Andrew Boon Ming Lim

Validating the allogeneic stem cell transplantation disease risk index: sample size, follow-up, and local data are important.

Background Reporting allogeneic hematopoietic stem cell transplantation (alloHSCT) outcomes by disease and disease stage can limit statistical power. Recently, the disease risk index (DRI) was developed and validated to stratify clusters of patients with various combinations of disease and stage for overall survival (OS), progression-free survival (PFS), and cumulative incidence of relapse (CIR). However, the DRI has not been tested for smaller cohorts or cohorts with shorter follow-up. Methods Data from recipients of a first alloHSCT between 2000 and 2011 (n=466; median follow-up, 55.2 months) were extracted from our database. Each patient was assigned to one of four risk categories according to the DRI. Results The DRI was validated as being significantly predictive of OS, PFS, and CIR (P<0.001 for all). The OS, PFS, and CIR from a contemporaneous cohort (n=324) from our institution were superior to the original training cohort. Using randomized patient subsets, the DRI stratified a cohort of 100 patients (OS, P=0.010; PFS, P=0.016; CIR, P=0.027), but failed to stratify a cohort of 50 patients (OS, P=0.385; PFS, P=0.167; CIR, P=0.026). When simulating shorter follow-up, the DRI stratified a cohort (n=322) with a median follow-up of 40.6 months for OS and PFS, but failed to stratify a cohort (n=242) with a median follow-up of 33.1 months. Conclusion The DRI is a simple, robust pre-alloHSCT risk stratification tool. However, users should calibrate with local data before using the DRI to estimate absolute OS, PFS, and CIR and understand its limitations when applied to smaller cohorts or cohorts with shorter follow-up.

Older recipient age is paradoxically associated with a lower incidence of chronic GVHD in Thymoglobulin recipients: a retrospective study exploring risk factors for GVHD in allogeneic transplantation with Thymoglobulin GVHD prophylaxis

Thymoglobulin (TG) given with conditioning for allogeneic haematopoietic SCT (alloHSCT) is effective in reducing the risk of acute and chronic GVHD (cGVHD). Whether conventional risk factors for GVHD apply to TG-conditioned alloHSCT is unknown. We retrospectively studied 356 adults from three centres who received TG 4.5 mg/kg prior to alloHSCT for haematologic malignancy. Donors were unrelated in 64%. At 3 years, OS was 61% (95% confidence interval (CI) 55–67%), cumulative incidence of relapse was 28% (95% CI 23–33%) and non-relapse mortality was 19% (14–24%). The cumulative incidences of grade 2–4, and grade 3–4 acute GVHD were 23% (95% CI 19–28%) and 10% (95% CI 6–13%), respectively. The cumulative incidence of cGVHD requiring systemic immunosuppression (cGVHD-IS) at 3 years was 32% (95% CI 27–37%). On multivariate analysis, counterintuitively, recipient age over 40 was associated with a significantly decreased risk of cGVHD-IS (P=0.001). We report for the first time a paradoxical association of older age with reduced cGVHD in TG recipients, and conclude that traditional risk factors for GVHD may behave differently in the context of pre-transplant TG.

Acute myeloid leukaemia relapsing after allogeneic haemopoietic stem cell transplantation: prognostic factors and impact of initial therapy of relapse

We sought to determine factors associated with the overall survival from relapse (OSR) of acute myeloid leukaemia (AML) after allogeneic haemopoietic stem cell transplantation (alloHSCT) and the effect of first salvage therapy and subsequent graft‐versus‐host disease (GVHD) on OSR.