Wael Saber

Validation and refinement of the Disease Risk Index for allogeneic stem cell transplantation

Because the outcome of allogeneic hematopoietic cell transplantation (HCT) is predominantly influenced by disease type and status, it is essential to be able to stratify patients undergoing HCT by disease risk. The Disease Risk Index (DRI) was developed for this purpose. In this study, we analyzed 13,131 patients reported to the Center for International Blood and Marrow Transplant Research who underwent HCT between 2008 and 2010. The DRI stratified patients into 4 groups with 2-year overall survival (OS) ranging from 64% to 24% and was the strongest prognostic factor, regardless of age, conditioning intensity, graft source, or donor type. A randomly selected training subgroup of 9849 patients was used to refine the DRI, using a multivariable regression model for OS. This refined DRI had improved prediction ability for the remaining 3282 patients compared with the original DRI or other existing schemes. This validated and refined DRI can be used as a 4- or 3-group index, depending on the size of the cohort under study, for prognostication; to facilitate the interpretation of single-center, multicenter, or registry studies; to adjust center outcome data; and to stratify patients entering clinical trials that enroll patients across disease categories.

Outcomes after matched unrelated donor versus identical sibling hematopoietic cell transplantation in adults with acute myelogenous leukemia

Approximately one-third of patients with an indication for hematopoietic cell transplantation (HCT) have an HLA-matched related donor (MRD) available to them. For the remaining patients, a matched unrelated donor (MUD) is an alternative. Prior studies comparing MRD and MUD HCT provide conflicting results, and the relative efficacy of MRD and MUD transplantation is an area of active investigation. To address this issue, we analyzed outcomes of 2223 adult acute myelogenous leukemia patients who underwent allogeneic HCT between 2002 and 2006 (MRD, n = 624; 8/8 HLA locus matched MUD, n = 1193; 7/8 MUD, n = 406). The 100-day cumulative incidence of grades B-D acute GVHD was significantly lower in MRD HCT recipients than in 8/8 MUD and 7/8 MUD HCT recipients (33%, 51%, and 53%, respectively; P < .001). In multivariate analysis, 8/8 MUD HCT recipients had a similar survival rate compared with MRD HCT recipients (relative risk [RR], 1.03; P = .62). 7/8 MUD HCT recipients had higher early mortality than MRD HCT recipients (RR, 1.40; P < .001), but beyond 6 months after HCT, their survival rates were similar (RR, 0.88; P = .30). These results suggest that transplantation from MUD and MRD donors results in similar survival times for patients with acute myelogenous leukemia.

Nonpermissive HLA-DPB1 mismatch increases mortality after myeloablative unrelated allogeneic hematopoietic cell transplantation

We examined current outcomes of unrelated donor allogeneic hematopoietic cell transplantation (HCT) to determine the clinical implications of donor-recipient HLA matching. Adult and pediatric patients who had first undergone myeloablative-unrelated bone marrow or peripheral blood HCT for acute myelogenous leukemia, acute lymphoblastic leukemia, chronic myelogenous leukemia, and myelodysplastic syndrome between 1999 and 2011 were included. All had high-resolution typing for HLA-A, -B, -C, and -DRB1. Of the total (n = 8003), cases were 8/8 (n = 5449), 7/8 (n = 2071), or 6/8 (n = 483) matched. HLA mismatch (6-7/8) conferred significantly increased risk for grades II to IV and III to IV acute graft vs host disease (GVHD), chronic GVHD, transplant-related mortality (TRM), and overall mortality compared with HLA-matched cases (8/8). Type (allele/antigen) and locus (HLA-A, -B, -C, and -DRB1) of mismatch were not associated with overall mortality. Among 8/8 matched cases, HLA-DPB1 and -DQB1 mismatch resulted in increased acute GVHD, and HLA-DPB1 mismatch had decreased relapse. Nonpermissive HLA-DPB1 allele mismatch was associated with higher TRM compared with permissive HLA-DPB1 mismatch or HLA-DPB1 match and increased overall mortality compared with permissive HLA-DPB1 mismatch in 8/8 (and 10/10) matched cases. Full matching at HLA-A, -B, -C, and -DRB1 is required for optimal unrelated donor HCT survival, and avoidance of nonpermissive HLA-DPB1 mismatches in otherwise HLA-matched pairs is indicated.

