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Palbociclib

Phase 3

Breast Neoplasm Female | Small molecule | Oncology |Pfizer, Inc.|Last Updated: Jun 23, 2026

Success Probability
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Trial Design
RandomizedDouble-BlindPLACEBO_CONTROLLEDDMCBiomarker
Total Trials1
Total Enrollment354
FDA Designations
No designations recorded
Clinical trial landscape

Palbociclib · 21 trials · 20 indications

Phase 3 4Phase 2 5Phase 1 12
NCT03447132Fulvestrant Versus Fulvestrant Plus Palbociclib in Operable Breast Cancer Responding to FulvestrantBreast Neoplasm Female
COMPLETED354 Analytics
NCT04966481Palbociclib 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 InhibitorHPV-unrelated Head and Neck Squamous Cell Carcinoma
RECRUITING81 Analytics
NCT02600923Palbociclib Plus Letrozole For Postmenopausal Women With HR(+) HER2(-) Advanced Breast Cancer For Whom Letrozole Is Deemed AppropriateAdvanced Breast Cancer Female
COMPLETED131 Analytics
NCT01942135Palbociclib (PD-0332991) Combined With Fulvestrant In Hormone Receptor+ HER2-Negative Metastatic Breast Cancer After Endocrine Failure (PALOMA-3)Metastatic Breast Cancer
COMPLETED521 Analytics
PHASE3COMPLETED
Fulvestrant Versus Fulvestrant Plus Palbociclib in Operable Breast Cancer Responding to Fulvestrant
Breast Neoplasm FemaleUnlock trial analytics
PHASE3RECRUITING
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
HPV-unrelated Head and Neck Squamous Cell CarcinomaUnlock trial analytics
PHASE3COMPLETED
Palbociclib Plus Letrozole For Postmenopausal Women With HR(+) HER2(-) Advanced Breast Cancer For Whom Letrozole Is Deemed Appropriate
Advanced Breast Cancer FemaleUnlock trial analytics
PHASE3COMPLETED
Palbociclib (PD-0332991) Combined With Fulvestrant In Hormone Receptor+ HER2-Negative Metastatic Breast Cancer After Endocrine Failure (PALOMA-3)
Metastatic Breast CancerUnlock trial analytics
Study Endpoints
Primary Endpoints
pCR according to Le Chevalier's classification
up to 5 years after the end of treatment period

pathological complete response will be assessed according to Le Chevalier's classification between two arms

Overall survival (OS)
Through completion of follow-up (estimated to be 15 months)

-Defined as the time from the date of treatment to the date of death, censored at the last follow-up otherwise.

Number of Participants With All-causality Treatment-emergent Adverse Events (TEAEs)
3 years

An adverse event (AE) was any untoward medical occurrence in a clinical investigation participant administered a product; the event did not need to have a causal relationship with the treatment. All AEs reported after initiation of study drug treatment were considered as TEAE. AE severity was graded according to Common Terminology Criteria for AEs (CTCAE) version 4.03. Grade 1 AEs are mild AEs; Grade 2 AEs are moderate AEs; Grade 3 AEs are severe AEs, Grade 4 AEs are life-threatening consequences and Grade 5 AEs are deaths related to AEs. Each AE was counted once for the participant in the most severe severity.

Number of Participants With Palbociclib-related TEAEs
3 years

An AE was any untoward medical occurrence in a clinical investigation participant administered a product; the event did not need to have a causal relationship with the treatment. All AEs reported after initiation of study drug treatment were considered as TEAE. AE severity was graded according to CTCAE version 4.03. Grade 1 AEs are mild AEs; Grade 2 AEs are moderate AEs; Grade 3 AEs are severe AEs, Grade 4 AEs are life-threatening consequences and Grade 5 AEs are deaths related to AEs. Palbociclib-related TEAEs were determined by the investigator.

Number of Participants With Serious Adverse Events (SAEs)
3 years

An SAE was any untoward medical occurrence at any dose that resulted in death; was life threatening; required inpatient hospitalization or prolongation of existing hospitalization; resulted in persistent or significant disability/incapacity; resulted in congenital anomaly/birth defect. AEs included both SAEs and AEs. Palbociclib-related SAEs were determined by the investigator.

Progression-Free Survival (PFS) as Assessed by the Investigator
From randomization date to date of first documentation of progression or death (assessed up to 12 months)

PFS is the time from the date of randomization to the date of the first documentation of objective progression of disease (PD)or death due to any cause in absence of documented PD. Participants lacking an evaluation of tumor response after randomization had their PFS time censored on the date of randomization with the duration of a day. Participants with documentation of PD or death after a long interval (2 or more incomplete or non-evaluable assessments) since the last tumor assessment were censored at the time of last objective assessment that did not show PD. The length of PFS was calculated as PFS time (months) =\[progression/death date(censor date) - randomization date + 1\]/30.4. Progression is defined using Response Evaluation Criteria in Solid Tumors(RECIST v1.1) a 20% increase in the sum of diameters of target lesions and the sum must also demonstrate an absolute increase of at least 5mm or unequivocal progression of existing non-target lesions or the appearance of new lesions.

