Metastatic Breast Cancer
Conditions
Keywords
cyclin-dependent kinase 4/6i (CDK4/6i)
Brief summary
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.
Interventions
Palbociclib + an aromatase inhibitor therapy
Aromatase inhibitor therapy
Sponsors
Study design
Eligibility
Inclusion criteria
* Confirmed HR+/HER2- status after MBC diagnosis. * Received palbociclib + AI or AI as first-line therapy
Exclusion criteria
* Evidence of prior treatment with other CDK4/6I, AI, tamoxifen, raloxifene, toremifene, or Fulvestrant for MBC * First structured activity greater than 90 days after MBC diagnostic date * Treatment with a CDK4/6 inhibitor as part of a clinical trial
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Overall Survival (OS) in Postmenopausal Female or Male Participants With Metastatic Breast Cancer | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Number of Participants According to Real-World Tumor Responses (rwTR): Postmenopausal Female or in Male Participants With Metastatic Breast Cancer | 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 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. |
| Real-World Response Rate (rwTR) in Postmenopausal Female or in Male Participants With Metastatic Breast Cancer | 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. |
| Number of Participants According to Initial Dose of Palbociclib: Palbociclib + Aromatase Inhibitor Arm Only | 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. |
| Time to Dose Adjustment for Palbociclib- Palbociclib + Aromatase Inhibitor Arm Only | 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. |
| Real-World Progression Free Survival (rwPFS) in Postmenopausal Female or in Male Participants With Metastatic Breast Cancer | 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 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. |
| Time to Next Line of Treatment | 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. |
| Time to Subsequent Chemotherapy | 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. |
| Real-World Progression Free Survival 2 (rwPFS2) in Postmenopausal Female or in Male Participants With Metastatic Breast Cancer | 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 among reporting groups. |
| Duration of Treatment | 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. |
Countries
United States
Participant flow
Recruitment details
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.
Pre-assignment details
All participants who were eligible for the retrospective database analysis were included for the study (i.e., 2888).
Participants by arm
| Arm | Count |
|---|---|
| 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. | 1,324 |
| 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. | 1,564 |
| Total | 2,888 |
Baseline characteristics
| Characteristic | Palbociclib + Aromatase Inhibitor | Aromatase Inhibitor | Total |
|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 808 Participants | 1148 Participants | 1956 Participants |
| Age, Categorical Between 18 and 65 years | 516 Participants | 416 Participants | 932 Participants |
| Race/Ethnicity, Customized Black | 107 Participants | 136 Participants | 243 Participants |
| Race/Ethnicity, Customized Unknown | 317 Participants | 369 Participants | 686 Participants |
| Race/Ethnicity, Customized White | 900 Participants | 1059 Participants | 1959 Participants |
| Sex: Female, Male Female | 1314 Participants | 1545 Participants | 2859 Participants |
| Sex: Female, Male Male | 10 Participants | 19 Participants | 29 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 420 / 1,324 | 736 / 1,564 |
| other Total, other adverse events | 0 / 0 | 0 / 0 |
| serious Total, serious adverse events | 0 / 0 | 0 / 0 |
Outcome results
Overall Survival (OS) in Postmenopausal Female or Male Participants With Metastatic Breast Cancer
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.
Time frame: 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).
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Palbociclib + Aromatase Inhibitor | Overall Survival (OS) in Postmenopausal Female or Male Participants With Metastatic Breast Cancer | 49.1 Months |
| Aromatase Inhibitor | Overall Survival (OS) in Postmenopausal Female or Male Participants With Metastatic Breast Cancer | 43.2 Months |
Duration of Treatment
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.
Time frame: 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).
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Palbociclib + Aromatase Inhibitor | Duration of Treatment | 12.3 Months |
| Aromatase Inhibitor | Duration of Treatment | 5.5 Months |
Number of Participants According to Initial Dose of Palbociclib: Palbociclib + Aromatase Inhibitor Arm Only
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.
Time frame: 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.
| Arm | Measure | Category | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Palbociclib + Aromatase Inhibitor | Number of Participants According to Initial Dose of Palbociclib: Palbociclib + Aromatase Inhibitor Arm Only | Palbociclib 75 mg/day | 48 Participants |
| Palbociclib + Aromatase Inhibitor | Number of Participants According to Initial Dose of Palbociclib: Palbociclib + Aromatase Inhibitor Arm Only | Palbociclib 125 mg/day | 1110 Participants |
| Palbociclib + Aromatase Inhibitor | Number of Participants According to Initial Dose of Palbociclib: Palbociclib + Aromatase Inhibitor Arm Only | Palbociclib 100 mg/day | 144 Participants |
| Palbociclib + Aromatase Inhibitor | Number of Participants According to Initial Dose of Palbociclib: Palbociclib + Aromatase Inhibitor Arm Only | Missing | 22 Participants |
Number of Participants According to Real-World Tumor Responses (rwTR): Postmenopausal Female or in Male Participants With Metastatic Breast Cancer
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.
Time frame: 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.
