Treatment Experiences with CDK4&6 Inhibitors Among Women with Metastatic Breast Cancer: A Qualitative Study

PURPOSE: To describe patients’ perspectives on the use of and potential challenges and barriers with adherence/persistence to cyclin-dependent kinase 4 and 6 inhibitors (CDK4&6i’s) to treat metastatic breast cancer (MBC). METHODS: This qualitative study consisted of 60-minute semi-structured telephone interviews with patients with MBC in the US who were either current or recent CDK4&6i users, identified from administrative claims of survey-eligible commercial and Medicare Advantage patients in the HealthCore Integrated Research Database between November 1, 2018 and November 1, 2019. Patients were recruited by email and/or mailed letter. The 60-minute telephone interviews were conducted by a trained facilitator using a study-developed interview discussion guide that included topics impacting treatment choice and adherence/persistence. Interviews were audio-recorded, transcribed, and thematically analyzed. RESULTS: All 462 eligible patients were sent a recruitment email and/or letter to which 36 patients responded, consented to participate, and met study inclusion criteria; 25 patients scheduled interviews, and 24 completed them. Study participants were predominately white, non-Hispanic (96%) with a mean age of 59.5 years. Participants reported a largely positive experience and mentioned very few adherence/persistence issues. They further reported appreciating the ease and convenience of oral oncolytics, coped with side effects, had strong medical and social support, and experienced few cost issues. CONCLUSION: The few adherence/persistence issues reported by participants contrasts with other findings of suboptimal oral oncolytic use. Interview themes indicated several factors that likely contributed to the lack of adherence/persistence issues: trusted relationship with oncologist, belief in importance of medication, positive medication views, strong medical and social support, and minimal personal drug cost. Future research should focus on whether and how much these factors impact adherence/persistence in more diverse populations. If adherence/persistence issues are identified in these populations, then it would be appropriate to study the development of interventions that target factors associated with better adherence/persistence.