Number/Percentage of Participants with Treatment-Emergent Adverse Events (AEs) Leading to Permanent Discontinuation of Study Treatment and Serious Adverse Events (SAEs)
Baseline up to 28 days after last dose of study intervention

An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. An SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. Treatment-emergent are events between first dose of study drug and up to 28 days after last dose that were absent before treatment or that worsened relative to pretreatment state.

Phase 2 open-label, randomized: Event-free survival (EFS) based on Investigator assessment.
Baseline to Month 24.

EFS is defined as the time from randomization until first event (ie, progression, recurrence following response, second malignancy or death without progression or recurrence).

Phase 1: First Cycle Dose-Limiting Toxicities (DLT)
First cycle (cycle length is approximately 21 days)

For Dose Escalation/Determination Part: DLT defined as any of the following events occurring during the first treatment cycle and considered at least possibly-related to study medication:Grade 4 neutropenia lasting greater than 7 days;Grade 4 thrombocytopenia lasting greater than 7 days or need for platelet transfusion for a platelet count of \< 20,000 per cubic millimeters twice within a 7-day period;greater than 14-day delay in the start of a subsequent course because of neutropenia or thrombocytopenia;Grade 3 or greater non-hematologic toxicities despite optimal treatment;any Grade 2 or greater non-hematologic toxicity requiring discontinuation or interruption of palbociclib for 7 or more consecutive days during the first cycle or any grade non-hematologic toxicity that delays the start of Cycle 2 by more than 14 days;clinically significant non-hematologic laboratory test abnormality Grade 3 or greater not resolving to Grade 1 or baseline within 7 days.

Phase 1: Dose Expansion Parts: Frequency of adverse events
At least 28 days after last dose

For Dose Expansion and Tumor-Specific Expansion Parts: Adverse events to be reported during treatment and for at least 28 days after last dose.

Phase 1: Dose Expansion Parts: Percentage of Participants With Complete Response or Partial Response
Through the end of treatment (up to at least 28 days after last dose)

For Dose Expansion and Tumor-Specific Expansion Parts: patients with confirmed Complete Response or Partial Response per Response Evaluation Criteria in Solid Tumors (RECIST, v.1.1) or modified Response Assessment in Neuro-Oncology (RANO) for central nervous system malignancies, or International Neuroblastoma Response Criteria (INRC) for neuroblastoma, during study treatment, assessed approximately every 2 to 4 cycles (each cycle is approximately 21 days).

Difference in Anti-proliferative Activity of Patients Given Letrozole Versus Tamoxifen During the Window Phase
baseline to day 15

Log fold change in anti-proliferative activity of Letrozole versus Tamoxifen within cohorts of hormone receptor positive breast cancer for patients with invasive lobular and ductal carcinoma during the window phase. Higher absolute value indicates larger change in the anti-proliferative activity

Pathologic Complete Response (pCR) of Patients Given Endocrine Therapy Plus Palbociclib and of Endocrine Therapy Alone During the Treatment Phase
day 15 to 24 weeks

Residual Cancer Burden index (RCB) between hormone receptor positive invasive breast cancer patients given endocrine therapy plus palbociclib (Arm C) and endocrine therapy alone (Arm D). RCB score is used to assess the response to neoadjuvant chemotherapy in breast cancer patients and is in a scale of 0 to infinity. Higher RCB score indicates more tumor burden remaining, thus worse outcome.

Number of Participants With Treatment-Emergent Adverse Events (TEAEs; All Causalities) at Phase 1
Maximum treatment duration (approximately 55 months)

An adverse event (AE) was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. Serious adverse event (SAE) was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly.

Number of Participants With Treatment-Related Adverse Events at Phase 1
Maximum treatment duration (approximately 55 months)

An AE was any untoward medical occurrence attributed to study drug in a participant who received study drug. An SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly.

Number of Participants With Dose Limiting Toxicities at Phase 1
Cycle 2 (4 weeks)

Dose limiting toxicity was defined as any of the following TEAEs occurring during the second cycle of treatment and possibly attributable to the combination of letrozole plus Palbociclib: 1. Grade 4 hematologic toxicity (including platelets \<25,000/μL, ANC \<500/μL). 2. Grade 3 neutropenia associated with a documented infection or fever ≥38.5°C. 3. Grade ≥3 non-hematologic toxicities, except those that have not been maximally treated (eg, nausea, vomiting, diarrhea, hypertension). 4. Delay by ≥1 week in receiving the next scheduled dose of either study treatment due to persisting treatment-related toxicities (platelet count \<50,000/μL; ANC \<1,000/μL; nonhematologic toxicities of Grade ≥3 severity). 5. Inability to deliver at least 80% of the planned Palbociclib or letrozole doses during Cycle 2 due to toxicity possibly attributable to the study treatment.

