Multiple myeloma is the second-most common form of blood cancer in the U.S, comprising about 1% of all cancers. There are approximately 30,330 new cases of myeloma in the U.S. every year, and 12,650 deaths caused by the disease. In the U.S., it is estimated that 1 in 150 men and women will develop myeloma at some point in their lifetimes.
The diagnosis of multiple myeloma is made by the presence of elevated abnormal plasma cells in the bone marrow. However, treatment decisions are based on symptoms of organ damage from the disease, such as bone damage, high blood calcium, anemia, kidney failure, and/or recurrent infections. In some cases, individuals present with “smoldering” or asymptomatic myeloma. These patients are subject to “watchful waiting,” observation without therapy while monitoring for the development of symptoms. Standard treatments for symptomatic myeloma include chemotherapy with drugs like bortezomib (Velcade®), lenalidomide (Revlimid®), ixazomib (Ninlaro®), and panobinostat (Farydak®), autologous stem cell transplantation, and, in some cases, radiation therapy.
In 2015, daratumumab (Darzalex™) and elotuzumab (Empliciti™) were approved by the FDA. Daratumumab is an antibody that binds to CD38, a protein found in most multiple myeloma cells. It was approved for patients who have received at least three prior lines of therapy. Elotuzumab targets the SLAMF7 receptor, which is present on both myeloma cells and natural killer (NK) cells. This enhances the immune response through multiple mechanisms: by attaching to the myeloma cells, it marks them for destruction, and by attaching to the NK cells, it primes the immune cells to search for and attack the myeloma cells. It was approved, in combination with two other therapies, for patients who have received one to three prior medications.