Trial Outcomes & Findings for Real-World Effectiveness of Palbociclib in Combination With an Aromatase Inhibitor (NCT NCT05361655)

NCT ID: NCT05361655

Last Updated: 2024-06-07

Results Overview

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.

Recruitment status

COMPLETED

Target enrollment

2888 participants

Primary outcome timeframe

From index date to death due to any cause or censoring date of 30-Sep-2020 (approximately up to 68 months)

Results posted on

2024-06-07

Participant Flow

Postmenopausal women or men with human epidermal growth factor receptor positive(HR+)/human epidermal growth factor receptor 2 negative(HER2-)metastatic breast cancer(MBC)who initiated first line treatment with palbociclib + aromatase inhibitor(AI)or AI alone from February 2015 through March 2020 and were registered in the Flatiron Health Analytic Database were included in the study. Participants were followed until death or study end (date of data cutoff, 30-Sep-2020), whichever occurred first.

All participants who were eligible for the retrospective database analysis were included for the study (i.e., 2888).

Participant milestones

Participant milestones
Measure
Palbociclib + Aromatase Inhibitor
Participants with HR+/HER2- MBC who initiated first line treatment with palbociclib + aromatase inhibitor between 03 Feb 2015 to 31 Mar 2020 were included and observed.
Aromatase Inhibitor
Participants with HR+/HER2- MBC who initiated first line treatment with aromatase inhibitor alone between 03 Feb 2015 to March 2020 were included and observed.
Overall Study
STARTED
1324
1564
Overall Study
COMPLETED
1324
1564
Overall Study
NOT COMPLETED
0
0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Real-World Effectiveness of Palbociclib in Combination With an Aromatase Inhibitor

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure
Palbociclib + Aromatase Inhibitor
n=1324 Participants
Participants with HR+/HER2- MBC who initiated first line treatment with palbociclib + aromatase inhibitor between 03 Feb 2015 to 31 Mar 2020 were included and observed.
Aromatase Inhibitor
n=1564 Participants
Participants with HR+/HER2- MBC who initiated first line treatment with aromatase inhibitor alone between 03 Feb 2015 to March 2020 were included and observed.
Total
n=2888 Participants
Total of all reporting groups
Age, Categorical
<=18 years
0 Participants
n=5 Participants
0 Participants
n=7 Participants
0 Participants
n=5 Participants
Age, Categorical
Between 18 and 65 years
516 Participants
n=5 Participants
416 Participants
n=7 Participants
932 Participants
n=5 Participants
Age, Categorical
>=65 years
808 Participants
n=5 Participants
1148 Participants
n=7 Participants
1956 Participants
n=5 Participants
Sex: Female, Male
Female
1314 Participants
n=5 Participants
1545 Participants
n=7 Participants
2859 Participants
n=5 Participants
Sex: Female, Male
Male
10 Participants
n=5 Participants
19 Participants
n=7 Participants
29 Participants
n=5 Participants
Race/Ethnicity, Customized
White
900 Participants
n=5 Participants
1059 Participants
n=7 Participants
1959 Participants
n=5 Participants
Race/Ethnicity, Customized
Black
107 Participants
n=5 Participants
136 Participants
n=7 Participants
243 Participants
n=5 Participants
Race/Ethnicity, Customized
Unknown
317 Participants
n=5 Participants
369 Participants
n=7 Participants
686 Participants
n=5 Participants

PRIMARY outcome

Timeframe: From index date to death due to any cause or censoring date of 30-Sep-2020 (approximately up to 68 months)

Population: FAS population comprised of all eligible participants enrolled in the study. Analysis was performed using sIPTW method to balance participant characteristics among reporting groups. sIPTW method created balanced virtual groups and hence overall number of participants analyzed was different from numbers in participant flow (not balanced).

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.

