On July 30, 2024 Agendia, Inc. reported that the NSABP B-42 study evaluating the MammaPrint assay in predicting the benefit of extended endocrine therapy (EET) in early-stage breast cancer patients was published in the July issue of Journal of Clinical Oncology (Press release, Agendia, JUL 30, 2024, View Source [SID1234645189]).

Schedule your 30 min Free 1stOncology Demo!
Discover why more than 1,500 members use 1stOncology™ to excel in:

Early/Late Stage Pipeline Development - Target Scouting - Clinical Biomarkers - Indication Selection & Expansion - BD&L Contacts - Conference Reports - Combinatorial Drug Settings - Companion Diagnostics - Drug Repositioning - First-in-class Analysis - Competitive Analysis - Deals & Licensing

                  Schedule Your 30 min Free Demo!

The published study, Utility of the 70-gene MammaPrint Assay for Prediction of Benefit from Extended Letrozole Therapy in the NRG Oncology/NSABP B-42 Trial, found that MammaPrint was predictive of EET benefit in early-stage hormone receptor positive (HR+) breast cancer patients who were classified by MammaPrint (MP) as Low Risk (0.000 to +0.355), having exhibited improved outcomes with EET.

NSABP B-42 (NCT00382070) was a prospective randomized, double-blind, placebo-controlled, phase III trial that enrolled 3,966 postmenopausal women with HR+ early-stage breast cancer who were disease-free after 5 years of endocrine therapy (with an Aromatase inhibitor (AI) or ≥3 years of tamoxifen followed by an AI). Patients were then randomized to receive 5 additional years of either letrozole or placebo. Results showed EET modestly reduced risk of recurrence in postmenopausal women and established a need to further stratify patients who could benefit from EET.

In a subset of 1,866 randomized patients, which were representative of the parent trial, MammaPrint classified tumors as either MammaPrint High Risk (n=706) or MammaPrint Low Risk (n=1160). MammaPrint Low Risk tumors were further stratified into UltraLow Risk (+0.356 to +1.000) (n=252) or Low (non-UltraLow) Risk (n=908). The data revealed that only MammaPrint Low (non-UltraLow) Risk tumors showed a statistically significant 10-year EET benefit of 9.5% for disease-free survival (DFS) and 7.9% for breast cancer-free interval (BCFI). Conversely, MammaPrint UltraLow and High Risk tumors did not derive statistically significant EET benefit. This highlights that MammaPrint Low (non-UltraLow) Risk is a predictive biomarker for improved outcomes with EET. These findings underscore MammaPrint’s utility in accurately predicting a subset of patients who benefit from the addition of EET to their treatment regimens, establishing MammaPrint as the most comprehensive standalone genomic test for short and long-term treatment planning.

"The work published by the NSABP B-42 group confirms the utility of MammaPrint for identifying women with early-stage HR+ breast cancer who will or will not benefit from extended endocrine therapy," said William Audeh, MD, MS, Chief Medical Officer at Agendia. "While we know that clinical factors are associated with the risk of developing a late recurrence in ER+ breast cancer, they do not indicate whether those late recurrences are preventable. These data support the utility of MammaPrint in predicting which women have a risk of late recurrence which is preventable by extended endocrine therapy. We are pleased to be able to add this study to the growing body of literature supporting the use of MammaPrint for answering many important questions in early breast cancer management with the goal of improving the standard of care in breast cancer."