Trial Outcomes & Findings for Patient Characteristics, Treatment Patterns, and Clinical Outcomes in Patients Diagnosed With HR+/HER2 Advanced/Metastatic Breast Cancer on Palbociclib + Aromatase Inhibitor (AI) Combination Therapy (NCT NCT04394247)

Last Updated: 2023-03-21

Results Overview

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.

Recruitment status

COMPLETED

Target enrollment

242 participants

Primary outcome timeframe

From start of treatment to end of follow-up, up to a maximum of approximately 5 years

Results posted on

2023-03-21

Participant Flow

Participants who received palbociclib with aromatase inhibitor(AI) as first-line therapy on or after 03 February 2015 through 31 July 2019 were observed retrospectively; data cutoff was 01 February 2020, resulting in a minimum potential 6-month follow-up period. The data was abstracted from charts during a 6 month period of time from 30 June 2020 to 31 December 2020.

Participant milestones

Participant milestones
Measure	Palbociclib With Aromatase Inhibitor Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Overall Study STARTED	242
Overall Study COMPLETED	242
Overall Study NOT COMPLETED	0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Here, number analyzed signifies participants evaluable for this baseline measure.

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Age, Continuous	60.39 Years STANDARD_DEVIATION 13.72 • n=242 Participants
Sex: Female, Male Female	238 Participants n=242 Participants
Sex: Female, Male Male	4 Participants n=242 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	15 Participants n=242 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	225 Participants n=242 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	2 Participants n=242 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=242 Participants
Race (NIH/OMB) Asian	10 Participants n=242 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	1 Participants n=242 Participants
Race (NIH/OMB) Black or African American	29 Participants n=242 Participants
Race (NIH/OMB) White	196 Participants n=242 Participants
Race (NIH/OMB) More than one race	0 Participants n=242 Participants
Race (NIH/OMB) Unknown or Not Reported	6 Participants n=242 Participants
Year of Initial Diagnoses	2016 Years n=242 Participants
Year of A/MBC Diagnoses	2017 Year n=242 Participants
Age at A/MBC Diagnosis	64.68 Years STANDARD_DEVIATION 12.22 • n=242 Participants
Age at Death Less than (<) 50 years	1.7 Percentage of participants n=242 Participants
Age at Death Between 50-64 years	9.9 Percentage of participants n=242 Participants
Age at Death Between 65-74 years	5.4 Percentage of participants n=242 Participants
Age at Death Greater than or equal to (>=) 75 years	8.7 Percentage of participants n=242 Participants
Age at Death Missing	74.0 Percentage of participants n=242 Participants
Insurance Carrier at A/MBC Diagnosis Medicare/Medicaid	61.6 Percentage of Participants n=242 Participants
Insurance Carrier at A/MBC Diagnosis Commercial	28.5 Percentage of Participants n=242 Participants
Insurance Carrier at A/MBC Diagnosis Not Stated in Participant Record	8.7 Percentage of Participants n=242 Participants
Insurance Carrier at A/MBC Diagnosis None	1.2 Percentage of Participants n=242 Participants
Menopausal Status at A/MBC Diagnosis Post-menopausal	85.5 Percentage of participants n=242 Participants
Menopausal Status at A/MBC Diagnosis Pre-menopausal	9.9 Percentage of participants n=242 Participants
Menopausal Status at A/MBC Diagnosis Peri-menopausal	0.8 Percentage of participants n=242 Participants
Menopausal Status at A/MBC Diagnosis Not Stated in Participant Record	2.1 Percentage of participants n=242 Participants
Menopausal Status at A/MBC Diagnosis Not Applicable	1.7 Percentage of participants n=242 Participants
Region of Residence at A/MBC Diagnosis Northeast	0.4 Percentage of participants n=242 Participants
Region of Residence at A/MBC Diagnosis South	4.1 Percentage of participants n=242 Participants
Region of Residence at A/MBC Diagnosis North Central	95.0 Percentage of participants n=242 Participants
Region of Residence at A/MBC Diagnosis West	0.4 Percentage of participants n=242 Participants
Stage at Initial Breast Cancer Diagnosis 0	0.8 Percentage of participants n=242 Participants
Stage at Initial Breast Cancer Diagnosis I	2.9 Percentage of participants n=242 Participants
Stage at Initial Breast Cancer Diagnosis IA	1.2 Percentage of participants n=242 Participants
Stage at Initial Breast Cancer Diagnosis II	6.6 Percentage of participants n=242 Participants
Stage at Initial Breast Cancer Diagnosis IIA	8.3 Percentage of participants n=242 Participants
