One of the issues with haplo peripheral blood stem cell transplants is rates of acute GvHD, which seem very similar to a standard unrelated transplant. So significant acute GvHD, and also CRS when the stem cell products is infused and that can be as high as 20% in this severe form which is life-threatening.
So those are the two major things and of course, the issue of trying to maintain engraftment in graft versus leukemia...
One of the issues with haplo peripheral blood stem cell transplants is rates of acute GvHD, which seem very similar to a standard unrelated transplant. So significant acute GvHD, and also CRS when the stem cell products is infused and that can be as high as 20% in this severe form which is life-threatening.
So those are the two major things and of course, the issue of trying to maintain engraftment in graft versus leukemia. So we’ve been studying JAK inhibitors for many years and have shown in mouse models for some time that this is a very reasonable approach to reduced graft versus host disease. And especially when given early on, not after the fact but in a prophylactic setting. So we’ve pursued two large prophylaxis studies. One in the haplo setting which was just presented today.
And one in the matched sib and matched unrelated donor setting, which is using a different drug called Baricitinib. Both of these trials are aimed at early prophylaxis for GvHD with JAK inhibitors. So the haplo study was presented today and showed that the rates of CRS were dramatically reduced to almost insignificant levels. So that’s no longer a problem and that has been historically associated with life-threatening complications and early deaths. So that’s great.
The second thing is that, the rates of acute GvHD were extremely low, out of 20 patients, only one patient developed grade two GvHD, and everyone else developed no GvHD or grade one GvHD. And also the relapse rates were extremely low as well. So the one year GvHD relapse free survival was approximately 80%. For haplo transplants, that’s quite exceptional. And also about a third of the patients came into transplant with minimal residual disease, measured using some technique, either FISH, cytogenetics, or flow-based MRD testing. So all of these things put together suggest that prophylaxis with JAK inhibitors is in humans, looks exactly like what we’ve been seeing for years in mice, and that it’s very effective at preventing GvHD without altering anti-leukemic effects in graft versus leukemia.
