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PF-07220060

Phase 3

Breast Cancer | Small molecule | Oncology |Pfizer, Inc.|Last Updated: Aug 20, 2026

Target and mechanism

Target class-Ciclib (Cdk)
ModalitySmall molecule

Also known as PF-07220060 CDK4 inhibitor, Atirmociclib

Success Probability

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Market & Valuation

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Trial Design

RandomizedACTIVE_CONTROLLEDDMC
Total Trials2
Total Enrollment1,156

FDA Designations

No designations recorded

Clinical trial landscape

PF-07220060 · 7 trials · 8 indications

Phase 3 1Phase 2 2Phase 1 4
NCT06760637Study of PF-07220060 With Letrozole in Adults With HR-positive HER2-negative Breast Cancer Who Have Not Received Anticancer Treatment for Advanced/Metastatic DiseaseBreast Cancer
ACTIVE NOT_RECRUITING1,035 Analytics
PHASE3ACTIVE NOT_RECRUITING
Study of PF-07220060 With Letrozole in Adults With HR-positive HER2-negative Breast Cancer Who Have Not Received Anticancer Treatment for Advanced/Metastatic Disease
Breast CancerUnlock trial analytics

Study Endpoints

Primary Endpoints

Progression Free Survival (PFS) by BICR
From the date of randomization until disease progression or death due to any cause (up to approximately 4 years)

Time from the date of randomization to the date of the first documentation of objective progressive disease as determined by blinded independent central review (BICR) per RECIST v1.1, or death due to any cause, whichever occurs first

Percentage of Participants With Complete Cell Cycle Arrest (CCCA) at Day 14
Day 14

CCCA was determined by antigen Kiel 67 (Ki-67) value as decided by Sponsor. Ki-67 was extensively used as a prognostic and predictive biomarker for cancer diagnosis and treatment. Ki-67 expression was measured by immunohistochemistry. Assessment at Day 14 was done in blinded manner by centrally assessed biopsy.

Number of participants with dose limiting toxicities in the Dose Escalation Portion
Baseline up to day 28 of Cycle 1.

First cycle (28 days) dose limiting toxicities (Parts 1A, 1B, 1C, 1F)

Incidence of clinically significant AEs
Weekly during Cycle 1 and 2 and then every 28 days through study completion, up to approximately 24 months; Each cycle is 28 days

Adverse Events

Incidence of clinically significant laboratory assessments
Weekly during Cycle 1 and 2 (each cycle is 28 days) and then every 28 days through study completion, up to approximately 24 months

safety laboratory abnormalities

Incidence of clinically significant abnormal vital and ECG parameters
Day 1, Day 8, Day 15 of Cycle 1 and starting from Cycle 2, and then every 28 days through study completion, up to approximately 24 months (Each cycle is 28 days)

vital signs and heart rate corrected QT interval

Food Effect
Day -7 through the end of Cycle 1

Maximal Concentration, Time to Maximum Plasma Concentration, Area under the Plasma Concentration (Part 1D)

DDI
D1 to the end of Cycle 1

Maximal Concentration, Time to Maximum Plasma Concentration, Area under the Plasma Concentration (Part 1E)

Plasma PF-07220060 Maximum Observed Plasma Concentration (Cmax)
Pre-dose, 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, 8, 12, 16, 24, 36, 48, 72, 96 and 120 hours post PF-07220060 dose for Period 1; Pre-dose, 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, 8, 12, 16, 24, 36, 48, 72, 96, 120 and 144 hours post PF-07220060 dose for Period 2
Plasma PF-07220060 Area under the plasma concentration versus time curve (AUC)
Pre-dose, 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, 8, 12, 16, 24, 36, 48, 72, 96 and 120 hours post PF-07220060 dose for Period 1; Pre-dose, 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, 8, 12, 16, 24, 36, 48, 72, 96, 120 and 144 hours post PF-07220060 dose for Period 2
Area under the Plasma Concentration-Time profile from time 0 to time of last quantifiable data point (AUClast)) of test and reference atirmociclib formulations after a high fat/high calorie meal (If data does not permit AUCinf)
Pre-dose, 0, 0.5, 0.75, 1, 1.5, 2, 3, 4 ,6 , 8, 12, 16, 24, 36, 48, 72, 96, 120 hours post dose in period 1 and period 2

AUClast was area under the plasma concentration time-curve from zero (pre-dose) to the last measured concentration (If data does not permit reporting of AUCinf). The geometric coefficient of variation is expressed in percentage. The ratio (Test/Reference) of adjusted means and 90% CI are then expressed as percentages.