Risk factors for catheter-related thrombosis (CRT) in cancer patients: a patient-level data (IPD) meta-analysis of clinical trials and prospective studies

Background: Knowledge of independent, baseline risk factors for catheter‐related thrombosis (CRT) may help select adult cancer patients who are at high risk to receive thromboprophylaxis. Objectives: We conducted a meta‐analysis of individual patient‐level data to identify these baseline risk factors. Patients/Methods: MEDLINE, EMBASE, CINAHL, CENTRAL, DARE and the Grey literature databases were searched in all languages from 1995 to 2008. Prospective studies and randomized controlled trials (RCTs) were eligible. Studies were included if original patient‐level data were provided by the investigators and if CRT was objectively confirmed with valid imaging. Multivariate logistic regression analysis of 17 prespecified baseline characteristics was conducted. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated. Results: A total sample of 5636 subjects from five RCTs and seven prospective studies was included in the analysis. Among these subjects, 425 CRT events were observed. In multivariate logistic regression, the use of implanted ports as compared with peripherally implanted central venous catheters (PICCs), decreased CRT risk (OR, 0.43; 95% CI, 0.23–0.80), whereas past history of deep vein thrombosis (DVT) (OR, 2.03; 95% CI, 1.05–3.92), subclavian venipuncture insertion technique (OR, 2.16; 95% CI, 1.07–4.34) and improper catheter tip location (OR, 1.92; 95% CI, 1.22–3.02), increased CRT risk. Conclusions: CRT risk is increased with use of PICCs, previous history of DVT, subclavian venipuncture insertion technique and improper positioning of the catheter tip. These factors may be useful for risk stratifying patients to select those for thromboprophylaxis. Prospective studies are needed to validate these findings.

Better leukemia-free and overall survival in AML in first remission following cyclophosphamide in combination with busulfan compared with TBI

Cyclophosphamide combined with total body irradiation (Cy/TBI) or busulfan (BuCy) are the most widely used myeloablative conditioning regimens for allotransplants. Recent data regarding their comparative effectiveness are lacking. We analyzed data from the Center for International Blood and Marrow Transplant Research for 1230 subjects receiving a first hematopoietic cell transplant from a human leukocyte antigen-matched sibling or from an unrelated donor during the years 2000 to 2006 for acute myeloid leukemia (AML) in first complete remission (CR) after conditioning with Cy/TBI or oral or intravenous (IV) BuCy. Multivariate analysis showed significantly less nonrelapse mortality (relative risk [RR] = 0.58; 95% confidence interval [CI]: 0.39-0.86; P = .007), and relapse after, but not before, 1 year posttransplant (RR = 0.23; 95% CI: 0.08-0.65; P = .006), and better leukemia-free survival (RR = 0.70; 95% CI: 0.55-0.88; P = .003) and survival (RR = 0.68; 95% CI: 0.52-0.88; P = .003) in persons receiving IV, but not oral, Bu compared with TBI. In combination with Cy, IV Bu is associated with superior outcomes compared with TBI in patients with AML in first CR.