Progression-Free Survival (PFS) at Phase 2 - Investigator Assessment
From randomization date to date of first documentation of progression or death (assessed up to 41 months)

PFS was defined as the time from randomization (or the first dose of study treatment for non-randomized studies) to the first documentation of objective tumor progression or to death due to any cause, whichever occurred first. PFS calculated as (Weeks or Months) = (first event date minus randomization or the first dose date plus 1) divided by 7 (or 30.44 if in months). PFS is usually characterized by the median, 25% percentile,75% percentile and their 95% Confidence Intervals (CIs).

AUCinf
PK samples collected from time 0 to 120 hours post-dose

area under the plasma concentration versus time curve from time 0 to infinity

Cmax
PK samples collected from time 0 to 120 hours post-dose

maximum plasma concentration

Number of Participants With Dose Limiting Toxicities
From Day 1 until pre-dose Cycle 2 Day 1

Adverse events (AEs) considered as dose limiting toxicities (DLTs) included: hematologic: Grade 4 neutropenia lasting \>4 days; Febrile neutropenia (defined as neutropenia Grade\>=3 \[absolute neutrophil count {ANC}\<1000 cells/cubic millimeter {mm\^3}\] and a body temperature \>=38.5 \[degrees centigrade\]℃) requiring antibiotic or antifungal treatment; any Grade 4 thrombocytopenia (\<25000/mm\^3 or 25.0\*10\^9/\[liter\]L). Non-hematologic: Grade \>=3 toxicities, except those that had not been maximally treated (eg, nausea, vomiting, diarrhea). Any AE that caused a palbociclib treatment interruption of greater than 7 consecutive days or caused any combination of interruption/reduction for \>=14 days. Any AE that caused omission or reduction of at least 2 of the 3 weekly doses of nab-P.

Single-dose Pharmacokinetics (PK): Maximum Plasma Concentration (Cmax) for Palbociclib
Lead-in phase: Day 1 pre-dose, 2, 4, 6, 8, 10, 24, 48, 72, 96 and 120 hours post dose

Cmax of palbociclib in the single-dose part (lead-in phase) was observed directly from data.

Single-dose PK: Time to Reach Maximum Plasma Concentration (Tmax) for Palbociclib
Lead-in phase: Day 1 pre-dose, 2, 4, 6, 8, 10, 24, 48, 72, 96 and 120 hours post dose

Tmax for palbociclib in the single-dose part (lead-in phase) was observed directly from data as time of first occurrence.

Single-dose PK: Area Under the Plasma Concentration Versus Time Curve (AUC) From Time 0 to the Time 10 Hours (AUC10) for Palbociclib
Lead-in phase: Day 1 pre-dose, 2, 4, 6, 8, and 10 hours post dose

AUC10 for palbociclib in the single-dose part (lead-in phase) was obtained by linear/log trapezoidal method.

Single-dose PK: AUC From Time 0 to the Time 24 Hours (AUC24) for Palbociclib
Lead-in phase: Day 1 pre-dose, 2, 4, 6, 8, 10, and 24 hours post dose

AUC24 is AUCtau, where the dosing interval (tau) is 24 hours. AUC24 in the single-dose part (lead-in phase) for palbociclib was obtained by linear/log trapezoidal method.

Single-dose PK: AUC From Time 0 to the Time of Last Quantifiable Concentration (AUClast) for Palbociclib
Lead-in phase: Day 1 pre-dose, 2, 4, 6, 8, 10, 24, 48, 72, 96 and 120 hours post dose

AUClast for palbociclib in the single-dose part (lead-in phase) was obtained by linear/log trapezoidal method.

Single-dose PK: AUC From Time 0 Extrapolated to Infinite Time (AUCinf) for Palbociclib
Lead-in phase: Day 1 pre-dose, 2, 4, 6, 8, 10, 24, 48, 72, 96 and 120 hours post dose

AUCinf for palbociclib in the single-dose part (lead-in phase) was calculated as AUClast + (Clast/kel), where Clast was the predicted plasma concentration at the last quantifiable time point estimated from the log-linear regression analysis and kel was the rate constant for terminal phase obtained by linear regression of the log-linear concentration-time curve.

Single-dose PK: Rate Constant for Terminal Phase (Kel) for Palbociclib
Lead-in phase: Day 1 pre-dose, 2, 4, 6, 8, 10, 24, 48, 72, 96 and 120 hours post dose

Kel for palbociclib in the single-dose part (lead-in phase) was obtained by linear regression of the log-linear concentration-time curve.