Outcome measures

Outcome measures
Measure
Palbociclib + Aromatase Inhibitor
n=1572 Participants
Participants with HR+/HER2- MBC who initiated first line treatment with palbociclib + aromatase inhibitor between 03 Feb 2015 to 31 Mar 2020 were included and observed.
Aromatase Inhibitor
n=1137 Participants
Participants with HR+/HER2- MBC who initiated first line treatment with aromatase inhibitor alone between 03 Feb 2015 to March 2020 were included and observed.
Overall Survival (OS) in Postmenopausal Female or Male Participants With Metastatic Breast Cancer
49.1 Months
Interval 45.2 to 57.7
43.2 Months
Interval 37.6 to 48.0

SECONDARY outcome

Timeframe: From index date until disease progression or death due to any cause or censoring date (approximately up to 68 months)

Population: FAS population comprised of all eligible participants enrolled in the study. Analysis was performed using sIPTW method to balance participant characteristics among reporting groups. sIPTW method created balanced virtual groups and hence overall number of participants analyzed was different from numbers in participant flow(not balanced).

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 participants with 2 or more lines of therapy or at the date of their last visit during the study period (February 2015-September 2020) for participants with only 1 line of therapy. Kaplan-Meier method adjusted by stabilized IPTW was used.

Outcome measures

Outcome measures
Measure
Palbociclib + Aromatase Inhibitor
n=1572 Participants
Participants with HR+/HER2- MBC who initiated first line treatment with palbociclib + aromatase inhibitor between 03 Feb 2015 to 31 Mar 2020 were included and observed.
Aromatase Inhibitor
n=1137 Participants
Participants with HR+/HER2- MBC who initiated first line treatment with aromatase inhibitor alone between 03 Feb 2015 to March 2020 were included and observed.
Real-World Progression Free Survival (rwPFS) in Postmenopausal Female or in Male Participants With Metastatic Breast Cancer
19.3 Months
Interval 17.5 to 20.7
13.9 Months
Interval 12.5 to 15.2

SECONDARY outcome

Timeframe: From 30 days after index treatment initiation until CR, PR, SD or PD (approximately 67 months)

Population: FAS population comprised of all eligible participants enrolled in the study. Here, 'Overall Number of Participants Analyzed' signifies participants evaluable for this outcome measure.

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 visible disease; also included cases where some lesions increased in size and some lesions decreased in size; included cases where clinician indicated progressive disease; IR=study data not available for evaluation of efficacy for any reason, including participants lost to follow-up or assessment not undertaken or death. Analysis was performed using sIPTW method to balance participant characteristics.

Outcome measures

Outcome measures
Measure
Palbociclib + Aromatase Inhibitor
n=1263 Participants
Participants with HR+/HER2- MBC who initiated first line treatment with palbociclib + aromatase inhibitor between 03 Feb 2015 to 31 Mar 2020 were included and observed.
Aromatase Inhibitor
n=988 Participants
Participants with HR+/HER2- MBC who initiated first line treatment with aromatase inhibitor alone between 03 Feb 2015 to March 2020 were included and observed.
Number of Participants According to Real-World Tumor Responses (rwTR): Postmenopausal Female or in Male Participants With Metastatic Breast Cancer
Complete response
163 Participants
86 Participants
Number of Participants According to Real-World Tumor Responses (rwTR): Postmenopausal Female or in Male Participants With Metastatic Breast Cancer
Partial response
569 Participants
300 Participants
Number of Participants According to Real-World Tumor Responses (rwTR): Postmenopausal Female or in Male Participants With Metastatic Breast Cancer
Stable disease
350 Participants
273 Participants
Number of Participants According to Real-World Tumor Responses (rwTR): Postmenopausal Female or in Male Participants With Metastatic Breast Cancer
Progressive disease
155 Participants
260 Participants
Number of Participants According to Real-World Tumor Responses (rwTR): Postmenopausal Female or in Male Participants With Metastatic Breast Cancer
Indeterminate response
26 Participants
69 Participants

SECONDARY outcome

Timeframe: From 30 days after index treatment initiation until disease progression or death due to any cause or censoring date (approximately up to 67 months)

Population: FAS population comprised of all eligible participants enrolled in the study. Here, 'Overall Number of Participants Analyzed' signifies participants evaluable for this outcome measure.

