18 and older, any sex, with Metastatic Breast Cancer. Patients with the condition only — healthy volunteers not accepted.
Results — posted to ClinicalTrials.gov
Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.
Overall Survival (OS) in Postmenopausal Female or Male Participants With Metastatic Breast CancerPrimary· From index date to death due to any cause or censoring date of 30-Sep-2020 (approximately up to 68 months)
OS was defined as the time from the index date (start of palbociclib + AI or AI alone) to death. Participants who did not die, were censored at the end of study date (30-Sep-2020). Kaplan-Meier method adjusted by stabilized inverse probability of treatment weighting (sIPTW) was used.
Group
Value
95% CI
Palbociclib + Aromatase Inhibitor
49.1
45.2 – 57.7
Aromatase Inhibitor
43.2
37.6 – 48.0
Real-World Progression Free Survival (rwPFS) in Postmenopausal Female or in Male Participants With Metastatic Breast CancerSecondary· From index date until disease progression or death due to any cause or censoring date (approximately up to 68 months)
Real-world PFS was defined as the number of months from start of palbociclib + AI or AI alone to death from any cause or disease progression (based on clinical assessment or by radiographic scan/tissue biopsy), whichever occurred first. Disease progression was defined as at least a 20 percentage (%) increase in the sum of diameters of target lesions, taking as reference the smallest sum on study (this includes the baseline sum if that was the smallest on study). Participants who did not die and did not have disease progression were censored at the date of initiation of next line of therapy for
Group
Value
95% CI
Palbociclib + Aromatase Inhibitor
19.3
17.5 – 20.7
Aromatase Inhibitor
13.9
12.5 – 15.2
Number of Participants According to Real-World Tumor Responses (rwTR): Postmenopausal Female or in Male Participants With Metastatic Breast CancerSecondary· From 30 days after index treatment initiation until CR, PR, SD or PD (approximately 67 months)
Real-world best responses were assessed based on treating clinician's assessment of radiological evidence for change in burden of disease over course of treatment after 1 month of index treatment initiation. Responses were classified as complete response (CR), partial response (PR), stable disease (SD), progressive disease (PD), indeterminate response (IR). CR=Complete resolution of all visible disease. PR=partial reduction in size of visible disease in some or all areas without any areas of increase in visible disease. SD=no change in overall size of visible disease. PD: an increase in visibl
Complete response
Group
Value
95% CI
Palbociclib + Aromatase Inhibitor
163
Aromatase Inhibitor
86
Partial response
Group
Value
95% CI
Palbociclib + Aromatase Inhibitor
569
Aromatase Inhibitor
300
Stable disease
Group
Value
95% CI
Palbociclib + Aromatase Inhibitor
350
Aromatase Inhibitor
273
Progressive disease
Group
Value
95% CI
Palbociclib + Aromatase Inhibitor
155
Aromatase Inhibitor
260
Indeterminate response
Group
Value
95% CI
Palbociclib + Aromatase Inhibitor
26
Aromatase Inhibitor
69
Real-World Response Rate (rwTR) in Postmenopausal Female or in Male Participants With Metastatic Breast CancerSecondary· From 30 days after index treatment initiation until disease progression or death due to any cause or censoring date (approximately up to 67 months)
Real-world tumor response rate (rwTR) was defined as the percentage of participants with a real world complete response (rwCR) or real-world partial response (rwPR). CR: complete resolution of all visible disease. PR: partial reduction in size of visible disease in some or all areas without any areas of increase in visible disease. Analysis was performed using sIPTW method to balance participant characteristics.
Group
Value
95% CI
Palbociclib + Aromatase Inhibitor
57.98
Aromatase Inhibitor
39.04
Number of Participants According to Initial Dose of Palbociclib: Palbociclib + Aromatase Inhibitor Arm OnlySecondary· At index (anytime between 03-Feb-2015 to 31-Mar-2020, approximately up to 62 months)
Number of participants according to the initial dose of palbociclib (75 milligrams \[mg\]/day, 100mg/day, 125 mg/day or missing dose) are reported in this outcome measure.
