First Report of Severe Acute Graft-Versus-Host Disease After Allogeneic Stem Cell Transplant in a Patient With Myelodysplastic Syndrome Treated With Atezolizumab: Literature Review.

Checkpoint inhibitors have become a widely used and available immunotherapy option for treating a variety of malignancies, including hematological malignancies. Patients receiving these therapies may go on to receive a curative allogeneic hematopoietic stem cell transplant (allo-HSCT). This presents a clinical challenge as the safety and efficacy of HSCT is not well reported in this subset of patients and residual programmed death-ligand 1 inhibition could potentially enhance allogeneic T-cell responses, improving the graft-versus-tumor effect, but also increasing the incidence and severity of immune complications such as graft-versus-host disease (GVHD). Here, this report includes a detailed literature review summarizing all available data on HSCT outcomes in the setting of using checkpoint inhibitor therapy pre-transplant. Moreover, we report a case of acute GVHD after allo-HSCT in a patient with high-risk myelodysplastic syndrome who received prior atezolizumab therapy, highlighting the importance of further research into this specific population in order to improve transplant-related outcomes.