Stage at Initial Breast Cancer Diagnosis IIB	9.5 Percentage of participants n=242 Participants
Stage at Initial Breast Cancer Diagnosis III	2.5 Percentage of participants n=242 Participants
Stage at Initial Breast Cancer Diagnosis IIIA	5.0 Percentage of participants n=242 Participants
Stage at Initial Breast Cancer Diagnosis IIIB	0.4 Percentage of participants n=242 Participants
Stage at Initial Breast Cancer Diagnosis IIIC	0.8 Percentage of participants n=242 Participants
Stage at Initial Breast Cancer Diagnosis IV	55.4 Percentage of participants n=242 Participants
Stage at Initial Breast Cancer Diagnosis Not Stated in Participant Record	7 Percentage of participants n=242 Participants
Percentage of Participants With Histology Type Invasive Ductal Carcinoma	56.6 Percentage of participants n=242 Participants
Percentage of Participants With Histology Type Invasive Lobular Carcinoma	22.3 Percentage of participants n=242 Participants
Percentage of Participants With Histology Type Invasive Mixed (ductal and lobular)	4.5 Percentage of participants n=242 Participants
Percentage of Participants With Histology Type DCIS	0.8 Percentage of participants n=242 Participants
Percentage of Participants With Histology Type Other	15.7 Percentage of participants n=242 Participants
Percentage of Participants With Eastern Cooperative Oncology Group (ECOG) Performance Status ECOG- 0	23.6 Percentage of participants n=242 Participants
Percentage of Participants With Eastern Cooperative Oncology Group (ECOG) Performance Status ECOG- 1	24.0 Percentage of participants n=242 Participants
Percentage of Participants With Eastern Cooperative Oncology Group (ECOG) Performance Status ECOG- 1-2	0.4 Percentage of participants n=242 Participants
Percentage of Participants With Eastern Cooperative Oncology Group (ECOG) Performance Status ECOG- 2	8.3 Percentage of participants n=242 Participants
Percentage of Participants With Eastern Cooperative Oncology Group (ECOG) Performance Status ECOG- 3	3.3 Percentage of participants n=242 Participants
Percentage of Participants With Eastern Cooperative Oncology Group (ECOG) Performance Status ECOG- Not Stated in Participant Record	40 Percentage of participants n=242 Participants
Percentage of Participants With Any Prior Surgery Yes	52.5 Percentage of participants n=242 Participants
Percentage of Participants With Any Prior Surgery No	47.5 Percentage of participants n=242 Participants
Percentage of Participants With Types of Surgery Breast Conserving Surgery	20.2 Percentage of participants n=242 Participants
Percentage of Participants With Types of Surgery Mastectomy	32.2 Percentage of participants n=242 Participants
Percentage of Participants With Radiation Therapy Yes	32.6 Percentage of participants n=242 Participants
Percentage of Participants With Radiation Therapy No	67.4 Percentage of participants n=242 Participants
Percentage of Participants With Radiation Therapy Sites Chest Wall, Regional Lymph Nodes	7.4 Percentage of participants n=242 Participants
Percentage of Participants With Radiation Therapy Sites Partial Breast	0.8 Percentage of participants n=242 Participants
Percentage of Participants With Radiation Therapy Sites Whole Breast	7.4 Percentage of participants n=242 Participants
Percentage of Participants With Radiation Therapy Sites Whole Breast, Regional Lymph Nodes	5.0 Percentage of participants n=242 Participants
Percentage of Participants With Radiation Therapy Sites Chest Wall	5.0 Percentage of participants n=242 Participants
Percentage of Participants With Radiation Therapy Sites Unknown (site not known)	7.4 Percentage of participants n=242 Participants
Percentage of Participants With Comorbid Disease Burden Hypertension	48.8 Percentage of participants n=242 Participants
Percentage of Participants With Comorbid Disease Burden Diabetes	21.9 Percentage of participants n=242 Participants
Percentage of Participants With Comorbid Disease Burden Renal Disease	9.1 Percentage of participants n=242 Participants
Percentage of Participants With Comorbid Disease Burden Chronic Pulmonary Disease	5.8 Percentage of participants n=242 Participants
Percentage of Participants With Comorbid Disease Burden Anemia	4.5 Percentage of participants n=242 Participants
Percentage of Participants With Comorbid Disease Burden Congestive Heart Failure	4.1 Percentage of participants n=242 Participants
Percentage of Participants With Comorbid Disease Burden Cardiac Arrhythmias	2.9 Percentage of participants n=242 Participants
Percentage of Participants With Comorbid Disease Burden Peripheral Vascular Disease	1.2 Percentage of participants n=242 Participants
