Analysis of healthcare professional management of CDK4/6 inhibitor adverse events and variance with expert recommendations.

Abstract

e13103 Background: CDK4/6 inhibitors (CDK4/6is) are a mainstay of treatment for hormone receptor–positive breast cancer but can cause adverse events that require prompt recognition and management to maintain adherence by patients. We developed an online Interactive Decision Support Tool (www.clinicaloptions.com/CDK46AEtool) for healthcare professionals (HCPs) with case-specific recommendations for managing adverse events associated with CDK4/6i therapy. Methods: To use the online tool, HCPs entered the type of adverse event, symptom grade/severity, and their planned management strategy. The tool showed the management recommendation for that adverse event based on the prescription information and expert guidance and then asked if the recommendation changed HCPs’ intended management approach. Results: From April 2025 to January 2026, 80 HCPs entered 90 case scenarios into the tool; 76% treated > 10 patients with breast cancer/month, and 36% of HCPs practiced in the United States or Europe. Among the 90 cases, 41% were scenarios associated with ribociclib use, 40% with abemaciclib use, and 17% with palbociclib use. The most common adverse events entered regardless of specific CDK4/6i were cytopenias (39%), gastrointestinal toxicity (22%), and hepatotoxicity (18%). The predominant adverse events entered by HCPs varied with the specific CDK4/6i: abemaciclib, gastrointestinal toxicity (47%) and cytopenias (33%); palbociclib, cytopenias (71%); and ribociclib, hepatobiliary toxicity (35%) and cytopenias (30%). HCPs self-reported uncertainty or a difference in adverse event management strategy compared with recommendations based on the prescribing information and expert guidance for grade 1-3 ANC decrease/neutropenia (38%, n = 39); grade 2 diarrhea (38%, n = 13); grade 3 hepatotoxicity (67%, n = 12), and QTcF > 480 ms to ≤500 ms (83%, n = 6). Conclusions: These data suggest that some HCPs are challenged to optimally manage select adverse events associated with CDK4/6is and may not be managing their patients in concordance with consensus recommendations based on prescribing information and expert guidance. A detailed analysis of HCP CDK4/6i adverse event management vs recommendations, including by type of adverse event and severity, will be presented.