Increasing Incidence of Chronic Graft-versus-Host Disease in Allogeneic Transplantation: A Report from the Center for International Blood and Marrow Transplant Research

Although transplant practices have changed over the last decades, no information is available on trends in incidence and outcome of chronic graft-versus-host disease (cGVHD) over time. This study used the central database of the Center for International Blood and Marrow Transplant Research (CIBMTR) to describe time trends for cGVHD incidence, nonrelapse mortality, and risk factors for cGVHD. The 12-year period was divided into 3 intervals, 1995 to 1999, 2000 to 2003, and 2004 to 2007, and included 26,563 patients with acute leukemia, chronic myeloid leukemia, and myelodysplastic syndrome. Multivariate analysis showed an increased incidence of cGVHD in more recent years (odds ratio = 1.19, P < .0001), and this trend was still seen when adjusting for donor type, graft type, or conditioning intensity. In patients with cGVHD, nonrelapse mortality has decreased over time, but at 5 years there were no significant differences among different time periods. Risk factors for cGVHD were in line with previous studies. This is the first comprehensive characterization of the trends in cGVHD incidence and underscores the mounting need for addressing this major late complication of transplantation in future research.

Prognostic Mutations in Myelodysplastic Syndrome after Stem-Cell Transplantation

BACKGROUND Genetic mutations drive the pathogenesis of the myelodysplastic syndrome (MDS) and are closely associated with clinical phenotype. Therefore, genetic mutations may predict clinical outcomes after allogeneic hematopoietic stem‐cell transplantation. METHODS We performed targeted mutational analysis on samples obtained before transplantation from 1514 patients with MDS who were enrolled in the Center for International Blood and Marrow Transplant Research Repository between 2005 and 2014. We evaluated the association of mutations with transplantation outcomes, including overall survival, relapse, and death without relapse. RESULTS TP53 mutations were present in 19% of the patients and were associated with shorter survival and a shorter time to relapse than was the absence of TP53 mutations, after adjustment for significant clinical variables (P<0.001 for both comparisons). Among patients 40 years of age or older who did not have TP53 mutations, the presence of RAS pathway mutations was associated with shorter survival than was the absence of RAS pathway mutations (P=0.004), owing to a high risk of relapse, and the presence of JAK2 mutations was associated with shorter survival than was the absence of JAK2 mutations (P=0.001), owing to a high risk of death without relapse. The adverse prognostic effect of TP53 mutations was similar in patients who received reduced‐intensity conditioning regimens and those who received myeloablative conditioning regimens. By contrast, the adverse effect of RAS pathway mutations on the risk of relapse, as compared with the absence of RAS pathway mutations, was evident only with reduced‐intensity conditioning (P<0.001). In young adults, 4% of the patients had compound heterozygous mutations in the Shwachman–Diamond syndrome–associated SBDS gene with concurrent TP53 mutations and a poor prognosis. Mutations in the p53 regulator PPM1D were more common among patients with therapy‐related MDS than those with primary MDS (15% vs. 3%, P<0.001). CONCLUSIONS Genetic profiling revealed that molecular subgroups of patients undergoing allogeneic hematopoietic stem‐cell transplantation for MDS may inform prognostic stratification and the selection of conditioning regimen. (Funded by the Edward P. Evans Foundation and others.)

Early cytomegalovirus reactivation remains associated with increased transplant-related mortality in the current era: a CIBMTR analysis

Single-center studies have reported an association between early (before day 100) cytomegalovirus (CMV) reactivation and decreased incidence of relapse for acute myeloid leukemia (AML) following allogeneic hematopoietic cell transplantation. To substantiate these preliminary findings, the Center for International Blood and Marrow Transplant Research (CIBMTR) Database was interrogated to analyze the impact of CMV reactivation on hematologic disease relapse in the current era. Data from 9469 patients transplanted with bone marrow or peripheral blood between 2003 and 2010 were analyzed according to 4 disease categories: AML (n = 5310); acute lymphoblastic leukemia (ALL, n = 1883); chronic myeloid leukemia (CML, n = 1079); and myelodysplastic syndrome (MDS, n = 1197). Median time to initial CMV reactivation was 41 days (range, 1-362 days). CMV reactivation had no preventive effect on hematologic disease relapse irrespective of diagnosis. Moreover, CMV reactivation was associated with higher nonrelapse mortality [relative risk [RR] among disease categories ranged from 1.61 to 1.95 and P values from .0002 to <.0001; 95% confidence interval [CI], 1.14-2.61). As a result, CMV reactivation was associated with lower overall survival for AML (RR = 1.27; 95% CI, 1.17-1.38; P <.0001), ALL (RR = 1.46; 95% CI, 1.25-1.71; P <.0001), CML (RR = 1.49; 95% CI, 1.19-1.88; P = .0005), and MDS (RR = 1.31; 95% CI, 1.09-1.57; P = .003). In conclusion, CMV reactivation continues to remain a risk factor for poor posttransplant outcomes and does not seem to confer protection against hematologic disease relapse.

