Hai-Lin Wang

Providing Personalized Prognostic Information for Adult Leukemia Survivors

Prediction of subsequent leukemia-free survival (LFS) and chronic graft-versus-host disease (GVHD) in adults with acute leukemia who survived at least 1 year after allogeneic hematopoietic cell transplantation is difficult. We analyzed 3339 patients with acute myeloid leukemia and 1434 patients with acute lymphoblastic leukemia who received myeloablative conditioning and related or unrelated stem cells from 1990 to 2005. Most clinical factors predictive of LFS in 1-year survivors were no longer significant after 2 or more years. For acute myeloid leukemia, only disease status (beyond first complete remission) remained a significant adverse risk factor for LFS 2 or more years after transplantation. For lymphoblastic leukemia, only extensive chronic GVHD remained a significant adverse predictor of LFS in the second and subsequent years. For patients surviving for 1 year without disease relapse or extensive chronic GVHD, the risk of developing extensive chronic GVHD in the next year was 4% if no risk factors were present and higher if noncyclosporine-based GVHD prophylaxis, an HLA-mismatched donor, or peripheral blood stem cells were used. Estimates for subsequent LFS and extensive chronic GVHD can be derived for individual patients or populations using an online calculator (http://www.cibmtr.org/LeukemiaCalculators). This prognostic information is more relevant for survivors than estimates provided before transplantation.

Does FLT3 mutation impact survival after hematopoietic stem cell transplantation for acute myeloid leukemia? A Center for International Blood and Marrow Transplant Research (CIBMTR) analysis.

Patients with FMS like tyrosine kinase 3 (FLT3)‐mutated acute myeloid leukemia (AML) have a poor prognosis and are referred for early allogeneic hematopoietic stem cell transplantation (HCT).

Human leukocyte antigen supertype matching after myeloablative hematopoietic cell transplantation with 7/8 matched unrelated donor allografts: A report from the Center for International Blood and Marrow Transplant Research

The diversity of the human leukocyte antigen (HLA) class I and II alleles can be simplified by consolidating them into fewer supertypes based on functional or predicted structural similarities in epitope-binding grooves of HLA molecules. We studied the impact of matched and mismatched HLA-A (265 versus 429), -B (230 versus 92), -C (365 versus 349), and -DRB1 (153 versus 51) supertypes on clinical outcomes of 1934 patients with acute leukemias or myelodysplasia/myeloproliferative disorders. All patients were reported to the Center for International Blood and Marrow Transplant Research following single-allele mismatched unrelated donor myeloablative conditioning hematopoietic cell transplantation. Single mismatched alleles were categorized into six HLA-A (A01, A01A03, A01A24, A02, A03, A24), six HLA-B (B07, B08, B27, B44, B58, B62), two HLA-C (C1, C2), and five HLA-DRB1 (DR1, DR3, DR4, DR5, DR9) supertypes. Supertype B mismatch was associated with increased risk of grade II–IV acute graft-versus-host disease (hazard ratio =1.78, P=0.0025) compared to supertype B match. Supertype B07-B44 mismatch was associated with a higher incidence of both grade II–IV (hazard ratio=3.11, P=0.002) and III–IV (hazard ratio=3.15, P=0.01) acute graft-versus-host disease. No significant associations were detected between supertype-matched versus -mismatched groups at other HLA loci. These data suggest that avoiding HLA-B supertype mismatches can mitigate the risk of grade II–IV acute graft-versus-host disease in 7/8-mismatched unrelated donor hematopoietic cell transplantation when multiple HLA-B supertype-matched donors are available. Future studies are needed to define the mechanisms by which supertype mismatching affects outcomes after alternative donor hematopoietic cell transplantation.

Development of an Unrelated Donor Selection Score Predictive of Survival after HCT: Donor Age Matters Most

Donor factors, in addition to HLA matching status, have been associated with recipient survival in unrelated donor (URD) hematopoietic cell transplantation (HCT); however, there is no hierarchical algorithm that weights the characteristics of individual donors against each other in a quantitative manner to facilitate donor selection. The goal of this study was to develop and validate a donor selection score that prioritizes donor characteristics associated with better survival in 8/8 HLA-matched URDs. Two separate patient/donor cohorts, the first receiving HCT between 1999 and 2011 (n = 5952, c1), and the second between 2012 and 2014 (n = 4510, c2) were included in the analysis. Both cohorts were randomly spilt, 2:1, into training and testing sets. Despite studying over 10,000 URD transplants, we were unable to validate a donor selection score. The only donor characteristic associated with better survival was younger age, with 2-year survival being 3% better when a donor 10 years younger is selected. These results support previous studies suggesting prioritization of a younger 8/8 HLA-matched donor. This large dataset also shows that none of the other donor clinical factors tested were reproducibly associated with survival, and hence flexibility in selecting URDs based on other characteristics is justified. These data support a simplified URD selection process and have significant implications for URD registries.

