Patient Characteristics, Treatment Patterns, and Clinical Outcomes in Patients Diagnosed With HR+/HER2 Advanced/Metastatic Breast Cancer on Palbociclib + Aromatase Inhibitor (AI) Combination Therapy

Study Overview
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Brief Summary
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The study is designed to describe patient characteristics, treatment patterns, and clinical effectiveness outcomes in patients diagnosed with HR+/HER2- A/MBC who received palbociclib combination therapy with AI as first-line treatment in the US community oncology setting.

Official Title
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Patient Characteristics, Treatment Patterns, and Clinical Outcomes in Patients Diagnosed With HR+/HER2- Advanced/Metastatic Breast Cancer Receiving Palbociclib + Aromatase Inhibitor (AI) Combination Therapy as First-Line Treatment

Conditions
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Breast Cancer

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Female or male sex. Diagnosis (confirmed by clinical review) of A/MBC, defined as breast cancer at stage IIIB, stage IIIC, stage IV or identified as having distant metastasis. Age ≥18 years at A/MBC diagnosis. Initiated palbociclib in combination with an AI as first-line therapy after A/MBC diagnosis on or after 03 February 2015 through 31 July 2019. Note that the date of the start of the inclusion period reflects the month of palbociclib US FDA approval. Evidence of ER or PR positive disease, or absence of any indication of ER and PR negative disease closest to A/MBC diagnosis (ie, patients are eligible without affirmative indication of ER/PR+ status as long as ER/PR- indication is not present). Evidence of HER2 negative disease, or absence of any indication of HER2 positive disease closest to A/MBC diagnosis (ie, patients are eligible without affirmative indication of HER2- status as long as HER2+ indication is not present). Exclusion Criteria: Enrollment in an interventional clinical trial for A/MBC during the study observation period. Evidence of prior treatment with any CDK4/6 inhibitor in the adjuvant setting. Evidence of another primary cancer within 3 years prior to the initial line containing palbociclib.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Breast Cancer Patients<br>HR + /HER2- Advanced/Metastatic Breast Cancer patients in U.S.A | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of Participants With Treatment Regimen Distribution | Regimen medications were defined as systemic therapies included in line regimen based on synapse line of therapy algorithm. Treatment regimen distribution included: first-line regimen; palbociclib along with aromatase inhibitor and second-line regimen; CDK4/6 inhibitor plus endocrine and chemotherapy. Systemic anticancer treatment here refers to one or more sequential monotherapy or combination therapy regimens occurring within discrete lines of treatment, each ending with a disease progression. | From start of treatment to end of follow-up, up to a maximum of approximately 5 years | 
| Percentage of Participants With Sequence of Treatment Lines | Line of therapy was defined as line number (1; 2; 3; etc.) in the A/MBC setting assigned based on synapse line of therapy algorithm. Systemic anticancer treatment here refers to one or more sequential monotherapy or combination therapy regimens occurring within discrete lines of treatment, each ending with a disease progression. | From start of treatment to end of follow-up, up to a maximum of approximately 5 years | 
| Percentage of Participants With Their Starting Dose and End Dose | Percentage of participants with starting and end dose at 125 mg, 100 mg, 75 mg and unknown were reported. | From start of treatment to end of follow-up, up to a maximum of approximately 5 years | 
| Percentage of Participants With Type of Dose Adjustment | In this outcome measure type of dose adjustments were recorded and reported. It included dose increase, decrease, no adjustment and unknown categories. | From start of treatment to end of follow-up, up to a maximum of approximately 5 years | 
| Percentage of Participants With Their Reason For Treatment Discontinuation | Percentage of participants with discontinuation reason as progression, intolerance/toxicity, participant choice, treatment for other diseases, left health system, end of planned therapy, changes in insurance, death, hospice referral, physician choice, actionable mutation found, other/unknown were recorded and reported in this outcome measure. | From start of treatment to end of follow-up, up to a maximum of approximately 5 years | 
| Time to Dose Adjustment | Time to dose adjustment (TTDA) was defined as the time from the start of palbociclib and AI treatment until the date of treatment dose adjustment. | From start of treatment till treatment dose adjustment, up to a maximum of approximately 5 years | 
| Probability of Real-World Progression-Free Survival (rwPFS) at Month 3 | Probability of being event free (event defined as disease progression [PD] or death due to any cause) at 3 months. rwPFS was defined as the extent of time from the start of palbociclib and AI treatment until disease progression, date of death prior to initiation of the 2nd line treatment. Participants who were not indicated to be deceased at the time of analysis were censored for rwPFS analysis at the date of initiation of the 2nd line treatment, date of last contact or the end of study period whichever occurred first. Probability of participants with rwPFS at 3 months were reported in this outcome measure. Analysis was performed using Kaplan-Meier method. | 3 months after treatment initiation any time during 5 years of study period | 
