This clinical trial is focused on studying a treatment for patients with solid tumors, which are abnormal masses of tissue that can occur in various parts of the body. The treatment being tested is called Zenocutuzumab, also known by its code name MCLA-128. Zenocutuzumab is a type of medication known as a bispecific antibody, which is designed to target specific proteins called HER2 and HER3 that are found on the surface of some cancer cells. This study is particularly interested in patients whose tumors have a specific genetic change called an NRG1 fusion.

The purpose of the study is to understand how safe and tolerable Zenocutuzumab is for patients and to explore how it interacts with the cancer. The study is divided into two parts. In the first part, researchers aim to find the best dose of Zenocutuzumab that patients can tolerate. In the second part, the focus is on understanding the safety of the treatment and how well it works against the cancer, especially in patients with the NRG1 fusion. Patients will receive Zenocutuzumab through an infusion, which means the medication is given directly into the bloodstream through a vein.

Throughout the study, researchers will monitor patients for any side effects and assess how the cancer responds to the treatment. The study will also look at how long the treatment effects last in patients with the NRG1 fusion. This research is important for developing new treatments for solid tumors and could provide valuable information on how Zenocutuzumab works in these specific types of cancer. Participants will be closely observed by healthcare professionals to ensure their safety and to gather detailed information about the treatment’s effects.