A trial suggests that a new drug combination could soon become the first-line treatment for patients with HER2-positive metastatic breast cancer — a highly aggressive form that affects 15–20% of all breast cancer patients.
At the American Society of Clinical Oncology (ASCO) annual meeting, researchers demonstrated that the combination of trastuzumab deruxtecan (T-DXd) and pertuzumab was more effective than the standard treatment. Patients using this new treatment had a 44% lower chance of their disease getting worse or dying compared to those on the usual THP therapy, which includes chemotherapy and two HER2-blocking antibodies.
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Out of the 800 participants in the trial, around 400 patients treated with the T-DXd-pertuzumab combination saw a 15% complete remission rate—almost double that of those receiving standard care.
At a follow-up of 2.5 years, the T-DXd and pertuzumab combination reduced the risk of disease progression or death by 44 per cent compared to standard care. Median progression-free survival in the T-DXd group reached 40.7 months, compared to 26.9 months in the standard group.
“Seeing such a striking improvement was really impressive to us. We were taking a standard and almost doubling how long patients could have their cancer controlled for,” oncologist Sara Tolaney, lead researcher and chief of the breast oncology division at Dana-Farber Cancer Institute, told AFP.
Often called a ‘smart bomb’, T-DXd is already approved for use as a second-line treatment for HER2-positive cancers. In this trial, it was given earlier alongside the antibody pertuzumab. Some participants experienced side effects such as nausea, low white blood cell counts, and, in rare cases, lung scarring.
HER2-positive cancers are fuelled by an overactive HER2 gene, which causes tumours to grow and spread quickly. Typically, patients with metastatic HER2-positive breast cancer have an average survival of about five years after diagnosis.
