Pertuzumab

Researchers want to learn if patritumab deruxtecan (MK-1022) can treat certain breast cancers. The breast cancers being studied are HER2 positive unresectable locally advanced or metastatic (the cancer has spread to other parts of the body). The goals of this study are to learn: * About the safety and how well people tolerate of patritumab deruxtecan * How many people have the cancer respond (get smaller or go away) to treatment

Phase II unicentric randomized trial which will include early HER2 positive breast cancer patients, candidate to neoadjuvant therapy with trastuzumab and pertuzumab. Circulating tumor cells will be collected at neoadjuvant therapy baseline. Patients with pathological complete response will be randomized in 1:1 ratio for adjuvant trastuzumab (arm A) versus trastuzumab + pertuzumab (arm B) in a two factorial design: group A, with HER2 positive CTCs and group B, with HER2 negative/absent CTCs.

The purpose of this study is to establish a prospective, single-center platform research based on clinical subtypes to explore precision neoadjuvant therapy in patients with operable breast cancer who met the indications for neoadjuvant chemotherapy and by the update of basic translational research in the center, especially the refinement of typing, the discovery of new targets and the development of novel targeted drugs, verified the effectiveness of new targeted drugs in neoadjuvant therapy.

This phase II trial tests reduced post surgery (adjuvant) therapy for patients with early breast cancer who have confirmed that the disease has responded completely (pathologic complete response) after pre surgical treatment (neoadjuvant) therapy and do not have any tumor genetic material (molecular residual disease) circulating in their blood. Standard of care treatment after surgery consists of 1 year of pembrolizumab for patients with triple negative breast cancer or trastuzumab with or without pertuzumab to complete 1 year of treatment. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Pertuzumab and trastuzumab are monoclonal antibodies and forms of targeted therapy that attach to a receptor protein called HER2. HER2 is found on some cancer cells. When pertuzumab or trastuzumab attach to HER2, the signals that tell the cells to grow are blocked and the tumor cell may be marked for destruction by the body's immune system. Lowering the total amount of cancer therapy after breast surgery, may continue to keep the great tumor response to treatment, and may help lower the amount of side effects patients have.