Single-dose PK: Mean Residence Time (MRT) for Palbociclib
Lead-in phase: Day 1 pre-dose, 2, 4, 6, 8, 10, 24, 48, 72, 96 and 120 hours post dose

MRT for palbociclib in the single-dose part (lead-in phase) was calculated as AUMCinf/AUCinf, where AUMCinf was area under the first moment curve from time 0 to infinity.

Single-dose PK: Terminal Half-Life (t1/2) for Palbociclib
Lead-in phase: Day 1 pre-dose, 2, 4, 6, 8, 10, 24, 48, 72, 96 and 120 hours post dose

t1/2 for palbociclib in the single-dose part (lead-in phase) was calculated as Loge(2)/kel.

Single-dose PK: Apparent Oral Clearance (CL/F) for Palbociclib
Lead-in phase: Day 1 pre-dose, 2, 4, 6, 8, 10, 24, 48, 72, 96 and 120 hours post dose

CL/F for palbociclib in the single-dose part (lead-in phase) was calculated as Dose/AUCinf.

Single-dose PK: Apparent Volume of Distribution (Vz/F) for Palbociclib
Lead-in phase: Day 1 pre-dose, 2, 4, 6, 8, 10, 24, 48, 72, 96 and 120 hours post dose

Vz/F for palbociclib in the single-dose part (lead-in phase) was calculated as Dose/(AUCinf \* kel).

Multiple-dose PK: Maximum Plasma Concentration at Steady State (Css,Max) for Palbociclib
Cycle 1: pre-dose on Day 19, Day 20, Day 21, and 2, 4, 6, 8, 10, 24, 48, 72, 96, 120 hours post dose on Day 21

Css,max of palbociclib in the multiple-dose part (Cycle 1) was observed directly from data.

Multiple-dose PK: Minimum Plasma Concentration at Steady State (Css,Min) for Palbociclib
Cycle 1: pre-dose on Day 19, Day 20, Day 21, and 2, 4, 6, 8, 10, 24, 48, 72, 96, 120 hours post dose on Day 21

Css,min of palbociclib in the multiple-dose part (Cycle 1) was observed directly from data.

Multiple-dose PK: AUC Within a Dosing Interval of Tau (=24 Hours) at Steady State (AUCss,Tau) for Palbociclib
Cycle 1: pre-dose on Day 19, Day 20, Day 21, and 2, 4, 6, 8, 10, and 24 hours post dose on Day 21

AUCss,tau of palbociclib in the multiple-dose part (Cycle 1) was determined by linear/log trapezoidal method.

Multiple-dose PK: Average Plasma Concentration at Steady State (Css,av) for Palbociclib
Cycle 1: pre-dose on Day 19, Day 20, Day 21, and 2, 4, 6, 8, 10, and 24 hours post dose on Day 21

Css,av of palbociclib in the multiple-dose part (Cycle 1) was calculated as AUCss,tau/tau, where tau was 24 hours.

Multiple-dose PK: Time to Reach Maximum Plasma Concentration at Steady State (Tss,Max) for Palbociclib
Cycle 1: pre-dose on Day 19, Day 20, Day 21, and 2, 4, 6, 8, 10, and 24 hours post dose on Day 21

Tss,max of palbociclib in the multiple-dose part (Cycle 1) was observed directly from data as time of first occurrence within tau (=24 hours) at steady state.

Multiple-dose PK: Vz/F for Palbociclib
Cycle 1: pre-dose on Day 19, Day 20, Day 21, and 2, 4, 6, 8, 10, 24, 48, 72, 96, 120 hours post dose on Day 21

Vz/F of palbociclib in the multiple-dose part (Cycle 1) was calculated as Dose/(AUCss,tau \* kel), where AUCss,tau was the AUC within a dosing interval of tau (=24 hours) at steady state and kel was the terminal phase rate constant following multiple-dose calculated by a linear regression of the log-linear concentration-time curve.

Multiple-dose PK: t1/2 for Palbociclib
Cycle 1: pre-dose on Day 19, Day 20, Day 21, and 2, 4, 6, 8, 10, 24, 48, 72, 96, 120 hours post dose on Day 21

t1/2 of palbociclib in the multiple-dose part (Cycle 1) was calculated as ln (2)/kel, where kel was the terminal phase rate constant following multiple-dose calculated by a linear regression of the log-linear concentration-time curve.

Multiple-dose PK: CL/F for Palbociclib
Cycle 1: pre-dose on Day 19, Day 20, Day 21, and 2, 4, 6, 8, 10, and 24 hours post dose on Day 21

CL/F of palbociclib in the multiple-dose part (Cycle 1) was calculated as Dose/AUCss,tau, where AUCss,tau was the AUC within a dosing interval of tau (=24 hours) at steady state.