Percentage of Participants With Comorbid Disease Burden Rheumatic Disease	1.2 Percentage of participants n=242 Participants
Percentage of Participants With Comorbid Disease Burden Cerebrovascular Disease	0.8 Percentage of participants n=242 Participants
Percentage of Participants With Comorbid Disease Burden Dementia	0.8 Percentage of participants n=242 Participants
Percentage of Participants With Comorbid Disease Burden Myocardial Infarction	0.8 Percentage of participants n=242 Participants
Percentage of Participants With Comorbid Disease Burden Liver Disease	0.4 Percentage of participants n=242 Participants
Percentage of Participants With Comorbid Disease Burden Not Stated in Participant Record	1.2 Percentage of participants n=242 Participants
Percentage of Participants With Comorbid Disease Burden None of the Above	36.8 Percentage of participants n=242 Participants
Percentage of Participants With Charlson Comorbidity Index Score 0	65.3 Percentage of participants n=242 Participants
Percentage of Participants With Charlson Comorbidity Index Score 1	19.4 Percentage of participants n=242 Participants
Percentage of Participants With Charlson Comorbidity Index Score 2	9.1 Percentage of participants n=242 Participants
Percentage of Participants With Charlson Comorbidity Index Score 3	3.7 Percentage of participants n=242 Participants
Percentage of Participants With Charlson Comorbidity Index Score 4+	2.5 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis Bone (Bone only or in addition to other sites)	83.1 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis Bone Only	50.8 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis Chest Wall	0.0 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis CNS	2.5 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis Contralateral Breast	0.8 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis Distant Lymph Node (s)	18.6 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis Visceral Sites	32.2 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis Liver	9.9 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis Lung	21.5 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis Peritoneum	2.1 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis Pleural Nodules	5 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis Malignant Pleural Effusion	10.3 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis Skin	3.7 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis Ovary	0.4 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis Adrenal	1.7 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis Bone Marrow	1.7 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis Colon	0.8 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis Omentum	0.4 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis Soft Tissue	2.5 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis Stomach	1.2 Percentage of participants n=242 Participants
Percentage of Participants With Sites of Distant Metastasis Other: Specify	7.4 Percentage of participants n=242 Participants
Percentage of Participants With Number of Metastatic Sites 1	60.7 Percentage of participants n=242 Participants
Percentage of Participants With Number of Metastatic Sites 2	18.6 Percentage of participants n=242 Participants
Percentage of Participants With Number of Metastatic Sites >=3	20.2 Percentage of participants n=242 Participants
Percentage of Participants With Number of Metastatic Sites Participant is Not Metastatic	0.4 Percentage of participants n=242 Participants
Percentage of Participants With Disease Burden at Metastatic Sites in Liver Single Lesion	3.3 Percentage of participants n=242 Participants
Percentage of Participants With Disease Burden at Metastatic Sites in Liver Multiple Lesions	5.8 Percentage of participants n=242 Participants
Percentage of Participants With Disease Burden at Metastatic Sites in Liver Unknown Number of Lesions	0.8 Percentage of participants n=242 Participants
Percentage of Participants With Disease Burden at Metastatic Sites in Liver No Metastases at Site	90.1 Percentage of participants n=242 Participants
Percentage of Participants With Disease Burden at Metastatic Sites in Lung Single Lung	5.4 Percentage of participants n=242 Participants
Percentage of Participants With Disease Burden at Metastatic Sites in Lung Bilateral Lungs	13.2 Percentage of participants n=242 Participants
Percentage of Participants With Disease Burden at Metastatic Sites in Lung Unknown Single vs Bilateral Status	2.9 Percentage of participants n=242 Participants
