Patient-Reported Outcomes Predict Progression-Free Survival of Patients with Advanced Breast Cancer Treated with Abemaciclib

Background. Abemaciclib is a CDK4/6 inhibitor used to treat hormone receptor–positive, human epidermal growth factor receptor 2–negative advanced breast cancer. The prognostic value of patient-reported outcomes (PROs) has been minimally explored for treatment outcomes with CDK4/6 inhibitors. The performance of PROs compared with Eastern Cooperative Oncology Group performance status (ECOG-PS) is unknown. Materials and

Methods. This study pooled data from single-arm trial, MONARCH 1, and randomized trials, MONARCH 2 and 3. In total, 900 patients initiated abemaciclib and 384 comparator therapy. Pretreatment PRO association with progression-free survival (PFS) was modeled using Cox proportional hazards regression. Prediction performance was assessed via the C-statistic (c). PROs were recorded via the European …