Ibrance is indicated for the treatment of patients with hormone receptor positive, human epidermal growth factor receptor 2 negative advanced or metastatic breast cancer in combination with an aromatase inhibitor as initial endocrine-based therapy; or fulvestrant in patients with disease progression following endocrine therapy.1

Real-world Experience

What is RWD and RWE IBRANCE RWE Initiatives Flatiron IRIS

Study Design

An observational, retrospective analysis of Flatiron data evaluated the effectiveness of 1st line IBRANCE + letrozole vs placebo + letrozole in a real-world heterogeneous US population2

AI = aromatase inhibitor; CDK = cyclin-dependent kinase; EHR = electronic health record; HR+/HER2- = hormone receptor-positive, human epidermal growth factor receptor 2-negative; mBC = metastatic breast cancer.
​​​​​​​


The Flatiron population studied included a diverse group of HR+/HER2- mBC patients2

Select baseline patient characteristics*2​​​​​​​

Adapted from DeMichele A, et al. 2019.2
​​​​​​​
  • 42% of patients had de novo metastatic diagnosis†§​​​​​​​


Observational retrospective analyses are designed to evaluate associations among variables and cannot establish causality. Observational retrospective analyses are not intended for direct comparison with clinical trials.3,4





*1:1 propensity score matching (PSM) of baseline demographic and clinical characteristics was performed to ensure patient characteristics were generally balanced between the IBRANCE + letrozole and letrozole alone groups. PSM is a statistical matching technique that attempts to eliminate or reduce any bias caused by the lack of randomisation in observational studies. PSM identified 464 patients in each treatment group. Variable used in PSM model. Visceral disease was defined as metastatic disease in the lung and/or liver. Patients could have had other sites of metastases. No visceral disease was defined as no lung or liver metastases. #Bone-only disease was defined as metastatic disease in the bone only. §de novo vs not de novo were used as categories for initial diagnosis to metastatic diagnosis.
HR+/HER2- = hormone receptor-positive, human epidermal growth factor receptor 2-negative; mBC = metastatic breast cancer; n = number of patients.

References

  1. IBRANCE® (Palbociclib) Prescribing Information. Available from: http://labeling.pfizer.com/ShowLabeling.aspx?id=12240. Accessed September 17, 2021.
  2. DeMichele A, et al. SABCS 2019; Poster P1-19-02.
  3. Gerstein HC, et al. Lancet. 2019;393(10168):210-211​​​​​​​
  4. Corrigan-Curay J, et al. JAMA. 2018;320(9):867-868
©2020 Pfizer. All rights reserved. Date of preparation:  April 2021 PP-IBR-GLB-0513 

rwPFS

Median rwPFS (primary endpoint) was significantly longer among patients who received IBRANCE + LET vs placebo + LET*2

Adapted from DeMichele A, et al. 2019.1

Median follow-up was 24.4 and 23.1 months for PS-matched IBRANCE+ letrozole and letrozole alone, respectively.

Observational retrospective analyses are designed to evaluate associations among variables and cannot establish causality. Observational retrospective analyses are not intended for direct comparison with clinical trials.3,4




​​​​​​​*Real-world PFS was defined as the number of months from start of IBRANCE plus letrozole or letrozole alone to death or disease progression (concluded by the treating clinician based on radiology, laboratory evidence, pathology, or clinical assessment). If patients did not die or have disease progression, they were censored at the date of initiation of next line of therapy for those with 2 or more lines of therapy or their last visit during the study period (February 2015–May 2019) for patients with only one line of therapy. †Propensity score matching (PSM) stabilised weightadjusted numbers of patients at risk are shown.
CI = confidence interval; LET = letrozole; n = number of patients; PLA= placebo; PFS = progression-free survival; PSM = propensity score matching; rw = real world.

