A measure of tumor DNA repair function may identify patients with metastatic triple-negative breast cancer (mTNBC) without mutations who could benefit from platinum therapy agents, a new study published online early in theJournal of Clinical Oncology has shown.

For the single-arm phase II study, researchers sought to identify those with mTNBC who are expected to benefit from platinum-based chemotherapy. Researchers identified 86 patients and all patients received either first- or second-line cisplatin 75mg/m2 or carboplatin AUC 6 every 3 weeks.

Results showed that the overall response rate 25.6% (95% CI: 16.8-36) and 54.5% in patients with germline BRCA1/2 mutations.

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Researchers found that a “BRCA-like genomic instability signature discriminated responding and nonresponding tumors.”

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In addition, five of the six long-term responders to platinum therapy alive at a median of 4.5 years lacked germline BRCA1/2 mutations, and two had increased tumor HRD-LOH/HRD-LST scores, a measure of tumor DNA repair function.

The authors conclude that further prospective controlled trials are warranted to confirm these findings.

Preliminary findings were presented at the 35th Annual San Antonio Breast Cancer Symposium in San Antonio, Texas, in 2012.


  1. Isakoff SJ, Mayer EL, He L, et al. TBCRC009: a multicenter phase II clinical trial of platinum monotherapy with biomarker assessment in metastatic triple-negative breast cancer. J Clin Oncol. 2015. [Epub ahead of print]. doi: 10.1200/JCO.2014.57.6660.