Trial Outcomes & Findings for Comparative Real World Tumor Response in Pre-menopausal Metastatic Breast Cancer Patients Treated With Palbociclib + Aromatase Inhibitor or Aromatase Inhibitor Alone (NCT NCT05012644)

Last Updated: 2024-10-08

Results Overview

rwTR of complete response (CR) or partial response (PR) based on response assessments captured with chart review during first line therapy. Real-world response rate (rwRR) was estimated using nIPTW method to adjust for the potential imbalance between the 2 treatment cohorts. CR was documented as 'a complete response' to therapy, indication patient is in 'remission', 'all lesions' have disappeared, or 'no evidence of disease'. PR was documented as partial reduction in size of visible disease in some or all areas without any areas of increase in visible disease (decrease in disease volume even though disease is still present). nIPTW method was employed to reduce confounding due to potential selection biases.

Recruitment status

COMPLETED

Target enrollment

197 participants

Primary outcome timeframe

11 Years. From 01 January 2010 to 30 June 2020 were assessed. The study data cutoff date was on 31 December 2020.

Results posted on

2024-10-08

Participant Flow

Data from United States Oncology Network's (USON) iKnowMed (iKM) electronic health record (EHR) database combined with chart review in pre/perimenopausal patients with hormone receptor (HR) positive, human epidermal growth factor receptor (HER2) negative metastatic breast cancer (MBC) who initiated palbociclib plus aromatase inhibitor (AI) or AI alone as first-line therapy during the period of from 01 January 2010 to 30 June 2020 were assessed. The study data cutoff date was on 31 December 2020.

A total of 196 patients were included in the study, with 116 patients in the palbociclib plus AI cohort and 80 patients in the AI monotherapy cohort, after applying inclusion and exclusion criteria, using EHR structured data and chart review to confirm eligibility.

Participant milestones

Participant milestones
Measure	Palbociclib + AI Pre/perimenopausal patients, diagnosed with HR positive (+), HER2 negative (-) MBC who initiated palbociclib along with AI as first-line therapy on or after 01 January 2010 up to and including 30 June 2020	AI Monotherapy Pre/perimenopausal patients, diagnosed with HR+, HER2- MBC who initiated AI alone as first-line therapy on or after 01 January 2010 up to and including 30 June 2020
Overall Study STARTED	116	80
Overall Study Discontinued	64	67
Overall Study Ongoing	51	13
Overall Study COMPLETED	1	0
Overall Study NOT COMPLETED	115	80

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Comparative Real World Tumor Response in Pre-menopausal Metastatic Breast Cancer Patients Treated With Palbociclib + Aromatase Inhibitor or Aromatase Inhibitor Alone

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Palbociclib + AI (All Patients) n=116 Participants Patients who received palbociclib along with AI on or after 01 January 2010 up to and including 30 June 2020 for the treatment of MBC as part of their routine treatment were observed retrospectively.	AI Monotherapy (All Patients) n=80 Participants Patients who received AI alone on or after 01 January 2010 up to and including 30 June 2020 for the treatment of MBC as part of their routine treatment were observed retrospectively.	Total n=196 Participants Total of all reporting groups
Age, Customized <30 Years	2 Participants n=5 Participants	0 Participants n=7 Participants	2 Participants n=5 Participants
Age, Customized 30-44 Years	45 Participants n=5 Participants	29 Participants n=7 Participants	74 Participants n=5 Participants
Age, Customized >=45 Years	69 Participants n=5 Participants	51 Participants n=7 Participants	120 Participants n=5 Participants
Sex: Female, Male Female	116 Participants n=5 Participants	80 Participants n=7 Participants	196 Participants n=5 Participants
Sex: Female, Male Male	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race/Ethnicity, Customized Black or African American	14 Participants n=5 Participants	9 Participants n=7 Participants	23 Participants n=5 Participants
Race/Ethnicity, Customized White	76 Participants n=5 Participants	55 Participants n=7 Participants	131 Participants n=5 Participants
Race/Ethnicity, Customized Not Reported	19 Participants n=5 Participants	12 Participants n=7 Participants	31 Participants n=5 Participants
Race/Ethnicity, Customized Unknown	7 Participants n=5 Participants	4 Participants n=7 Participants	11 Participants n=5 Participants
Body Mass Index (BMI) (>= 25) Yes	75 Participants n=5 Participants	41 Participants n=7 Participants	116 Participants n=5 Participants
Body Mass Index (BMI) (>= 25) No	33 Participants n=5 Participants	26 Participants n=7 Participants	59 Participants n=5 Participants
Body Mass Index (BMI) (>= 25) Unknown	8 Participants n=5 Participants	13 Participants n=7 Participants	21 Participants n=5 Participants
Disease Site (s) Visceral	43 Participants n=5 Participants	29 Participants n=7 Participants	72 Participants n=5 Participants
Disease Site (s) Non-visceral	42 Participants n=5 Participants	17 Participants n=7 Participants	59 Participants n=5 Participants
Disease Site (s) Bone Only	31 Participants n=5 Participants	34 Participants n=7 Participants	65 Participants n=5 Participants
Number of Metastatic Site(s) 1	31 Participants n=5 Participants	30 Participants n=7 Participants	61 Participants n=5 Participants
Number of Metastatic Site(s) 2	42 Participants n=5 Participants	20 Participants n=7 Participants	62 Participants n=5 Participants
Number of Metastatic Site(s) 3+	43 Participants n=5 Participants	30 Participants n=7 Participants	73 Participants n=5 Participants
Stage at Diagnosis Stage 0	1 Participants n=5 Participants	0 Participants n=7 Participants	1 Participants n=5 Participants
Stage at Diagnosis Stage I	21 Participants n=5 Participants	9 Participants n=7 Participants	30 Participants n=5 Participants
Stage at Diagnosis Stage II	38 Participants n=5 Participants	26 Participants n=7 Participants	64 Participants n=5 Participants
Stage at Diagnosis Stage III	21 Participants n=5 Participants	21 Participants n=7 Participants	42 Participants n=5 Participants
Stage at Diagnosis Stage IV	30 Participants n=5 Participants	20 Participants n=7 Participants	50 Participants n=5 Participants
Stage at Diagnosis Unknown	5 Participants n=5 Participants	4 Participants n=7 Participants	9 Participants n=5 Participants
Eastern Cooperative Oncology Group (ECOG) Performance Status 0	34 Participants n=5 Participants	27 Participants n=7 Participants	61 Participants n=5 Participants
Eastern Cooperative Oncology Group (ECOG) Performance Status 1	42 Participants n=5 Participants	24 Participants n=7 Participants	66 Participants n=5 Participants
Eastern Cooperative Oncology Group (ECOG) Performance Status 2+	8 Participants n=5 Participants	9 Participants n=7 Participants	17 Participants n=5 Participants
Eastern Cooperative Oncology Group (ECOG) Performance Status Unknown	32 Participants n=5 Participants	20 Participants n=7 Participants	52 Participants n=5 Participants
Prior Neo/Adjuvant Chemotherapy Yes	50 Participants n=5 Participants	36 Participants n=7 Participants	86 Participants n=5 Participants
Prior Neo/Adjuvant Chemotherapy No	66 Participants n=5 Participants	44 Participants n=7 Participants	110 Participants n=5 Participants
Disease-free Interval < 12 Months	54 Participants n=5 Participants	32 Participants n=7 Participants	86 Participants n=5 Participants
Disease-free Interval >= 12 Months	14 Participants n=5 Participants	18 Participants n=7 Participants	32 Participants n=5 Participants
Disease-free Interval De Novo Metastatic	35 Participants n=5 Participants	22 Participants n=7 Participants	57 Participants n=5 Participants
Disease-free Interval Unknown	13 Participants n=5 Participants	8 Participants n=7 Participants	21 Participants n=5 Participants

