Summary:Hepatic regimen-related toxicity (RRT) is a serious complication of stem cell transplantation. Cytokine activation may be involved in the pathogenesis. Corticosteroids are potent inhibitors of cytokine production, and, therefore could play a role in the treatment of hepatic RRT. Between January 1994 and June 1998, 28 of 782 consecutive transplant patients (3.6%) developed hepatic RRT (20 veno-occlusive disease (VOD) and eight liver dysfunction of uncertain etiology (LDUE) as defined by Seattle criteria), and were treated with highdose methylprednisolone (MP, 500 mg/m 2 i.v. every 12 h for six doses), initiated upon increase in serum total bilirubin to у4 mg/dl. Other causes of liver dysfunction were excluded. Response to therapy with high-dose MP was defined as reduction in total bilirubin by 50% within 10 days of initiation of MP. Overall, 17 patients (61%) responded to treatment (12 patients with VOD, five patients with LDUE). The bilirubin in responding patients decreased from a mean of 8.6 mg/dl (range, 4-17.9) at the start of MP to 4.1 mg/dl (range, 0.5-17.9) 10 days later. There were no statistically significant differences between responders and non-responders in the day treatment with high-dose MP was initiated (P = 0.38), total serum bilirubin (P = 0.17) and percent weight gain at the time high-dose MP was started (P = 0.10) or the calculated probability of fatal outcome from VOD (18% for responders, 23% for non-responders; P = 0.30). A lower pre-transplant DLCOc was observed among non-responders (P = 0.04). At 100 days posttransplant, hepatic RRT resolved in all 13 survivors who responded to high-dose MP, and in one nonresponding patient. No serious toxicities due to highdose MP were observed. We conclude that resolution of hepatic RRT occurred in the majority of patients treated with high-dose MP in this study; however, randomized controlled trials are required to determine the efficacy of high-dose MP for treatment of hepatic RRT. Bone Marrow Transplantation (2000) 25, 737-743.