EBMT 2018 | Eradicating GvHD after haploidentical stem cell transplant

Denis C. Roy

Speaking from the 2018 European Society for Blood and Marrow Transplantation (EBMT) Annual Meeting in Lisbon, Portugal, Denis Claude Roy, MD, FRCP, of the University of Montreal, Montreal, Canada, discusses an innovative new photodynamic technique that eliminates the activated T-cells which can cause GvHD in haploidentical stem cell transplant recipients. This process has potential applications across a huge range of hematological malignancies.

Transcript (edited for clarity):

Patients with a high-risk leukemia that are undergoing a haploidentical stem cell transplant are facing difficult challenges in terms of treatment because there is incompatibility between the donor and the recipient. They’re at high risk of what we call graft versus host disease because they’re only half matched with the donor and therefore there’s a high risk of mortality. And how we overcome this is quite- there are a number of ways of addressing this and it’s not clear which is the best approach. And if you eliminate the immune cells, well then you get rid of the graft versus host disease, but then you have patients who relapse. If you leave in the T-cells you have higher rates of graft versus host disease.

So what we have done is actually a strategy that could be applied to many types of transplant, and we are taking donor cells and exposing them to patient cells, and the cells of the donor that are able to recognize the patient actually become activated. And when they acquire these biological properties they are able to integrate a dye which into the cells that react to the patient and then with light we are able to eliminate those cells, so the activity, the energy from the light is transferred to the medication and kills the cells that recognize the patient. So we’re able to do stem cell transplant with people that are only half matched, but in whom the donor cells don’t react to the patient, and yet the immune cells, the cells that react to infection and are able to fight leukemia, are preserved. So that’s pretty interesting and extremely exciting for patients to see that there is such an advance.

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