A2 appear in Palbociclib's recorded interaction sentences, 1 in all. openfda-label+europepmc · 2026-08-30
Interpretation pharmacokinetics
Show the evidence
CYP1A2pharmacokinetics
In vitro, palbociclib is not an inhibitor of CYP1A2, 2A6, 2B6, 2C8, 2C9, 2C19, and 2D6, and is not an inducer of CYP1A2, 2B6, 2C8, and 3A4 at clinically relevant concentrations.
recorded 2026-08-30 · last checked 2026-09-04
Q13
Was Palbociclib studied with fasting?
fasting is named in Palbociclib's label sentences: "The trial confirmed that the pharmacokinetic parameters of the generic and original palbociclib tablets were bioequivalent in healthy Chinese subjects under fasting conditions with rabeprazole pre-treatment." openfda-label+europepmc · 2026-08-30
1 recorded statement; fasting
Show the evidence
fasting
The trial confirmed that the pharmacokinetic parameters of the generic and original palbociclib tablets were bioequivalent in healthy Chinese subjects under fasting conditions with rabeprazole pre-treatment.
recorded 2026-08-30 · last checked 2026-09-04
Q14
What is recorded about Palbociclib and mTOR?
"In the relapsed/metastatic PDX77-TT2 model, short-term palbociclib exposure activated PI3K/mTOR signaling, whereas the combination of palbociclib and voxtalisib in long-term studies produced marked tumor suppression and extended survival." — where Palbociclib and mTOR appear together. Europe PMC · pathway abstract search · 2026-05-08
"In the relapsed/metastatic PDX77-TT2 model, short-term palbociclib exposure activated PI3K/mTOR signaling, whereas the combination of palbociclib and voxtalisib in long-term studies produced marked tumor suppression and extended survival."
senolyticPMID 41887392
"Using CRISPR/Cas9 screening, we identified MCL1 as a senolytic target to eliminate palbociclib-induced senescent CRC cells in the presence of palbociclib."
mTORPMID 41714320
"Using HR<sup>+</sup>/HER2<sup>-</sup> BC models with acquired resistance to the CDK4/6 inhibitors Palbociclib or Ribociclib, we uncovered a metabolic vulnerability in highly resistant clones, mediated by mTORC1 hyperactivation and autophagy suppression."
autophagyPMID 41714320
"Using HR<sup>+</sup>/HER2<sup>-</sup> BC models with acquired resistance to the CDK4/6 inhibitors Palbociclib or Ribociclib, we uncovered a metabolic vulnerability in highly resistant clones, mediated by mTORC1 hyperactivation and autophagy suppression."
mTORPMID 42103903
"To investigate therapeutic options, we utilized patient-derived xenograft (PDX) and tumoroid models established from PDX tumors derived from UDEC patient samples to evaluate everolimus (an mTOR inhibitor) and palbociclib (a CDK4/6 inhibitor), alone and in combination."
AMPKPMID 39617046
"Palbociclib enhanced radiotherapy susceptibility by inducing sustained DNA damage and AMPK activation."
autophagy
PMID 39865083
"Previously, we demonstrated that low doses of palbociclib activate autophagy, reversing initial G1 cell cycle arrest, while high concentrations induce off-target senescence."
PMID 39865083
"The autophagy inhibitor hydroxychloroquine (HCQ) induced on-target senescence at lower palbociclib doses."
AMPKPMID 35035775
"Knock down of ATM or the AMPK, or expression of activated mTOR significantly reduced the abilities of GZ17-6.02 and palbociclib to enhance autophagosome formation and autophagic flux."
recorded 2026-05-08 · last checked 2026-09-04
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