Aimee Keegan, PharmD, BCOP, discusses the treatment algorithms at City of Hope, which are largely based on the NCCN guidelines and the regimens outlined in their oncology clinical pathways. In early-stage breast cancer, where the intent is curative, providers tend to stay more on-label, using regimens clearly supported in the literature to give patients the best chance for a cure.

In the adjuvant setting for patients with hormone receptor-positive, HER2-negative breast cancer, the only approved CDK4/6 inhibitor is abemaciclib. Because abemaciclib is the only approved CDK4/6 inhibitor in the adjuvant setting, it is typically the agent of choice. This leaves less flexibility for switching between therapies or having different options due to individual patient care or intolerable side effects. Other agents, such as ribociclib and palbociclib, lack sufficient data to support their use in the adjuvant setting, and most payers won't approve or authorize off-label prescriptions, leading to prohibitively expensive costs for patients.

Dr. Keegan mentions that dose reductions are used in the adjuvant setting to help keep patients on treatment for as long as possible. Updated data from the monarchE trial compared patients on full-dose abemaciclib with those who received one or two dose reductions and found no significant difference in invasive disease-free survival between the two groups. This supports the practice of dose-reducing abemaciclib to balance quality of life while maintaining efficacy.

In the metastatic setting, the choice of therapy can be more individualized, with more options available compared to early-stage breast cancer. While the majority of providers at City of Hope still select CDK4/6 inhibitors as the first choice for patients, they can consider other factors, such as previous use of CDK4/6 inhibitors, time to progression, targetable mutations identified through testing, and the patient's overall condition and treatment intent. This flexibility allows for switching between agents like ribociclib, abemaciclib, and palbociclib based on adverse effects, enabling patients to continue treatment for as long as possible while maintaining the best possible quality of life.

*Video synopsis is AI-generated and reviewed by Pharmacy Times editorial staff.