Percentage of Participants With Disease Burden at Metastatic Sites in Lung No Metastases at Site	78.5 Percentage of participants n=242 Participants
Percentage of Participants With Disease Burden at Metastatic Sites in Bone Single Site	16.9 Percentage of participants n=242 Participants
Percentage of Participants With Disease Burden at Metastatic Sites in Bone Multiple Sites	64.5 Percentage of participants n=242 Participants
Percentage of Participants With Disease Burden at Metastatic Sites in Bone Unknown Number of Sites	1.7 Percentage of participants n=242 Participants
Percentage of Participants With Disease Burden at Metastatic Sites in Bone No Metastases at Site	16.9 Percentage of participants n=242 Participants
Percentage of Participants With Time to Metastasis <= 12 Months	5.7 Percentage of participants n=105 Participants • Here, number analyzed signifies participants evaluable for this baseline measure.
Percentage of Participants With Time to Metastasis 13-24 Months	3.8 Percentage of participants n=105 Participants • Here, number analyzed signifies participants evaluable for this baseline measure.
Percentage of Participants With Time to Metastasis 25-36 Months	8.6 Percentage of participants n=105 Participants • Here, number analyzed signifies participants evaluable for this baseline measure.
Percentage of Participants With Time to Metastasis > 36 Months	81.9 Percentage of participants n=105 Participants • Here, number analyzed signifies participants evaluable for this baseline measure.
Percentage of Participants With HER2 and Estrogen Receptor (ER) or Progesterone Receptor (PR) Status HER2 Status: HER2 negative	97.9 Percentage of participants n=242 Participants
Percentage of Participants With HER2 and Estrogen Receptor (ER) or Progesterone Receptor (PR) Status HER2 Status: equivocal	2.1 Percentage of participants n=242 Participants
Percentage of Participants With HER2 and Estrogen Receptor (ER) or Progesterone Receptor (PR) Status Hormone Receptor Status: ER+ / PR+	79.8 Percentage of participants n=242 Participants
Percentage of Participants With HER2 and Estrogen Receptor (ER) or Progesterone Receptor (PR) Status Hormone Receptor Status: ER+ / PR-	18.6 Percentage of participants n=242 Participants
Percentage of Participants With HER2 and Estrogen Receptor (ER) or Progesterone Receptor (PR) Status Hormone Receptor Status: ER+ / Not Applicable (NA)	0.8 Percentage of participants n=242 Participants
Percentage of Participants With HER2 and Estrogen Receptor (ER) or Progesterone Receptor (PR) Status Hormone Receptor Status: ER- / PR+	0.4 Percentage of participants n=242 Participants
Percentage of Participants With HER2 and Estrogen Receptor (ER) or Progesterone Receptor (PR) Status Hormone Receptor Status: ER- / PR-	0.4 Percentage of participants n=242 Participants
Percentage of Participants With Breast Cancer Susceptibility Gene (BRCA) 1 or 2 Testing Status Yes	19.0 Percentage of participants n=242 Participants
Percentage of Participants With Breast Cancer Susceptibility Gene (BRCA) 1 or 2 Testing Status No	81.0 Percentage of participants n=242 Participants
Percentage of Participants With Modalities of Treatment Received Prior to A/MBC Chemotherapy	12.1 Percentage of participants n=99 Participants • Here, number analyzed signifies participants evaluable for this baseline measure.
Percentage of Participants With Modalities of Treatment Received Prior to A/MBC Endocrine Therapy	7.1 Percentage of participants n=99 Participants • Here, number analyzed signifies participants evaluable for this baseline measure.
Percentage of Participants With Modalities of Treatment Received Prior to A/MBC Targeted Therapy	1.0 Percentage of participants n=99 Participants • Here, number analyzed signifies participants evaluable for this baseline measure.
Percentage of Participants With Endocrine Sensitivity and Endocrine Resistance Endocrine Sensitivity	84.9 Percentage of participants n=53 Participants • Here, number analyzed signifies participants evaluable for this baseline measure.
Percentage of Participants With Endocrine Sensitivity and Endocrine Resistance Primary Endocrine Resistance	28.5 Percentage of participants n=242 Participants • Here, number analyzed signifies participants evaluable for this baseline measure.
Percentage of Participants With Endocrine Sensitivity and Endocrine Resistance Secondary Endocrine Resistance	45.5 Percentage of participants n=242 Participants • Here, number analyzed signifies participants evaluable for this baseline measure.
Disease Free Interval	64.00 Months n=105 Participants • Here, number analyzed signifies participants evaluable for this baseline measure.