Area under the Plasma Concentration-Time profile (AUC) from time 0 extrapolated to extrapolated infinite time (AUCinf) of test and reference atirmociclib formulations after a high fat/high calorie meal (If data permits).
Pre-dose, 0, 0.5, 0.75, 1, 1.5, 2, 3, 4 ,6 , 8, 12, 16, 24, 36, 48, 72, 96, 120 hours post dose in period 1 and period 2

AUCinf was area under the plasma concentration versus time curve (AUC) from time zero (pre-dose) to extrapolated infinite time (0-inf , if data permits). It is obtained from AUC (0-t) plus AUC (t-inf). The geometric coefficient of variation is expressed in percentage. The ratio (Test/Reference) of adjusted means and 90% CI are then expressed as percentages.

Maximum Observed Plasma Concentration (Cmax) profile of test and reference atirmociclib formulations after a high fat/high calorie meal
Pre-dose, 0, 0.5, 0.75, 1, 1.5, 2, 3, 4 ,6 , 8, 12, 16, 24, 36, 48, 72, 96, 120 hours post dose in period 1 and period 2

Cmax was the maximum observed plasma concentration directly observed from data. The geometric coefficient of variation is expressed in percentage. The ratio (Test/Reference) of adjusted means and 90% CI are then expressed as percentages.

Percentage of Total Radiocarbon (14C) Excreted in Urine
From Predose up to 14 days post-dose

Percentage of 14C excreted in urine following 14C PF-07220060 dose administration was determined as: (total 14C urine/ 14C dose administered)\*100 where, 14C dose was administered dose of 14C PF-07220060.

Percentage of Total Radiocarbon (14C) Excreted in Feces: Cohort 1
From Predose up to 14 days post-dose

Percentage of 14C excreted in feces following 14C PF-07220060 oral dose administration was determined as: (total 14C feces/ 14C oral dose administered)\*100 where, 14C dose was administered dose of 14C PF-07220060.

Cumulative Percent Recovery of Total Radiocarbon (14C)
From Predose up to 14 days post-dose

Percentage recovery of total radioactivity (14C ) in urine and feces was determined based on total administered dose.

Percentage of Metabolite Detected in Plasma After Oral Administration of PF-07220060: Cohort 1
From Predose up to 96 hours post-dose

The percentage of five major metabolites detected in plasma after oral administration of PF-07220060: 480a, 480b, 496a, M3 and 496b are reported in this outcome measure. The processed samples were analyzed by liquid chromatography mass spectrometry- accelerator mass spectrometry (LC-MS-AMS). For calculation of metabolite percentage of total plasma radioactivity (RA), first composite time-normalized human plasma pools were prepared for each participant from plasma samples collected from 0-96 hours post-dose (i.e., a hamilton pool). Next, a multi-subject pool was created by combining equal volumes of each of the above individual participant pools. Results presented here are the single value output from these individual pooled multi-subject time-normalized samples.

Percentage of Metabolite Detected in Urine After Oral Administration of PF-07220060: Cohort 1
From Predose up to 144 hours post-dose

The percentage of five major metabolites detected in urine after oral administration of PF-07220060: 480a, 480b, 496a, M3 and 496b are reported in this outcome measure. The processed samples were analyzed by LC-MS-AMS. For calculation of percentage of metabolites, first composite time-normalized human urine pools were prepared for each participant from urine samples collected from 0-144 hours post-dose (i.e., a hamilton pool). Next, a multi-subject pool was created by combining equal volumes of each of the above individual participant pools. Results presented here are the single value output from these individual pooled multi-subject time-normalized samples.

