Treatment patterns and clinical outcomes with palbociclib-based therapy received in US community oncology practices

Background: Limited studies have evaluated palbociclib-based therapy use in patients with advanced/metastatic breast cancer in the real world. This retrospective study used medical records from US community oncology practices to address the gap. Materials & methods: Eligible patients receiving palbociclib-based therapy per label indication from 3 February 2015 to 31 December 2017 were included. Descriptive analyses were conducted for patient characteristics, treatment patterns and clinical outcomes. Results: The study included 233 patients who received palbociclib + aromatase inhibitor (P+AI) and 48 who received palbociclib + fulvestrant (P+F). Real-world progression-free rate for P+AI was 69.8% (46.8%) at 12 (24) months (P+F: 43.5% [39.9%]) months. Real-world survival rate was 89.8% (71.4%) at 12 (24) months (P+F: 76.3% [65.0%]). Conclusion: The study findings are consistent with previous studies of palbociclib-based therapy. Lay abstract Aim: Palbociclib, a drug that inhibits cancer cell growth, is approved to treat hormone receptor-positive, human epidermal growth factor receptor 2 negative advanced breast cancer in combination with hormone therapy drugs, such as aromatase inhibitor (P+AI) or fulvestrant (P+F). Clinical trials indicate that palbociclib is effective in patients with hormone receptor-positive/human epidermal growth factor receptor 2 negative advanced breast cancer; however, evidence from real-life use of these drugs is limited. Materials & methods: This study reviewed the medical records of patients who received P+AI or P+F in US community oncology clinics. Results: After 12 months of treatment with P+AI, 90 in 100 women were still alive and 70 in 100 were living without their cancer getting worse; of those patients who received P+F, 76 in 100 were still alive and 44 in 100 were living without their cancer getting worse. Conclusion: The findings from this study are consistent with previous studies of palbociclib.