PRIMARY outcome

Timeframe: From start of treatment to end of follow-up, up to a maximum of approximately 5 years

Population: Analysis population included all participants who met following criteria: 1) Diagnosis of A/MBC; 2) Aged \>=18 years at A/MBC diagnosis; 3) Initiated palbociclib in combination with AI as first-line therapy after A/MBC diagnosis on or after 03 February 2015 through 31 July 2019; 4) Evidence of ER or PR positive disease and HER2 negative disease or absence of any indication of ER and PR negative disease and HER2 positive disease closest to A/MBC diagnosis.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Percentage of Participants With Treatment Regimen Distribution First-line regimen	100 Percentage of participants
Percentage of Participants With Treatment Regimen Distribution Second-line regimen	39.67 Percentage of participants

PRIMARY outcome

Timeframe: From start of treatment to end of follow-up, up to a maximum of approximately 5 years

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Percentage of Participants With Sequence of Treatment Lines 1 Line	100 Percentage of participants
Percentage of Participants With Sequence of Treatment Lines 2 Lines	21.49 Percentage of participants
Percentage of Participants With Sequence of Treatment Lines 3 Lines	12.81 Percentage of participants
Percentage of Participants With Sequence of Treatment Lines 4 Lines	2.07 Percentage of participants
Percentage of Participants With Sequence of Treatment Lines 5 Lines or more	3.31 Percentage of participants

PRIMARY outcome

Timeframe: From start of treatment to end of follow-up, up to a maximum of approximately 5 years

Percentage of participants with starting and end dose at 125 mg, 100 mg, 75 mg and unknown were reported.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Percentage of Participants With Their Starting Dose and End Dose End Dose: Unknown	1.7 Percentage of participants
Percentage of Participants With Their Starting Dose and End Dose Starting Dose: 125 mg	89.7 Percentage of participants
Percentage of Participants With Their Starting Dose and End Dose Starting Dose: 100 mg	7.4 Percentage of participants
Percentage of Participants With Their Starting Dose and End Dose Starting Dose: 75 mg	1.2 Percentage of participants
Percentage of Participants With Their Starting Dose and End Dose Starting Dose: Unknown	1.7 Percentage of participants
Percentage of Participants With Their Starting Dose and End Dose End Dose: 125 mg	60.7 Percentage of participants
Percentage of Participants With Their Starting Dose and End Dose End Dose: 100 mg	27.7 Percentage of participants
Percentage of Participants With Their Starting Dose and End Dose End Dose: 75 mg	9.9 Percentage of participants

PRIMARY outcome

Timeframe: From start of treatment to end of follow-up, up to a maximum of approximately 5 years

In this outcome measure type of dose adjustments were recorded and reported. It included dose increase, decrease, no adjustment and unknown categories.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Percentage of Participants With Type of Dose Adjustment Increase	0.4 Percentage of participants
Percentage of Participants With Type of Dose Adjustment Decrease	31.0 Percentage of participants
Percentage of Participants With Type of Dose Adjustment No adjustment	66.9 Percentage of participants
Percentage of Participants With Type of Dose Adjustment Unknown	1.7 Percentage of participants

PRIMARY outcome

Timeframe: From start of treatment to end of follow-up, up to a maximum of approximately 5 years

Population: Analysis population (AP) included all participants who met following criteria: 1) Diagnosis of A/MBC; 2) Aged \>=18 years at A/MBC diagnosis; 3) Initiated palbociclib in combination with AI as first-line therapy after A/MBC diagnosis on or after 03 February 2015 through 31 July 2019; 4) Evidence of ER or PR positive disease and HER2 negative disease or absence of any indication of ER and PR negative disease and HER2 positive disease closest to A/MBC diagnosis.

