Comorbidity index does not predict outcome in allogeneic myeloablative transplants conditioned with fludarabine/i.v. busulfan (FluBu4).

The assessment of a hematopoietic stem cell transplant (HSCT)-specific comorbidity index (HCT-CI) has been developed to predict the risk of TRM in patients undergoing allogeneic HSCT. As the myeloablative fludarabine/i.v. busulfan (FluBu4) regimen has been associated with limited extra-hematologic toxicity, we analyzed whether the HCT-CI represents a useful tool in transplant patients conditioned with this regimen. Of the 52 consecutive patients who received an allogeneic HSCT with FluBu4 at our institution, 50 were evaluable for assessing pre-transplant HCT-CI. Patients were divided into three groups: score 0 (n=7); score 1-2 (n=17) and score >3 (n=26). The three groups did not differ significantly in age, diagnosis, previous lines of chemotherapy and type of donor. High-risk disease was present in 57% of low, 82% of intermediate and 85% of high HCT-CI score groups (P=ns). Two-year TRM and OS was 14.3 and 85.7% in the low score group, 23.5 and 58.8% in the intermediate score group and 15.4 and 50% in the high HCT-CI score group (P=ns). In this study, the HCT-CI lacked sensitivity to reliably predict TRM although patients with no comorbidities showed a trend for improved survival.