CROSS-COUNTRY DIFFERENCES IN REAL-WORLD LABORATORY MONITORING INTENSITY AND HEPATOTOXICITY ADVERSE EVENT DETECTION AMONG INITIATORS OF CDK4/6 INHIBITORS FOR ADVANCED BREAST CANCER
Author(s)
Patrycja Pluta, DVM1, Arun Sujenthiran, MD2, Kaiser Anam, MBBS2, Sascha van Boemmel-Wegmann, PhD1, Caitlin Clunie-O'Connor, PhD2, Dionne Ng, BA3, Lockwood Taylor, PhD, MPH4.
1Flatiron Health Germany, Berlin, Germany, 2Flatiron Health UK, London, United Kingdom, 3Flatiron Health Japan, Tokyo, Japan, 4Flatiron Health, New York, NY, USA.
1Flatiron Health Germany, Berlin, Germany, 2Flatiron Health UK, London, United Kingdom, 3Flatiron Health Japan, Tokyo, Japan, 4Flatiron Health, New York, NY, USA.
OBJECTIVES: Patients receiving cyclin-dependent kinase 4/6 inhibitors (CDK4/6is) for advanced breast cancer (aBC) require routine laboratory surveillance, including liver function test (LFT), to identify potential hepatotoxicity adverse events (hAEs) during treatment. This study characterized real-world patterns of LFT monitoring and hAE detection among women initiating CDK4/6i for aBC in the UK, Germany, and Japan.
METHODS: In this retrospective study, patients with aBC initiating CDK4/6is (palbociclib, ribociclib, abemaciclib) between January 2017 and March 2026 were selected from the de-identified electronic health record (EHR)-derived UK, Germany, and Japan Flatiron Health Research Databases. LFTs were assessed at baseline (within 30 days prior to initiating treatment) and for maximum 180 days post-initiation. hAE incidence, based on CTCAE thresholds of grade 3+ hAEs, was calculated as a proportion of women initiating therapy. Midpoint rounding of counts and proportions was performed in accordance with data privacy protections. Testing frequency was measured by the median number of LFTs/patient/month.
RESULTS: In the UK, Germany, and Japan; 245, 205, and 195 eligible CDK4/6is initiators for aBC were included, respectively. The median number of LFTs/patient/month was 2 for UK and Japan and 1 for Germany across the first two months of therapy. ALT was the most sensitive hAE marker, with grade 3+ hAEs occurring in 6.0%, 2.5%, and 11.0%, in the UK, Germany, and Japan, respectively. hAE incidence was generally consistent in the UK and Japan (mean: 2.1%/month) throughout follow-up, while incidence in Germany was comparatively lower (mean: 1.23%/month) coinciding with decreased testing rates.
CONCLUSIONS: hAE rates in CDK4/6i initiators align with known incidence across geographies, though countries with lower testing captured lower hAE rates. Capture of lab-based hAEs from global, harmonised, structured EHR data may be leveraged for safety and resource utilization studies in oncology.
METHODS: In this retrospective study, patients with aBC initiating CDK4/6is (palbociclib, ribociclib, abemaciclib) between January 2017 and March 2026 were selected from the de-identified electronic health record (EHR)-derived UK, Germany, and Japan Flatiron Health Research Databases. LFTs were assessed at baseline (within 30 days prior to initiating treatment) and for maximum 180 days post-initiation. hAE incidence, based on CTCAE thresholds of grade 3+ hAEs, was calculated as a proportion of women initiating therapy. Midpoint rounding of counts and proportions was performed in accordance with data privacy protections. Testing frequency was measured by the median number of LFTs/patient/month.
RESULTS: In the UK, Germany, and Japan; 245, 205, and 195 eligible CDK4/6is initiators for aBC were included, respectively. The median number of LFTs/patient/month was 2 for UK and Japan and 1 for Germany across the first two months of therapy. ALT was the most sensitive hAE marker, with grade 3+ hAEs occurring in 6.0%, 2.5%, and 11.0%, in the UK, Germany, and Japan, respectively. hAE incidence was generally consistent in the UK and Japan (mean: 2.1%/month) throughout follow-up, while incidence in Germany was comparatively lower (mean: 1.23%/month) coinciding with decreased testing rates.
CONCLUSIONS: hAE rates in CDK4/6i initiators align with known incidence across geographies, though countries with lower testing captured lower hAE rates. Capture of lab-based hAEs from global, harmonised, structured EHR data may be leveraged for safety and resource utilization studies in oncology.
Conference/Value in Health Info
2026-11, ISPOR Europe 2026, Vienna, Austria
Value in Health, Volume 29, Issue 12S
Code
RWD173
Topic
Epidemiology & Public Health, Real World Data & Information Systems, Study Approaches
Topic Subcategory
Health & Insurance Records Systems
Disease
Genetic, Regenerative & Curative Therapies, Oncology