Multiple-dose PK: Peak to Trough Fluctuation at Steady State (PTF) for Palbociclib
Cycle 1: pre-dose on Day 19, Day 20, Day 21, and 2, 4, 6, 8, 10, 24, 48, 72, 96, 120 hours post dose on Day 21

PTF of palbociclib in the multiple-dose part (Cycle 1) was determined as (Css,max - Css,min)/Css,av. Css,max and Css,min were observed directly from data while Css,av was calculated as AUCss,tau/tau, where tau was 24 hours.

Observed Accumulation Ratio (Rac) for Palbociclib
Lead-in phase: Day 1 pre-dose, 2, 4, 6, 8, 10, and 24 hours post dose; Cycle 1: pre-dose on Day 19, Day 20, Day 21, and 2, 4, 6, 8, 10, and 24 hours post dose on Day 21

Rac of palbociclib was determined as AUCss,tau/AUCsd,tau, where AUCss,tau (tau=24 hours) was from multiple-dose part (Cycle 1) and AUCsd,tau was AUC24 from single-dose part (lead-in phase).

Steady State Accumulation Ratio (Rss) for Palbociclib
Lead-in phase: Day 1 pre-dose, 2, 4, 6, 8, 10, 24, 48, 72, 96 and 120 hours post dose; Cycle 1: pre-dose on Day 19, Day 20, Day 21, and 2, 4, 6, 8, 10, 24 hours post dose on Day 21

Rss of palbociclib was calculated as AUCss,tau/AUCinf, where AUCss,tau (tau=24 hours) was from multiple-dose part (Cycle 1) and AUCinf was from single-dose part (lead-in phase).

Area Under the Concentration-Time Curve From Time 0 Extrapolated to Infinite Time (AUCinf)
Pre-dose and 1, 2, 4, 6, 8, 12, 24, 48, 72, 96, 120 hours post-dose for all participants. Additional pharmacokinetics samples were collected from participants in hepatic impairment cohorts (Cohorts 2, 3 and 4) at 144, 168, and 192 hours post-dose.

AUCinf is area under the plasma concentration time curve from time 0 extrapolated infinite time. It is calculated as AUClast + (Clast/kel), where AUClast is area under the concentration-time curve from time 0 to the time of the last quantifiable concentration, Clast is the predicted plasma concentration at the last quantifiable time point estimated from the log-linear regression analysis, and kel is the terminal phase rate constant calculated by a linear regression of the log-linear concentration-time curve.

Maximum Plasma Concentration (Cmax)
Pre-dose and 1, 2, 4, 6, 8, 12, 24, 48, 72, 96, 120 hours post-dose for for all participants. Additional pharmacokinetics samples were collected from participants in hepatic impairment cohorts (Cohorts 2, 3 and 4) at 144, 168, and 192 hours post-dose.

Cmax is maximum plasma concentration. It is observed directly from data.

Area Under the Curve From Time Zero to Extrapolated Infinite Time [AUC (0 - 8)]
8 days

AUC (0 - 8)= Area under the plasma concentration versus time curve (AUC) from time zero (pre-dose) to extrapolated infinite time (0 - 8). It is obtained from AUC (0 - t) plus AUC (t - 8).

Maximum Observed Plasma Concentration (Cmax)
8 days
Dose-normalised Area Under the Curve From Time Zero to Extrapolated Infinite Time [AUC (0 - 8)]
0-120 hours

AUC (0 - 8)DN= Area under the plasma concentration versus time curve (AUC) from time zero (pre-dose) to extrapolated infinite time (0 - 8) divided by dose. It is obtained from AUC (0 - t) plus AUC (t - 8) all divided by the administered dose.

Dose-Normalised Maximum Observed Plasma Concentration (Cmax)
0-120 hours
Midazolam Area Under the Curve From Time Zero to Extrapolated Infinite Time [AUC (0 - 8)]
0-36hrs post midazolam dose

AUC (0 - 8)= Area under the plasma concentration versus time curve (AUC) from time zero (pre-dose) to extrapolated infinite time (0 - 8). It is obtained from AUC (0 - t) plus AUC (t - 8).

Area Under the Curve From Time Zero to Extrapolated Infinite Time [AUC (0 - 8)] of PD-0332991
0-192 hrs

AUC (0 - 8)= Area under the plasma concentration versus time curve (AUC) from time zero (pre-dose) to extrapolated infinite time (0 - 8). It is obtained from AUC (0 - t) plus AUC (t - 8).

