Managing QTc Prolongation With CDK4/6 Inhibitor Therapy: A Case-Based Discussion

In Managing QTc Prolongation With CDK4/6 Inhibitor Therapy: A Case-Based Discussion, our panel delves into a metastatic breast cancer case on the management of a 67-year-old woman with hormone receptor–positive, HER2-negative metastatic breast cancer involving the lung and bone who began first-line therapy with an aromatase inhibitor plus ribociclib. At the start of cycle 2, routine monitoring revealed QTc prolongation to 505 ms, raising concerns for a potential drug-related cardiac adverse event. Pharmacists play an important role in evaluating ECG results, reviewing concomitant medications for additional QT-prolonging agents, and assessing electrolyte levels or other reversible causes. Before making treatment decisions, the care team may also want to review repeat ECG findings, cardiac history, and any recent medication changes. Management may include temporarily holding ribociclib, correcting contributing factors, and considering dose reduction or treatment modification once the QTc interval improves. In

Throughout the conversation, the experts provide a comprehensive reflection on the field and the factors that may shape how clinicians approach care moving forward.

Our next episode, Future Directions for CDK4/6 Inhibitors and the Expanding Role of Pharmacists in Breast Cancer Care, further explores potential future clinical trials needed to further define the role of CDK4/6 inhibitors, including agents such as palbociclib, ribociclib, and abemaciclib in breast cancer management. Faculty also share perspectives on how the use of these therapies—and the role of pharmacists in caring for patients with early and metastatic breast cancer—may evolve over the next five years.