What is BCMA? So BCMA stands for B-cell maturation antigen. It is expressed, it's basically found on the surface of myeloma cells. So it becomes a very good target in terms of finding new treatments that can potentially kill myeloma cells. BCMA is a protein that is found exclusively on multiple myeloma cells. It's not found on other cells of the body. So the conventional wisdom is that the CAR T product will attack exclusively the myeloma cells without having any off-target effects on any healthy tissues. And it actually has been to target antigen for a half a dozen CAR T products as well as a half a dozen bites. Why are CAR T's going after, not just CAR T's, a lot of our new therapies going after BCMA, kind of what does it do and why are we targeting it? So it is a protein that's expressed on myeloma cells, really kind of mature plasma cells. So myeloma is a cancer that develops from the plasma cells. Those are the cells that make antibodies that fight off infections. So BCMA, we don't see it on early plasma cells in development, so that's good because the treatment's not going to knock out the cell leading to good functional plasma cells. We see it on very mature plasma cells and on cancer cells, the myeloma cells. So we want a target that's not going to cause a lot of damage. So the BCMA is a great target because of that. So we don't get a lot of off, so we call it on-target, but off-organ toxicity, meaning there's not BCMA expressed in the liver or in the heart or the lungs. And in particular, what BCMA does is it really leads to the kind of growth of myeloma cells. So you're kind of shutting off that signal that allows the cancer to kind of grow and divide and then obviously cause damage to the body. So it's a target that works well, the way the BCMA functions to drive cancer, and it's a target that doesn't cause a lot of unexpected side effects. So those are a couple of the reasons why we go after it in myeloma therapy. When it comes to tumor antigens which are expressed on the surface of the cell, and BCMA is a good example, for instance, in general, it is relatively easy and feasible to measure the presence but also the density of these molecules. And this can be done through well-established methods like flow cytometry. However, it is not done routinely because we know in general that the molecule BCMA, for instance, is always very highly expressed, except in a few cases. But definitely, we know very well, and that is the rationale, actually, behind developing these drugs which target a given tumor antigen. It has been proven before the development of the drug that this tumor antigen is usually present, highly present on the surface of the cell, and can represent a reliable target for the drug.
HealthTree • February 16, 2024
