EBMT 2020 | ATG and/or post-Cy for GvHD prophylaxis

Post-transplant cyclophosphamide has been really the big star in terms of GvHD prophylaxis over the five past years. However, we should not neglect that ATG, which is 40 years old has lots of available data and the research in terms of mechanism of action, is also a very important invalid option for GvHD prophylaxis.

During this EBMT 2020 virtual meeting PT-Cy and use of ATG have been discussed extensively. It will take us hours to go through all the details. However, it is clear that post-transplant cyclophosphamide is now well-established as a GvHD prophylaxis regimen, not only in the haploidentical setting, but now it is spreading into the actually identical and unrelated settings.

So, this is good news. However, what we have seen during this EBMT meeting is that for instance, in the match sibling donor setting, AML, for instance, registry-based data from the acute leukemia working party of EBMT when you compare ATG to PT-Cy, ATG is more potent in terms of chronic GvHD control.

So, ATG still have to play some role despite the enthusiasm for post cyclophosphamide. And here I would like to highlight a new phase three randomized trial just published a couple of months ago in the journal of clinical oncology. And this is from the team of professor Huang in Beijing, China, which looked into ATG Thymoglobulin for GvHD prophylaxis compared to a care standard of GvHD prophylaxis in the HLA identical sibling.

And the results are very interesting in line to what we have been advocating for many years, actually about the use of ATG in all transplant setting as a very powerful tool for GvHD prophylaxis. So, this phase three trial from China is now establishing definitely the use of ATG Thymoglobulin in the HLA identical transplant setting. So, now we have two major agents for GvHD prophylaxis, PT-Cy and ATG.

So, the question, why not combining both of them. And that was actually the topic of a very lovely session we had during this EBMT where professor Huang from Beijing, professor Bless from Misay and professor Nagler from Tel-HaShomer discussed opportunities for combining these two agents and actually our own data.

But also data from many other centers are showing now that especially when you use peripheral blood stem cells in the haploidentical setting combination of low dose ATG like Thymoglobulin and PT-Cy is feasible, safe, and can allow to generate very low incidents of acute, but also chronic GvHD. So, I think the research field in terms of GvHD prophylaxis is progressing clearly in the right direction. And we are eagerly awaiting the results of many other ongoing randomized trials. So please stay tuned.