Percentage of Metabolite Detected in Feces After Oral Administration of PF-07220060: Cohort 1
From Predose up to 196 hours post-dose

The percentage of five major metabolites detected in feces after oral administration of PF-07220060: 480a, 480b, 496a, M3 and 496b are reported in this outcome measure. The processed samples were analyzed by LC-MS-AMS. For calculation of percentage of metabolites, first composite time-normalized human fecal homogenate pools were prepared for each participant from fecal samples collected from 0-196 hours post-dose (i.e., a hamilton pool). Next, a multi-subject pool was created by combining equal volumes of each of the above individual participant pools. Results presented here are the single value output from these individual pooled multi-subject time-normalized samples.

Percentage of Metabolite Detected in Feces After IV Administration of PF-07220060: Cohort 2
From Predose up to 196 hours post-dose

The percentage of five major metabolites detected in feces after IV administration of PF-07220060: 480a, 480b, 496a, M3 and 496b are reported in this outcome measure. The processed samples were analyzed by LC-MS-AMS. For calculation of percentage of metabolites, first composite time-normalized human fecal homogenate pools were prepared for each participant from fecal samples collected from 0-196 hours post-dose (i.e., a hamilton pool). Next, a multi-subject pool was created by combining equal volumes of each of the above individual participant pools. Results presented here are the single value output from these individual pooled multi-subject time-normalized samples.

Secondary Endpoints

Overall Survival (OS)
From the date of randomization until death due to any cause (up to approximately 13 years).
Progression Free Survival (PFS) by Investigator
From the date of randomization until disease progression or death due to any cause (up to approximately 4 years)
OR by BICR and by investigator
From randomization to progression or death whichever occurs first (up to approximately 4 years)
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Study Design & Arms

AllocationRANDOMIZED
MaskingNONE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Arm AEXPERIMENTALPF-07220060 tablet taken by mouth plus Letrozole tablet taken by mouth
Arm BACTIVE_COMPARATORInvestigator's Choice of CDK4/6 inhibitor (tablet/capsule) taken by mouth with letrozole tablet taken by mouth
Arm A/Experimental/PF-07220060 plus letrozoleEXPERIMENTALPF-07220060 given as tablet by mouth twice a day for 14 days. Letrozole given as tablet by mouth once a day for 14 days.
Arm B/Control/letrozoleACTIVE_COMPARATORLetrozole given by mouth once a day for 14 days.
1A Monotherapy Escalation Arm 1EXPERIMENTALPF-07220060 Monotherapy Escalation
1A Monotherapy Escalation Arm 2EXPERIMENTALPF-07220060 Monotherapy Escalation
1A Monotherapy Escalation Arm 3EXPERIMENTALPF-07220060 Monotherapy Escalation
1A Monotherapy Escalation Arm 4EXPERIMENTALPF-07220060 Monotherapy Escalation
1B Combination Dose Finding Arm 1EXPERIMENTALPF-07220060 with Letrozole combination Escalation
1B Combination Dose Finding Arm 2EXPERIMENTALPF-07220060 with Letrozole Combination Escalation
1C Combination Dose Finding Arm 1EXPERIMENTALPF-07220060 with Fulvestrant Combination Escalation
1C Combination Dose Finding Arm 2EXPERIMENTALPF-07220060 with Fulvestrant Combination Escalation
2B Combination Dose ExpansionEXPERIMENTALPF-07220060 with Letrozole Combination Expansion
2C Combination Dose ExpansionEXPERIMENTALPF-07220060 with fulvestrant Combination Expansion
1D Monotherapy Food EffectEXPERIMENTALPF-07220060 Monotherapy Food Effect
1A Monotherapy Escalation Arm 5EXPERIMENTALPF-07220060 Monotherapy Escalation
1F Combination Dose FindingEXPERIMENTALPF-07220060 with Enzalutamide Escalation
1E DDI CohortEXPERIMENTALPF-07220060 DDI with Midazolam
2D Combination Dose ExpansionEXPERIMENTALPF-07220060 with enzalutamide Combination Expansion
2A Combination Dose ExpansionEXPERIMENTALPF-07220060 with fulvestrant combination dose expansion
2E Combination Dose ExpansionEXPERIMENTALPF-07220060 Monotherapy OR PF-07220060 plus fulvestrant combination therapy
Cohort 1, Period 1: PF-07220060EXPERIMENTALIn Cohort 1, Period 1 participants will receive a single dose of PF-07220060 tablet given orally and administered with food on Day 1.
Cohort 1, Period 2: PF-07220060 and itraconazoleEXPERIMENTALIn Cohort 1 Period 2, participants will receive oral dose of itraconazole once daily from Day 1 to Day 9. On the morning of Day 4, participants will first receive one oral dose of itraconazole followed by a single oral dose of PF-07220060 tablet
Cohort 2, Period 1: PF-07220060EXPERIMENTALIn Cohort 2, Period 1 participants will receive a single dose of PF-07220060 tablet given orally and administered with food on Day 1.
Cohort 2, Period 2: PF-07220060 probenecidEXPERIMENTALIn Cohort 2, Period 2, participants will receive oral dose of probenecid four times a day from Day 1 to Day 9. On the morning of Day 3, participants will first receive one oral dose of probenecid followed by a single oral dose of PF-07220060 tablet.
Regimen A; Treatment Sequence AEXPERIMENTALSingle Oral Dose of reference tablet formulation PF-07220060, then at least 7 day washout, followed by a single oral dose of test tablet formulation PF-07220060
Regimen B; Treatment Sequence BEXPERIMENTALSingle Oral Dose of test tablet formulation PF-07220060, then at least 7 day washout, followed by a single oral dose of reference tablet formulation PF-07220060
Period 1EXPERIMENTALSingle dose PF-07220060 alone
Period 2EXPERIMENTALSingle dose PF-07220060 given after multiple doses of carbamazepine
Cohort 1EXPERIMENTALParticipants will receive one dose of \[14C\] PF-07220060 by mouth
Cohort 2EXPERIMENTALParticipants will take one dose of PF-07220060 by mouth and one dose as an IV (intravenous) infusion of \[14C\] PF-07220060.