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.

Outcome measures

Outcome measures
Measure
Palbociclib + Aromatase Inhibitor
n=1263 Participants
Participants with HR+/HER2- MBC who initiated first line treatment with palbociclib + aromatase inhibitor between 03 Feb 2015 to 31 Mar 2020 were included and observed.
Aromatase Inhibitor
n=988 Participants
Participants with HR+/HER2- MBC who initiated first line treatment with aromatase inhibitor alone between 03 Feb 2015 to March 2020 were included and observed.
Real-World Response Rate (rwTR) in Postmenopausal Female or in Male Participants With Metastatic Breast Cancer
57.98 Percentage of participants
39.04 Percentage of participants

SECONDARY outcome

Timeframe: At index (anytime between 03-Feb-2015 to 31-Mar-2020, approximately up to 62 months)

Population: FAS population comprised of all eligible participants enrolled in the study.

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.

Outcome measures

Outcome measures
Measure
Palbociclib + Aromatase Inhibitor
n=1324 Participants
Participants with HR+/HER2- MBC who initiated first line treatment with palbociclib + aromatase inhibitor between 03 Feb 2015 to 31 Mar 2020 were included and observed.
Aromatase Inhibitor
Participants with HR+/HER2- MBC who initiated first line treatment with aromatase inhibitor alone between 03 Feb 2015 to March 2020 were included and observed.
Number of Participants According to Initial Dose of Palbociclib: Palbociclib + Aromatase Inhibitor Arm Only
Palbociclib 75 mg/day
48 Participants
Number of Participants According to Initial Dose of Palbociclib: Palbociclib + Aromatase Inhibitor Arm Only
Palbociclib 125 mg/day
1110 Participants
Number of Participants According to Initial Dose of Palbociclib: Palbociclib + Aromatase Inhibitor Arm Only
Palbociclib 100 mg/day
144 Participants
Number of Participants According to Initial Dose of Palbociclib: Palbociclib + Aromatase Inhibitor Arm Only
Missing
22 Participants

SECONDARY outcome

Timeframe: At index (anytime between 03-Feb-2015 to 30-Sep-2020, approximately up to 68 months)

Population: FAS population comprised of all eligible participants enrolled in the study. Here 'Overall Number of Participants Analyzed' signifies the total number of participants evaluable for this outcome measure.

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.

Outcome measures

Outcome measures
Measure
Palbociclib + Aromatase Inhibitor
n=1302 Participants
Participants with HR+/HER2- MBC who initiated first line treatment with palbociclib + aromatase inhibitor between 03 Feb 2015 to 31 Mar 2020 were included and observed.
Aromatase Inhibitor
Participants with HR+/HER2- MBC who initiated first line treatment with aromatase inhibitor alone between 03 Feb 2015 to March 2020 were included and observed.
Time to Dose Adjustment for Palbociclib- Palbociclib + Aromatase Inhibitor Arm Only
Initial dose of 125mg/day
85 Days
Interval 52.0 to 195.0
Time to Dose Adjustment for Palbociclib- Palbociclib + Aromatase Inhibitor Arm Only
Initial dose of 100mg/day
95 Days
Interval 39.0 to 236.0
Time to Dose Adjustment for Palbociclib- Palbociclib + Aromatase Inhibitor Arm Only
Initial dose of 75mg/day
112 Days
Interval 39.0 to 171.0

SECONDARY outcome

Timeframe: 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)

Population: FAS population comprised of all eligible participants enrolled in the study. sIPTW method created balanced virtual groups and hence overall number of participants analyzed was different from numbers in participant flow (not balanced).

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.

