Transparent tumor tomography visualising tumor microenvironment, showing vascular network in a mouse model for HER2-positive breast cancer
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Dana-Farber Cancer Institute investigators have found that a year of treatment with an antibody and chemotherapy drug conjugate is highly effective at preventing recurrence of HER2-positive breast cancer in patients with stage 1 disease. The Phase II ATEMPT clinical study, published in the Journal of Clinical Oncology, showed that 97% of the patients treated with a trastuzumab emtansine (T-DM1) after surgery were still living and free of invasive cancer five years after treatment.

The researchers also sought to identify biomarkers over the course of the study to determine which patients were most likely to have their cancer recur and found that those who scored higher on the HER2DX test, measure of clinical factors and the activity of four genes in the tumor tissue, had a higher risk of recurrence.

“Patients with stage 1 HER2-positive breast cancer have recurrence rates of 5–30%. Post-surgical treatment with chemotherapy and the antibody trastuzumab, which binds to HER2, can significantly reduce the risk of recurrence in these patients. But the side effects can have a detrimental impact on patients’ quality of life,” said lead author Paolo Tarantino, MD, a clinical research fellow at Dana-Farber and researcher at the European Institute of Oncology in Milan, Italy. “In this study, we evaluated T-DM1, which links trastuzumab to a powerful chemotherapy agent, for effectiveness and toxicity in this group of patients.”

The trial enrolled 512 patients at cancer centers in the U.S. with 384 of them receiving T-DM1 and the remaining 128 treated with chemotherapy and trastuzumab. After five years, 97% of the T-DM1 patients showed no evidence of recurrence and the rate of clinically relevant toxicities between the treatments was similar to those in the chemotherapy-trastuzumab cohort.

However, the study also showed that patient-reported outcomes pointed to better quality of life measures in the D-TM1 group including less neuropathy, less hair loss and better work productivity when compared with the chemotherapy and trastuzumab patients.

The authors noted that the chemotherapy and trastuzumab regimen the study compared C-TM1 therapy to has shown in earlier clinical studies was associated with a 10-year invasive disease-free survival rate of 91.3% for patients with small node-negative HER2-positive tumors, which has resulted in it being included in worldwide treatment guidelines and adopted globally. Yet the treatment regimen is also associated with adverse events that affect patients’ quality of life. This had made finding ways to improve the efficacy of that treatment while also lessening the adverse events and area of active interest among clinicians.

Senior author Sara Tolaney, MD, chief, division of breast oncology at the Dana-Farber Cancer Institute said their study has done just that. “The ATEMPT trial has taught us that one year of T-DM1 after surgery for patients with a stage 1 HER2-positive cancer leads to outstanding long term outcomes, making it a reasonable treatment approach for select patients.”

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