Case 1: Clinical Implications From MonarchE in HR+ Early Breast Cancer

Heather McArthur, MD; Massimo Cristofanilli, MD, FACP; Sunil Badve, MD, FRCPath; and Joyce O’Shaughnessy, MD, share insight on applying data presented from the monarchE study and the use of adjuvant abemaciclib in clinical practice for high-risk, HR+ early breast cancer.

Joyce O’ Shaughnessy, MD: What’s your experience with toxicity management? Have you had any particular difficulties? Has anything you’ve found helped the patients stay on it? Heather, what do you think?

Heather McArthur, MD: In regard to toxicity, particularly with respect to the diarrhea, I expect that almost everybody is going to experience diarrhea, and my nursing team is hyperaware of this issue. Good communication and early recognition are critically important. I find that if I can get patients through the first couple of months of treatment comfortably, they do very well after that. It’s important to be very proactive in those first couple of months and introduce loperamide early on. I don’t do it routinely as prophylaxis, but I do it at the earliest sign of onset of diarrhea.

Joyce O’ Shaughnessy, MD: Thanks. Massimo, how about you? Any other challenges or guidance about toxicity?

Massimo Cristofanilli, MD, FACP: Patient education with your ancillary team is very important, even a pharmacist being involved early on. I’ve seen motivated patients who would go through this initial phase starting very early on loperamide, maybe even making some changes in their diet and talking to the dietician, and some of these patients are well over a year and a half already in their treatment and aren’t changing the dose.

Some other patients coming out of neoadjuvant therapy, as we have discussed in other meetings, aren’t always motivated. They feel the first fatigue and the first diarrhea that comes and they want to drop, no matter how much you explain the data and the reduction of risk. Very few patients who I’ve treated decide to drop after 2 or 3 months simply because they didn’t want to deal with an additional toxicity, primarily diarrhea and fatigue. We’ll learn more about patient compliance and how to manage this adverse effect, but with the more mature data indicated and the benefit there for patients who complete their treatment, we may be able to go to this place even with patients who have less motivation who feel they have already done enough and don’t want to continue.

Joyce O’ Shaughnessy, MD: We’ll see some dose reductions, too. Some patients need it. It was about 42% who needed a dose reduction, so we’ll see how their benefit plays out over time, along with toxicity, because there are different ways to get people through those 2 years. I know you use abemaciclib [Verzenio], and we’ve talked about the FDA [Food and Drug Administration] approval. Let’s go around and get a summary from everybody about the practicalities of how we incorporate this into our practice. I’ll start with Sunil.

Sunil Badve, MD, FRCPath: Ki67 is proving to be a very valid marker for selection of cell cycle-based therapies in addition to what we have known for a long time in terms of chemotherapy. The challenge is standardization of reagent kits and, most importantly, assessment by pathologists. There’s considerable variation even on the same slides, and there has been considerable work done within the last decade by the International Ki67 in Breast Cancer Working Group to minimize this. Following guidelines is clearly important.

Joyce O’ Shaughnessy, MD: Thanks so much. How about Heather?

Heather McArthur, MD: Adjuvant abemaciclib should be considered and discussed in conjunction with hormone therapy for our high-risk patients with hormone receptor–positive breast cancer using either the FDA or the ASCO [American Society of Clinical Oncology] or NCCN [National Comprehensive Cancer Network] guidelines. It has become a standard of care with an impressive reduction in invasive disease-free survival and distant relapse-free survival events early on in the course of disease.

Joyce O’ Shaughnessy, MD: Thanks. And Massimo?

Massimo Cristofanilli, MD, FACP: I definitely think that abemaciclib at this point is standard of care for this high-risk category of patients, and we’re learning more about how to deal with adverse effects and possible complications. Two years of treatment for patients who have managed the initial few months is relatively easy. As oncologists, we want to see that these data persist over time. Maybe it’s going to affect overall survival. Maybe it’s going to also reduce late recurrence, and it’s a carryover effect from the initial effect. There are many questions that we want to be addressed, but only time and longer follow-up and maybe more biomarker studies will be able to tell us. Obviously, it’s the standard of care, but how much does it change the natural history of the disease for these high-risk patients?

Joyce O’ Shaughnessy, MD: Thank you. I’d just add that for me, the sooner I can start talking about this with patients, the better. Of course, when you first meet the patient, that’s the best time, but there are patients who are into their chemotherapy, even early into their endocrine therapy, and we’ve got to introduce it. The sooner they hear about it, the easier it probably is. Because like you said, it’s 1 more thing for them and 1 more hill to climb. It’s well worth it, of course, but expectations make a difference. Thank you so much for a great, super helpful discussion.

Transcript Edited for Clarity

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