Interventions

NameTypeDescription
PF-07220060DRUGCDK4 inhibitor
letrozoleDRUGendocrine therapy
abemaciclibDRUGCDK4/6 inhibitor
palbociclibDRUGCDK4/6 inhibitor
ribociclibDRUGCDK4/6 inhibitor
FulvestrantCOMBINATION_PRODUCTEndocrine Therapy
MidazolamDRUGBenzodiazepine used for DDI
EnzalutamideCOMBINATION_PRODUCTAndrogen Receptor inhibitor
ItraconazoleDRUGCapsule given orally
ProbenecidDRUGTablet given orally
Carbamazepine ER TabletDRUGCarbamazepine dosing titration regimen in Period 2 from Day 1 to 18
Oral [14C]PF-07220060DRUGA single oral dose of \[14C\]PF-07220060, will be administered as a liquid formulation in Cohort 1.
Oral PF-07220060DRUGA single oral dose of PF-07220060, will be administered as a liquid formulation in Cohort 2.
IV [14C] PF-07220060DRUGA single IV infusion of \[14C\]PF-07220060 will be administered in Cohort 2 at Tmax after the administration of the unlabeled oral dose.
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites463

Inclusion Criteria: * Histological confirmation of breast cancer with evidence of locally advanced or metastatic disease, which is not amenable to surgical resection or radiation therapy with curative intent. * Documented estrogen receptor (ER) and/or progesterone receptor (PR)-positive tumor * Doc...

Countries:United StatesArgentinaAustraliaBelgiumBrazilBulgariaCanadaChinaCzechiaDenmarkFinlandFranceGermanyGreeceHungaryIndiaIrelandIsraelItalyJapanNetherlandsPolandSlovakiaSouth KoreaSpainSwedenSwitzerlandTaiwanTurkey (Türkiye)United KingdomMexico
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Competitive Landscape -Breast Cancer 402 trials

