Observational Study on Adverse Effects and Tolerability of the Combination Therapy of Abemaciclib and Antihormonal Therapy

Breast cancer is a malignant disease of the breast that can occur in various forms. Accurate diagnosis is essential for selecting the best treatment for each individual. Treatment depends on the stage of the cancer—that is, how far it has progressed. This study includes patients with locally advanced (Stage 2B, 3A/B) or metastatic (Stage 4 = spread) breast cancer. The presence of hormone receptors and the HER2 receptor on the cancer cells also plays an important role. If these receptors are present, specific medications can be used.

The current standard of care consists—depending on the individual situation—either of chemotherapy followed by surgery, or of surgery followed by additional treatment such as radiation therapy, further chemotherapy, or anti-hormone therapy. For hormone receptor-positive breast cancer, antihormonal therapy is an integral part of treatment. The choice of antihormonal therapy depends, among other things, on whether the patient is postmenopausal. In the MINERVA study, however, this factor does not play a role; both premenopausal and postmenopausal women are included. CDK4/6 inhibitors are a newer class of drugs that specifically inhibit the growth of cancer cells and can enhance the effect of anti-hormone therapy.

The MINERVA study is investigating one such CDK4/6 inhibitor—abemaciclib—a drug that is already approved for treatment. The goal is to gather additional data on tolerability and efficacy. In addition, side effects of the therapy are recorded and documented using the CANKADO app. The goal is to determine whether close digital monitoring of side effects offers additional benefits for patients. Patients are specifically assigned to two groups by the treating medical staff; all participants are aware of their assignment. One study arm receives abemaciclib and an aromatase inhibitor (anastrozole, letrozole, or exemestane), while the other is treated with abemaciclib and the antiestrogen fulvestrant. After a maximum of 2 years, progression-free survival will be assessed and compared.

Women over the age of 18 with hormone receptor-positive, HER2-negative, locally advanced, or metastatic breast cancer are eligible to participate. A prerequisite is a willingness to use the digital app to record side effects. Patients must not have received any systemic therapy for breast cancer prior to study enrollment, with the exception of anti-hormone therapy lasting no more than three months before the start of abemaciclib treatment. Exclusion criteria include serious pre-existing conditions or prior treatment with certain medications.