Breast Cancer Experts Spotlight Early-Phase and Real-World Research at the 2024 ESMO Congress

Paolo Tarantino, MD

For those who missed any key sessions in breast cancer at the 2024 ESMO Congress, or those who just want to know more about trends and updates across the field, breast cancer experts sat down in a series of interviews with OncLive® to spotlight studies of interest from the conference. Read on to see their thoughts and insights.

Paolo Tarantino, MDolo Tarantino, MD, of Dana-Farber Cancer Institute

A very interesting phase 2 neoadjuvant trial [NCT03815890] was presented that evaluated the combination of either nivolumab [Opdivo] and ipilimumab [Yervoy]for 2 infusions, or nivolumab and relatlimab-rmbw [Opdualag], an anti–LAG-3 antibody, among patients with primarily stage I/II triple-negative breast cancer [TNBC] and high tumor-infiltrating lymphocytes [TILs], [defined as] more than 50%. We're talking about just 2 infusions of immunotherapy.

Patients saw an approximately 50% pathologic complete response [pCR] rate. There were severe toxicities with the nivolumab and ipilimumab combination, including permanent toxicities. However, with relatlimab and nivolumab, there were much less toxicities. That is a very appealing strategy, and short-term immunotherapy treatment for patients with TNBC and high TILs. The pCR is similar to what you would expect with multi-agent chemotherapy. These data were published in Nature Medicine, and I look forward seeing more from the dataset.

Oleg Gluz, MD, of Breast Center Niederrhein

A [real-world] registry-based trial from the Netherlands on patients with stage I TNBC [is an important one to highlight]. This is a large group of patients, particularly in Germany, and [comprises] 30% of patients with TNBC. [However,] we don’t have any data for this patient group [regarding] what would be the best [neoadjuvant] chemotherapy.

Our investigators analyzed approximately 600 patients with stage I disease and provided some interesting insights, such as the prognostic [value] of pCR in this small TNBC subset. However, the combination of anthracycline or taxane and carboplatin does not provide additional benefit vs carboplatin-free treatment. This trial will be important to discuss during tumor boards [and for making] decisions in my own weekly practice.

Nicholas P. McAndrew, MD, MSCE, of the University of California, Los Angeles Health

A [real-world] neoadjuvant study in TNBC evaluated patients with stage I disease who received neoadjuvant chemotherapy. It showed that, interestingly, patients who did not achieve a complete response [CR] with neoadjuvant chemotherapy and had stage I TNBC had a 4-year overall survival rate of 93%. These are early-stage patients, and T1 tumors were [included]. This is a group in which we're not necessarily using neoadjuvant therapy a lot of the time.

However, if we identify patients who don't have a CR, their risk is still substantially high. Seven percent of them are not alive at 4 years; that's substantial. There's a lot of additional work to be done, and it makes sense to consider using neoadjuvant therapy in stage I TNBC to risk stratify patients for future considerations of therapeutic approaches.

Maria Vittoria Dieci, MD, of the University of Padua

The ESMO Congress is an incredible platform for research, and there are many studies, especially in the poster sessions, that deserve attention. I would like to highlight a poster that was presented by [my colleague] Federica Miglietta, [an oncology fellow at the University of Padua] on the expression of PD-L1, which is the biomarker used to select patients for immunotherapy in the metastatic setting for TNBC. She evaluated PD-L1 status in the metastatic samples of patients with triple-negative and estrogen receptor [ER]–low PD-1--negative tumors. We know, for example, that in Italy there is no access to immunotherapy for patients with low ER expression, meaning expression between 1% and 9% whereas in some other countries, patients with ER-low, HER2-negative disease are considered as triple-negative in terms of immunotherapy eligibility. There is this gap across countries, so we asked ourselves whether it was useful to evaluate PD-L1 in this population, and what the rate of PD-1 positivity is.

We found that there was no difference in the rate of PD-L1 positivity between classic TNBC and ER-low metastatic breast cancer. Moreover, we also looked at those cases [in which patients] switched from ER-positive with a HER2-negative phenotype in the primary tumor to a TNBC or ER-low, HER2-negative phenotype. In these patients, PD-L1 status in the metastatic samples were similar to those [patients] who were triple negative at [baseline and remained so]. This reinforces the concept of re-biopsy at first relapse, to re-characterize and confirm the diagnosis of relapsed breast cancer, and also to re-characterize the tumor phenotype. If it turns out to be TNBC or ER-low disease, PD-1 status should be evaluated [so oncologists can] discuss the opportunity [for the patient to] start a new therapy.

Nancy Lin, MD, of Dana-Farber Cancer Institute

There were a series of talks and abstracts related to endocrine therapy in premenopausal patients with ER-positive breast cancer. These covered the gamut, including the role of ovarian suppression in patients with HER2-positive breast cancer. In fact, there's quite a remarkable effect size there. [Another study] looked at the impact of adherence in young women taking endocrine therapy for breast cancer, where reduced adherence led to detriment in outcomes. Those were some important findings that we can use in our daily practice as we counsel young patients [receiving] endocrine therapy, which of course has adverse effects [AEs]. It's so important [for a patient] to understand what they’re getting from those AEs.

For more of OncLive’s coverage from the 2024 ESMO Congress, click here.