ASHP Midyear: New Oral Treatment, Antibody Drug Conjugates Offer Additional Options for Breast Cancer

Julia Ziegengeist, PharmD, BCOP, clinical pharmacist coordinator of breast medical oncology at Levine Cancer Institute and Atrium Health, highlights the emergence of new oral treatment options for breast cancer patients, particularly those with ESR1 mutations. These oral therapies provide an additional treatment option that can delay the need for intravenous chemotherapy. Pharmacists are seen as playing a crucial role in this setting, helping to identify appropriate patients for these new treatments and monitor for drug interactions and adverse effects. As patients progress and become resistant to endocrine therapies, the focus shifts to chemotherapy options, including oral agents like capecitabine as well as the increasing use of antibody drug conjugates earlier in the treatment course. She notes the complexity of sequencing these newer treatments, but emphasizes the benefits of having more options available.

Pharmacy Times: How have oral selective estrogen receptor degraders (SERDs) changed the landscape of HR+ breast cancer treatment?

Julia Ziegengeist: So I've done a couple of things. They certainly allow an additional treatment option for patients who we identify have that ESR1 mutation, which allows us to have an additional treatment option in our back pocket, which is a great thing. The other thing that they've done is, it is an oral option, so it's fantastic for patients to kind of delay that time to when they need to utilize intravenous (IV) chemotherapy, and also we anticipate that hopefully we'll be able to use these agents in combination with some of our targeted oral agents as well for that added benefit.

Pharmacy Times: What are the primary treatment options for HR+, HER2- metastatic breast cancer beyond endocrine therapy?

Julia Ziegengeist: So once we get past our endocrine resistant setting, patients no longer can utilize those endocrine therapies, we're really turning to our chemotherapy. So it can be our oral options, such as capecitabine or for our BRACA1 and [BRACA]2 immune patients, olaparib, but then we're also utilizing our antibody drug conjugates, so things like trastuzumab deruxtecan, sacituzumab govitecan, or we may also see datapodamab deruxtecan incorporated into the guidelines soon as well, and we're starting to see those antibody drug conjugates be used earlier and earlier in this setting. So, to be determined, kind of what our guidelines will look like in the future, but do anticipate some updates here.

Pharmacy Times: How can pharmacists contribute to optimizing treatment outcomes for patients with HR+ breast cancer?

Julia Ziegengeist: So I can think of a variety of ways that patients can help with us being embedded in clinic. So in the early stage setting, a lot of our oral adjutant therapies have very complicated inclusion criteria, so determining which patients are candidate for which treatments is going to be critical, and then also kind of anticipating some of those needs in terms of monitoring drug interactions, so that once we get them started on that treatment, we can provide the best outcomes and support them through it as best we can also when we get to kind of our metastatic patients as well, kind of thinking about tailoring their treatment options to what they may have tolerated in the past, what they may or may not have received in the past, and then also helping them through in that supportive care management strategy.

Pharmacy Times: What role do pharmacists play in patient education and counseling regarding targeted therapies?

Julia Ziegengeist: Pharmacists are critical in this. We oftentimes are the ones spending the most amount of time with the patient, talking to them about these drugs, and so we're discussing a lot of what they can expect. We're talking a lot about the [adverse] effects, how to manage it supportively at home, via over the counter medications, when to contact clinic, and for a lot of these targeted medications, this is going to be critical for patients to alert us when they have things like shortness of breath or some of these other [adverse] effects. So, pharmacists are critical in this area.

Pharmacy Times: What emerging therapies or treatment strategies show promise for HR+ breast cancer?

Julia Ziegengeist: We have several antibody drug conjugates that are kind of coming onto the scene that may allow us to have some additional options, and having more options is always a good thing, but it does kind of complicate and muddy the waters of sequencing things like that, so to be determined, what we see in that space, but I think also adding on some of those other targeted oral therapies opens up some options for things like circulating tumor DNA monitoring. So one big thing that we may see incorporated into practice in the future is monitoring that circulating tumor DNA for either progression or development of certain mutations, so that we can maybe switch patient to treatment earlier to allow them to continue on and have that increased survival prior to progression.

Pharmacy Times: Is there anything else you would like to add?

Julia Ziegengeist: The other thing I just want to add is that pharmacists can play this critical role in these treatments, again, through that identification and then also monitoring, counseling patients, and helping to manage these supportive care regimens. I think in breast cancer, it's a lot of data to keep up with, but I think kind of attending these sessions like this, and then also looking through those abstracts as things come out is a great way to stay up to date.