Chronic graft-versus-host disease: implications of the National Institutes of Health consensus development project on criteria for clinical trials.

Chronic graft-versus-host disease (GVHD) has been a difficult problem to address and clinical research in this area lags behind other innovations in hematopoietic stem cell transplantation (HCT). Recently the international transplant community has focused more on chronic GVHD. This new focus is well represented by the development of the National Institutes of Health sponsored chronic GVHD consensus project, which has unified the transplant community's approach to chronic GVHD through the activities of focused working groups. From December 2005 through May 2006, a series of consensus documents have been published addressing the areas of diagnosis and staging, histopathology, strategies for the development and validation of biomarkers, response criteria, ancillary therapy and supportive care and the design of clinical trials. This paper summarizes and discusses these reports, focusing specifically on diagnosis and scoring and response criteria. Although these documents represent a huge effort by the research community, they must be prospectively implemented and validated. These new criteria should advance the standards and uniformity of chronic GVHD clinical research. The ultimate success of this project is dependent on whether these recommendations move the field forward. This is an opportunity for the transplant community to unite and make a significant impact in chronic GVHD.