Study to evaluate the benefits of an additional treatment based on specific testing to assess an individual's risk of disease recurrence

Breast cancer (mammary carcinoma) is a malignant disease of the breast tissue characterized by the uncontrolled proliferation of breast cells. In some cases, the accelerated growth of cancer cells can be attributed to specific genetic mutations. Treatment of the disease depends on numerous factors, such as the patient’s overall health, the tumor’s growth rate (Ki-67 index), the presence of detectable hormone receptors on the surface of the cancer cells (estrogen receptor-positive, progesterone receptor-positive), and the increased expression of the HER2 protein on the cells (HER2-positive). The stage of the disease is also very important. Starting at stage 4, the disease is considered to have spread to other parts of the body (metastases). “Early breast cancer,” as defined in this study, refers to a situation where the disease is confined to the breast or has affected at most a few lymph nodes.

Treatment for early breast cancer typically involves three steps: an initial phase of therapy (neoadjuvant), surgery on the breast and, if necessary, the lymph nodes, and a final phase of therapy (adjuvant), which may involve various medications or radiation therapy. Although the chance of a cure is very high with this approach, there are still patients who show renewed disease activity (recurrence) over time. This depends largely on the characteristics of the cancer cells and, consequently, on whether all of them were actually destroyed by the therapy. New methods for analyzing the characteristics of tumor cells (molecular genetics) could help to better predict an individual’s risk of recurrence. Based on this, an additional third phase of therapy could represent another treatment option for reducing risk. The choice of medication is based on the tumor’s molecular genetic characteristics.

The goal of this Phase 2 study is to test the effect of a third phase of therapy, which is specifically selected based on the tumor’s molecular genetic characteristics. After neoadjuvant therapy is completed, the response to treatment is first assessed. The tumors of patients with a poor response to therapy and an increased risk of recurrence are then analyzed for molecular genetic characteristics. Based on these markers, patients are divided into seven different groups. Patients in each group receive drug therapy specifically tailored to the genetic characteristics of their tumor. The following drugs may be used for this purpose: atezolizumab, inavolisib, ipatasertib, olaparib, sacituzumab-govitecan, or trastuzumab/pertuzumab. One group serves as a control group and does not receive any additional therapy.

The study is open-label, which means that both the medical staff and the patients know which medications are being administered. Follow-up examinations after surgery will take place for up to four years, during which the effectiveness of the therapy and the occurrence of side effects from the various medications will be evaluated.

Women and men aged 18 and older with breast cancer and an increased risk of recurrence after neoadjuvant therapy are eligible to participate in this study. The breast cancer must not have metastasized yet.