Chronic Graft-versus-host Disease, Part 1: How Preclinical Models Shape Our Understanding of Biology and Pave the Way for Future Therapeutic Interventions.

Chronic graft-versus-host disease (cGVHD) is the leading cause of nonrelapse morbidity and mortality post-allogeneic hematopoietic stem cell transplant. Murine cGVHD models have laid the groundwork for the clinical translation of multiple recently Food and Drug Administration-approved therapies for second- and third-line treatments of patients with cGVHD. However, not all patients respond to these therapies, and in those that do, responses are often partial or transient. Significant gaps remain in our understanding of cGVHD biology, which limits our ability to develop additional and more precise therapeutics that can be used alone or in combination for treating patients with cGVHD. Current and future preclinical investigations focusing on disease mechanisms that are as yet unexplored will elucidate new pathways to be exploited for improving the outcomes of patients with cGVHD. This review focuses on preclinical data derived from cGVHD animal models with particular emphases on (1) cGVHD basic biology; (2) the utility of integrating preclinical data from mouse models and human samples for clinical translation; and (3) burgeoning areas of preclinical investigation which hold future therapeutic potential, including targeting of fibrosis, lymphocyte metabolism, and cellular therapies for cGVHD.