Area Under the Curve From Time Zero to Last Quantifiable Concentration (AUClast) of PD-0332991
0-192hrs

Area under the plasma concentration time-curve from zero to the last measured concentration (AUClast)

Maximum Observed Plasma Concentration (Cmax) of PD-0332991
1-24hrs
Time to Reach Maximum Observed Plasma Concentration (Tmax) of PD-0332991
1-24hrs
Plasma Decay Half-Life (t1/2) of PD-0332991
0-192hrs

Plasma decay half-life is the time measured for the plasma concentration to decrease by one half.

Apparent Oral Clearance (CL/F) of PD-0332991
0-192hrs

Clearance of a drug is a measure of the rate at which a drug is metabolized or eliminated by normal biological processes. Clearance obtained after oral dose (apparent oral clearance) is influenced by the fraction of the dose absorbed. Clearance was estimated from population pharmacokinetic (PK) modeling. Drug clearance is a quantitative measure of the rate at which a drug substance is removed from the blood.

Apparent Volume of Distribution (Vz/F) of PD-0332991
0-192hrs

Volume of distribution is defined as the theoretical volume in which the total amount of drug would need to be uniformly distributed to produce the desired plasma concentration of a drug. Apparent volume of distribution after oral dose (Vz/F) is influenced by the fraction absorbed.

Cumulative radioactivity recovery in urine.
0-192hrs

Cumulative radioactivity recovered in urine is the percent of the administered radioactive dose that is observed in the cumulative urine samples.

Cumulative radioactivity recovery in feces.
0-192hrs

Cumulative radioactivity recovered in fecal is the percent of the administered radioactive dose that is observed in the cumulative fecal samples.

