How Pharmacists Support CDK4/6 Inhibitor Management and Patient Care

In this Pharmacy Times interview, Jodi Taraba, PharmD, MSc, BCOP, discusses the expanding role of pharmacists in managing patients on CDK4/6 inhibitors, highlighting their importance in the metastatic and adjuvant settings as use of these therapies continues to grow. She explains how pharmacists are essential in navigating the intensive laboratory monitoring schedules, addressing side effects such as neutropenia, liver function abnormalities, and diarrhea—particularly with abemaciclib—and ensuring patients can tolerate therapy long term. Given the complexity of care and the strain on physicians and nurse practitioners, Taraba emphasizes that pharmacists are uniquely positioned to provide critical support in optimizing treatment outcomes and improving patient care.

Pharmacy Times: How has the evidence base for CDK4/6 inhibitors in metastatic breast cancer influenced their use in earlier disease settings?

Jodi Taraba, PharmD, MSc, BCOP: Yeah, given our experience in the metastatic setting, we've really gained a lot of experience there and made that transition into the early stage better and very smooth. Given the recent press release with the overall survival data with abemaciclib, we'll have to see how things practice this shift in that setting, but anticipate that we'll continue to use abemaciclib in those high-risk patients. This may, in those patients that would qualify for either ribociclib or abemaciclib, maybe shift perhaps in the direction of abemaciclib. But given our experience in the metastatic setting, we feel very comfortable moving into the early-stage setting and managing patients there.

Pharmacy Times: Each CDK4/6 inhibitor has unique dosing and toxicity profiles. How do you approach choosing the right agent for the right patient?

Taraba: So when we look at the different CDK4/6 inhibitors, ribociclib and palbociclib have similar side effect profiles compared to abemaciclib, which has a slightly different side effect profile. We’re used to seeing neutropenia with ribociclib and palbociclib, whereas diarrhea is a little more prevalent in the abemaciclib population.

When we’re looking at selecting therapy for patients, the first thing that always comes to mind is the data as far as outcomes and efficacy, and that’s usually how we initially select therapy. For example, in the metastatic setting, ribociclib with the overall survival data is usually our first choice. At that point, we then check initial labs and baseline EKG and make sure patients qualify for ribociclib.

Once we’ve done that, we really focus on patient factors—any comorbidities or lifestyle considerations that might sway us one way or the other—to ensure that we’re selecting the appropriate therapy that works best not only from an efficacy standpoint but also for the patient as well.

Pharmacy Times: From your perspective, what unique role do pharmacists play in optimizing the use of CDK4/6 inhibitors?

Taraba: I think pharmacists can play a really impactful role with this class of drugs for a number of reasons. The first is that we’ve seen the growth in the use of CDK4/6 inhibitors, initially in the metastatic setting and now moving into the adjuvant setting as well, so the number of patients on these therapies is growing.

Secondly, we know that the laboratory monitoring is fairly intensive upfront, with every two-week monitoring for those first couple of months and then monthly after that.

Third, their side effect profile requires quite a bit of management—whether it’s monitoring for neutropenia, sometimes having to hold therapy and recheck labs, or, in patients that develop liver function abnormalities, having to check labs more frequently. And of course, managing the diarrhea from abemaciclib can be relatively time-intensive upfront to get patients to a dose that they can tolerate.

So I think those three things really highlight the need for incorporating pharmacists into medication management. Given the complexities, the growing number of patients, and the strains already on the healthcare team of physicians and nurse practitioners with full schedules, I think it opens up a wonderful opportunity for pharmacists to really get involved in this.