Outcome measures

Outcome measures
Measure
Palbociclib + Aromatase Inhibitor
n=1572 Participants
Participants with HR+/HER2- MBC who initiated first line treatment with palbociclib + aromatase inhibitor between 03 Feb 2015 to 31 Mar 2020 were included and observed.
Aromatase Inhibitor
n=1137 Participants
Participants with HR+/HER2- MBC who initiated first line treatment with aromatase inhibitor alone between 03 Feb 2015 to March 2020 were included and observed.
Duration of Treatment
12.3 Months
Interval 10.5 to 14.1
5.5 Months
Interval 4.7 to 6.7

SECONDARY outcome

Timeframe: From start of study treatment to start of next line of therapy (up to 68 months)

Population: FAS population comprised of all eligible participants enrolled in the study. sIPTW method created balanced virtual groups and hence overall number of participants analyzed was different from numbers in participant flow (not balanced).

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.

Outcome measures

Outcome measures
Measure
Palbociclib + Aromatase Inhibitor
n=1572 Participants
Participants with HR+/HER2- MBC who initiated first line treatment with palbociclib + aromatase inhibitor between 03 Feb 2015 to 31 Mar 2020 were included and observed.
Aromatase Inhibitor
n=1137 Participants
Participants with HR+/HER2- MBC who initiated first line treatment with aromatase inhibitor alone between 03 Feb 2015 to March 2020 were included and observed.
Time to Next Line of Treatment
18.4 Months
Interval 16.3 to 20.3
8.3 Months
Interval 7.2 to 10.2

SECONDARY outcome

Timeframe: From start of study treatment to administration of different chemotherapeutic agent (up to 68 months)

Population: FAS population comprised of all eligible participants enrolled in the study. sIPTW method created balanced virtual groups and hence overall number of participants analyzed was different from numbers in participant flow (not balanced).

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.

Outcome measures

Outcome measures
Measure
Palbociclib + Aromatase Inhibitor
n=1572 Participants
Participants with HR+/HER2- MBC who initiated first line treatment with palbociclib + aromatase inhibitor between 03 Feb 2015 to 31 Mar 2020 were included and observed.
Aromatase Inhibitor
n=1137 Participants
Participants with HR+/HER2- MBC who initiated first line treatment with aromatase inhibitor alone between 03 Feb 2015 to March 2020 were included and observed.
Time to Subsequent Chemotherapy
37.4 Months
Interval 33.7 to 40.7
29.2 Months
Interval 26.8 to 33.5

SECONDARY outcome

Timeframe: 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)

Population: FAS population comprised of all eligible participants enrolled in the study. sIPTW method created balanced virtual groups and hence overall number of participants analyzed was different from numbers in participant flow (not balanced).

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 among reporting groups.

Outcome measures

Outcome measures
Measure
Palbociclib + Aromatase Inhibitor
n=1572 Participants
Participants with HR+/HER2- MBC who initiated first line treatment with palbociclib + aromatase inhibitor between 03 Feb 2015 to 31 Mar 2020 were included and observed.
Aromatase Inhibitor
n=1137 Participants
Participants with HR+/HER2- MBC who initiated first line treatment with aromatase inhibitor alone between 03 Feb 2015 to March 2020 were included and observed.
Real-World Progression Free Survival 2 (rwPFS2) in Postmenopausal Female or in Male Participants With Metastatic Breast Cancer
32.6 Months
Interval 29.4 to 35.2
20.7 Months
Interval 18.9 to 22.6

Adverse Events

Palbociclib + Aromatase Inhibitor

Serious events: 0 serious events
Other events: 0 other events
Deaths: 420 deaths

Aromatase Inhibitor

Serious events: 0 serious events
Other events: 0 other events
Deaths: 736 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Pfizer ClinicalTrials.gov Call Center

Pfizer Inc.

Phone: 1-800-718-1021

Results disclosure agreements

  • Principal investigator is a sponsor employee Pfizer has the right to review disclosures, requesting a delay of less than 60 days. Investigator will postpone single center publications until after disclosure of pooled data (all sites), less than 12 months from study completion/termination at all participating sites. Investigator may not disclose previously undisclosed confidential information other than study results.
  • Publication restrictions are in place

Restriction type: OTHER