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The content of this website has been produced in line with the IBRANCE® Summary of Product Characteristics for Great Britain. IBRANCE® (palbociclib) Prescribing Information for Great Britain click here. IBRANCE® (palbociclib) Prescribing Information for Northern Ireland click here. Adverse event reporting information can be found at the bottom of the page.

P-REALITY

Confidence Through Experience1,6-13

This study was an observational, retrospective analysis of Electronic Health Records (EHRs) from the Flatiron Health Analytic Database to evaluate the effectiveness of 1st line IBRANCE® (palbociclib) in combination with letrozole vs placebo + letrozole in a heterogeneous real-world US population.1

​​​​​​​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.2,3

In the real-world setting, patients treated with palbociclib + letrozole in first-line setting demonstrated significant improvement in rwPFS duration and OS compared with patients who received letrozole alone*1


Palbociclib + letrozole demonstrated 8 months longer rwPFS (20.0 months) compared with patients who received letrozole alone (11.9 months). 

Median OS was not reached for patients receiving IBRANCE + letrozole and was 43.1 months with letrozole alone


* After sIPTW-adjusted analysis and using PSM as a sensitivity analysis
† These data include patients with HR+ HER2- ABC who either received treatment with palbociclib plus AI or AI alone in the first-line setting

Benefit was consistent across heterogeneous population and various patient subgroups encountered in routine clinical practice, including patients over 70 years and bone-only and visceral disease patients1

RWE supports the use of IBRANCE® plus AI as a standard of care for first-line treatment of patients with HR+ HER2- mBC1

Study Description

Observational, retrospective analysis of EHRs from the Flatiron health analytic database reference1.

Study Design

* PSM is a sensitivity analysis used to analyse the robustness of the primary analysis results by matching patients based on baseline demographics and clinical characteristics1.

sIPTW is a statistical approach used to minimise bias in retrospective real-world studies. It is calculated using the PS, the probability of a subject being assigned to a particular treatment (e.g. Drug A vs Drug B) given a set of observed key covariates (e.g. patient age or performance status) that may impact on this treatment decision4,5.

Statistical analysis: What is PSM and sIPTW? ​​​​​​​

What is PSM?

PSM is a statistical matching technique that attempts to eliminate or reduce any bias in real-world studies that are caused by the lack of randomisation4.

The PS is the probability of a subject being assigned to a particular treatment given a set of observed key covariates (e.g. age or performance status) that may impact on this treatment decision4.

What is sIPTW?

sIPTW is a statistical approach increasingly used to minimise bias in retrospective real-world studies, where randomisation is not possible4,5

- Patients are weighted differently in the sample to create two cohorts that have balanced characteristics, enabling a fair comparison across the two arms4,5

-  sIPTW is calculated using the PS, the probability of a subject being assigned to a particular treatment (e.g. Drug A vs Drug B) given a set of observed key covariates (e.g. patient age or performance status) that may impact on this treatment decision4,5

Patient Baseline Characteristics

The study population studied included a diverse group of HR+/HER2- mBC patients.1

​​​​​​​Differences in baseline characteristics between the IBRANCE® plus letrozole and letrozole alone groups were generally balanced after sIPTW adjustment.
​​​​​​​

Key Baseline Characteristics1

* Variable used in the propensity score matching model; de novo versus not de novo were used as categories for initial diagnosis to metastatic diagnosis
​​​​​​​
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.

Progression Free Survival

In the real-world setting of an observational, retrospective analysis of data, 1st line IBRANCE® in combination with letrozole was more effective than placebo + letrozole in a US heterogeneous population1

Median rwPFS was significantly longer among patients who received IBRANCE® + LET vs placebo + LET1

​​​​​​​

Real-world PFS in Overall Population (Unadjusted Analysis)

Adapted from DeMichele A, et al. 2021.1

Real-world PFS in Overall Population (sIPTW Adjusted Analysis)

Adapted from DeMichele A, et al. 2021.1

Real-world OS in the Patient Subgroups (sIPTW-adjusted analysis)1

​​​​​​* Race by cohort interaction was the only subgroup variable-by-treatment cohort interaction that was significant (p=0.0010); however, race data were not known in the “not documented” race group

Bone-only 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.

The total patient population for different subgroups varied due to the application of sIPTW. Therefore, the total n number for each subgroup may not have always equalled the N number of the treatment arm (due to rounding error and categorisation differences).