Top 20 of 92 competitors

CompanyTickerTrialsLead PhaseDrugs
AstraZeneca PLCAZN47PHASE3Fulvestrant, Capivasertib
Merck & Co., Inc.MRK12PHASE3Pembrolizumab, Paclitaxel, Doxorubicin, Epirubicin, Cyclophosphamide
Eli Lilly and CompanyLLY27PHASE3Abemaciclib, Standard Adjuvant Endocrine Therapy
BioNTech SE Sponsored ADRBNTX7PHASE3DB-1303/BNT323, T-DM1
Gilead Sciences, Inc.GILD13PHASE3Sacituzumab Govitecan-hziy, Eribulin, Capecitabine Product, Gemcitabine, Vinorelbine
Novartis AG Sponsored ADRNVS30PHASE3Ribociclib
Pfizer Inc.PFE34PHASE3ARV-471, Fulvestrant
BeOne Medicines Ltd. Sponsored ADRONC5PHASE3BGB-43395, Letrozole, Abemaciclib, Palbociclib, Ribociclib
Olema Pharmaceuticals, Inc.OLMA5PHASE3Palazestrant, Fulvestrant, Anastrozole, Letrozole, Exemestane
Jazz Pharmaceuticals Public Limited CompanyJAZZ3PHASE3Zanidatamab, Trastuzumab, Eribulin, Vinorelbine, Gemcitabine
Celcuity Inc.CELC3PHASE3Gedatolisib, Palbociclib, Fulvestrant, Alpelisib
Relay Therapeutics, Inc.RLAY2PHASE3Zovegalisib, Capivasertib, Fulvestrant
GSK plc Sponsored ADRGSK2PHASE3Niraparib
Greenwich LifeSciences, Inc.GLSI1PHASE3GLSI-100
Bristol-Myers Squibb CompanyBMY5PHASE2Iza-bren, Nab-paclitaxel, Paclitaxel, Capecitabine, Carboplatin
BriaCell Therapeutics CorpBCTX2PHASE3SV-BR-1-GM, Cyclophosphamide, Interferon infiltration of the inoculation site, Retifanlimab, Treatment of Physician's Choice
Incyte CorporationINCY4PHASE2Ruxolitinib, Capecitabine, Regorafenib
Natera, Inc.NTRA3PHASE2Discontinuation of the anti-HER2 maintenance therapy
Puma Biotechnology, Inc.PBYI3PHASE2Neratinib, Loperamide, Colesevelam
Atossa Therapeutics, Inc.ATOS1PHASE2endoxifen, goserelin
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Recent Changes (Last 90 Days)

LOWAug 20, 2026NCT04557449lastUpdatePostDate: changed
LOWAug 20, 2026NCT04557449lastUpdatePostDate: changed
MEDIUMAug 15, 2026NCT06465368TRIAL_REMOVED: changed
MEDIUMAug 15, 2026NCT06465368TRIAL_REMOVED: changed
MEDIUMAug 15, 2026NCT06465368TRIAL_REMOVED: changed

Frequently asked questions about PF-07220060

What is Atirmociclib used for?

Atirmociclib is an investigational small molecule being studied for the treatment of breast cancer, including advanced or metastatic breast cancer. It is also being evaluated in healthy participants for pharmacokinetic studies and in participants with hepatic impairment. The drug is currently in clinical development and has not been approved by regulatory authorities.

What does Atirmociclib target?

Atirmociclib is a CDK inhibitor, belonging to the -ciclib class of drugs that target cyclin-dependent kinases. Specifically, it is a CDK4 inhibitor, which means it works by inhibiting CDK4, a key regulator of cell cycle progression. This mechanism is being studied in the context of hormone receptor-positive breast cancer.

Who makes Atirmociclib?

Atirmociclib is being developed by Pfizer, Inc., a multinational pharmaceutical company listed on the New York Stock Exchange under the ticker symbol PFE. Pfizer is conducting clinical trials to evaluate the safety, tolerability, and efficacy of Atirmociclib in various patient populations.

What phase is Atirmociclib in?

Atirmociclib is in Phase 1 clinical development. While some completed trials were Phase 1 and Phase 2, the most advanced ongoing trial is a Phase 3 study. However, the drug is still investigational and has not received FDA approval. It remains in active clinical development across multiple studies.

What clinical trials is Atirmociclib in?

Atirmociclib has been studied in several clinical trials. NCT06267963 was a Phase 1 study in healthy adults, NCT06465368 was a Phase 2 study in postmenopausal women with breast cancer, NCT06760637 is an active Phase 3 study in HR-positive HER2-negative breast cancer, and NCT07130097 was a Phase 1 study comparing tablet formulations in healthy participants.

Is Atirmociclib the same as PF-07220060?

Yes, Atirmociclib is also known as PF-07220060. The drug is referred to by both names in clinical trial registries and scientific literature. Researchers and clinicians may use either name when discussing the drug, and both refer to the same investigational CDK4 inhibitor being developed by Pfizer.