| Probability of Real-World Progression-Free Survival (rwPFS) at Month 6 | Probability of being event free (event defined as PD or death due to any cause) at 6 months. rwPFS was defined as the extent of time from the start of palbociclib and AI treatment until disease progression, date of death prior to initiation of the 2nd line treatment. Participants who were not indicated to be deceased at the time of analysis were censored for rwPFS analysis at the date of initiation of the 2nd line treatment, date of last contact or the end of study period whichever occurred first. Probability of participants with rwPFS at 6 months were reported in this outcome measure. Analysis was performed using Kaplan-Meier method. | 6 months after treatment initiation any time during 5 years of study period | 
| Probability of Real-World Progression-Free Survival (rwPFS) at Month 12 | Probability of being event free (event defined as PD or death due to any cause) at 12 months. rwPFS was defined as the extent of time from the start of palbociclib and AI treatment until disease progression, date of death prior to initiation of the 2nd line treatment. Participants who were not indicated to be deceased at the time of analysis were censored for rwPFS analysis at the date of initiation of the 2nd line treatment, date of last contact or the end of study period whichever occurred first. Probability of participants with rwPFS at 12 months were reported in this outcome measure. Analysis was performed using Kaplan-Meier method. | 12 months after treatment initiation any time during 5 years of study period | 
| Probability of Real-World Progression-Free Survival (rwPFS) at Month 18 | Probability of being event free (event defined as PD or death due to any cause) at 18 months. rwPFS was defined as the extent of time from the start of palbociclib and AI treatment until disease progression, date of death prior to initiation of the 2nd line treatment. Participants who were not indicated to be deceased at the time of analysis were censored for rwPFS analysis at the date of initiation of the 2nd line treatment, date of last contact or the end of study period whichever occurred first. Probability of participants with rwPFS at 18 months were reported in this outcome measure. Analysis was performed using Kaplan-Meier method. | 18 months after treatment initiation any time during 5 years of study period | 
| Probability of Real-World Progression-Free Survival (rwPFS) at Month 24 | Probability of being event free (event defined as PD or death due to any cause) at 24 months. rwPFS was defined as the extent of time from the start of palbociclib and AI treatment until disease progression, date of death prior to initiation of the 2nd line treatment. Participants who were not indicated to be deceased at the time of analysis were censored for rwPFS analysis at the date of initiation of the 2nd line treatment, date of last contact or the end of study period whichever occurred first. Probability of participants with rwPFS at 24 months were reported in this outcome measure. Analysis was performed using Kaplan-Meier method. | 24 months after treatment initiation any time during 5 years of study period | 
| Probability of Real-World Progression-Free Survival (rwPFS) at Month 30 | Probability of being event free (event defined as PD or death due to any cause) at 30 months. rwPFS was defined as the extent of time from the start of palbociclib and AI treatment until disease progression, date of death prior to initiation of the 2nd line treatment. Participants who were not indicated to be deceased at the time of analysis were censored for rwPFS analysis at the date of initiation of the 2nd line treatment, date of last contact or the end of study period whichever occurred first. Probability of participants with rwPFS at 30 months were reported in this outcome measure. Analysis was performed using Kaplan-Meier method. | 30 months after treatment initiation any time during 5 years of study period | 
| Probability of Real-World Progression-Free Survival (rwPFS) at Month 36 | Probability of being event free (event defined as PD or death due to any cause) at 36 months. rwPFS was defined as the extent of time from the start of palbociclib and AI treatment until disease progression, date of death prior to initiation of the 2nd line treatment. Participants who were not indicated to be deceased at the time of analysis were censored for rwPFS analysis at the date of initiation of the 2nd line treatment, date of last contact or the end of study period whichever occurred first. Probability of participants with rwPFS at 36 months were reported in this outcome measure. Analysis was performed using Kaplan-Meier method. | 36 months after treatment initiation any time during 5 years of study period | 
| Probability of Real-World Overall Survival (rwOS) at Month 3 | rwOS was defined as the time from the start of palbociclib and AI treatment until the date of death, date of last contact or the end of study period. Participants who were not indicated to be deceased at the time of analysis were censored for rwOS analysis at the date of last contact or the end of study period whichever occurred first. Probability of participants with rwOS at 3 months were reported in this outcome measure. Analysis was performed using Kaplan-Meier method. | 3 months after treatment initiation any time during 5 years of study period | 
