New Test May Predict Chemo Benefit in Breast Cancer

Updated NCCN Clinical Practice Guidelines in Oncology now recognize that MammaPrint and BluePrint testing can help identify a specific subset of hormone receptor positive, HER2-negative (HR+/HER2–) early-stage breast cancer patients most likely to benefit from anthracycline-based chemotherapy, Agendia, Inc. announced in a news release.

By using these precision oncology tools, healthcare providers can better determine which patients with cancer should receive more intensive treatment based on the specific genomic profile of their tumors.

Main data that support the findings

The updated guidelines are based on a three-year analysis of outcomes from a cohort of 1,261 patients with HR+/HER2- early-stage breast cancer. The findings show that patients categorized as MammaPrint High Risk 2 and BluePrint Luminal B derive the most significant benefit from anthracycline-based therapy.

Specifically, the study compared two types of treatment: adjuvant taxane with cyclophosphamide (TC) and anthracycline and taxane-based chemotherapy (AC-T). For patients in the High Risk 2 and Luminal B group, those treated with TC had a significantly worse three-year invasive disease-free survival (IDFS) of 89.3%. In contrast, patients in this same category who received AC-T had a 100% three-year IDFS, representing an absolute benefit of 10.7% for the anthracycline-based regimen.

The data for patients with MammaPrint High Risk 1 and BluePrint Luminal B tumors showed different results. In this group, there was no significant difference in three-year IDFS between those who received AC-T (95.6%) and those who received TC (94.6%). This suggest that patients with High Risk 1 tumors do not derive a meaningful benefit from the addition of anthracyclines to their chemotherapy plan.

"I am delighted that oncologists finally have a way to identify HR+/HER2- early breast cancer patients who will benefit from anthracycline therapy," said Dr. Joyce A. O’Shaughnessy, principal investigator for the FLEX Study and a member of CURE’s advisory board, in the news release. "I think the biologic rationale and the data underpinning the observation that High Risk 2 Luminal (by BluePrint) breast cancer patients benefit from anthracycline therapy are quite strong."

Trial details

The evidence for the guideline update comes from the prospective, real-world FLEX Study. This analysis included 1,261 patients with HR+/HER2- early-stage breast cancer who were followed for a median of 3.2 years. These patients were classified with MammaPrint High Risk 1 or High Risk 2 scores and were treated with either TC or AC-T chemotherapy.

To ensure the data were reliable, researchers used propensity score matching to balance differences between the treatment groups. This process accounted for factors such as age, tumor size and nodal status for both the High Risk 1 and High Risk 2 groups separately.

"The NCCN guideline update is based on the strongest real-world evidence to date that MammaPrint can help identify which patients are most likely to benefit from anthracycline-based therapy," said Dr. William Audeh, chief medical officer at Agendia, in the news release. He noted that the FLEX study reinforces the value of using precision genomics to tailor treatments to the underlying biology of a tumor.

Safety

Anthracycline-based chemotherapy regimens are among the most effective adjuvant treatments for early-stage breast cancer. These treatments can lower the yearly risk of death by at least one third compared to not receiving chemotherapy. However, for some patients, the absolute benefit of this treatment may be small when compared to potential side effects.

Short-term toxicity and longer-term risks are important considerations for patients and caregivers. These risks include cardiotoxicity and secondary leukemia. Because of these potential complications, there has been uncertainty regarding how to select the optimal regimen for each individual. The use of MammaPrint and BluePrint helps resolve this uncertainty by identifying which patients have the most to gain from these intensive treatments and which patients may be able to avoid them.

Reference:

1. “Agendia Announces NCCN Guideline Update Recognizing MammaPrint to Guide Personalized Anthracycline Use in HR+/HER2- Early‑Stage Breast Cancer,” news release; https://agendia.com/agendia-announces-nccn-guideline-update-recognizing-mammaprint-to-guide-personalized-anthracycline-use-in-hr-her2-early-stage-breast-cancer/

Editor's note: This article is for informational purposes only and is not a substitute for professional medical advice, as your own experience will be unique. Use this article to guide discussions with your oncologist. Content was generated with AI and reviewed by a human editor.

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