At the recent San Antonio Breast Cancer Symposium (SABCS), researchers from around the world presented breaking developments in the treatment and care of patients with breast cancer. In this interview, Dr. Jason Mouabbi, an Assistant Professor in the Development of Breast Medical Oncology at The University of Texas MD Anderson Cancer Center, shares the four abstracts which he believes will have the greatest impact on practice in the year to come.

Oncology Data Advisor: Welcome to Oncology Data Advisor, a resource for the multidisciplinary cancer team. Today I'm joined by Dr. Jason Mouabbi of the MD Anderson Cancer Center, to go over updates and highlights from the recent San Antonio Breast Cancer Symposium (SABCS).

Jason Mouabbi, MD: Hello everyone. I'm Jason Mouabbi from MD Anderson. I'm a Breast Medical Oncologist, and I'm here today to talk to you about the best of the San Antonio Breast Cancer Symposium 2022. I would like to highlight four abstracts that were presented that have the most implications to be practice changing in 2023.

The first abstract was presented at one of the general sessions for the study called CAPItello. This study looked at a protein kinase B (AKT) inhibitor called capivasertib in combination with endocrine therapy in patients who progressed on a prior endocrine therapy in the metastatic setting and who have hormone receptor–positive, HER2-low or negative breast cancer. This study met its primary end point, which is improvement of progression-free survival in all patients who received the drug. The improvement was seen as almost doubling of the progression-free survival, and it also met its secondary end point where it also improved the outcomes in patient with an altered mutation in the phosphatidylinositol-3 (PI3K) kinase/AKT/mammalian target of rapamycin (mTOR) pathway. So, this is a very exciting treatment because it's an area of unmet need and having more therapies available will really expand the landscape for our patients.

The second abstract that also might change practice in the upcoming year is the Serena 2 study that was also presented in one of general sessions, and here we looked at an oral selective estrogen receptor degrader (SERD) called camizestrant. It met its primary end point when they compared it against fulvestrant by showing also almost doubling of the progression-free survival. Now of course, overall survival data are still immature at this point, but this is very exciting because we are in need of those oral SERDs. Last year in San Antonio, we saw one of them come into the landscape, which is called elacestrant, and this year there is a second one with the short, exciting efficacy called camizestrant.

The third abstract that I selected that might also have some implication right now, on Monday, going back to our clinic, is called the RIGHT choice study. Historically, we thought that patients with metastatic breast cancer that have aggressive subtypes, meaning they have visceral crisis, compromised organs and so forth. We felt like instead of giving them endocrine therapy plus the target therapy, we should be treating them with chemotherapy. This study was made to challenge that, so they randomized patients to chemotherapy versus endocrine therapy, plus a CDK4/6 inhibitor, and they found that using endocrine therapy plus a CDK4/6 inhibitor is better than using chemotherapy. Those patients had better outcomes when they compared to chemotherapy, and better response rates to that endocrine therapy plus CDK4/6 inhibitor. So, this is something that has implication right away for our treatment paradigm.

The last abstract that I want to highlight, it's also something that we can start using the first day back to clinic is called the POSITIVE trial. This study looked at two things: first, was the outcomes of patients that are premenopausal that are on endocrine therapy that want to interrupt briefly their endocrine therapy to get pregnant. So, they looked at their outcomes when they interrupt this endocrine therapy. The other thing they looked at is whether it's safe and the outcome of the pregnancy. Although the study showed a short-term follow-up; however, it seems to be a safe thing to do, meaning that we can interrupt endocrine therapy for a short period of time. In the study they looked at two years of interruption, where the patient was allowed to stop the treatment she's on in order to get pregnant and deliver a baby. They found that the outcomes on the baby, again, a short-term and follow-up, but it seems to be safe.

This is very exciting. A lot of patients ask us, "Is it safe for me to stop the endocrine therapy and get pregnant?" Now we have at least some data that says that, at least in the short-term, it is safe. Of course, the study will need long-term follow-up, and, in the future, we will get better data on whether it's safe in the long run. Thank you very much.

Oncology Data Advisor: Thank you, Dr. Mouabbi. That's great information. Thank you so much for updating us and giving us this great information.

Dr. Mouabbi: Thank you.

About Dr. Mouabbi

Jason Mouabbi, MD, is an Assistant Professor in the Department of Breast Medical Oncology at The University of Texas MD Anderson Cancer Center, where his research focuses on the management of breast cancer subtypes and their impact on treatment, with specific specialization and interest in lobular breast cancer. Dr. Mouabbi has been the recipient of multiple honors and awards, including the Guiding Researchers and Advocates to Scientific Partnerships (GRASP) Advocate Choice Award in 2022 and the Lester & Sue Smith Breast Cancer Award of Excellence in 2021.

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