| Probability of Real-World Overall Survival (rwOS) at Month 6 | rwOS was defined as the time from the start of palbociclib and AI treatment until the date of death, date of last contact or the end of study period. Participants who were not indicated to be deceased at the time of analysis were censored for rwOS analysis at the date of last contact or the end of study period whichever occurred first. Probability of participants with rwOS at 6 months were reported in this outcome measure. Analysis was performed using Kaplan-Meier method. | 6 months after treatment initiation any time during 5 years of study period | 
| Probability of Real-World Overall Survival (rwOS) at Month 12 | rwOS was defined as the time from the start of palbociclib and AI treatment until the date of death, date of last contact or the end of study period. Participants who were not indicated to be deceased at the time of analysis were censored for rwOS analysis at the date of last contact or the end of study period whichever occurred first. Probability of participants with rwOS at 12 months were reported in this outcome measure. Analysis was performed using Kaplan-Meier method. | 12 months after treatment initiation any time during 5 years of study period | 
| Probability of Real-World Overall Survival (rwOS) at Month 18 | rwOS was defined as the time from the start of palbociclib and AI treatment until the date of death, date of last contact or the end of study period. Participants who were not indicated to be deceased at the time of analysis were censored for rwOS analysis at the date of last contact or the end of study period whichever occurred first. Probability of participants with rwOS at 18 months were reported in this outcome measure. Analysis was performed using Kaplan-Meier method. | 18 months after treatment initiation any time during 5 years of study period | 
| Probability of Real-World Overall Survival (rwOS) at Month 24 | rwOS was defined as the time from the start of palbociclib and AI treatment until the date of death, date of last contact or the end of study period. Participants who were not indicated to be deceased at the time of analysis were censored for rwOS analysis at the date of last contact or the end of study period whichever occurred first. Probability of participants with rwOS at 24 months were reported in this outcome measure. Analysis was performed using Kaplan-Meier method. | 24 months after treatment initiation any time during 5 years of study period | 
| Probability of Real-World Overall Survival (rwOS) at Month 30 | rwOS was defined as the time from the start of palbociclib and AI treatment until the date of death, date of last contact or the end of study period. Participants who were not indicated to be deceased at the time of analysis were censored for rwOS analysis at the date of last contact or the end of study period whichever occurred first. Probability of participants with rwOS at 30 months were reported in this outcome measure. Analysis was performed using Kaplan-Meier method. | 30 months after treatment initiation any time during 5 years of study period | 
| Probability of Real-World Overall Survival (rwOS) at Month 36 | rwOS was defined as the time from the start of palbociclib and AI treatment until the date of death, date of last contact or the end of study period. Participants who were not indicated to be deceased at the time of analysis were censored for rwOS analysis at the date of last contact or the end of study period whichever occurred first. Probability of participants with rwOS at 36 months were reported in this outcome measure. Analysis was performed using Kaplan-Meier method. | 36 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without First Line Treatment Discontinuation or Death at Month 3 | Probability of participants without first-line treatment discontinuation or death at month 3 were reported in this outcome measure. Real-world time to treatment discontinuation (rwTTD) was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: date the participant discontinued first-line therapy or date of death. Participant alive and without first-line therapy discontinuation were censored at the earliest of last known use of first-line therapy or end of study period. Analysis was performed using Kaplan-Meier method. | 3 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without First Line Treatment Discontinuation or Death at Month 6 | Probability of participants without first-line treatment discontinuation or death at month 6 were reported in this outcome measure. rwTTD was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: date the participant discontinued first-line therapy or date of death. Participant alive and without first-line therapy discontinuation were censored at the earliest of last known use of first-line therapy or end of study period. Analysis was performed using Kaplan-Meier method. | 6 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without First Line Treatment Discontinuation or Death at Month 12 | Probability of participants without first-line treatment discontinuation or death at month 12 were reported in this outcome measure. rwTTD was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: