Real-World Use Patterns, Effectiveness, and Tolerability of Sacituzumab Govitecan for Triple-Negative Breast Cancer With Kevin Kalinsky, MD, MS

Oncology Data Advisor: Welcome to Oncology Data Advisor, an online resource for the multidisciplinary cancer team. Today, we are joined by Dr. Kevin Kalinsky, who is the Director of the Glenn Family Breast Center at Winship Cancer Institute of Emory University. Dr. Kalinsky is here to share with us the results he presented at ESMO regarding real-world use patterns, effectiveness, and tolerability of sacituzumab govitecan for second-line or later treatment of metastatic triple-negative breast cancer.

Thank you for joining us today, Dr. Kalinsky. Would you like to introduce yourself and your research and what you do?

Kevin Kalinsky, MD, MS: Hello, I am Kevin Kalinsky. I'm a Professor of Medicine and Director of the Glenn Family Breast Center at Emory University, Winship Cancer Institute, and I'm a Breast Cancer Medical Oncologist.

Oncology Data Advisor: Awesome and thank you again for joining us today. So, we'll start out with this first question. We are wondering, what were the results regarding the real-world use patterns, effectiveness, and tolerability of sacituzumab govitecan for second-line and later treatment metastatic triple-negative breast cancer that you're presenting at ESMO?

Dr. Kalinsky: So, for our patients with metastatic triple-negative breast cancer, we'd seen from the ASCENT trial, which was a pivotal phase 3 trial, that there was an overall survival benefit, as well as improvement in progression-free survival and response when we looked at chemotherapy compared to sacituzumab govitecan. Sacituzumab govitecan was clearly statistically significant and clinically significant, doing much better. So, it became a standard of care.

One of our concerns when we look at a clinical trial population is whether, given the strict criteria that we have for patients going into clinical trials, this is reflected in a real-world setting. And so, that's why we undertook the analysis that we did. Ultimately, we showed that in fact the efficacy that we see for patients with metastatic triple-negative breast cancer in terms of the overall survival looks relatively similar to what we saw in the ASCENT study in that the median overall survival in the real world was 14 months—around 14 months—for those patients who were receiving it second-line. Then if patients were receiving it more than second-line, the overall survival was a little bit less at about 10 months. We also saw that the rate of discontinuation, toxicities, and management of these toxicities was relatively similar to what we saw in the clinical trial.

Oncology Data Advisor: I wanted to ask if you had more detail you would like to go into about how these results differed from other clinical trials of sacituzumab govitecan.

Dr. Kalinsky: Right. So, one of the notable aspects of this real-world analysis is that it's a diverse patient population. Nearly a quarter of patients were identified as Black, and one of the issues that we have in clinical trials across the board is that our underrepresented minorities are underrepresented in these clinical trials. In the ASCENT trial, that rate was around 10% or so. And so, in this analysis, which included patients with a diverse background, we're seeing this benefit that had a real-world overall survival that was similar to what was reported in the ASCENT trial.

The other thing that commonly comes up is the utilization of growth factors, and this was something that was captured in the ASCENT trial because one of the main side effects that we can see with sacituzumab in the real world, beyond patients losing their hair and besides gastrointestinal issues, one of the practical issues is that it can decrease your white cells. We saw that approximately a little shy of 60% of patients required growth factor support, also, understanding that the majority of those patients had received growth factors support from their prior chemotherapy as well.

Oncology Data Advisor: Just to touch on what you had said about how this trial was more diverse and everything, I think that is definitely really exciting, I was wondering if you could touch on how you believe these results in any way could change the future landscape of how we treat TNBC.

Dr. Kalinsky: It's important for our patients when we're giving them agents that we know that it's offering benefit across the spectrum of patients, that it's not just biased to a specific cohort of patients. What I will say is we did look to see whether there are any differences in terms of outcome, including improvement in survival between different races, and we did not see that. To me, that was encouraging because it's just reiterating the importance that we utilize sacituzumab in our patients right now with metastatic triple-negative breast cancer. The other comment that I'll make is that we did see dose reductions and interruptions due to side effects. About a quarter of patients required a dose reduction, and about 7% of patients had to discontinue due to side effects. And so, it's important that we be aware of these potential side effects when we think about offering patients these drugs. But to me, these data mostly are just reassuring that what we've seen in a clinical trial population applies to patients in the real world as well.

Oncology Data Advisor: Would like to comment on what you believe the future direction are for this research regarding real-world use patterns, effectiveness, and tolerability, what that would be like?

Dr. Kalinsky: It's important across the board that when we have new treatments for our patients, we are also evaluating how these drugs do both efficacy-wise and tolerability-wise in the real world, so now we've done this with sacituzumab. I think ongoing questions in the metastatic triple-negative space will include questions such as whether there are any predictors for toxicity. The other potentially question, as additional agents are approved in the metastatic space, is sequencing of these drugs—if there are additional antibody-drug conjugates (ADCs), how we should be utilizing these agents in the real world, because sometimes those are the means by which we're able to address important questions.

Oncology Data Advisor: Definitely. Final question that I have for you is if there are any additional abstracts from ESMO you'd like to highlight regarding metastatic TNBC or any others that you think we should keep an eye on?

Dr. Kalinsky: So, for metastatic triple-negative breast cancer, I'll say at ESMO, the studies that are being presented are primarily early-phase studies, including antibody-drug conjugates, other mechanisms of targeting different alterations on the tumor such as B7-H4, targeted therapies, additional Trop-2 antibody data that we'll be seeing. But for metastatic triple-negative breast cancer, what I would say is those are, at least what's being presented at ESMO, early-on in development and exciting, but these data that we're presenting today are reflecting our current clinical practice and reinforce how we've been treating patients.

Oncology Data Advisor: Excellent. It's definitely exciting, and we'll keep an eye out for this research, and we'll definitely keep up with you in the future. I wanted to thank you so much for your time and your research, Dr. Kalinsky. I appreciate it.

Dr. Kalinsky: Great. Thanks for including me.

About Dr. Kalinsky

Kevin Kalinsky, MD, MS, is a Breast Medical Oncologist, Professor of Medicine, and Director of the Glenn Family Breast Center at Emory University, Winship Cancer Institute. Dr. Kalinsky's research and passion revolves around evolving the treatment landscape and developing new therapeutic approaches for breast cancer, as well as further developing prevention methods.

Transcript edited for clarity. Any views expressed above are the speaker's own and do not necessarily reflect those of Oncology Data Advisor.