[Evolving treatment strategies for chronic graft-versus-host disease]

Chronic graft-versus-host disease (GVHD) affects various organs and causes significant morbidity and mortality after allogeneic hematopoietic cell transplantation. The 2005 National Institutes of Health consensus criteria for chronic GVHD have set international standards for endpoints and designing and reporting of clinical trials; these criteria were revised in 2014 to incorporate accumulated evidence and controversies. In addition, preclinical studies of chronic GVHD have identified treatment targets such as regulatory T cells, B-cell signaling, Th17 cells, Tc17 cells, follicular helper T cells, follicular regulatory T cells, and fibrosis-promoting factors. These efforts led to the approval of ibrutinib, belumosudil, and ruxolitinib by the U.S. Food and Drug Administration for treating chronic GVHD after failure of one or more lines of systemic therapy, and an increasing number of investigational agents that target different biological pathways of chronic GVHD are under development in clinical trials. To address challenges in a rapidly evolving field, a third National Institutes of Health consensus project was held in 2020, in which investigators, patient advocacy organizations, and pharmaceutical companies aimed to define basic and clinical research roadmaps that may lead to significant change in chronic GVHD management over the next 5 years.