date the participant discontinued first-line therapy or date of death. Participant alive and without first-line therapy discontinuation were censored at the earliest of last known use of first-line therapy or end of study period. Analysis was performed using Kaplan-Meier method. | 12 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without First Line Treatment Discontinuation or Death at Month 18 | Probability of participants without first-line treatment discontinuation or death at month 18 were reported in this outcome measure. rwTTD was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: date the participant discontinued first-line therapy or date of death. Participant alive and without first-line therapy discontinuation were censored at the earliest of last known use of first-line therapy or end of study period. Analysis was performed using Kaplan-Meier method. | 18 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without First Line Treatment Discontinuation or Death at Month 24 | Probability of participants without first-line treatment discontinuation or death at month 24 were reported in this outcome measure. rwTTD was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: date the participant discontinued first-line therapy or date of death. Participant alive and without first-line therapy discontinuation were censored at the earliest of last known use of first-line therapy or end of study period. Analysis was performed using Kaplan-Meier method. | 24 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without First Line Treatment Discontinuation or Death at Month 30 | Probability of participants without first-line treatment discontinuation or death at month 30 were reported in this outcome measure. rwTTD was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: date the participant discontinued first-line therapy or date of death. Participant alive and without first-line therapy discontinuation were censored at the earliest of last known use of first-line therapy or end of study period. Analysis was performed using Kaplan-Meier method. | 30 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without First Line Treatment Discontinuation or Death at Month 36 | Probability of participants without first-line treatment discontinuation or death at month 36 were reported in this outcome measure. rwTTD was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: date the participant discontinued first-line therapy or date of death. Participant alive and without first-line therapy discontinuation were censored at the earliest of last known use of first-line therapy or end of study period. Analysis was performed using Kaplan-Meier method. | 36 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without Subsequent Line of Therapy Initiation or Death at Month 3 | Probability of participants without subsequent line of therapy initiation or death at month 3 were reported in this outcome measure. Real-world time to next treatment (rwTTNT) was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: start of subsequent line of treatment, date of death, date of last contact or the end of study period. Participant alive and without subsequent line of therapy initiation were censored at the earliest of the following events: date of last contact or end of the study period. Analysis was performed using Kaplan-Meier method. | 3 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without Subsequent Line of Therapy Initiation or Death at Month 6 | Probability of participants without subsequent line of therapy initiation or death at month 6 were reported in this outcome measure. rwTTNT was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: start of subsequent line of treatment, date of death, date of last contact or the end of study period. Participant alive and without subsequent line of therapy initiation were censored at the earliest of the following events: date of last contact or end of the study period. Analysis was performed using Kaplan-Meier method. | 6 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without Subsequent Line of Therapy Initiation or Death at Month 12 | Probability of participants without subsequent line of therapy initiation or death at month 12 were reported in this outcome measure. rwTTNT was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: start of subsequent line of treatment, date of death, date of last contact or the end of study period. Participant alive and without subsequent line of therapy initiation were censored at the earliest of the following events: date of last contact or end of the study period. Analysis was performed using Kaplan-Meier method. | 12 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without Subsequent Line of Therapy Initiation or Death at Month 18 | Probability of participants without subsequent line of therapy initiation or death at month 18 were reported in this outcome measure. rwTTNT was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: start of subsequent line of treatment, date of death, date of last contact or the end of study period. Participant alive and without subsequent line of therapy initiation were censored at the earliest of the following events: date of last contact or end of the study period. Analysis was performed using Kaplan-Meier method. | 18 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without Subsequent Line of Therapy Initiation or Death at Month 24 | Probability of participants