Dr. Ramaswamy on the Real-World Data Implications of Palbociclib in HR-Positive Breast Cancer

Bhuvaneswari Ramaswamy, MD, assistant professor, The Ohio State University (OSU) Medical Center, breast medical oncologist, Translational Therapeutics Program, section chief, Breast Medical Oncology, director, Medical Oncology Fellowship Program in Breast Cancer, The Ohio State College of Medicine, OSU Cancer Center (OSUCC)–James, discusses the importance of real-world data when considering the efficacy of the CDK 4/6 inhibitor palbociclib (Ibrance) in hormone receptor (HR)–positive breast cancer.

The current treatment landscape of HR-positive breast cancer involves an array of targeted and biologically relevant therapies that have substantially improved patient outcomes, Ramaswamy begins. Among these are CDK4/6 inhibitors, which are considered a standard of care in this space.

Although palbociclib has been widely studied in clinical trials, there has been some conflicting evidence regarding its role and benefit in real-world populations, Ramaswamy states. Several prospective datasets have shown that this agent improves overall survival (OS) in the metastatic setting, Ramaswamy says. However, the phase 3 PALOMA-2 trial (NCT01740427), demonstrated that palbociclib plus the aromatase inhibitor letrozole (Femara) did not provide a survival benefit for postmenopausal patients, Ramaswamy details.

Real-world data are vital to confirming the real-world effectiveness and tolerability of palbociclib, as well as clarifying the sequencing of CDK4/6 inhibitors in practice. Palbociclib is still commonly utilized in the frontline settingdespite results from PALOMA-2, and real-world data has shown an OS benefit with this agent, Ramaswamy says. Additionally, many clinical trial populations are not representative of patients that present in clinic and real-world data can identify efficacy-effectiveness gaps for these agents, she adds.

Investigators have suggested that differences in study design, disease biology, or varying targets, could be affecting OS outcomes in randomized studies, Ramaswamy continues. Real-world data can also address these lingering questions regarding conflicting clinical trial results.

Lastly, data from these trials can help identify which patients may benefit from initial treatment with an anti-estrogen approach rather than a CDK4/6 inhibitor, which could help combat the development of treatment resistance, Ramaswamy concludes.