Group
Value
95% CI
Palbociclib + Aromatase Inhibitor
48
Palbociclib + Aromatase Inhibitor
1110
Palbociclib + Aromatase Inhibitor
144
Palbociclib + Aromatase Inhibitor
22
Time to Dose Adjustment for Palbociclib- Palbociclib + Aromatase Inhibitor Arm OnlySecondary· At index (anytime between 03-Feb-2015 to 30-Sep-2020, approximately up to 68 months)
Time to dose adjustment for participants who received palbociclib 125 mg/day, 100 mg/day, or 75 mg/day as initial dose was presented in this outcome measure.
Initial dose of 125mg/day
Group
Value
95% CI
Palbociclib + Aromatase Inhibitor
85
52 – 195
Initial dose of 100mg/day
Group
Value
95% CI
Palbociclib + Aromatase Inhibitor
95
39 – 236
Initial dose of 75mg/day
Group
Value
95% CI
Palbociclib + Aromatase Inhibitor
112
39 – 171
Duration of TreatmentSecondary· From start of study treatment to end of treatment, start of subsequent line of therapy, or death from any cause, whichever occurred first (up to 68 months)
Duration of treatment was defined as days from index prescription order date to end of treatment, start of subsequent line of therapy, or death from any cause, whichever occurred first. Kaplan-Meier method adjusted by stabilized IPTW was used.
Group
Value
95% CI
Palbociclib + Aromatase Inhibitor
12.3
10.5 – 14.1
Aromatase Inhibitor
5.5
4.7 – 6.7
Time to Next Line of TreatmentSecondary· From start of study treatment to start of next line of therapy (up to 68 months)
Time to next line of treatment represents the interval from commencement of one treatment to initiation of the next line of therapy. Analysis was performed using sIPTW method to balance participant characteristics among reporting groups.
Group
Value
95% CI
Palbociclib + Aromatase Inhibitor
18.4
16.3 – 20.3
Aromatase Inhibitor
8.3
7.2 – 10.2
Time to Subsequent ChemotherapySecondary· From start of study treatment to administration of different chemotherapeutic agent (up to 68 months)
Time to subsequent chemotherapy represents the time interval to administration of a different chemotherapeutic agent after the first course of therapy was administered. Analysis was performed using sIPTW method to balance participant characteristics among reporting groups.
Group
Value
95% CI
Palbociclib + Aromatase Inhibitor
37.4
33.7 – 40.7
Aromatase Inhibitor
29.2
26.8 – 33.5
Real-World Progression Free Survival 2 (rwPFS2) in Postmenopausal Female or in Male Participants With Metastatic Breast CancerSecondary· From start of study treatment until disease progression, or death from any cause following second line of therapy, whichever occurred first (approximately up to 68 months)
rwPFS2 was defined as the time from the index date to the date of the first documentation of a rwPD or death due to any cause after starting second line of therapy, whichever occurs first. Disease progression was defined as at least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study (this includes the baseline sum if that was the smallest on study). In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. Analysis was performed using sIPTW method to balance participant characteristics
Group
Value
95% CI
Palbociclib + Aromatase Inhibitor
32.6
29.4 – 35.2
Aromatase Inhibitor
20.7
18.9 – 22.6
Sponsor's own description
A retrospective study of de-identified (to preserve patient privacy) patient information from the Flatiron Health Analytic Database to compare effectiveness (i.e., overall survival) of first line palbociclib + aromatase inhibitor (AI) versus AI alone treatment in postmenopausal women or men with hormone receptor positive/human epidermal growth factor receptor 2 negative (HR+/HER2-) metastatic breast cancer (MBC) in the United States clinical practices.
Publications & conference data
8 peer-reviewed publications reference this trial (live from Europe PMC):
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Publications: Europe PMC API search by NCT ID, retrieved 10 June 2026
Drug + disease cross-links: matched in real time against Drug Landscape's normalised drug + company + condition tables
Sponsor: as reported to ClinicalTrials.gov by Pfizer
Last refreshed: 7 June 2024
Drug Landscape aggregates and links these public records for informational use only. Always verify against the primary source before clinical or regulatory decisions. Canonical URL: https://druglandscape.com/trial/NCT05361655.