Trial · NCT03519178

A Study of PF-06873600 in People With Cancer

NCT03519178, Phase 1, Phase 2, Terminated, Pfizer; results first posted 2024-07-31

3 sourcestrials-2026-11-12-0.5.0

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ConductScience Library. A Study of PF-06873600 in People With Cancer. Trials, record NCT03519178. Release trials-2026-11-12-0.5.0, 12 Nov 2026. https://conductscience.org/library/trials/NCT03519178

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Trial

As registered on ClinicalTrials.gov, in the graph's capture of the registry.

Title: A Study of PF-06873600 in People With Cancer
NCT number: NCT03519178
Status: Terminated
Phases: Phase 1, Phase 2
Enrollment: 155 participants, actual
Lead sponsor: Pfizer
Conditions: HR+ HER2- Metastatic Breast Cancer, Ovarian Cancer, Fallopian Tube Cancer, Primary Peritoneal Cancer, Triple Negative Breast Cancer, Male Breast Cancer
Interventions: PF-06873600, Endocrine Therapy 1, Endocrine Therapy 2
First posted: 2018-05-08
Last updated: 2025-11-14
Results first posted: 2024-07-31

Source ClinicalTrials.gov

Registered outcomes24

Each outcome the trial registered, primary first, in ClinicalTrials.gov's words.

