Study to Evaluate the Safety and Tolerability of a New Drug (AMG 305) in Patients with Advanced/Metastatic Breast Cancer

Malignant solid tumors are cancers in which uncontrolled cell proliferation leads to the formation of a mass. This is considered a primary tumor when this proliferation of organ-specific cells first occurs in that organ. Solid tumors can occur in various organ systems. In breast cancer (mammary carcinoma), the cells of the breast gland tissue are affected. There are already many well-tested and therefore approved forms of treatment for breast cancer, which depend heavily on how widespread the disease is (stage) and the specific characteristics of the tumor cells. Nevertheless, not all patients achieve a complete recovery, and there are situations where standard treatment is no longer effective, so researchers continue to seek ways to improve treatment options. AMG-305 is the name of a completely novel drug that has not yet been approved for the treatment of cancer. It is an antibody that can simultaneously recognize and bind to both tumor cells and the body’s own immune cells (bispecific), thereby combating the tumor cells through multiple mechanisms. In tumor cells, AMG-305 recognizes the proteins known as mesothelin (MSLN) and P-cadherin (CDH3).

The goal of this Phase 1 study is to investigate the safety and efficacy of AMG 305 and to determine the optimal dose for further studies. In Part 1 of the study, participants receive the drug AMG 305 as an infusion through a venous line. The dose will be increased gradually, and the occurrence of dose-limiting side effects will be monitored. In Part 2, patients will receive the most effective and safest dose of AMG 305, which was determined in the first part. The study is open-label and has only one arm; that is, participants are guaranteed to receive the drug, and both medical staff and patients know which drug is being administered. Treatments and follow-up visits as part of the study will take place over a period of up to 2 years, during which the efficacy of the therapy and the occurrence of side effects associated with the various doses of the medication will be evaluated.

Patients aged 18 and older with an advanced-stage malignant solid tumor, such as breast cancer, are eligible to participate in this study.