What is BCMA and why is it a good target? So B-cell maturation antigen or BCMA is a target that people really are excited about and that's because it's expressed in essentially all myeloma cells. So and it's not expressed in normal cells in general. So this target has been seized upon as something that's really special in myeloma. So I would say why has BCMA been an attractive target? That's because it's very selectively expressed on myeloma cells. If your goal is to invent new treatments for multiple myeloma, you want to make sure that's one of the criteria. You want to make sure that the treatment won't be toxic, right? And that means that your treatment won't kill normal cells, right? If you look at BCMA, the target is only expressed on plasma cells, normal plasma cells. That's just a very small population of white blood cells in your body and on myeloma cells. So the only price that you will have to pay for an effective treatment in these patients is you'll lose your plasma cells. And that's just a very small fraction of all the immune cells that you have in your body. So you're willing to pay that price if you think that the treatment is effective, which we know the anti-BCMA treatments are effective right now. Again, I'm just saying we know much more about how these treatments work, what are the side effects that you can expect. And also we have begun to develop biomarkers that will tell us who's at risk for more severe toxicity and who isn't and so forth. So what I mean is we have found ways of dealing with these kinds of problems when we develop new CAR T cell treatments. BCMA stands for B-cell Maturation Antigen and is essentially a protein that sits on the surface of myeloma cells. BCMA is actually quite an important protein for myeloma cells because it's the way that plasma cells are activated and they grow and divide. What we do find in myeloma patients is that BCMA is highly expressed across pretty much all myeloma patients, although what we do find is that expression can be variable between one patient to another patient. It's found on myeloma cells, but it's also found on late B cells and these are also immune cells. What that means is that if you do deliver a therapy such as a CAR T cell which targets BCMA, you're going to wipe out those plasma cells, those myeloma cells, but you're also going to wipe out your healthy plasma cells and some of your other B cells which are important as part of your immune system. What that means for patients essentially is that this sort of therapy can significantly lower your immune system and can increase your risk of infections and typically we're seeing a higher risk of viral infections as well as bacterial infections. We're seeing your normal antibody levels dropped to low levels and many of our patients are recommended to receive antibody replacement therapy which we call intravenous immunoglobulin to try and maintain safe levels of antibodies to protect you from those severe infections. We have noticed in patients who have stopped responding to CAR T cell therapy that when you look at their myeloma cells, the BCMA has gone. And interestingly when you look into the genes within that myeloma cells, they've got rid of the chromosome that encodes the protein on the surface. So we know this, we know that myeloma cells are clever, they manage to evade therapies and they are able to down regulate or disappear BCMA from the surface. Fortunately what it appears that this isn't a very common event, it seems to be fairly rare although data is still coming out. So CAR T cells is one way of targeting BCMA but there are other ways. We have the bispecific T cell engager, these are fragments of antibodies which with one arm will grab hold of the BCMA and with the other arm will grab hold of the T cells through CD3 and pull them together. And then we also have antibody drug conjugates. The first one is called bulantumab mafidotin and this is an antibody that hits BCMA and is linked to a powerful toxin which causes that myeloma cell to die. These drugs and bispecific T cell engagers are also highly effective in multiple myeloma.