List	Outcome	Time frame	Description
Primary	Number of Participants With Dose Limiting Toxicities (DLTs) - Part 1	Cycle 1 (within 28 days after the first dose of study intervention)	DLT was defined as any of the following adverse events (AEs) occurring in the first cycle of treatment (28 days) which were attributable to one, the other, or both agents in the combination: Hematologic - grade(G) 4 neutropenia lasting \>7 days; Febrile neutropenia defined as an absolute neutrophil count (ANC) \<1.0 \* 10\^9/L with a single temperature of \>38.3°C, or a sustained temperature of ≥38°C, for more than 1 hour; G≥3 neutropenia with associated infection; G3 thrombocytopenia with clinically significant bleeding as indicated by ≥ G2 bleeding; G4 thrombocytopenia. Nonhematologic: Confirmed case of Drug Induced Liver Injury (DILI) (Hy's Law); G≥3 AEs that were clinically significant.
Primary	Number of Participants With Adverse Events (AEs) and Serious AEs (SAEs) - Part 1 + Part 2	Day 1 up to 28 days after the last dose of study intervention, up to approximately 24 months	An AE was defined as the appearance of (or worsening of any pre-existing) undesirable sign(s), symptom(s), or medical condition(s) that occurred after participants' signed informed consent has been obtained. An SAE was an AE resulting in any of the following outcomes: was fatal or life-threatening; resulted in persistent or significant disability/incapacity; constituted a congenital anomaly/birth defect; was medically significant; required inpatient hospitalization or prolongation of existing hospitalization. Treatment Related AEs were treatment emergent AEs with cause categorized by the investigator as related to study treatment.
Primary	Number of Participants With Worst Post-Baseline Hematology Results Based on Common Terminology Criteria for Adverse Events (CTCAE) Grade: Part 1 + Part 2	Day 1 up to 28 days after the last dose of study intervention, up to approximately 24 months	Severity was graded as NCI CTCAE version 4.03:Grade 1: asymptomatic or mild symptoms, clinical or diagnostic observations only, intervention not indicated; Grade 2: moderate, minimal, local or noninvasive intervention indicated, limiting age-appropriate instrumental activities of daily life (ADL); Grade 3: severe or medically significant but not immediately life-threatening, hospitalization or prolongation of existing hospitalization indicated, disabling, limiting self-care ADL; Grade 4: life-threatening consequence, urgent intervention indicated; Grade 5: death related to AE.
Primary	Number of Participants With Worst Post-Baseline Chemistry Results Based on Common Terminology Criteria for Adverse Events (CTCAE) Grade: Part 1 + Part 2	Day 1 up to 28 days after the last dose of study intervention, up to approximately 24 months	Severity was graded as NCI CTCAE version 4.03:Grade 1: asymptomatic or mild symptoms, clinical or diagnostic observations only, intervention not indicated; Grade 2: moderate, minimal, local or noninvasive intervention indicated, limiting age-appropriate instrumental activities of daily life (ADL); Grade 3: severe or medically significant but not immediately life-threatening, hospitalization or prolongation of existing hospitalization indicated, disabling, limiting self-care ADL; Grade 4: life-threatening consequence, urgent intervention indicated; Grade 5: death related to AE.
Primary	Number of Participants With Post-Baseline Vital Sign Abnormalities Meeting Pre-Defined Categorization - Part 1 + Part 2	Day 1 up to 28 days after the last dose of study intervention, up to approximately 24 months	Pre-defined criteria included: 1) systolic blood pressure (SBP) (mm Hg) minimum (min) value \<90; 2) SBP change from baseline (CFB) (mm Hg) maximum (max) decrease \>=30 or max increase \>=30; 3) diastolic blood pressure (DBP) (mm Hg) min \<50; 4) DBP CFB (mm Hg) max decrease \>=20 or max increase \>=20; 5) supine heart rate (HR) beats per minute (bpm) min \<40 or max \>120.
Primary	Number of Participants With Post-Baseline Electrocardiogram (ECG) Changes Meeting Pre-Defined Categorization - Part 1 + Part 2	Day 1 up to 28 days after the last dose of study intervention, up to approximately 24 months	ECG pre-defined categories for QTc interval adjusted according to Fridericia formula (QTcF) (msec) included: 450 \<= max. \<=480, 481 \<= max. \<=500, max \>=501; QTcF CFB: 30 \< max \<=60, max \>60; for PR and QRS: PR (msec): max \>=300; PR increase from baseline: Baseline \>200 and max. \>=25% increase, Baseline \<=200 and max. \>=50% increase; QRS (msec): max \>=200; QRS (msec) increase from baseline: Baseline \>100 and max. \>=25% increase, Baseline \<=100 and max. \>=50% increase. Categories, with at least 1 participant having ECG abnormality in any of the reporting arms, were reported in this outcome measure.
Primary	Overall Response Rate (ORR): Part 2	From the start of the treatment until disease/clinical progression or death or early study discontinuation, whichever happened earlier (approximately up to 24 months)	ORR: percentage of participants with confirmed complete response (CR) or partial response (PR). Response evaluation criteria in solid tumors (RECIST) v1.1: a) CR = disappearance of all non-nodal target lesions. In addition, any pathological lymph nodes assigned as target lesions that had a reduction in short axis to less than (\<) 10 millimeter (mm). Disappearance of all non-target lesions. In addition, all lymph nodes assigned a non-target lesion must be non-pathological in size (\<10 mm short axis) and b) PR = at least a 30 percent (%) decrease in the sum of diameter of all target lesions, taking as reference the baseline sum of diameters. Any radiological assessments taken more than 30 days after the last dose of study therapy or after antineoplastic agents other than study treatments taken by the participants was excluded from the best overall response derivation. Confirmation of CR or PR was to be at least 4 weeks apart from the previous radiological assessment.
Secondary	Maximum Observed Plasma Concentration (Cmax) of PF-06873600 Following a Single Oral Dose of Study Intervention on Cycle 1 Day 1 - Part 1 + Part 2	Part 1: pre-dose, 0.25, 0.5, 1, 2, 3, 4, 6, 12 hours post-dose on Cycle 1 Day 1 (C1D1); Part 2: pre-dose, 1, 2, 4, 6 hours post-dose on C1D1	The maximum observed concentration of PF-06873600 after single dose of study intervention when given as a single agent (Part 1A and Part 1C), in combination with letrozole, and in combination with fulvestrant (Part 1B and Part 2) was reported. The Cmax value was observed directly from data.
Secondary	Time to Reach Cmax at Steady State (Tmax) of PF-06873600 Following a Single Oral Dose of Study Intervention on Cycle 1 Day 1 - Part 1 + Part 2	Part 1: pre-dose, 0.25, 0.5, 1, 2, 3, 4, 6, 12 hours post-dose on C1D1; Part 2: pre-dose, 1, 2, 4, 6 hours post-dose on C1D1	Tmax of PF-06873600 after single dose of study intervention when given as a single agent (Part 1A and Part 1C), in combination with letrozole, and in combination with fulvestrant (Part 1B and Part 2) was reported.
Secondary	Area Under the Concentration-Time Profile From Time 0 to the Time of the Last Quantifiable Concentration (AUClast) of PF-06873600 Following a Single Oral Dose of Study Intervention on Cycle 1 Day 1 - Part 1	Pre-dose, 0.25, 0.5, 1, 2, 3, 4, 6, 12 hours post-dose on C1D1	AUClast of PF-06873600 after single dose of study intervention when given as a single agent (Part 1A and Part 1C), in combination with letrozole, and in combination with fulvestrant (Part 1B) was reported.

