Busulfan levels are influenced by prior treatment and are associated with hepatic veno-occlusive disease and early mortality but not with delayed complications following marrow transplantation.

Long-term outcome was analyzed in 28 patients transplanted between 1989 and 1992 following busulfan and cyclophosphamide and who had busulfan levels studied. While there was no significant correlation of busulfan levels with diagnosis, patients who had received extensive prior chemotherapy had a significantly higher area under the curve (AUC; P = 0.02) and maximum busulfan levels (Cmax; P = 0.03). High AUC was associated with the development of hepatic veno-occlusive disease (P = 0.03) and with early transplant-related mortality (P = 0.06). No significant correlation of busulfan levels with relapse, late non-relapse death, late complications, nor event-free survival was detected.