Individualizing Breast Cancer Therapy Amid New SABCS Data

At the San Antonio Breast Cancer Symposium (SABCS) in San Antonio, Allison Butts, PharmD, BCOP, highlighted several emerging topics shaping clinical decision-making, including the growing role of circulating tumor DNA, evolving strategies around sequencing antibody-drug conjugates, and interdisciplinary discussions on omitting sentinel lymph node surgery and its downstream impact on pharmacologic management. She also noted significant attention around recent public discourse on hormone replacement therapy, emphasizing the value of conference-led programming to clarify the nuances and current limitations of available data.

Pharmacy Times: SABCS continues to highlight rapidly evolving treatment strategies in breast cancer. From your perspective as an oncology pharmacist, which emerging themes or data presented this year have the greatest potential to impact medication management or supportive-care practices?

Allison Butts, PharmD, BCOP: So at the time of filming, we're on Thursday, so there's still quite a bit of conference left. I think coming into the conference, there were a few things that I was really excited to hear expert opinions on and see more data in, and that includes things like the utility of circulating tumor DNA, which we've already heard a fair amount about with sequencing therapies, especially in regards to the multiple antibody-drug conjugates that we now have on the market in the breast cancer space. And then also, more from an interdisciplinary standpoint, thinking about the implications of omitting sentinel lymph node surgery and how that could impact our pharmacologic therapy. That's definitely something that we've talked about a lot in our practice, so really excited to hear more about that.

Another kind of hot-button issue that's been around for the past couple of weeks has been the update on hormone replacement therapy and how that might impact the breast cancer space. Obviously, the media has really been involved in this, and there's been a lot of patient questions as a result of that. So it's been really good, just in these first couple days of the conference, to see that the San Antonio conference has gotten ahead of that, and they've had some good programming looking at the nuances of that data, and really how we should be thinking about it, and really the absence of data still in the breast cancer space. So there's been a lot going on just in the first half of the conference.

Pharmacy Times: Many abstracts at SABCS focus on optimizing therapy sequencing, managing toxicities, and improving adherence. Which of these areas do you believe pharmacists are uniquely positioned to influence, and why?

Butts: So I think we're seeing that treatment planning is increasingly nuanced. It's increasingly individualized to our patient populations. More and more we need to be taking into account comorbidities, other medications patients are on, their preferences—all these different things—to be able to really help the treatment team make those decisions. So, for example, there was a particular presentation yesterday that was looking at the DESTINY-Breast09 trial data that was talking about how trastuzumab deruxtecan with pertuzumab may become a new standard of care for first-line metastatic HER2-positive disease. I thought it was really interesting because the presenter was talking about how we should probably tailor our first-line treatment approach between the current standard of THP and this potential new standard of therapy based on disease burden, toxicity considerations, again, comorbidities, and potentially other biomarkers the patient expresses, to really be able to tease out for an individual patient what treatment is best.

That same discussion looked at new data that came out of the conference for the HER2CLIMB-05 trial that looked at adding adjuvant tucatinib—excuse me, adding tucatinib—to maintenance trastuzumab/pertuzumab in the metastatic HER2-positive space, which again adds another element of how do we select the patients that we should add this third drug on for maintenance therapy versus those who could go on for years with just the two monoclonal antibodies? So, like I said, increasingly nuanced in terms of how we select patients for these varying degrees of treatment intensities, not unlike how we treat adjuvant patients, where now we standardly tailor therapies. We're looking at potentially doing that in the metastatic space also. So it's really interesting. I think the pharmacist has a huge role in being able to have a say in how those decisions are made.

Pharmacy Times: With so many new agents and combinations showcased at SABCS, what are the key considerations pharmacists should keep in mind when integrating new evidence into institutional protocols or pathway updates?

Butts: Yeah. I think anytime there's a conference—whether that's ASCO, ESMO, San Antonio, you name it—there's a lot of data that's very exciting to say, “Let's hit the ground running with this. Let's adopt it on Monday. This is great.” So I think we really need to be careful in that just because there's data for a particular regimen doesn't mean that it's ready for prime time. It doesn't mean that it's ready for every single patient. So I think we really need to be critical of that data, and I think we need to be really intentional and pragmatic in how we're utilizing that data. Sometimes we kind of need to cool our jets and let the dust settle a little bit before we really determine how this new, exciting data should be put into practice.

You know, there's always downstream consequences with payers, costs, toxicities, complexity of sequencing—all these things always come into play. It feels like you get one therapy, and then there's ten other questions that follow in terms of how we should be using it. So cautiously optimistic of what we're seeing, but yeah, there's always a certain degree of pause, I think, that we should have with new data.