PRIMARY outcome

Timeframe: 11 Years. From 01 January 2010 to 30 June 2020 were assessed. The study data cutoff date was on 31 December 2020.

Population: Pre/perimenopausal patients who were treated with palbociclib plus AI or AI monotherapy as first-line treatment for HR positive, HER2 negative MBC in the US clinical practice setting from the USON database who met the inclusion/exclusion criteria of the study protocol. The study period began at patients' starting date of the first-line MBC treatment during the period of 01 January 2010 through 30 June 2020 to study end (data cutoff 31 December 2020).

Outcome measures

Outcome measures
Measure	Palbociclib + AI n=116 Participants Patients who received palbociclib along with AI on or after 01 January 2010 up to and including 30 June 2020 for the treatment of MBC as part of their routine treatment were observed retrospectively. Normalized inverse probability of treatment weighting (nIPTW) adjustment was applied.	AI Monotherapy n=80 Participants Patients who received AI alone on or after 01 January 2010 up to and including 30 June 2020 for the treatment of MBC as part of their routine treatment were observed retrospectively. Normalized inverse probability of treatment weighting (nIPTW) adjustment was applied.
Real World Tumor Response (rwTR) of All Participants (Adjusted by Normalized Inverse Probability of Treatment Weighting [nIPTW])	52.1 Percentage of Participants	46.2 Percentage of Participants

PRIMARY outcome

Timeframe: 11 Years. From 01 January 2010 to 30 June 2020 were assessed. The study data cutoff date was on 31 December 2020.

Population: A subgroup of patients with at least 1 tumor assessment on treatment, from pre/perimenopausal patients treated with palbociclib plus AI or AI monotherapy as first-line treatment for HR positive, HER2 negative MBC in the US clinical practice setting from the USON database who met the eligibility of the study protocol. Began at patients' starting date of the first-line MBC treatment from 01 January 2010 to 30 June 2020 to study end (data cutoff 31 December 2020).

rwTR of complete CR or PR based on response assessments captured with chart review during first line therapy. rwRR was estimated using nIPTW method to adjust for the potential imbalance between the 2 treatment cohorts. CR was documented as 'a complete response' to therapy, indication patient is in 'remission', 'all lesions' have disappeared, or 'no evidence of disease'. PR was documented as partial reduction in size of visible disease in some or all areas without any areas of increase in visible disease (decrease in disease volume even though disease is still present). nIPTW method was employed to reduce confounding due to potential selection biases.

Outcome measures

Outcome measures
Measure	Palbociclib + AI n=103 Participants Patients who received palbociclib along with AI on or after 01 January 2010 up to and including 30 June 2020 for the treatment of MBC as part of their routine treatment were observed retrospectively. Normalized inverse probability of treatment weighting (nIPTW) adjustment was applied.	AI Monotherapy n=71 Participants Patients who received AI alone on or after 01 January 2010 up to and including 30 June 2020 for the treatment of MBC as part of their routine treatment were observed retrospectively. Normalized inverse probability of treatment weighting (nIPTW) adjustment was applied.
Real World Tumor Response in Patients With Tumor Assessment (Adjusted by nIPTW)	60.0 Percentage of Participants	49.9 Percentage of Participants

Adverse Events

Palbociclib + AI

Serious events: 0 serious events

Other events: 0 other events

Deaths: 27 deaths

AI Monotherapy

Serious events: 0 serious events

Other events: 0 other events

Deaths: 38 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
Publication restrictions are in place