New Advances in Treating Acute Lymphoblastic Leukemia | Mark Litzow, MD | #EHA 2025

My name is Dr. Mark Litzow. I am a hematologist at the Mayo Clinic in Rochester, Minnesota. And I'd like to talk with you a little bit today about the major advances that we're making in the treatment of acute lymphoblastic leukemia. There are two types of acute lymphoblastic leukemia, and it's based on the cells that they arise from. There are some cells in our blood, in our immune system, called lymphocytes, and there are some that are B cells. And these cells can sometimes turn into leukemia. There's also T cells that come from cells called thymocytes. So patients sometimes can have a T cell ALL. That one is less common. We've actually made the most advances in the treatment of B cell, acute lymphoblastic leukemia, or ALL, we say. And this has been based on immune therapy. So making use of the immune system to attack the leukemia cells. So there are some proteins in our blood that are called antibodies. And we can make antibodies in the lab that react against cells. And so there are several different types of what we call monoclonal antibodies that react against leukemia cells. The first one was rituximab. It reacts against a protein in the cell named CD20. More recently, CD19, which is on virtually all B cells, we have medications that can react against the CD19 and kill the leukemia cells. One such agent is benetumumab, which brings a normal T cell close to the leukemia cell and kills it. There's also some medications that are antibodies where we've attached a drug to it. And so the antibody delivers the drug to the leukemia cell so that it can kill it. And so there's less side effects. And that's an agent called inotuzumab. So we have now done studies combining some of these antibody treatments with chemotherapy and shown that we can improve the survival and outcome with the use of these agents. And what we think we can do now and are planning, some of these studies have already happened, planning for the future, is to use more of these immunotherapy approaches in order to lessen the amount of chemotherapy that we're giving and lessen some of the side effects related to chemotherapy. Another big immunotherapy is what we call CAR T cells. And these are chimeric antigen receptor T cells. So we've actually put an antibody inside the T cell. It sits out on the surface of the T cell. So it can bring the T cell even closer to the leukemia cells and help kill it. And CAR T cells are being used in multiple different blood cancers, in multiple myeloma, in lymphoma. And here I'm talking about acute lymphoblastic leukemia, which is the first, one of the first areas where CAR T cells were utilized. It's also, I should say, utilized in a chronic form of leukemia, chronic lymphocytic leukemia. But they've been very helpful in the treatment of acute lymphoblastic leukemia. They've mostly been used in the situation where the leukemia, unfortunately, has come back after treatment. But we're now thinking that we can move CAR T cells earlier into the treatment in order to help improve the survival and outcome. So we're quite encouraged by these results and think it's going to help cure more patients of their ALL. In T cell ALL, we haven't made as many advances, but CAR T cells are also starting to have a role in that disease. There's also some new agents that are looking to be beneficial in T cell ALL. So we hope that we'll make some of the same progress in that subtype of ALL that we've made in the B cell subtype of ALL. So we're quite encouraged about the future and think it's a bright one and that we're going to make further advances.