Real world incidence and management of adverse events in patients with HR+, HER2- metastatic breast cancer receiving CDK4 &amp; 6 inhibitors in a United States community setting
Creators: name: Price, Gregory L.
name: Sudharshan, Lavanya
name: Ryan, Paula
name: Rajkumar, Jonathan
name: Sheffield, Kristin M.
name: Smyth, Emily Nash
name: Guimaraes, Claudia Morato
name: Rybowski, Sarah
name: Carter, Gebra Cuyun
name: Gathirua-Mwangi, Wambui Grace
name: Huang, Yu-Jing
Publisher: name: Taylor & Francis
Year: 2022
Subjects: subject: Medicine
subject: Cell Biology
subject: Pharmacology
subject: Sociology
subject: FOS: Sociology
subject: Immunology
subject: FOS: Clinical medicine
subject: Cancer
subject: 110309 Infectious Diseases
subject: FOS: Health sciences
subject: 60506 Virology
subject: FOS: Biological sciences

description: <b>Objective</b> To examine the real-world incidence and management of select adverse events (AEs) among female patients with hormone receptor positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (MBC), receiving a cyclin-dependent kinase 4 and 6 (CDK4 and 6) inhibitor (palbociclib, abemaciclib, or ribociclib). <b>Methods</b> This retrospective study analyzed data from the US Oncology Network iKnowMed electronic health record database for 396 patients with an initial MBC diagnosis on/after January 1, 2014, and receipt of first CDK4 and 6 regimen between January 1, 2017 and December 31, 2018. In this descriptive study, the proportion of patients who experienced select AEs and associated dose modifications or discontinuations were reported. The occurrence of select health care resource utilization categories was also reported. <b>Results</b> Median follow-up time was 451, 262, and 355 days for patients in the palbociclib, abemaciclib, and ribociclib cohorts, respectively. The most common AEs were neutropenia (palbociclib, 44.8%; abemaciclib, 10.6%; ribociclib, 36.3%), diarrhea (palbociclib, 8.0%; abemaciclib, 43.0%; ribociclib, 8.8%), and fatigue (palbociclib, 12.9%; abemaciclib, 17.6%; ribociclib, 16.5%). AEs resulted in a treatment hold among 91 (23.0%), a dose reduction among 86 (21.7%), and permanent discontinuation among 48 (12.1%) patients overall. <b>Conclusions</b> This real-world study provides insight into the occurrence of AEs which varied by CDK4 and 6 inhibitor. Compared to clinical trials, frequencies of AEs were numerically lower but dose reductions due to AEs were numerically higher. It is possible these differences reflect proactive management of AEs on the part of clinicians to help patients remain on therapy. Cyclin-dependent kinase 4 and 6 inhibitors (CDK4 and 6 inhibitors) have changed the landscape for the treatment of metastatic breast cancer (MBC) among patients who are hormone receptor positive (HR+) and human epidermal growth factor receptor 2 negative (HER2-). An understanding of the real-world management of adverse events (AEs) will help optimize treatment strategies. Here, data from the US Oncology Network electronic health record database for 396 HR+, HER2-, MBC patients receiving a CDK4 and 6 inhibitor were examined to describe the proportion of patients who experienced select AEs and the associated outcomes of these AEs. Compared to clinical trials, frequencies of AEs were numerically lower but dose reductions due to AEs were numerically higher. It is possible that these differences reflect a proactive management of AEs on the part of clinicians to help patients remain on therapy.