without subsequent line of therapy initiation or death at month 24 were reported in this outcome measure. rwTTNT was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: start of subsequent line of treatment, date of death, date of last contact or the end of study period. Participant alive and without subsequent line of therapy initiation were censored at the earliest of the following events: date of last contact or end of the study period. Analysis was performed using Kaplan-Meier method. | 24 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without Subsequent Line of Therapy Initiation or Death at Month 30 | Probability of participants without subsequent line of therapy initiation or death at month 30 were reported in this outcome measure. rwTTNT was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: start of subsequent line of treatment, date of death, date of last contact or the end of study period. Participant alive and without subsequent line of therapy initiation were censored at the earliest of the following events: date of last contact or end of the study period. Analysis was performed using Kaplan-Meier method. | 30 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without Subsequent Line of Therapy Initiation or Death at Month 36 | Probability of participants without subsequent line of therapy initiation or death at month 36 were reported in this outcome measure. rwTTNT was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: start of subsequent line of treatment, date of death, date of last contact or the end of study period. Participant alive and without subsequent line of therapy initiation were censored at the earliest of the following events: date of last contact or end of the study period. Analysis was performed using Kaplan-Meier method. | 36 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without Subsequent Chemotherapy or Death at Month 3 | Probability of participants without subsequent chemotherapy or death at month 3 were reported in this outcome measure. Real-world time to chemotherapy (rwTTC) was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: start of subsequent chemotherapy or date of death. Participant alive and without subsequent chemotherapy were censored at the earliest of the following events: date of last contact or end of the study period, whichever came later. Analysis was performed using Kaplan-Meier method. | 3 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without Subsequent Chemotherapy or Death at Month 6 | Probability of participants without subsequent chemotherapy or death at month 6 were reported in this outcome measure. rwTTC was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: start of subsequent chemotherapy or date of death. Participant alive and without subsequent chemotherapy were censored at the earliest of the following events: date of last contact or end of the study period, whichever came later. Analysis was performed using Kaplan-Meier method. | 6 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without Subsequent Chemotherapy or Death at Month 12 | Probability of participants without subsequent chemotherapy or death at month 12 were reported in this outcome measure. rwTTC was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: start of subsequent chemotherapy or date of death. Participant alive and without subsequent chemotherapy were censored at the earliest of the following events: date of last contact or end of the study period, whichever came later. Analysis was performed using Kaplan-Meier method. | 12 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without Subsequent Chemotherapy or Death at Month 18 | Probability of participants without subsequent chemotherapy or death at month 18 were reported in this outcome measure. rwTTC was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: start of subsequent chemotherapy or date of death. Participant alive and without subsequent chemotherapy were censored at the earliest of the following events: date of last contact or end of the study period, whichever came later. Analysis was performed using Kaplan-Meier method. | 18 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without Subsequent Chemotherapy or Death at Month 24 | Probability of participants without subsequent chemotherapy or death at month 24 were reported in this outcome measure. rwTTC was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: start of subsequent chemotherapy or date of death. Participant alive and without subsequent chemotherapy were censored at the earliest of the following events: date of last contact or end of the study period, whichever came later. Analysis was performed using Kaplan-Meier method. | 24 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without Subsequent Chemotherapy or Death at Month 30 | Probability of participants without subsequent chemotherapy or death at month 30 were reported in this outcome measure. rwTTC was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: start of subsequent chemotherapy or date of death. Participant alive and without subsequent chemotherapy were censored at the earliest of the following events: date of last contact or end of the study period, whichever came later. Analysis was performed using Kaplan-Meier method. | 30 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without Subsequent Chemotherapy or Death at Month 36 | Probability of participants without subsequent chemotherapy or death at month 36 