For patients with hematologic malignancies and disorders, allogeneic hematopoietic stem cell transplantation offers a potentially curative treatment option. Many patients develop graft-versus-host disease (GVHD), a serious complication and leading cause of nonrelapse mortality. Corticosteroids are the standard first-line treatment for GVHD; however, patients often become steroid-refractory or remain corticosteroid-dependent. New second-line treatment options are needed to improve patient outcomes. Here we review the role of JAK1 and JAK2 in acute and chronic GVHD. We also describe the study designs of the Phase II REACH1 (NCT02953678) and the Phase III REACH2 (NCT02913261) and REACH3 (NCT03112603) clinical trials that are currently recruiting patients to evaluate the JAK1/JAK2 inhibitor ruxolitinib in patients with corticosteroid-refractory acute or chronic GVHD.
Keywords: JAK; allogeneic stem cell transplant; refractory graft-versus-host disease.