1 to 10 of 24Source ClinicalTrials.gov

See all 24 registered outcomes

Outcomes24

Each outcome the trial posted results for, in ClinicalTrials.gov's words.

Type	Outcome	Time frame	Population	Units	Measured as
PRIMARY	Number of Participants With Dose Limiting Toxicities (DLTs) - Part 1	Cycle 1 (within 28 days after the first dose of study intervention)	Analysis population consisted of all enrolled participants who received at least 1 dose of study intervention and who did not have major treatment deviations during the first cycle (ie, evaluable for the maximum tolerated dose \[MTD\]).	Participants	COUNT_OF_PARTICIPANTS
PRIMARY	Number of Participants With Adverse Events (AEs) and Serious AEs (SAEs) - Part 1 + Part 2	Day 1 up to 28 days after the last dose of study intervention, up to approximately 24 months	The safety analysis set included all enrolled participants who received at least 1 dose of study intervention.	Participants	COUNT_OF_PARTICIPANTS
PRIMARY	Number of Participants With Worst Post-Baseline Hematology Results Based on Common Terminology Criteria for Adverse Events (CTCAE) Grade: Part 1 + Part 2	Day 1 up to 28 days after the last dose of study intervention, up to approximately 24 months	The safety analysis set included all enrolled participants who received at least 1 dose of study intervention. For each laboratory parameter, only participants with evaluable laboratory results were included in the analysis.	Participants	COUNT_OF_PARTICIPANTS
PRIMARY	Number of Participants With Worst Post-Baseline Chemistry Results Based on Common Terminology Criteria for Adverse Events (CTCAE) Grade: Part 1 + Part 2	Day 1 up to 28 days after the last dose of study intervention, up to approximately 24 months	The safety analysis set included all enrolled participants who received at least 1 dose of study intervention. For each laboratory parameter, only participants with evaluable laboratory results were included in the analysis.	Participants	COUNT_OF_PARTICIPANTS
PRIMARY	Number of Participants With Post-Baseline Vital Sign Abnormalities Meeting Pre-Defined Categorization - Part 1 + Part 2	Day 1 up to 28 days after the last dose of study intervention, up to approximately 24 months	The safety analysis set included all enrolled participants who received at least 1 dose of study intervention. For each vital sign measurement, only participants with evaluable vital sign results were included in the analysis.	Participants	COUNT_OF_PARTICIPANTS
PRIMARY	Number of Participants With Post-Baseline Electrocardiogram (ECG) Changes Meeting Pre-Defined Categorization - Part 1 + Part 2	Day 1 up to 28 days after the last dose of study intervention, up to approximately 24 months	The safety analysis set included all enrolled participants who received at least 1 dose of study intervention. Only participants with evaluable ECG results were included in the analysis.	Participants	COUNT_OF_PARTICIPANTS
PRIMARY	Overall Response Rate (ORR): Part 2	From the start of the treatment until disease/clinical progression or death or early study discontinuation, whichever happened earlier (approximately up to 24 months)	For Part 2: the response evaluable population included all participants who received at least 1 dose of study treatment and had baseline disease and at least 1 post baseline disease assessment.	Percentage of participants	NUMBER
SECONDARY	Maximum Observed Plasma Concentration (Cmax) of PF-06873600 Following a Single Oral Dose of Study Intervention on Cycle 1 Day 1 - Part 1 + Part 2	Part 1: pre-dose, 0.25, 0.5, 1, 2, 3, 4, 6, 12 hours post-dose on Cycle 1 Day 1 (C1D1); Part 2: pre-dose, 1, 2, 4, 6 hours post-dose on C1D1	The PK parameter analysis population included all enrolled participants treated who had sufficient information to estimate at least 1 of the PK parameters of interest. Geometric Coefficient of Variation was not presented for parameters with participants with evaluable data \<3 at that time point. For groups where 2 participants were evaluable for the PK parameter, exact data were presented, instead of the geometric mean (geometric coefficient of variation \[CV\]).	Nanogram per milliliter	GEOMETRIC_MEAN
SECONDARY	Time to Reach Cmax at Steady State (Tmax) of PF-06873600 Following a Single Oral Dose of Study Intervention on Cycle 1 Day 1 - Part 1 + Part 2	Part 1: pre-dose, 0.25, 0.5, 1, 2, 3, 4, 6, 12 hours post-dose on C1D1; Part 2: pre-dose, 1, 2, 4, 6 hours post-dose on C1D1	The PK parameter analysis population included all enrolled participants treated who had sufficient information to estimate at least 1 of the PK parameters of interest.	Hour	MEDIAN
SECONDARY	Area Under the Concentration-Time Profile From Time 0 to the Time of the Last Quantifiable Concentration (AUClast) of PF-06873600 Following a Single Oral Dose of Study Intervention on Cycle 1 Day 1 - Part 1	Pre-dose, 0.25, 0.5, 1, 2, 3, 4, 6, 12 hours post-dose on C1D1	The PK parameter analysis population included all enrolled participants treated who had sufficient information to estimate at least 1 of the PK parameters of interest. Geometric Coefficient of Variation was not presented for parameters with participants with evaluable data \<3 at that time point. For groups where 2 participants were evaluable for the PK parameter, exact data were presented, instead of the geometric mean (geometric CV).	Hour*nanogram per milliliter	GEOMETRIC_MEAN

