Courtney Moore, APRN, FNP-C, OCN, recommends taking patients' individual needs into account when making treatment decisions.

CDK4/6 inhibitors have transformed care for patients with hormone receptor–positive, HER2-negative breast cancer, but their benefits can be offset by challenging toxicities. Oncology nurses and advanced practice providers (APPs) play a pivotal role in facilitating quality care for patients on CDK4/6 inhibitors, from monitoring for adverse events (AEs) to personalizing treatment plans that enhance patient safety and quality of life.

In a recent interview with Oncology Nursing News following a Case-Based Roundtable discussion, Courtney Moore, APRN, FNP-C, OCN, a nurse practitioner at Norton Cancer Institute Medical Oncology and Hematology in Louisville, Kentucky, shared strategies for managing neutropenia, QTc prolongation, and gastrointestinal toxicities, as well as tailoring therapy to a patient’s comorbidities.

Moore also discussed how follow-up visits can be used to address emerging side effects, reinforce education, and involve pharmacists to reduce drug–drug interaction risks. Whether selecting between agents or adjusting doses, she emphasized that individualized care must remain the guiding principle to maximize efficacy while minimizing harm.

What are the most common adverse events (AEs) to watch for with palbociclib (Ibrance), ribociclib (Kisqali), and abemaciclib (Verzenio)?

With palbociclib and ribociclib, one of the biggest AEs is neutropenia. We really monitor our patients’ CBCs. They need to come in every 2 weeks for the first couple of cycles, and then we will watch it monthly after that for ribociclib.

Another thing is the QTc. We’re going to be doing EKGs at baseline, and then 2 weeks after they start the medication, and as needed from there, there is also concern for hepatic toxicities, especially with the ribociclib, so we will be checking their CMP throughout the process as well, to make sure we’re not seeing an uptick in any of the liver enzymes. Then, generally, these medications can cause some fatigue. Abemaciclib can cause diarrhea.

How can oncology nurses manage diarrhea and other gastrointestinal AEs from CDK4/6 inhibitors?

We need to hone in with the patient on these follow-ups. When we’re checking for labs or doing EKGs, we can talk to them about any of these other AEs and how we can manage those. If they’re having a lot of diarrhea, prescribe Imodium or Lomotil, or something like those medications, to help bring those AEs down as much as possible.

How should CDK4/6 inhibitor treatment be personalized for patients with comorbidities?

The risk factors tie into the AE profiles of these medications. Between the CDK4/6 inhibitors, there are a couple that lean more toward neutropenia as a major AE, and we want to be aware of whether the patient is on any immunosuppressive therapies or has any other rheumatologic disorders or autoimmune disorders so that we can keep a close eye on them.

Ribociclib has the potential to cause some cardiology AEs. If we have patients that already has arrhythmias such as atrial fibrillation, we want to avoid ribociclib because it can prolong the QTc interval. Being aware of your patient and what other comorbidities they may have is important when you’re making that decision.

Why is individualized care critical when prescribing CDK4/6 inhibitors?

If you have a patient with some gastrointestinal toxicities already, you don’t want to start them on a medication that has a high rate of diarrhea. You would want to choose a different medication. If you have an elderly patient that has atrial fibrillation, you’re not going to want to start them on a medication that can cause QTc prolongation. If you have a patient who is already on immunosuppression medications, you don’t want to choose medication that can increase the possibility of neutropenia for the patient.

What are the next steps for older adults not benefiting from or tolerating CDK4/6 inhibitors?

Where do we go from here? If we’re not seeing the benefits that we want to see, what next steps can we take in how we further treat the patient past that? This occurs a lot in our elderly population. What kind of modifications do we need to look towards to help prevent any of these toxic situations and best protect our patients? If they’re not tolerating treatment well, how do we go about these conversations about stopping treatment or possibly trying something different or withholding treatment altogether?

These patients tend to be on a lot of medications. They tend to have a lot of comorbidities already, so doing more patient-focused evaluations is very important. Medications can interact with other medications, so bringing in other disciplines, such as pharmacists, to help go through these lists of medications and how they can affect other medications and figure out a dosing schedule that is more helpful for the patient.

The biggest thing we can all take away from this is to focus on the individual patients, rather than thinking, “This is the best medication for this population, period.” You have to drive the personalized care.

This transcript has been edited for clarity and conciseness.