Allogeneic Stem Cell Transplantation for Advanced Myelodysplastic Syndrome: Comparison of Outcomes between CD34+ Selected and Unmodified Hematopoietic Stem Cell Transplantation

In this study, we compared transplantation outcomes of allogeneic hematopoietic stem cell transplantation (HSCT) in patients with advanced myelodysplastic syndrome (MDS) who received a CD34⁺ cell-selected and those who received an unmodified allograft. This analysis initially included 181 patients, 60 who received a CD34⁺ cell-selected transplant and 121 who received an unmodified transplant. Owing to significant differences in disease characteristics, the analysis was limited to patients with <10% blasts before HSCT (n = 145). Two groups were defined: low risk, with low- and intermediate-risk cytogenetics (CD34⁺, n = 39; unmodified, n = 46), and high risk: poor and very poor risk cytogenetics (CD34⁺, n = 19; unmodified, n = 41). In the low-risk group, the incidence of grade II-IV acute graft-versus-host disease (aGVHD) at 1 year post-transplantation was 18% in the CD34⁺ subgroup versus 41.3% in the unmodified subgroup (P = .015). There were no differences between the subgroups in the incidence of grade III-IV aGVHD. The incidence of chronic graft-versus-host disease (cGVHD) at 3 years in the 2 subgroups was 5.3% and 56%, respectively (P < .001). At 3 years post-transplantation, relapse, overall survival (OS), and relapse-free survival (RFS) were similar in the CD34⁺ and unmodified subgroups: 8.1% versus 19.4% (P = .187), 58.5% versus 53.7% (P = .51), and 59.5% versus 52.4% (P = .448). However, the composite outcome combining extensive cGVHD-free status and relapse-free status (CRFS) at 3 years was 59.5% in the CD34⁺ group versus 19.2% in the unmodified group (P < .001). In the high-risk group, grade II-IV aGVHD at 1 year was 31.6% in the CD34⁺ subgroup versus 24.4% in the unmodified subgroup (P = .752). There were no differences between the subgroups in the incidence of grade III-IV aGVHD. The incidence of cGVHD at 3 years in the 2 subgroups was 0% versus 27.6% (P = .013). At 3 years post-transplantation, relapse, OS, RFS, and CRFS in the 2 subgroups were 31.6% versus 69.3% (P = .007), 35.5% versus 14.5% (P = .068), 31.6% versus 10.7% (P = .045), and 31.6% versus 6.1% (P = .001), respectively. Cytogenetic abnormalities at diagnosis and transplant type had significant univariate associations with RFS in the high-risk cohort. Only cytogenetics (P = .03) remained associated with this outcome in a multivariate model. OS was similar in the 2 transplant groups; however, CRFS was superior in the CD34⁺ cell-selected transplant group.

T Cell Depletion as an Alternative Approach for Patients 55 Years or Older Undergoing Allogeneic Stem Cell Transplantation as Curative Therapy for Hematologic Malignancies

T cell-depleted (TCD) allogeneic hematopoietic stem cell transplantation (HSCT) is curative treatment for hematologic malignancies in adults, shown to reduce graft-versus-host disease (GVHD) without increased relapse. We retrospectively reviewed a single-center, 11-year experience of 214 patients aged ≥ 55 years to determine tolerability and efficacy in the older adult. Most patients (70%) had myeloid diseases, and most acute leukemias were in remission. Median age was 61 years, with related and unrelated donors ≥8/10 HLA matched. Hematopoietic cell transplantation-specific comorbidity index scores were intermediate and high for 84%. Conditioning regimens were all myeloablative. Grafts were peripheral blood stem cells (97%) containing CD3 dose ≤103-4/kg body weight, without pharmacologic GVHD prophylaxis. With median follow-up of 70 months among survivors, Kaplan-Meier estimates of overall and relapse-free survival were 44% and 41%, respectively (4 years). Cumulative incidence of nonrelapse mortality at day +100 was only 10%. Incidence of GVHD for acute (grades II to IV) was 9% at day +100 and for chronic was 7% at 2 and 4 years (8 extensive, 1 overlap). Median Karnofsky performance status for patients > 2 years post-transplant was 90%. As 1 of the largest reports for patients ≥2 aged ≥55 years receiving TCD HSCTs, it demonstrates curative therapy with minimal GVHD, similar to that observed in a younger population.

