This study attempted to characterize causes of treatment failure, identify associated prognostic factors, and develop shorter-term end points for trials testing investigational products or regimens for second-line systemic treatment of chronic graft-versus-host disease (GVHD). The study cohort (312 patients) received second-line systemic treatment of chronic GVHD. The primary end point was failure-free survival (FFS) defined by the absence of third-line treatment, nonrelapse mortality, and recurrent malignancy during second-line treatment. Treatment change was the major cause of treatment failure. FFS was 56% at 6 months after second-line treatment. Lower steroid doses at 6 months correlated with subsequent withdrawal of immunosuppressive treatment. Multivariate analysis showed that high-risk disease at transplantation, lower gastrointestinal involvement at second-line treatment, and severe NIH global score at second-line treatment were associated with increased risks of treatment failure. These three factors were used to define risk groups, and success rates at 6 months were calculated for each risk group either without or with various steroid dose limits at 6 months as an additional criterion of success. These success rates could be used as the basis for a clinically relevant and efficient shorter-term end point in clinical studies that evaluate agents for second-line systemic treatment of chronic GVHD.