Plasma AUCinf for PD-0332991
0 hour/predose, 1, 2, 4, 6, 8, 12, 24, 48, 72, 96, and 120 hours post dose
Plasma Cmax for PD-0332991
0 hour/predose, 1, 2, 4, 6, 8, 12, 24, 48, 72, 96, and 120 hours post dose
Secondary Endpoints
pCR according to Sataloff's classification
up to 5 years after the end of treatment period
radiological response
up to 5 years after the end of treatment period
Rate of breast conservative surgery
up to 5 years after the end of treatment period
Unlock Study Endpoints
Study Design & Arms
AllocationRANDOMIZED
MaskingQUADRUPLE
ModelPARALLEL
PurposeTREATMENT
Treatment Arms
ArmTypeDescription
Fulvestrant 500mg + Palbociclib 125mgACTIVE_COMPARATOR\+ Goserelin 3.6 mg if pre or peri menopausal patient - duration 4 months
Fulvestrant 500mg + PlacebosPLACEBO_COMPARATOR\+ Goserelin 3.6 mg if pre or peri menopausal patient - duration 4 months
Arm 1: Palbociclib + CetuximabEXPERIMENTAL* Palbociclib by mouth 125 mg/daily on Days 1-21 of each 28 day cycle * Cetuximab: Initial dose 400mg/m\^2 intravenous (IV); Subsequent doses 250 mg/m\^2 IV, weekly
Arm 2: CetuximabACTIVE_COMPARATOR-Cetuximab: Initial dose 400mg/m\^2 intravenous (IV); Subsequent doses 250 mg/m\^2 IV, weekly
Palbociclib + LetrozoleEXPERIMENTALpalbociclib and letrozole combination
Arm AEXPERIMENTALGiven until objective progression, symptomatic deterioration, unacceptable toxicity, death, or withdrawal of consent, whichever occurs first.
Arm BACTIVE_COMPARATORGiven until objective progression, symptomatic deterioration, unacceptable toxicity, death, or withdrawal of consent, whichever occurs first.
Arm 1OTHERCetuximab
Arm 2EXPERIMENTALPalbociclib plus Cetuximab
Arm 3OTHERPalbociclib plus Fulvestrant
Arm 4OTHERPalbociclib plus Letrozole
Phase 2 Arm AEXPERIMENTALPalbociclib in combination with irinotecan and temozolomide.
Phase 1EXPERIMENTALPalbociclib in combination with temozolomide and irinotecan and/or with topotecan and cyclophosphamide.
Phase 2 Arm BACTIVE_COMPARATORIrinotecan and temozolomide alone.
Phase 1 Tumor specific cohort - NeuroblastomaEXPERIMENTALPalbociclib in combination with topotecan and cyclophosphamide.
Arm A Tamoxifen followed by Endocrine TherapyEXPERIMENTALTamoxifen is given in the Window of Treatment phase for 2 weeks followed by Endocrine Therapy for 24 weeks.
Arm B Letrozole Followed By Endocrine TherapyEXPERIMENTALLetrozole is given in the Window of Treatment phase for 2 weeks followed by Endocrine Therapy for 24 weeks.
Tamoxifen Followed By Endocrine Therapy and PalbociclibEXPERIMENTALTamoxifen is given in the Window of Treatment phase for 2 weeks followed by Endocrine Therapy in combination with Palbociclib for 24 weeks.
Letrozole Followed By Endocrine Therapy and PalbociclibEXPERIMENTALLetrozole is given in the Window of Treatment phase for 2 weeks followed by Endocrine Therapy in combination with Palbociclib for 24 weeks.
Palbociclib plus CetuximabEXPERIMENTALPalbociclib, 125 mg, orally once daily (QD) with food on Day 1 to Day 21 followed by 7 days off treatment in a 28-day cycle; in combination with Cetuximab, 400 mg/m2 initial dose as a 120-minute IV infusion followed by 250 mg/m2 weekly infused over 60 minutes.
Placebo plus CetuximabACTIVE_COMPARATORPlacebo orally QD with food on Day 1 to Day 21 followed by 7 days off treatment in a 28-day cycle; in combination with Cetuximab, 400 mg/m2 initial dose as a 120-minute IV infusion followed by 250 mg/m2 weekly infused over 60 minutes.
palbociclib tablet with/without PPIEXPERIMENTALpalbociclib tablet formulation alone in period 1 + palbociclib tablet formulation plus rabeprazole in period 2
Palbociclib + Nab-PaclitaxelEXPERIMENTALPalbociclib oral dosing on Days 1 to 21 of each 28-day cycle. Nab-paclitaxel IV dosing on Days -2, 6, and 13 of Cycle 1, and on Days 1, 8, and 15 of subsequent cycles.
Cohort 1EXPERIMENTALCombination therapy of palbociclib and letrozole
Healthy VolunteersEXPERIMENTALCohort of Healthy Volunteers
Mild Hepatic ImpairmentEXPERIMENTALCohort of mild hepatic impairment subjects meeting the criteria for Child-Pugh Class A
Moderate Hepatic ImpairmentEXPERIMENTALCohort of moderate hepatic impairment subjects meeting the criteria for Child-Pugh Class B
Severe Hepatic ImpairmentEXPERIMENTALCohort of severe hepatic impairment subjects meeting the criteria for Child-Pugh Class C
Normal Renal FunctionEXPERIMENTAL -
Mild Renal ImpairmentEXPERIMENTAL -
Moderate Renal ImpairmentEXPERIMENTAL -
Severe Renal ImpairmentEXPERIMENTAL -
Treatment A (Reference)OTHER -
Treatment B (Test)OTHER -
Treatment C (Test)OTHER -
Healthy Subjects of Japanese DescentEXPERIMENTALEnrolled Japanese subjects will receive four palbociclib single doses of differing dose amounts in fixed sequence over four treatment periods.
Healthy Non-Asian SubjectsEXPERIMENTALEnrolled healthy non-Asian subjects will receive a single 125mg oral dose of palbociclib in a single treatment period.
Single-Arm Fixed-SequenceEXPERIMENTALSubjects will receive two different interventions in fixed-sequence two-period study. In the first period the subjects will receive a single-dose of palbociclib. In the second period, subjects will receive 12 days of rifampin and a single dose of palbociclib on day 8. In both periods, subjects will undergo pharmacokinetic sampling at prespecified time points up to 120 hours post palbociclib dose.
Palbociclib given to Healthy VolunteersEXPERIMENTAL -