References

  1. IBRANCE® (Palbociclib) Prescribing Information. Available from: http://labeling.pfizer.com/ShowLabeling.aspx?id=12240. Accessed September 17, 2021.
  2. DeMichele A, et al. SABCS 2019; Poster P1-19-02.
  3. Gerstein HC, et al. Lancet. 2019;393(10168):210-211.
  4. Corrigan-Curay J, et al. JAMA. 2018;320(9):867-868.
©2020 Pfizer. All rights reserved. Date of preparation:  April 2021 PP-IBR-GLB-0513 

rwOS

Median rwOS was not reached with IBRANCE + LET vs 43.1 months with placebo + LET*2

Adapted from DeMichele A, et al. 2021.3

Although median OS was reached in the LET alone group, significant censoring in the OS analysis highlights the need for subsequent evaluation with longer follow-up

At the time of analysis, more patients had died in the placebo + LET group (n=182;
39.2%) than in the IBRANCE + LET group (n=113; 24.4%)2

At 2 years’ follow-up, OS rate was 80.1% with IBRANCE + LET vs 63.9% with placebo + LET2


*OS was defined as time in months from start of IBRANCE plus letrozole or letrozole alone to death due to any cause recorded by Flatiron in the data extract. Date of death was derived from a recent mortality data set generated by combining multiple data sources and benchmarked against the National Death Index. If patients did not die, they were censored at the study cut-off date of May 31, 2019. Propensity score matching (PSM) stabilised weight-adjusted numbers of patients at risk are shown.

CI = confidence interval; LET = letrozole; n = number of patients; NE = not estimable; NR = not reached; OS = overall survival;  PLA = placebo; PFS = progression-free survival; PSM = propensity score matching; rw = real world.. 

A consistent OS benefit with IBRANCE + letrozole vs letrozole alone was observed generally across all studied subgroups except race*2

*Race by Cohort interaction was the only subgroup variable-by-treatment cohort interaction that was significant (p=0.0102); Boneonly disease was defined as metastatic disease in the bone only; Visceral disease was defined as metastatic disease in the lung and/or liver; patients could have had other sites of metastases. No visceral disease was defined as no lung or liver metastases.


CI = confidence interval;  LET = letrozole; n/N = number of patients; OS = overall survival: ; PLA = placebo.

Observational retrospective analyses are designed to evaluate associations among variables and cannot establish causality. Observational retrospective analyses are not intended for direct comparison with clinical trials.3,4


References

  1. IBRANCE® (Palbociclib) Prescribing Information. Available from: http://labeling.pfizer.com/ShowLabeling.aspx?id=12240. Accessed September 17, 2021.
  2. DeMichele A, et al. SABCS 2019; Poster P1-19-02.
  3. Gerstein HC, et al. Lancet. 2019;393(10168):210-211.
  4. Corrigan-Curay J, et al. JAMA. 2018;320(9):867-868.
©2020 Pfizer. All rights reserved. Date of preparation:  April 2021 PP-IBR-GLB-0513 

Study limitations

• EHR reviews are subject to missing or erroneous data entry2 
• Disease progression was assessed based on the individual treating physician’s clinical assessment or interpretation of radiographic or pathologic results rather than standard criteria such as RECIST2
• Because treatment was not randomised, bias related to treatment selection for individual patients is possible2
• PSM does not account for unobserved variables that may cause biased estimation2
• Comorbid conditions are not well captured in the Flatiron EHR database and may be an important confounder in the OS results2
• Although the cohort is large, some subgroup analyses, such as younger patients (≤50 years), may not be sufficiently powered to detect significant differences2
• Retrospective database analyses cannot conclude causality and are not intended for direct comparisons with clinical trials2
• Findings from patients included in the Flatiron database may not be generalised to other patient populations2

EHR = electronic health record; OS = overall survival; PSM = propensity score matching; RECIST = Response Evaluation Criteria in Solid Tumors.
  1. IBRANCE® (Palbociclib) Prescribing Information. Available from: http://labeling.pfizer.com/ShowLabeling.aspx?id=12240. Accessed September 17, 2021.
  2. ​​​​​​​DeMichele A, et al. SABCS 2019; Poster P1-19-02.

Reference

  1. IBRANCE® (Palbociclib) Prescribing Information. Available from: http://labeling.pfizer.com/ShowLabeling.aspx?id=12240. Accessed September 17, 2021

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All rights reserved. Date of preparation: June 2020 PP-IBR-GLB-0254

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