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SABCS 2025: EBC

CME

Decera Clinical Education Independent Conference Highlights of the San Antonio Breast Cancer Symposium 2025: Early Breast Cancer

Physicians: Maximum of 0.50 AMA PRA Category 1 Credit™

Released: March 02, 2026

Expiration: September 01, 2026

Virginia Kaklamani
Virginia Kaklamani, MD, DSc
Erica L. Mayer
Erica L. Mayer, MD, MPH, FASCO
CME/CE Information

Activity

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CITRINE: Adjuvant Carboplatin Intensified Chemotherapy vs SoC Chemotherapy in Patients With High-Risk Early TNBC

Erica L. Mayer, MD, MPH, FASCO:
An abstract of interest that was presented at SABCS 2025 was the phase III CITRINE trial evaluating adjuvant carboplatin-intensified chemotherapy vs SoC chemotherapy in patients with high-risk early triple-negative breast cancer (TNBC) (n =  800). 

The CITRINE study enrolled patients who had either node-positive or node-negative disease, and patients were randomized to receive dose-dense epirubicin plus cyclophosphamide and paclitaxel with or without carboplatin. The primary endpoint was DFS, and the key secondary endpoints were recurrence-free survival, DDFS, OS, and safety.19 

Of note, the CITRINE trial asked the question: Does the addition of carboplatin to SoC anthracycline- and taxane-based chemotherapy regimens add benefit? This is an important question because it has been a point of debate over the past decade, as studies and meta-analyses in both the preoperative and adjuvant settings have tried to provide the answer.

CITRINE: DFS (Primary Endpoint)

Erica L. Mayer, MD, MPH, FASCO:
After a median follow-up of 44.7 months, investigators showed that the addition of carboplatin led to a significant improvement in DFS by approximately 7% compared with the SoC regimen (hazard ratio: 0.64; 95% CI: 0.43-0.95; P = .03). Of interest, the benefit provided by adding carboplatin occurred quite early in the first year when the curves first began to separate. Between 1 and 3 years, the curves stabilize and remain parallel. Therefore, the addition of carboplatin appears to have an effect in those patients with early disease recurrence.

Results for recurrence-free survival, DFS, and OS showed similar trends in numeric benefit with the carboplatin-intensified chemotherapy vs SoC chemotherapy.19

CITRINE: Safety Summary

Erica L. Mayer, MD, MPH, FASCO:
Let us look at the safety data for this study. More grade 3/4 treatment-related AEs were reported in the carboplatin arm vs the SoC arm (66.7% vs 55.0%, respectively). Although this number is higher numerically, I would not say it is dramatically higher. In general, AEs were reasonably balanced between both study arms, and discontinuations due to AEs were less common in the carboplatin arm (0.5%) vs the SoC arm (4.5%).19

These findings help answer the previously posed question. If you are giving adjuvant anthracycline- and taxane-based chemotherapy to patients with TNBC, it is reasonable to consider the addition of carboplatin. However, as far as the relevance of these data, particularly for those with access to the KEYNOTE-522 regimen, this combination is of less value since most patients with stage II to III TNBC should receive neoadjuvant chemotherapy plus pembrolizumab.20 They would not be candidates for the type of adjuvant approach studied in CITRINE.

In a country that does not have easy access to preoperative pembrolizumab, adjuvant carboplatin-intensified chemotherapy would be reasonable to consider. Furthermore, some patients do not receive preoperative therapy and end up having significant disease at the time of surgery.

Studies of Neoadjuvant PARPi Plus PD-1/PD-L1 Inhibitors in EBC

Erica L. Mayer, MD, MPH, FASCO:
The last 2 studies I wish to focus on are evaluating PARP use in TNBC. The first study is called TBCRC-056, and the second is called OlympiaN. Set in the neoadjuvant setting, both studies enrolled patients with BRCA-mutated early TNBC. These are patients for whom we often use PARP inhibitors at different points in their treatment. In these studies, investigators wanted to look at the activity of preoperative PARP inhibitor therapy. Prior efforts in this space have demonstrated a pCR rate of 53% with 6-month talazoparib monotherapy.21 What makes TBCRC-056 and OlympiaN different is that both studies were designed to evaluate neoadjuvant treatment with a PARP inhibitor and PD-1/L1 inhibitor.

First, I will discuss the TBCRC-056 trial in more detail. This study specifically enrolled patients with stage I-III BRCA- or PALB2-mutated TNBC; the SABCS 2025 report focuses on those with early TNBC (n = 46). Of these patients, 37% had stage I, 46% had stage II, and 17% had stage III TNBC. Furthermore, approximately 25% had node-positive disease. Patients were randomized into 2 cohorts. Cohort A received upfront niraparib plus dostarlimab for 18 weeks, whereas cohort B was treated with niraparib monotherapy for 3 weeks followed by niraparib plus dostarlimab for 15 weeks. After which, patients in both cohorts either underwent surgery or continued additional preoperative treatment for residual disease.  The coprimary endpoints were pCR in both study arms combined and change in stromal tumor-infiltrating lymphocytes at 3 weeks in each study arm.

The pCR rate was 50% (90% CI: 37.1-62.9) for both study arms, and the residual cancer burden 0/1 rate was 60%. There was a high level of activity with niraparib with or without dostarlimab, including among those with node-positive and stage III disease. In addition, TBCRC-056 demonstrated that both treatment approaches led to significant increases in stromal tumor-infiltrating lymphocytes—an 11.4% increase with niraparib plus dostarlimab (P = .009) and 22.7% increase with niraparib monotherapy (P = .0003). Therefore, both arms met the coprimary endpoints.

In general, the reported AEs were representative of the known safety profiles for niraparib and dostarlimab. Although most patients were able to complete treatment, approximately 13% discontinued therapy due to early toxicities or inadequate response/disease progression.22

Now let us look at the OlympiaN trial. It also enrolled patients with stage I to II BRCA-mutated TNBC and separated them into 2 cohorts. Cohort A comprised those at “very-low risk” (ie, stage T1B-C/N0) and were treated with olaparib monotherapy; cohort B included those at “low risk” (ie, stage T2/N0 or T1/N1) and were treated with olaparib plus durvalumab. Both arms received treatment for 4-6 cycles, which was then followed by surgery. The primary endpoint was pCR.

Because these patients generally had node-negative and stage T1B or T1C, this study evaluated a lower-risk population compared with the TBCRC-056 trial. Yet the pCR rates in OlympiaN were robust—68% in cohort A and 80% in cohort B. Furthermore, the residual cancer burden 0/1 rate was 84% across both cohorts. Finally, the observed AEs were consistent with the known safety profiles of olaparib and durvalumab.23

Data from the 2 studies suggest that we may have the option to take a nonchemotherapy treatment approach, particularly built around the use of prolonged PARP inhibitor therapy in the setting, for patients with BRCA-mutated early TNBC. The patients in these studies achieved pCR rates that are not much dissimilar than what was seen in KEYNOTE-522.20

These studies could not answer 1 key question, which is: ‘What is the contribution of the immunotherapy agent in this setting?’ Both studies will have extensive correlative analyses that will try to dissect what the PD-(L)1 inhibitor is contributing. Future work will need to help us identify the patients who will have a remarkable response and be ideal candidates for this treatment approach in the future. 

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