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Palbociclib + Aromatase Inhibitor | Number of Participants According to Real-World Tumor Responses (rwTR): Postmenopausal Female or in Male Participants With Metastatic Breast Cancer | Partial response | 569 Participants |
| Palbociclib + Aromatase Inhibitor | Number of Participants According to Real-World Tumor Responses (rwTR): Postmenopausal Female or in Male Participants With Metastatic Breast Cancer | Progressive disease | 155 Participants |
| Palbociclib + Aromatase Inhibitor | Number of Participants According to Real-World Tumor Responses (rwTR): Postmenopausal Female or in Male Participants With Metastatic Breast Cancer | Stable disease | 350 Participants |
| Palbociclib + Aromatase Inhibitor | Number of Participants According to Real-World Tumor Responses (rwTR): Postmenopausal Female or in Male Participants With Metastatic Breast Cancer | Indeterminate response | 26 Participants |
| Palbociclib + Aromatase Inhibitor | Number of Participants According to Real-World Tumor Responses (rwTR): Postmenopausal Female or in Male Participants With Metastatic Breast Cancer | Complete response | 163 Participants |
| Aromatase Inhibitor | Number of Participants According to Real-World Tumor Responses (rwTR): Postmenopausal Female or in Male Participants With Metastatic Breast Cancer | Indeterminate response | 69 Participants |
| Aromatase Inhibitor | Number of Participants According to Real-World Tumor Responses (rwTR): Postmenopausal Female or in Male Participants With Metastatic Breast Cancer | Complete response | 86 Participants |
| Aromatase Inhibitor | Number of Participants According to Real-World Tumor Responses (rwTR): Postmenopausal Female or in Male Participants With Metastatic Breast Cancer | Partial response | 300 Participants |
| Aromatase Inhibitor | Number of Participants According to Real-World Tumor Responses (rwTR): Postmenopausal Female or in Male Participants With Metastatic Breast Cancer | Stable disease | 273 Participants |
| Aromatase Inhibitor | Number of Participants According to Real-World Tumor Responses (rwTR): Postmenopausal Female or in Male Participants With Metastatic Breast Cancer | Progressive disease | 260 Participants |
Real-World Progression Free Survival 2 (rwPFS2) in Postmenopausal Female or in Male Participants With Metastatic Breast Cancer
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.
Time frame: 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).
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Palbociclib + Aromatase Inhibitor | Real-World Progression Free Survival 2 (rwPFS2) in Postmenopausal Female or in Male Participants With Metastatic Breast Cancer | 32.6 Months |
| Aromatase Inhibitor | Real-World Progression Free Survival 2 (rwPFS2) in Postmenopausal Female or in Male Participants With Metastatic Breast Cancer | 20.7 Months |
Real-World Progression Free Survival (rwPFS) in Postmenopausal Female or in Male Participants With Metastatic Breast Cancer
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.
Time frame: 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).
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Palbociclib + Aromatase Inhibitor | Real-World Progression Free Survival (rwPFS) in Postmenopausal Female or in Male Participants With Metastatic Breast Cancer | 19.3 Months |
| Aromatase Inhibitor | Real-World Progression Free Survival (rwPFS) in Postmenopausal Female or in Male Participants With Metastatic Breast Cancer | 13.9 Months |
Real-World Response Rate (rwTR) in Postmenopausal Female or in Male Participants With Metastatic Breast Cancer
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.
Time frame: 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.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Palbociclib + Aromatase Inhibitor | Real-World Response Rate (rwTR) in Postmenopausal Female or in Male Participants With Metastatic Breast Cancer | 57.98 Percentage of participants |
| Aromatase Inhibitor | Real-World Response Rate (rwTR) in Postmenopausal Female or in Male Participants With Metastatic Breast Cancer | 39.04 Percentage of participants |
Time to Dose Adjustment for Palbociclib- Palbociclib + Aromatase Inhibitor Arm Only
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.
Time frame: 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.
| Arm | Measure | Group | Value (MEDIAN) |
|---|---|---|---|
| Palbociclib + Aromatase Inhibitor | Time to Dose Adjustment for Palbociclib- Palbociclib + Aromatase Inhibitor Arm Only | Initial dose of 125mg/day | 85 Days |
| Palbociclib + Aromatase Inhibitor | Time to Dose Adjustment for Palbociclib- Palbociclib + Aromatase Inhibitor Arm Only | Initial dose of 100mg/day | 95 Days |
| Palbociclib + Aromatase Inhibitor | Time to Dose Adjustment for Palbociclib- Palbociclib + Aromatase Inhibitor Arm Only | Initial dose of 75mg/day | 112 Days |
Time to Next Line of Treatment
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.
Time frame: 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).
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Palbociclib + Aromatase Inhibitor | Time to Next Line of Treatment | 18.4 Months |
| Aromatase Inhibitor | Time to Next Line of Treatment | 8.3 Months |
Time to Subsequent Chemotherapy
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.
Time frame: 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).
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Palbociclib + Aromatase Inhibitor | Time to Subsequent Chemotherapy | 37.4 Months |
| Aromatase Inhibitor | Time to Subsequent Chemotherapy | 29.2 Months |