External Beam Radiation Therapy in Combination With Talquetamab for the Treatment of Multiple Myeloma Patients With Extramedullary Disease

This phase I/II trial tests the safety and effectiveness of extramedullary disease (EMD)-directed external beam radiation therapy (EBRT) in combination with talquetamab for the treatment of multiple myeloma patients with extramedullary disease. Extramedullary disease in multiple myeloma involves the infiltration of organs and soft tissues by malignant plasma cells and has proven difficult to treat. Radiation therapy uses high energy x-rays, particles, or radioactive seeds to kill cancer cells and shrink cancers. EBRT is a type of radiation therapy that delivers high-energy beams to the cancer from outside of the body. In this trial, the EBRT will be directed to a site of extramedullary disease. Talquetamab is a monoclonal antibody that may interfere with the ability of cancer cells to grow and spread. A monoclonal antibody is a type of protein that can bind to certain targets in the body, such as molecules that cause the body to make an immune response (antigens). Combining EMD-directed EBRT with talquetamab may be safe, tolerable, and/or effective in treating multiple myeloma patients with extramedullary disease.