Challenges in Conducting Studies in Chronic Graft--Host Disease.

The lack of standardized criteria for measuring therapeutic response has been a major obstacle to the development of therapeutic trials in chronic graft--host disease (cGvHD). Nevertheless, recent advances have been made in understanding of the biology and pathophysiology of cGvHD, as well as establishing more precise criteria for the diagnosis and classification of disease manifestations. The momentum has shifted, and currently there is a long list of new potential treatment targets being identified for cGvHD. Consequently, new drugs are being implemented for its prophylaxis and treatment. It is crucial to continue that trend and develop better systems to test new drugs in clinical practice that would eventually translate toward seeking regulatory review and approval. We provide a historical perspective and current challenges in conducting cGvHD clinical trials.