1 to 10 of 24Source ClinicalTrials.gov

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Results by group2,693

Each measurement the trial posted, group by group, in the words and numbers it posted.

Outcome	Group	Value	Units
Number of Participants With Dose Limiting Toxicities (DLTs) - Part 1	Part 1A PF-06873600 1 mg Twice a Day (BID)	0	Participants
Number of Participants With Dose Limiting Toxicities (DLTs) - Part 1	Part 1A PF-06873600 2 mg BID	0	Participants
Number of Participants With Dose Limiting Toxicities (DLTs) - Part 1	Part 1A PF-06873600 5 mg BID	0	Participants
Number of Participants With Dose Limiting Toxicities (DLTs) - Part 1	Part 1A PF-06873600 10 mg BID	0	Participants
Number of Participants With Dose Limiting Toxicities (DLTs) - Part 1	Part 1A PF-06873600 25 mg BID	0	Participants
Number of Participants With Dose Limiting Toxicities (DLTs) - Part 1	Part 1A PF-06873600 25 mg BID Biomarker	0	Participants
Number of Participants With Dose Limiting Toxicities (DLTs) - Part 1	Part 1A PF-06873600 35 mg BID	2	Participants
Number of Participants With Dose Limiting Toxicities (DLTs) - Part 1	Part 1A PF-06873600 35 mg Intermittent Dosing 5 Days on / 2 Days Off	0	Participants
Number of Participants With Dose Limiting Toxicities (DLTs) - Part 1	Part 1A PF-06873600 50 mg BID	4	Participants
Number of Participants With Dose Limiting Toxicities (DLTs) - Part 1	Part 1B PF-06873600 25 mg BID Immediate Release (IR)/Fulvestrant Combination	0	Participants

1 to 10 of 2,693Source ClinicalTrials.gov

See all 2,693 results by group

Participant flow225

How many started, completed or left each group, period by period.

Period	Milestone	Group	Participants
PF-06873600 Treatment	STARTED	Part 1A PF-06873600 1 mg Twice a Day (BID)	1
PF-06873600 Treatment	STARTED	Part 1A PF-06873600 2 mg BID	2
PF-06873600 Treatment	STARTED	Part 1A PF-06873600 5 mg BID	2
PF-06873600 Treatment	STARTED	Part 1A PF-06873600 10 mg BID	3
PF-06873600 Treatment	STARTED	Part 1A PF-06873600 25 mg BID	9
PF-06873600 Treatment	STARTED	Part 1A PF-06873600 25 mg BID Biomarker	7
PF-06873600 Treatment	STARTED	Part 1A PF-06873600 35 mg BID	4
PF-06873600 Treatment	STARTED	Part 1A PF-06873600 35 mg Intermittent Dosing 5 Days on / 2 Days Off	13
PF-06873600 Treatment	STARTED	Part 1A PF-06873600 50 mg BID	10
PF-06873600 Treatment	STARTED	Part 1B PF-06873600 25 mg BID Immediate Release (IR)/Fulvestrant Combination	9

1 to 10 of 225Source ClinicalTrials.gov

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Adverse events3,315

Each adverse event the trial posted, group by group: the participants affected out of those at risk.

