A Study of PF-06873600 in People With Cancer

Study at a glance

From the registry record, last updated by the sponsor on 14 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title

PHASE 1/2A DOSE ESCALATION AND EXPANSION STUDY EVALUATING SAFETY, TOLERABILITY, PHARMACOKINETIC, PHARMACODYNAMICS AND ANTI-TUMOR ACTIVITY OF PF-06873600 AS A SINGLE AGENT AND IN COMBINATION WITH ENDOCRINE THERAPY

ClinicalTrials.gov ID

NCT03519178

Acronym / sponsor ID

C3661001

Conditions

HR+ HER2- Metastatic Breast Cancer, Ovarian Cancer, Fallopian Tube Cancer, Primary Peritoneal Cancer, Triple Negative Breast Cancer, Male Breast Cancer

Keywords

Hormone Receptor (HR) Positive Breast Cancer, Estrogen receptor (ER) positive, Progesterone receptor (PR) positive, Cyclin-dependent kinase (CDK), Human epidermal growth factor receptor 2 (HER2) negative, Advanced breast cancer, Metastatic breast cancer (MBC), Triple negative breast cancer (TNBC)

Phase

Phase 1/2

Study type

Interventional

Recruitment status

TerminatedReason stopped: Per business decision, but not due to safety concerns or regulatory request.

Enrolment

155 participants (actual)

Lead sponsor

PfizerIndustry (pharma, biotech, devices)

Study start

7 Mar 2018 (actual)

Primary completion

5 Apr 2023 (actual)

Study completion

30 Oct 2024 (actual)

First posted

8 May 2018 (actual)

Results

Posted 31 Jul 2024

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Study design

Primary purpose

Treatment

Allocation

Non-randomised

Intervention model

Sequential

Masking

None (open label)

Number of arms

8

Who may qualify

Ages

18 years and older

Sex

All

Healthy volunteers

Not accepted

Age groups

Adult, Older adult

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Primary outcome

1. Number of Participants With Dose Limiting Toxicities (DLTs) - Part 1

   Time frame: 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.

2. Number of Participants With Adverse Events (AEs) and Serious AEs (SAEs) - Part 1 + Part 2

   Time frame: 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.

3. Number of Participants With Worst Post-Baseline Hematology Results Based on Common Terminology Criteria for Adverse Events (CTCAE) Grade: Part 1 + Part 2

   Time frame: 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.

4. Number of Participants With Worst Post-Baseline Chemistry Results Based on Common Terminology Criteria for Adverse Events (CTCAE) Grade: Part 1 + Part 2

   Time frame: 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.

5. Number of Participants With Post-Baseline Vital Sign Abnormalities Meeting Pre-Defined Categorization - Part 1 + Part 2

   Time frame: 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.

6. Number of Participants With Post-Baseline Electrocardiogram (ECG) Changes Meeting Pre-Defined Categorization - Part 1 + Part 2

   Time frame: 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.

7. Overall Response Rate (ORR): Part 2

   Time frame: 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.

Results and safety

Loading the posted results from ClinicalTrials.gov…

Research links

• Official record on ClinicalTrials.govLast updated by the sponsor 14 Nov 2025.
• Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
• To obtain contact information for a study center near you, click here.Link provided by the sponsor.
• Individual participant dataSharing planned: Yes. Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.

Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

54 sites in 6 countries: see every site and its status.