Kadcyla Combo Drug Enhances Survival in Early Breast Cancer

A new clinical trial has demonstrated that a combination drug can help early-stage breast cancer patients remain cancer-free following treatment. The combination drug, Kadcyla, is already approved for treating advanced HER2-positive breast cancer, according to researchers.

The recent findings indicate that patients with stage 1 breast cancer who received Kadcyla remained free of invasive cancer five years post-treatment. Dr. Sara Tolaney, the chief of breast oncology at Dana-Farber Cancer Institute in Boston and senior author of the study, stated, "One year of [Kadcyla] 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."

HER2-positive breast cancers are driven by a protein that typically helps regulate cell growth. However, cancer cells producing an excess of HER2 tend to grow more rapidly and are more prone to spreading to other regions of the body. According to Dr. Paolo Tarantino, the lead researcher also from Dana-Farber, patients with early HER2-positive breast cancer experience cancer recurrence 5% to 30% of the time after initial treatment.

The immunotherapy drug trastuzumab works by blocking the HER2 protein, thereby inhibiting HER2-positive cancers. When administered alongside chemotherapy following breast cancer surgery, trastuzumab can significantly decrease the likelihood of cancer recurrence in these patients. However, Tarantino noted that the side effects could adversely impact patients' quality of life.

Kadcyla aims to combine the benefits of both chemotherapy and immunotherapy while minimizing toxic side effects. It is a single drug that merges trastuzumab with the chemotherapy drug emtansine. To test the effectiveness of Kadcyla, researchers conducted a clinical trial involving 512 patients at cancer centers across the United States. Out of these, 384 patients received Kadcyla, and 128 were treated with a combination of chemotherapy and trastuzumab.

Five years following the treatment, 97% of the patients who received Kadcyla showed no evidence of cancer recurrence. The rates of toxic side effects were similar in both groups, but patient-reported outcomes indicated a higher quality of life for those treated with Kadcyla. Specifically, patients experienced less nerve damage, reduced hair loss, and improved work productivity compared to those who received chemotherapy and trastuzumab separately.

The trial received partial funding from Genentech, the manufacturer of Kadcyla. The results were published on June 27 in the Journal of Clinical Oncology.