Co-Infections by Double-Stranded DNA Viruses after Ex Vivo T Cell-Depleted, CD34+ Selected Hematopoietic Cell Transplantation

Recipients of ex vivo T cell-depleted (TCD) hematopoietic cell transplantation (HCT) are at risk of infection by double-stranded (ds) DNA viruses. We report rates of dsDNA viremia, end-organ disease (EOD), infection-related mortality, and overall survival (OS) in a contemporary cohort of adult TCD HCT recipients routinely monitored for cytomegalovirus (CMV), adenovirus (ADV), human herpesvirus 6 (HHV6), and Epstein-Barr virus (EBV). Healthcare utilization in the first 6 months post-HCT was compared between patients with dsDNA viremia versus no viremia. This was an observational study of adult patients with acute leukemia and myelodysplastic syndrome who received CD34⁺ selected, peripheral blood HCT at Memorial Sloan Kettering Cancer Center from March 2012 through December 2014. Patients were prospectively monitored by quantitative PCR assays for CMV, ADV, HHV6, and EBV in whole blood or plasma. The cumulative incidence of viremia(s) at day +180, EOD at 1 year, and OS at 1 year were estimated by the Kaplan-Meier method and compared by the log-rank test among patient with and without viremia/EOD. Standardized incidence ratios were used to compare overall length of hospital stay (LOS), number of readmissions after HCT, and length of readmissions through day +180. Of 156 patients, 96 (62%) were CMV recipient seropositive. Forty-two patients received grafts from matched related (27%), 86 from matched unrelated (55%), and 28 from mismatched (18%) donors. Overall, 132 patients (85%) had ≥1 viremia and 52 (33%) ≥2 viremias by day +180. The cumulative incidences for CMV, HHV6, ADV, and EBV viremia were 44%, 61%, 7%, and 16%, respectively, with median times of onset 28 days (interquartile range [IQR], 25 to 33), 33 days (IQR, 25 to 47), 60 days (IQR, 19 to 84), and 79 days (IQR, 54 to 106) post-HCT, respectively. Twenty-eight patients (18%) developed EOD by dsDNA viruses at 1 year post-HCT. Treatment for CMV accounted for 91% total antiviral treatment-days. Compared with patients with no viremia, patients with CMV viremia, HHV6 viremia, or ≥2 viremias experienced longer LOS (P <.001) and a higher number of readmissions (P <.001) by day +180. OS rate at 1 year was 79% and was similar between patients with or without dsDNA viremias. EOD was associated with lower 1-year OS rates (63.4%) versus without EOD (81.1%) (P = .02). Of 33 patients who died, 10 died due to infection, and 7 of these infection-related deaths were due to dsDNA viruses. Viremia by dsDNA viruses occurred in 85% of TCD HCT recipients by day +100 and 33% of patients experienced ≥2 viremias by day +180. CMV accounted for most antiviral use. CMV, HHV6, or ≥2 viremias were associated with more readmissions and longer LOS. One year OS rate was 78%. EOD by dsDNA viruses was associated with decreased 1-year OS. Infections by dsDNA viruses pose a substantial burden after TCD HCT.

Intestinal Microbiota and Relapse After Hematopoietic-Cell Transplantation

Purpose The major causes of mortality after allogeneic hematopoietic-cell transplantation (allo-HCT) are relapse, graft-versus-host disease (GVHD), and infection. We have reported previously that alterations in the intestinal flora are associated with GVHD, bacteremia, and reduced overall survival after allo-HCT. Because intestinal bacteria are potent modulators of systemic immune responses, including antitumor effects, we hypothesized that components of the intestinal flora could be associated with relapse after allo-HCT. Methods The intestinal microbiota of 541 patients admitted for allo-HCT was profiled by means of 16S ribosomal sequencing of prospectively collected stool samples. We examined the relationship between abundance of microbiota species or groups of related species and relapse/progression of disease during 2 years of follow-up time after allo-HCT by using cause-specific proportional hazards in a retrospective discovery-validation cohort study. Results Higher abundance of a bacterial group composed mostly of Eubacterium limosum in the validation set was associated with a decreased risk of relapse/progression of disease (hazard ratio [HR], 0.82 per 10-fold increase in abundance; 95% CI, 0.71 to 0.95; P = .009). When the patients were categorized according to presence or absence of this bacterial group, presence also was associated with less relapse/progression of disease (HR, 0.52; 95% CI, 0.31 to 0.87; P = .01). The 2-year cumulative incidences of relapse/progression among patients with and without this group of bacteria were 19.8% and 33.8%, respectively. These associations remained significant in multivariable models and were strongest among recipients of T-cell-replete allografts. Conclusion We found associations between the abundance of a group of bacteria in the intestinal flora and relapse/progression of disease after allo-HCT. These might serve as potential biomarkers or therapeutic targets to prevent relapse and improve survival after allo-HCT.