Influence of Age on Acute and Chronic GVHD in Children Undergoing HLA-Identical Sibling Bone Marrow Transplantation for Acute Leukemia: Implications for Prophylaxis.

Relapse remains the major cause of mortality after hematopoietic cell transplantation (HCT) for pediatric acute leukemia. Previous research has suggested that reducing the intensity of calcineurin inhibitor-based graft-versus-host disease (GVHD) prophylaxis may be an effective strategy for abrogating the risk of relapse in pediatric patients undergoing matched sibling donor (MSD) HCT. We reasoned that the benefits of this strategy could be maximized by selectively applying it to those patients least likely to develop GVHD. We conducted a study of risk factors for GVHD, to risk-stratify patients based on age. Patients age <18 years with leukemia who received myeloablative, T cell-replete MSD bone marrow transplantation and calcineurin inhibitor-based GVHD prophylaxis between 2000 and 2013 and were entered into the Center for International Blood and Marrow Transplant Research registry were included. The cumulative incidence of grade II-IV acute GVHD (aGVHD) was 19%, that of grade II-IV aGVHD 7%, and that of chronic GVHD (cGVHD) was 16%. Compared with age 13 to 18 years, age 2 to 12 years was associated with a lower risk of grade II-IV aGVHD (hazard ratio [HR], .42; 95% confidence interval [CI], .26 to .70; P = .0008), grade II-IV aGVHD (HR, .24; 95% CI, .10 to .56; P = .001), and cGVHD (HR, .32; 95% CI, .19 to .54; P < .001). Compared with 2000-2004, the risk of grade II-IV aGVHD was lower in children undergoing transplantation in 2005-2008 (HR, .36; 95% CI, .20 to .65; P = .0007) and in 2009-2013 (HR, .24; 95% CI. .11 to .53; P = .0004). Similarly, the risk of grade III-IV aGVHD was lower in children undergoing transplantation in 2005-2008 (HR, .23; 95% CI, .08 to .65; P = .0056) and 2009-2013 (HR, .16; 95% CI, .04 to .67; P = .0126) compared with those doing so in 2000-2004. We conclude that aGVHD rates have decreased significantly over time, and that children age 2 to 12 years are at very low risk for aGVHD and cGVHD. These results should be validated in an independent analysis, because these patients with high-risk malignancies may be good candidates for trials of reduced GVHD prophylaxis.

Characteristics of Graft-Versus-Host Disease (GvHD) After Post-Transplantation Cyclophosphamide Versus Conventional GvHD Prophylaxis.

Post-transplantation cyclophosphamide (PTCy) has been shown to effectively control graft-versus-host disease (GvHD) in haploidentical (Haplo) transplantations. In this retrospective registry study, we compared GvHD organ distribution, severity, and outcomes in patients with GvHD occurring after Haplo transplantation with PTCy GvHD prophylaxis (Haplo/PTCy) versus HLA-matched unrelated donor transplantation with conventional prophylaxis (MUD/conventional). We evaluated 2 cohorts: patients with grade 2 to 4 acute GvHD (aGvHD) including 264 and 1163 recipients of Haplo and MUD transplants; and patients with any chronic GvHD (cGvHD) including 206 and 1018 recipients of Haplo and MUD transplants, respectively. In comparison with MUD/conventional transplantation ± antithymocyte globulin (ATG), grade 3-4 aGvHD (28% versus 39%, P = .001), stage 3-4 lower gastrointestinal (GI) tract aGvHD (14% versus 21%, P = .01), and chronic GI GvHD (21% versus 31%, P = .006) were less common after Haplo/PTCy transplantation. In patients with grade 2-4 aGvHD, cGvHD rate after Haplo/PTCY was also lower (hazard ratio [HR] = .4, P < .001) in comparison with MUD/conventional transplantation without ATG in the nonmyeloablative conditioning setting. Irrespective of the use of ATG, non-relapse mortality rate was lower (HR = .6, P = .01) after Haplo/PTCy transplantation, except for transplants that were from a female donor into a male recipient. In patients with cGvHD, irrespective of ATG use, Haplo/PTCy transplantation had lower non-relapse mortality rates (HR = .6, P = .04). Mortality rate was higher (HR = 1.6, P = .03) during, but not after (HR = .9, P = .6) the first 6 months after cGvHD diagnosis. Our results suggest that PTCy-based GvHD prophylaxis mitigates the development of GI GvHD and may translate into lower GvHD-related non-relapse mortality rate.

Allogeneic Transplantation to Treat Therapy-Related Myelodysplastic Syndrome and Acute Myelogenous Leukemia in Adults.

Patients who develop therapy-related myeloid neoplasm, either myelodysplastic syndrome (t-MDS) or acute myelogenous leukemia (t-AML), have a poor prognosis. An earlier Center for International Blood and Marrow Transplant Research (CIBMTR) analysis of 868 allogeneic hematopoietic cell transplantations (allo-HCTs) performed between 1990 and 2004 showed a 5-year overall survival (OS) and disease-free survival (DFS) of 22% and 21%, respectively. Modern supportive care, graft-versus-host disease prophylaxis, and reduced-intensity conditioning (RIC) regimens have led to improved outcomes. Therefore, the CIBMTR analyzed 1531 allo-HCTs performed in adults with t-MDS (n = 759) or t-AML (n = 772) between and 2000 and 2014. The median age was 59 years (range, 18 to 74 years) for the patients with t-MDS and 52 years (range, 18 to 77 years) for those with t-AML. Twenty-four percent of patients with t-MDS and 11% of those with t-AML had undergone a previous autologous (auto-) HCT. A myeloablative conditioning (MAC) regimen was used in 49% of patients with t-MDS and 61% of patients with t-AML. Nonrelapse mortality at 5 years was 34% (95% confidence interval [CI], 30% to 37%) for patients with t-MDS and 34% (95% CI, 30% to 37%) for those with t-AML. Relapse rates at 5 years in the 2 groups were 46% (95% CI, 43% to 50%) and 43% (95% CI, 40% to 47%). Five-year OS and DFS were 27% (95% CI, 23% to 31%) and 19% (95% CI, 16% to 23%), respectively, for patients with t-MDS and 25% (95% CI, 22% to 28%) and 23% (95% CI, 20% to 26%), respectively, for those with t-AML. In multivariate analysis, OS and DFS were significantly better in young patients with low-risk t-MDS and those with t-AML undergoing HCT with MAC while in first complete remission, but worse for those with previous auto-HCT, higher-risk cytogenetics or Revised International Prognostic Scoring System score, and a partially matched unrelated donor. Relapse remains the major cause of treatment failure, with little improvement seen over the past 2 decades. These data mandate caution when recommending allo-HCT in these conditions and indicate the need for more effective antineoplastic approaches before and after allo-HCT.