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Percentage of Participants With Their Reason For Treatment Discontinuation Progression	26.4 Percentage of participants
Percentage of Participants With Their Reason For Treatment Discontinuation Intolerance/toxicity	14.9 Percentage of participants
Percentage of Participants With Their Reason For Treatment Discontinuation Participant Choice	2.5 Percentage of participants
Percentage of Participants With Their Reason For Treatment Discontinuation Treatment for Other Diseases	2.5 Percentage of participants
Percentage of Participants With Their Reason For Treatment Discontinuation Left Health System	0 Percentage of participants
Percentage of Participants With Their Reason For Treatment Discontinuation End of Planned Therapy	2.1 Percentage of participants
Percentage of Participants With Their Reason For Treatment Discontinuation Changes in Insurance	1.2 Percentage of participants
Percentage of Participants With Their Reason For Treatment Discontinuation Death	1.2 Percentage of participants
Percentage of Participants With Their Reason For Treatment Discontinuation Hospice Referral	1.2 Percentage of participants
Percentage of Participants With Their Reason For Treatment Discontinuation Physician Choice	0.8 Percentage of participants
Percentage of Participants With Their Reason For Treatment Discontinuation Actionable Mutation Found	0.4 Percentage of participants
Percentage of Participants With Their Reason For Treatment Discontinuation Other/Unknown	2.9 Percentage of participants

PRIMARY outcome

Timeframe: From start of treatment till treatment dose adjustment, up to a maximum of approximately 5 years

Population: AP: all participants who met following criteria: 1)Diagnosis of A/MBC;2)Aged \>=18years at A/MBC diagnosis;3)Initiated palbociclib in combination with AI as first-line therapy after A/MBC diagnosis on/after 03 February 2015-31 July 2019;4)Evidence of ER/PR positive disease and HER2 negative disease/absence of any indication of ER and PR negative disease and HER2 positive disease closest to A/MBC diagnosis. Overall number of participants analyzed=participants evaluable for this outcome measure.

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=76 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Time to Dose Adjustment	55.0 Days Interval 1.0 to 1435.0

PRIMARY outcome

Timeframe: 3 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Real-World Progression-Free Survival (rwPFS) at Month 3	0.95 Probability of being event free Interval 0.92 to 0.97

PRIMARY outcome

Timeframe: 6 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Real-World Progression-Free Survival (rwPFS) at Month 6	0.84 Probability of being event free Interval 0.8 to 0.89

PRIMARY outcome

Timeframe: 12 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Real-World Progression-Free Survival (rwPFS) at Month 12	0.75 Probability of being event free Interval 0.7 to 0.81

PRIMARY outcome

Timeframe: 18 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Real-World Progression-Free Survival (rwPFS) at Month 18	0.66 Probability of being event free Interval 0.59 to 0.72

PRIMARY outcome

Timeframe: 24 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Real-World Progression-Free Survival (rwPFS) at Month 24	0.59 Probability of being event free Interval 0.53 to 0.67

PRIMARY outcome

Timeframe: 30 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Real-World Progression-Free Survival (rwPFS) at Month 30	0.53 Probability of being event free Interval 0.46 to 0.61

PRIMARY outcome

Timeframe: 36 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Real-World Progression-Free Survival (rwPFS) at Month 36	0.48 Probability of being event free Interval 0.4 to 0.57

PRIMARY outcome

Timeframe: 3 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Real-World Overall Survival (rwOS) at Month 3	0.99 Probability of being alive Interval 0.97 to 1.0

PRIMARY outcome

Timeframe: 6 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Real-World Overall Survival (rwOS) at Month 6	0.97 Probability of being alive Interval 0.94 to 0.99

PRIMARY outcome

Timeframe: 12 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Real-World Overall Survival (rwOS) at Month 12	0.9 Probability of being alive Interval 0.87 to 0.94

PRIMARY outcome

Timeframe: 18 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Real-World Overall Survival (rwOS) at Month 18	0.84 Probability of being alive Interval 0.79 to 0.89

PRIMARY outcome

Timeframe: 24 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Real-World Overall Survival (rwOS) at Month 24	0.78 Probability of being alive Interval 0.72 to 0.84

PRIMARY outcome

Timeframe: 30 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Real-World Overall Survival (rwOS) at Month 30	0.73 Probability of being alive Interval 0.67 to 0.8

