Abstract PS10-17: Palbociclib (P) in combination with fulvestrant (F) or letrozole (L) in endocrine-sensitive patients (pts) with hormone receptor (HR)[+]/HER2[-] metastatic breast cancer (MBC): detailed safety analysis from a multicenter, randomized, open-label, phase II trial (PARSIFAL)

Background: P led to a meaningful improvement in clinical outcomes when used in combination with endocrine therapy for first- or later-line regimen in HR[+]/HER2[-] MBC. Grade 3-4 neutropenia was the most common adverse event (AE) in the P-containing regimens. Although venous thromboembolic events (VTE) have been rarely reported in registrational trials, a systematic review and meta-analysis of randomized controlled trials demonstrated a higher...