Abstract P6-18-36: Real world treatment patterns and outcomes of patients receiving palbociclib plus aromatase inhibitor in the United States: Sub-groups analysis based on age, performance status and sites of metastases from the IRIS study
Authors: Taylor-Stokes G , Mitra D , Waller J , Gibson K , Milligan G , Zhan L , Iyer S 
Published: May 2019

Background: Ibrance Real World Insights (IRIS) is a multi-country study aimed to describe clinical characteristics, treatment patterns and clinical outcomes of patients receiving palbociclib plus aromatase inhibitor. Previously the results on the overall population within the US have been communicated. The current analysis focuses on subgroups stratified by age, performance status and visceral status.

Materials and methods: A retrospective chart review of HR+/HER2- ABC/MBC patients who received palbociclib plus aromatase inhibitor as initial endocrine based therapy for their advanced disease was conducted between June and October 2017. Physicians completed electronic case report forms, extracting data on patient demographics, clinical characteristics, treatment history/patterns and clinical outcomes.Progression free and survival rates at 12 and 24 months were estimated via Kaplan-Meier analysis.

Results: Data for the US are reported here. In total 63 physicians completed 360 eCRFs with a mean follow up time since palbociclib initiation of 12 months. Majority of the patients were &gt;65 years (53%), and had ECOG status of 0 (30%) or 1 (56%). Overall 293 (81%) patients had metastatic disease, of which 50% had visceral metastases. Across all sub-groups, majority of patients prescribed an initial palbociclib dose of 125mg did not require a change of dose while on treatment. The 12-month and 24-month progression free and overall survival rates across subgroups are presented in Table 1. Patients with a performance status of ECOG=1 had a slightly lower progression and survival rates at 12 and 24 months compared to those with a score =0. Likewise, patients with visceral disease were observed to have slightly lower progression free and survival rates than others.

Table 1:Clinical Outcomes for the different sub-groups.Patient Sub-groups AgeECOG statusVisceral Status Up to 65 n=169Over 65 n=1910 n=1071 n=200Visceral metastases n=147Non-visceral metastases n=146Progression free survival rate at 12 months, %86.382.194.386.580.285.8Progression free survival rate at 24 months, %59.769.071.267.450.780.6Overall survival rate At 12 months, %97.992.8100.099.590.599.3Overall survival rate at 24 months, %95.185.695.796.487.290.7

Conclusions: The analysis indicates consistent trends in different clinical outcomes were observed with palbociclib plus aromatase inhibitor across patients sub-groups based on age, performance status and visceral metastases.

Citation Format: Taylor-Stokes G, Mitra D, Waller J, Gibson K, Milligan G, Zhan L, Iyer S. Real world treatment patterns and outcomes of patients receiving palbociclib plus aromatase inhibitor in the United States: Sub-groups analysis based on age, performance status and sites of metastases from the IRIS study [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-18-36.