Type	Event	Organ system	Group	Affected	At risk
other	Anaemia	Blood and lymphatic system disorders	Part 1A PF-06873600 1 mg BID	0	1
other	Anaemia	Blood and lymphatic system disorders	Part 1A PF-06873600 2 mg BID	0	2
other	Anaemia	Blood and lymphatic system disorders	Part 1A PF-06873600 5 mg BID	0	2
other	Anaemia	Blood and lymphatic system disorders	Part 1A PF-06873600 10 mg BID	0	3
other	Anaemia	Blood and lymphatic system disorders	Part 1A PF-06873600 25 mg BID	5	9
other	Anaemia	Blood and lymphatic system disorders	Part 1A PF-06873600 25 mg BID Biomarker	1	7
other	Anaemia	Blood and lymphatic system disorders	Part 1A PF-06873600 35 mg BID	4	4
other	Anaemia	Blood and lymphatic system disorders	Part 1A PF-06873600 35 mg Intermittent Dosing 5 Days on / 2 Days Off	4	13
other	Anaemia	Blood and lymphatic system disorders	Part 1A PF-06873600 50 mg BID	6	10
other	Anaemia	Blood and lymphatic system disorders	Part 1B PF-06873600 25 mg BID IR/Fulvestrant Combination	5	9

1 to 10 of 3,315Source ClinicalTrials.gov

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Adverse event totals45

The totals the trial posted for each group.

Total	Group	Affected	At risk
Total, all-cause mortality	Part 1A PF-06873600 1 mg BID	0	1
Total, all-cause mortality	Part 1A PF-06873600 2 mg BID	0	2
Total, all-cause mortality	Part 1A PF-06873600 5 mg BID	0	2
Total, all-cause mortality	Part 1A PF-06873600 10 mg BID	0	3
Total, all-cause mortality	Part 1A PF-06873600 25 mg BID	1	9
Total, all-cause mortality	Part 1A PF-06873600 25 mg BID Biomarker	0	7
Total, all-cause mortality	Part 1A PF-06873600 35 mg BID	0	4
Total, all-cause mortality	Part 1A PF-06873600 35 mg Intermittent Dosing 5 Days on / 2 Days Off	1	13
Total, all-cause mortality	Part 1A PF-06873600 50 mg BID	3	10
Total, all-cause mortality	Part 1B PF-06873600 25 mg BID IR/Fulvestrant Combination	1	9

1 to 10 of 45Source ClinicalTrials.gov

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Papers0

The papers the trial lists on ClinicalTrials.gov.

None in this release.

Grants0

The grants NIH RePORTER links to the trial, newest funded first: NIH's, and some of AHRQ's, CDC's, FDA's and VA's. Each shows its title, principal investigators, organization and funder in its newest year.

None in this release.

Trial comparisons0

Comparisons of the trial's two groups, calculated by ConductScience from the counts it posted.

None in this release.

Tests0

The ConductCognition tests this trial's registered outcomes name, as ScienceGraph matched them in trial-tests-2026-11-12-0.2.1.

None in this release.

Data dates

The day each source was copied for this release.

ClinicalTrials.gov: 2026-11-12; ClinicalTrials.gov
Results, from AACT: 2026-03-23; AACT
NIH grant links: 2026-11-13; NIH RePORTER

Sources 3

ClinicalTrials.gov's posted results, through CTTI's AACTFreely available. Acknowledgement requested
ClinicalTrials.govNo license stated
NIH RePORTER's clinical studies and project filesPublic domain

Each source's terms

ClinicalTrials.gov's posted results, through CTTI's AACTClinicalTrials.gov data via Aggregate Analysis of ClinicalTrials.gov (AACT), CTTI. CTTI makes its materials freely available and requests acknowledgement. https://aact.ctti-clinicaltrials.org/documentation/299
ClinicalTrials.govnone stated
NIH RePORTER's clinical studies and project filesPublic domain (NIH RePORTER)

ClinicalTrials.gov's data carry an international copyright outside the United States: https://clinicaltrials.gov/about-site/terms-conditions.

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