were reported in this outcome measure. rwTTC was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: start of subsequent chemotherapy or date of death. Participant alive and without subsequent chemotherapy were censored at the earliest of the following events: date of last contact or end of the study period, whichever came later. Analysis was performed using Kaplan-Meier method. | 36 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without a First Line Therapy Dose Adjustment at Month 3 | Probability of participants without a first-line therapy dose adjustment at month 3 were reported in this outcome measure. Real-world time to dose adjustment (rwTTDA) was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: date of first-line treatment dose adjustment or discontinuation, date of death, date of last contact or the end of study period. Participant alive and without a first-line therapy dose adjustment were censored at the earliest of the following events: first-line discontinuation, death, date of last contact, or end of the study period. Analysis was performed using Kaplan-Meier method. | 3 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without a First Line Therapy Dose Adjustment at Month 6 | Probability of participants without a first-line therapy dose adjustment at month 6 were reported in this outcome measure. rwTTDA was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: date of first-line treatment dose adjustment or discontinuation, date of death, date of last contact or the end of study period. Participant alive and without a first-line therapy dose adjustment were censored at the earliest of the following events: first-line discontinuation, death, date of last contact, or end of the study period. Analysis was performed using Kaplan-Meier method. | 6 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without a First Line Therapy Dose Adjustment at Month 12 | Probability of participants without a first-line therapy dose adjustment at month 12 were reported in this outcome measure. rwTTDA was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: date of first-line treatment dose adjustment or discontinuation, date of death, date of last contact or the end of study period. Participant alive and without a first-line therapy dose adjustment were censored at the earliest of the following events: first-line discontinuation, death, date of last contact, or end of the study period. Analysis was performed using Kaplan-Meier method. | 12 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without a First Line Therapy Dose Adjustment at Month 18 | Probability of participants without a first-line therapy dose adjustment at month 18 were reported in this outcome measure. rwTTDA was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: date of first-line treatment dose adjustment or discontinuation, date of death, date of last contact or the end of study period. Participant alive and without a first-line therapy dose adjustment were censored at the earliest of the following events: first-line discontinuation, death, date of last contact, or end of the study period. Analysis was performed using Kaplan-Meier method. | 18 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without a First Line Therapy Dose Adjustment at Month 24 | Probability of participants without a first-line therapy dose adjustment at month 24 were reported in this outcome measure. rwTTDA was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: date of first-line treatment dose adjustment or discontinuation, date of death, date of last contact or the end of study period. Participant alive and without a first-line therapy dose adjustment were censored at the earliest of the following events: first-line discontinuation, death, date of last contact, or end of the study period. Analysis was performed using Kaplan-Meier method. | 24 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without a First Line Therapy Dose Adjustment at Month 30 | Probability of participants without a first-line therapy dose adjustment at month 30 were reported in this outcome measure. rwTTDA was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: date of first-line treatment dose adjustment or discontinuation, date of death, date of last contact or the end of study period. Participant alive and without a first-line therapy dose adjustment were censored at the earliest of the following events: first-line discontinuation, death, date of last contact, or end of the study period. Analysis was performed using Kaplan-Meier method. | 30 months after treatment initiation any time during 5 years of study period | 
| Probability of Participants Without a First Line Therapy Dose Adjustment at Month 36 | Probability of participants without a first-line therapy dose adjustment at month 36 were reported in this outcome measure. rwTTDA was defined as length of time from the start of first-line therapy with palbociclib plus an aromatase inhibitor to the earliest of one the following: date of first-line treatment dose adjustment or discontinuation, date of death, date of last contact or the end of study period. Participant alive and without a first-line therapy dose adjustment were censored at the earliest of the following events: first-line discontinuation, death, date of last contact, or end of the study period. Analysis was performed using Kaplan-Meier method. | 36 months after treatment initiation any time during 5 years of study period |