A Look Ahead to the 2020 SABCS Virtual Symposium

At the 2020 SABCS Virtual Symposium, important results from many clinical trials on breast cancer will be reported. Here, renowned experts have highlighted some of their most anticipated abstracts, which will be covered online as a part of CCO’s Independent Conference Coverage of SABCS 2020. After the meeting, remember to check the CCO Web site for a downloadable highlights slideset summarizing the data from these studies and a CME-certified online expert analysis activity featuring expert commentaries on the clinical implications of the data.

Top Picks: Early Breast Cancer
The most anticipated results from SABCS 2020 likely to have an impact on patient care are in the setting of early breast cancer (EBC). Results will be presented from the phase III PENELOPE-B (GS1-02) and monarchE (GS1-01) trials evaluating adjuvant CDK4/6 inhibitor therapy in combination with standard adjuvant endocrine therapy for patients with hormone receptor (HR)–positive/HER2-negative EBC at high risk of relapse after completion of locoregional therapy with (neo)adjuvant chemotherapy. PENELOPE-B is the second study of adjuvant palbociclib in the curative setting that failed to demonstrate a benefit in patients with higher-risk HR-positive/HER2-negative EBC. This is in contrast to monarchE that did show a reduction in the risk of recurrence with adjuvant abemaciclib in this patient population. As some oncologists are beginning to prescribe adjuvant abemaciclib for patients with very high–risk EBC prior to its approval by the FDA, SABCS 2020 will provide an important update of the monarchE data.

Advances in how to optimally use adjuvant chemotherapy, endocrine therapy, and radiation therapy for EBC will also be presented. The prospective, randomized phase III SWOG S1007 RxPonder Trial (GS3-00) is one of the most important trials at SABCS 2020 as it will tell us whether premenopausal or postmenopausal patients with HR-positive/HER2-negative EBC, 1-3 positive lymph nodes, and a 21-gene recurrence score of 0-25 will benefit from adjuvant chemotherapy in addition to standard adjuvant endocrine therapy. Similarly, the ADAPT HR+/HER2- trial (GS4-04) will also inform whether patients with intermediate or high-risk luminal HR-positive/HER2-negative EBC (0-3 positive lymph nodes) and a recurrence score < 26 can benefit from endocrine therapy alone in the adjuvant setting. Finally, data from the PRIME RT trial (GS2-03) may support the omission of radiation in patients older than 64 years of age with lower-risk HR-positive/HER2-negative EBC.

Additional Studies of Potential Interest
The CCO Conference Coverage of SABCS 2020 will also include coverage of additional important studies in EBC, including:

• GS4-10 and GS4-11: Development and validation of prognostic tools for EBC
• PD3-03: Final OS analysis from the phase III ExteNET trial evaluating adjuvant neratinib in patients with HER2-positive EBC

Top Picks: Metastatic Breast Cancer
There are also studies of note in the setting of metastatic breast cancer (MBC) being reported at SABCS 2020. For patients with HR-positive/HER2-negative MBC who previously received neoadjuvant or adjuvant taxane in the early-disease setting, positive results from the phase III CONTESSA trial (GS4-01) evaluating the all-oral regimen of tesetaxel, a novel oral taxane, plus a reduced dose of capecitabine vs capecitabine alone will be presented.

For patients with locally recurrent inoperable or metastatic triple-negative breast cancer (TNBC), an update of the phase III KEYNOTE-355 study (GS3-01) will provide key information on PFS outcomes for each chemotherapy partner as well as additional efficacy endpoints for first-line pembrolizumab plus chemotherapy. This therapy was approved by the FDA in November 2020 for patients with locally recurrent unresectable or metastatic TNBC and PD-L1 positive with CPS ≥ 10, based on the significant PFS benefit shown in a prespecified interim analysis of KEYNOTE-355.

Additional Studies of Potential Interest
The CCO Conference Coverage of SABCS 2020 will also include coverage of additional important studies in MBC including:

• GS1-04: A biomarker analysis across the phase III MONALESSA studies correlating PFS benefit with ribociclib and intrinsic advanced breast cancer subtype in patients with HR-positive/HER2-negative MBC
• GS3-04: Primary results from cohort A of the phase III IPATunity130 trial evaluating first-line ipatasertib plus paclitaxel for PIK3CA/AKT1/PTEN-altered advanced TNBC
• GS4-02: Final analysis of the phase III E2112 study evaluating addition of entinostat to endocrine therapy for HR-positive MBC
• PD2-07: Evaluation of alpelisib plus letrozole in patients with PIK3CA-mutated, HR-positive/HER2-negative MBC after progression on a CDK4/6 inhibitor plus fulvestrant in the phase III BYLieve study
• PD3-08 and PD13-04: Updates from the phase II HER2CLIMB trial looking at outcomes with tucatinib plus trastuzumab/capecitabine by HR status in patients with HER2-positive MBC as well as the impact of tucatinib on health-related quality of life in patients who have active brain metastases
• PD13-09 and PS9-02: Updates from the phase III NALA trial looking at outcomes with neratinib plus capecitabine in patients with HER2-positive MBC and baseline central nervous system disease as well as the impact of this regimen on health-related quality of life
• PD1-05: Latest findings from the phase II SUMMIT basket trial on neratinib plus trastuzumab plus fulvestrant for HR-positive MBC with activating HER2 mutations

Remember to Check Back!
Please check back to the CCO Web site after the meeting to get more information about these interesting and important studies from SABCS 2020, including a downloadable highlights slideset along with a CME-certified expert analysis activity where these experts will explore the clinical implications of the data.

Your Thoughts
What studies being presented at SABCS 2020 are you most interested in and do you think will have the biggest impact on clinical practice? Join the conversation below!