Overall Survival

IBRANCE® plus letrozole prolonged real-world OS compared with letrozole alone (median NR vs 43.1 months; HR=0.66; [95% CI: 0.53–0.82]; p=0.0002) in a heterogeneous population of patients with HR+ HER2- mBC.1

Real-World OS in Overall Population (Unadjusted Analysis)

Adapted from DeMichele A, et al. 2021.1

Real-World OS in Overall Population (sIPTW Adjusted Analysis)

Adapted from DeMichele A, et al. 2021.1

Subsequent treatment lines following first-line treatment with IBRANCE® plus letrozole or letrozole alone14

* Table does not include all patients receiving CDK4/6s inhibitors (clinical study drugs are excluded). In the UK, a CDK4/6 inhibitor is not permitted after progression on a CDK4/6 inhibitor.

† Data for the rationale of switching from letrozole to fulvestrant (i.e. due to intolerance or progression) are unavailable.

Data on the timing of IBRANCE® addition to the patient’s treatment regimen or whether patients switched treatment due to intolerance are unavailable.

Real-world OS in the Patient Subgroups (sIPTW-adjusted analysis)1

This data includes patients with HR+ HER2- ABC who either received treatment with palbociclib plus AI or AI alone in the first-line setting.1,2 

Race by Cohort interaction and Metastatic Sites by Cohort interaction were the only subgroup variable-by-treatment cohort interaction that were significant (P<0.0001 and p=0.0050, respectively); however, race data were not known in the “not documented” race group

† Bone-only 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. The total patient population for different subgroups varied due to the application of sIPTW. Therefore, the total n number for each subgroup may not have always equalled the N number of the treatment arm (due to rounding error and categorization differences). 


AI :  Aromatase Inhibitor, CDK : Cyclin-Dependent Kinase, CI : Confidence Interval, Dx : Diagnosis, ECOG PS : Eastern Cooperative Oncology Group Performance Status, EHR : Electronic Health Record, HR : Hazard Ratio, HR+/HER2- : Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-negative, LET : Letrozole, mBC : metastatic Breast Cancer, N/n : Number of patients, ND : Not Documented, NE : Not Estimable, NR : Not Reached, OS : Overall Survival, PLA : Placebo, PFS : Progression-Free Survival, PS : Propensity Score, PSM : Propensity Score Matching, RECIST : Response Evaluation Criteria In Solid Tumors, RW : Real World, rwPFS : real-world Progression Free Survival, Y: Year/Years, sIPTW : stabilised Inverse Probability of Treatment Weighting

 ▼ This medicinal product is subject to additional monitoring. This will allow quick identification of new safety information. Healthcare professionals are asked to report any suspected adverse reactions. See section 4.8 of the SmPC for how to report adverse reactions.

References
  1. DeMichele A, et al. Breast Cancer Res 2021;23:37–47.
  2. Gerstein HC, et al. Lancet. 2019;393(10168):210-211.
  3. Corrigan-Curay J, et al. JAMA. 2018;320(9):867-868.
  4. Austin PC. Multivariate Behav Res 2011;46:399–42.
  5. Wang G, Aban I. J Nucl Cardiol 2015;22:611–613.
  6. Finn RS, et al. N Engl J Med 2016;375:1925–193.
  7. Cristofanilli M, et al. Lancet Oncol 2016;17:425–439.
  8. Rugo HS. Breast Cancer Res Treat 2019;174:719–729.
  9. Turner NC, et al. N Engl J Med 2018;379:1926–1936.
  10. IBRANCE® Summary of Product Characteristics for Great Britain click here. IBRANCE® Summary of Product Characteristics for Northern Ireland click here.
  11. Pfizer. Data on file. IBRANCE Real-World Insights (IRIS) – A Global Real-World Study on 12. Palbociclib Outcomes – Results from the UK, 2020
  12. Taylor-Stokes G, et al. Poster 269P. Presented at European Society for Medical Oncology Virtual Congress, 19–21 September 2020
  13. Ettl J, et al. Breast Cancer Res 2020;22:27.
  14.  Pfizer. Data on file. 2021.
PP-IBR-GBR-3751. July 2021

Real World Evidence

  • Real-world patient data for IBRANCE® in advanced Breast Cancer
  • IBRANCE® Real World Evidence
  • IRIS (UK) Study

Indication

  • IBRANCE® is indicated for the treatment of HR+ HER2- locally advanced or metastatic breast cancer:
       - In combination with an aromatase inhibitor; or
    ​​​​​​​   - In combination with fulvestrant in women who have received prior ET

    In pre- or perimenopausal women, the ET should be combined with a LHRH agonist

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PP-PFE-GBR-2688. December 2020

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