Hematopoietic Stem-Cell Transplantation for Advanced Systemic Mastocytosis

PURPOSE Advanced systemic mastocytosis (SM), a fatal hematopoietic malignancy characterized by drug resistance, has no standard therapy. The effectiveness of allogeneic hematopoietic stem-cell transplantation (alloHCT) in SM remains unknown. PATIENTS AND METHODS In a global effort to define the value of HCT in SM, 57 patients with the following subtypes of SM were evaluated: SM associated with clonal hematologic non-mast cell disorders (SM-AHNMD; n = 38), mast cell leukemia (MCL; n = 12), and aggressive SM (ASM; n = 7). Median age of patients was 46 years (range, 11 to 67 years). Donors were HLA-identical (n = 34), unrelated (n = 17), umbilical cord blood (n = 2), HLA-haploidentical (n = 1), or unknown (n = 3). Thirty-six patients received myeloablative conditioning (MAC), and 21 patients received reduced-intensity conditioning (RIC). RESULTS Responses in SM were observed in 40 patients (70%), with complete remission in 16 patients (28%). Twelve patients (21%) had stable disease, and five patients (9%) had primary refractory disease. Overall survival (OS) at 3 years was 57% for all patients, 74% for patients with SM-AHNMD, 43% for those with ASM, and 17% for those with MCL. The strongest risk factor for poor OS was MCL. Survival was also lower in patients receiving RIC compared with MAC and in patients having progression compared with patients having stable disease or response. CONCLUSION AlloHCT was associated with long-term survival in patients with advanced SM. Although alloHCT may be considered as a viable and potentially curative therapeutic option for advanced SM in the meantime, given that this is a retrospective analysis with no control group, the definitive role of alloHCT will need to be determined by a prospective trial.

Tocilizumab for the Treatment of Steroid Refractory Graft-versus-Host Disease

Corticosteroid refractory graft-versus-host disease (GVHD) is one of the major challenges in the management of allogeneic stem cell transplant recipients. Although numerous agents have been employed to treat this patient population, no standardized second-line therapy exists. In this study, we report our experience with the administration of tocilizumab, an anti-interleukin 6 receptor antibody, in the treatment of steroid refractory GVHD. Tocilizumab was administered to 8 patients with refractory acute (n = 6) or chronic GVHD (cGVHD) (n = 2) once every 3 to 4 weeks. The majority of patients with acute GVHD (aGVHD) had grade IV organ involvement of the skin or gastrointestinal tract, whereas both patients with cGVHD had long-standing severe skin sclerosis at the time of treatment. There were no allergic or infusion-related adverse events. Treatment was discontinued in one patient over concerns that tocilizumab may have worsened preexisting hyperbilirubinemia. Several patients also had transient elevations in serum transaminase values. Infections were the primary adverse events associated with tocilizumab administration. Four patients (67%) with aGVHD had either partial or complete responses apparent within the first 56 days of therapy. One patient with cGVHD had a significant response to therapy, whereas the second had stabilization of disease that allowed for a modest reduction in immune suppressive medications. These results indicate that tocilizumab has activity in the treatment of steroid refractory GVHD and warrants further investigation as a therapeutic option for this disorder.