Sequence 1EXPERIMENTALSubjects randomized to Sequence 1 will receive Treatment A followed by Treatment B. Treatment A is a single 2 mg oral dose of midazolam alone. Treatment B is made up of 8 daily 125 mg oral doses of PD-0332991 and a single 2 mg oral midazolam dose on day 7 immediately after the day 7 PD-0332991 dose.
Sequence 2EXPERIMENTALSubjects randomized to Sequence 2 will receive Treatment B followed by Treatment A with a washout of no less than 14 days in between.Treatment B is made up of 8 daily 125 mg oral doses of PD-0332991 and a single 2 mg oral midazolam dose on day 7 immediately after the day 7 PD-0332991 dose. There will be a minimum washout of 14 days prior to beginning Treatment A. Treatment A is a single 2 mg oral dose of midazolam alone.
Radio-labeled Dose ArmEXPERIMENTAL -
ReferenceACTIVE_COMPARATORThis is the reference formulation
NF1EXPERIMENTALThis is a test formulation
NF2EXPERIMENTALThis is a test formulation
SOLEXPERIMENTALThis is a test formulation
Interventions
NameTypeDescription
Fulvestrant 500mgDRUGAll patients in all arms will receive Fulvestrant 500mg
Palbociclib 125mgDRUGDose reduction to 100 mg and 75 mg
Goserelin 3.6 MGDRUGOnly for pre or peri menopausal patient
PlacebosDRUGPlacebo
PalbociclibDRUGAdministered on an outpatient basis
CetuximabDRUGGiven intravenously over approximately 60 minutes
LetrozoleDRUGLetrozole will be administered orally at 2.5 mg once daily as continuous daily dosing schedule according to product labeling and in compliance with its local prescribing information.
FulvestrantDRUGFulvestrant 500 mg intramuscularly on Days 1 and 15 of Cycle 1, and then on Day 1 of each subsequent 28 day cycle.
PlaceboDRUGPlacebo orally continuously dosed for 3 weeks followed by 1 week off; repeated at each subsequent cycle.
TemozolomideDRUGPhase 1 and Phase 2: Administered at 100 mg/m2 (oral or intravenous), on days 1-5 of a 21-day cycle
IrinotecanDRUGPhase 1 and Phase 2: Administered at 50 mg/m2 (intravenous), on days 1-5 of a 21-day cycle
TopotecanDRUGPhase 1 only : Administered at 0.75 mg/m2 (intravenous), on days 1-5 of a 21-day cycle
CyclophosphamideDRUGPhase 1 only: Administered at 250 mg/m2 (intravenous), on days 1-5 of a 21-day cycle
TamoxifenDRUG -
Endocrine TherapyDRUG -
PD 0332991DRUG125 mg/d capsules orally for 3 out of 4 weeks in repeated cycles
RabeprazoleDRUGrabeprazole as PPI
Nab-PaclitaxelDRUGNab-paclitaxel IV dosing on Days -2, 6, and 13 of Cycle 1, and on Days 1, 8, and 15 of subsequent cycles.
Palbociclib 75 mg CapsuleDRUGSingle oral 75 mg dose of palbociclib followed by serial PK sampling up to 192 hours post-dose (up to 120 hours post-dose for the healthy volunteer cohort).
Palbociclib Formulation ReferenceDRUG125 mg single dose of palbociclib formulation with 16 micrometer API particle size and dissolution level 1, which is representative of the intended commercial hard gelatin capsule.
Palbociclib Formulation TestDRUG125 mg single dose of palbociclib formulation with 41 micrometer API particle size and dissolution level 1
Palbociclib 75mgDRUGIn Period 1, Japanese subjects will receive a single oral 75mg dose of palbociclib with food. Serial PK assessments will be collected over the next 120 hours.
Palbociclib 100mgDRUGIn Period 3, Japanese subjects will receive a single oral 100mg dose of palbociclib with food. Serial PK assessments will be collected over the next 120 hours.
RifampinDRUGIn period 2, subjects will receive 12 daily oral doses of 600mg of rifampin and a single 125mg oral dose of palbociclib on day 8. Subjects will undergo palbociclib pharmacokinetic sampling at prespecified time points up to 120 hours post palbociclib dose.
palbociclib capsule: phase 1 and 2 studiesDRUG125 mg dose of palbociclib. Formulation used in phase 1 and 2 studies
Palbociclib capsule: phase 3 studiesDRUG125 mg dose of palbociclib. Formulation used in phase 3 studies
Palbociclib capsule: ICHDRUG125 mg dose of palbociclib. Intended final market formulation
MidazolamDRUGTreatment A includes a single 2 mg oral dose of midazolam alone. Treatment B includes a single 2 mg oral midazolam dose on day 7 immediately after the day 7 PD-0332991 dose.
PD-0332991DRUGTreatment B includes 8 daily 125 mg oral doses of PD-0332991.
[14C]-PD-0332991RADIATIONA single 125 mg oral dose of PD-0332991 containing approximately 100 microcurie of \[14C\]-PD-0332991.
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Eligibility Criteria
Age Range18 Years to N/A
SexFEMALE
Healthy VolunteersNo
Study Sites14

Inclusion Criteria: 1. Written informed consent prior to beginning specific protocol procedures including expected cooperation of the patients for the treatment and follow-up must be obtained and documented according to the local regulatory requirements. 2. Age \>18. 3. Postmenopausal women or pre-...

Countries:AlgeriaEgyptJordanLebanonMoroccoSaudi ArabiaTunisiaUnited Arab EmiratesUnited StatesArgentinaBrazilColombiaMexicoAustraliaBelgiumCanadaGermanyIrelandItalyJapanNetherlandsPortugalRomaniaRussiaSouth KoreaTaiwanTurkey (Türkiye)UkraineUnited KingdomChinaThailandCzechiaFranceIndiaPolandSlovakiaSpainSwedenHungarySerbiaSouth Africa
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Recent Changes (Last 90 Days)
LOWMay 26, 2026NCT05226871primaryCompletionDate: changed
LOWMay 26, 2026NCT03709680primaryCompletionDate: changed
LOWMay 24, 2026NCT04966481studyFirstPostDate: changed
LOWMay 24, 2026NCT05226871studyFirstPostDate: changed
LOWMay 24, 2026NCT03709680studyFirstPostDate: changed