PRIMARY outcome

Timeframe: 36 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Real-World Overall Survival (rwOS) at Month 36	0.69 Probability of being alive Interval 0.62 to 0.77

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without First Line Treatment Discontinuation or Death at Month 3	0.93 Probability Interval 0.9 to 0.96

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without First Line Treatment Discontinuation or Death at Month 6	0.84 Probability Interval 0.8 to 0.89

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without First Line Treatment Discontinuation or Death at Month 12	0.67 Probability Interval 0.61 to 0.74

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without First Line Treatment Discontinuation or Death at Month 18	0.56 Probability Interval 0.5 to 0.63

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without First Line Treatment Discontinuation or Death at Month 24	0.49 Probability Interval 0.42 to 0.56

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without First Line Treatment Discontinuation or Death at Month 30	0.41 Probability Interval 0.34 to 0.48

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without First Line Treatment Discontinuation or Death at Month 36	0.36 Probability Interval 0.3 to 0.44

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without Subsequent Line of Therapy Initiation or Death at Month 3	0.97 Probability Interval 0.96 to 0.99

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without Subsequent Line of Therapy Initiation or Death at Month 6	0.89 Probability Interval 0.85 to 0.93

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without Subsequent Line of Therapy Initiation or Death at Month 12	0.73 Probability Interval 0.68 to 0.79

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without Subsequent Line of Therapy Initiation or Death at Month 18	0.62 Probability Interval 0.56 to 0.69

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without Subsequent Line of Therapy Initiation or Death at Month 24	0.55 Probability Interval 0.49 to 0.63

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without Subsequent Line of Therapy Initiation or Death at Month 30	0.47 Probability Interval 0.4 to 0.55

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without Subsequent Line of Therapy Initiation or Death at Month 36	0.41 Probability Interval 0.34 to 0.5

PRIMARY outcome

Timeframe: 3 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without Subsequent Chemotherapy or Death at Month 3	0.98 Probability Interval 0.97 to 1.0

PRIMARY outcome

Timeframe: 6 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without Subsequent Chemotherapy or Death at Month 6	0.93 Probability Interval 0.9 to 0.97

PRIMARY outcome

Timeframe: 12 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without Subsequent Chemotherapy or Death at Month 12	0.83 Probability Interval 0.78 to 0.88

PRIMARY outcome

Timeframe: 18 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without Subsequent Chemotherapy or Death at Month 18	0.74 Probability Interval 0.68 to 0.8

PRIMARY outcome

Timeframe: 24 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without Subsequent Chemotherapy or Death at Month 24	0.69 Probability Interval 0.63 to 0.76

PRIMARY outcome

Timeframe: 30 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without Subsequent Chemotherapy or Death at Month 30	0.63 Probability Interval 0.56 to 0.71

PRIMARY outcome

Timeframe: 36 months after treatment initiation any time during 5 years of study period

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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without Subsequent Chemotherapy or Death at Month 36	0.58 Probability Interval 0.5 to 0.66

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without a First Line Therapy Dose Adjustment at Month 3	0.82 Probability Interval 0.77 to 0.87

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without a First Line Therapy Dose Adjustment at Month 6	0.76 Probability Interval 0.71 to 0.82

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without a First Line Therapy Dose Adjustment at Month 12	0.73 Probability Interval 0.67 to 0.79

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without a First Line Therapy Dose Adjustment at Month 18	0.69 Probability Interval 0.63 to 0.76

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without a First Line Therapy Dose Adjustment at Month 24	0.68 Probability Interval 0.62 to 0.74

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without a First Line Therapy Dose Adjustment at Month 30	0.67 Probability Interval 0.6 to 0.74

PRIMARY outcome

Timeframe: 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 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.

Outcome measures

Outcome measures
Measure	Palbociclib With Aromatase Inhibitor n=242 Participants Participants with advanced/metastatic breast cancer (A/MBC), hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative disease, received palbociclib capsule orally once daily with AI as first-line therapy were observed retrospectively during the study. The data of these participants were studied in this observational study.
Probability of Participants Without a First Line Therapy Dose Adjustment at Month 36	0.65 Probability Interval 0.59 to 0.73

Adverse Events

Palbociclib With Aromatase Inhibitor

Serious events: 0 serious events

Other events: 0 other events

Deaths: 62 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

Email: [email protected]

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