Evaluation of disease risk comorbidity index after allogeneic stem cell transplantation in a cohort with patients transplanted with in-vitro partially T-cell depleted grafts.

Outcomes of haematopoietic stem cell transplantation (HSCT) are influenced by comorbidities, disease type and status at transplantation. Several prognostic scores can be used, such as the Disease Risk Index (DRI) or the Haematopoietic Cell Transplantation-specific Comorbidity Index (HCT-CI). Recently a new prognostic tool, the Disease Risk Comorbidity Index (DRCI), combining the DRI and the HCT-CI was published. DRCI determines 6 patients group (very low risk (VLR), low risk (LR), intermediate risk-1 (IR-1), intermediate risk-2 (IR-2), high risk (HR) and very high risk (VHR)) with a significant predictive value for overall survival (OS), disease-free survival (DFS), relapse incidence (RI) and graft-versus-host disease-free/relapse-free survival (GRFS). However, DRCI has not been evaluated for patients allografted with partially in-vitro t-cell depleted (pTDEP) grafts. In our centre, we offer pTDEP to reduce graft-versus-host disease for patients in complete remission at transplant time. In this retrospective study, we investigated the DRCI in 404 adult patients (including 37.6% pTDEP) undergoing a first HSCT for haematological malignancies from 2008 to 2018. Because of the small number of patients in LR, VLR and LR were combined for analysis. In the entire cohort, 2-years OS was 84.4% for LR (95%CI: 71.6-97.2%), 61.6% for IR-1 (54.8-68.4%), 45.7% (33.3-58.1%) for IR-2, 31% (19.4-42.6%) for HR and 30.9% for VHR (14.5-47.3%) (p-value <0.001). In addition, DRCI was predictive of DFS, RI and GRFS but not of non-relapsed mortality and graft-versus-host disease. Our study confirms similar results with the original publication but gives less accurate prognosis information than DRI and HCT-CI when used separately. In conclusion, DRCI does not seem to offer more relevant information than DRI and HCT-CI to help physicians and patients for HSCT decision.