Thiotepa, busulfan, and cyclophosphamide as a preparative regimen for marrow transplantation: risk factors for early regimen-related toxicity.

One hundred twenty-seven adults with advanced hematologic malignancies received thiotepa 450-750 mg/m2, busulfan 10 or 12 mg/kg, and cyclophosphamide 120 or 150 mg/kg as a preparative regimen for autologous (86 patients) or allogeneic (41 patients) marrow transplantation. Early regimen-related toxicity (RRT) was scored according to the Seattle toxicity grading system. Grade 1-4 RRT occurred in 94% of the patients. Grade 3-4 RRT was noted in 19 patients (9% of the autologous and 27% of the allogeneic marrow recipients) and included 6% hepatic, 5% pulmonary, 3% renal, 2% mucosal, 2% bladder, 2% cardiac, and 1% CNS toxicity at the grade 3 or 4 level. No patient experienced life-threatening or fatal gastrointestinal or cutaneous toxicity. A stepwise logistic regression analysis suggested that the higher busulfan dose, Zubrod performance status of 2 or 3, and ten or more previous cycles of chemotherapy were factors predictive of grade 3-4 RRT. The regimen-related mortality for all patients was 8% (95% Cl 4-14%). The incidence and spectrum of RRT for this novel drug combination are similar to those reported for the standard preparative regimens. Heavily pretreated patients with poor performance status receiving the higher busulfan dose have a higher incidence of severe or fatal RRT.