Allotransplantation for patients age 40 years and greater with non-Hodgkin Lymphoma (NHL): encouraging progression-free survival

Non-Hodgkin lymphoma (NHL) disproportionately affects older patients, who do not often undergo allogeneic hematopoietic cell transplantation (HCT). We analyzed Center for International Blood and Marrow Transplant Research data on 1248 patients age ≥40 years receiving reduced-intensity conditioning (RIC) or nonmyeloablative (NMA) conditioning HCT for aggressive (n = 668) or indolent (n = 580) NHL. Aggressive lymphoma was more frequent in the oldest cohort 49% for age 40 to 54 versus 57% for age 55 to 64 versus 67% for age ≥65; P = .0008). Fewer patients aged ≥65 had previous autografting (26% versus 24% versus 9%; P = .002). Rates of relapse, acute and chronic GVHD, and nonrelapse mortality (NRM) at 1 year post-HCT were similar in the 3 age cohorts (22% [95% confidence interval (CI), 19% to 26%] for age 40 to 54, 27% [95% CI, 23% to 31%] for age 55 to 64, and 34% [95% CI, 24% to 44%] for age ≥65. Progression-free survival (PFS) and overall survival (OS) at 3 years was slightly lower in the older cohorts (OS: 54% [95% CI, 50% to 58%] for age 40 to 54; 40% [95% CI, 36% to 44%] for age 55 to 64, and 39% [95% CI, 28% to 50%] for age ≥65; P < .0001). Multivariate analysis revealed no significant effect of age on the incidence of acute or chronic GVHD or relapse. Age ≥55 years, Karnofsky Performance Status <80, and HLA mismatch adversely affected NRM, PFS, and OS. Disease status at HCT, but not histological subtype, was associated with worse NRM, relapse, PFS, and OS. Even for patients age ≥55 years, OS still approached 40% at 3 years, suggesting that HCT affects long-term remission and remains underused in qualified older patients with NHL.

In silico prediction of nonpermissive HLA-DPB1 mismatches in unrelated HCT by functional distance

In silico prediction of high-risk donor-recipient HLA mismatches after unrelated donor (UD) hematopoietic cell transplantation (HCT) is an attractive, yet elusive, objective. Nonpermissive T-cell epitope (TCE) group mismatches were defined by alloreactive T-cell cross-reactivity for 52/80 HLA-DPB1 alleles (TCE-X). More recently, a numerical functional distance (FD) scoring system for in silico prediction of TCE groups based on the median impact of exon 2-encoded amino acid polymorphism on T-cell alloreactivity was developed for all DPB1 alleles (TCE-FD), including the 28/80 common alleles not assigned by TCE-X. We compared clinical outcome associations of nonpermissive DPB1 mismatches defined by TCE-X or TCE-FD in 8/8 HLA-matched UD-HCT for acute leukemia, myelodysplastic syndrome, and chronic myelogenous leukemia between 1999 and 2011 (N = 2730). Concordance between the 2 models was 92.3%, with most differences arising from DPB1*06:01 and DPB1*19:01 being differently assigned by TCE-X and TCE-FD. In both models, nonpermissive mismatches were associated with reduced overall survival (hazard ratio [HR], 1.15, P < .006 and HR, 1.12, P < .03), increased transplant-related mortality (HR, 1.31, P < .001 and HR, 1.26, P < .001) as well as acute (HR, 1.16, P < .02 and HR, 1.22, P < .001) and chronic (HR, 1.20, P < .003 and HR, 1.22, P < .001) graft-versus-host disease (GVHD). We show that in silico prediction of nonpermissive DPB1 mismatches significantly associated with major transplant outcomes is feasible for any DPB1 allele with known exon 2 sequence based on experimentally elaborated FD scores. This proof-of-principle observation opens new avenues for developing HLA risk-prediction models in HCT and has practical implications for UD searches.

HLA-Mismatch Is Associated With Worse Outcomes After Unrelated Donor Reduced Intensity Conditioning Hematopoietic Cell Transplantation: An Analysis From The CIBMTR

Over the past 2 decades, reduced-intensity conditioning allogeneic hematopoietic cell transplantation (RIC HCT) has increased substantially. Many patients do not have fully HLA-matched donors, and the impact of HLA mismatch on RIC HCT has not been examined in large cohorts. We analyzed 2588 recipients of 8/8 HLA-high resolution matched (n = 2025) or single-locus mismatched (n = 563) unrelated donor (URD) RIC HCT from 1999 to 2011. Overall survival (OS) was the primary outcome. Secondary endpoints included treatment-related mortality (TRM), relapse, disease-free survival (DFS), and acute/chronic graft-versus-host disease (GVHD). Adjusted 1- and 3-year OS was better in 8/8- versus 7/8-matched recipients (54.7% versus 48.8%, P = .01, and 37.4% versus 30.9%, P = .005, respectively). In multivariate models 7/8 URD RIC HCT recipients had more grades II to IV acute GVHD (RR = 1.29, P = .0034), higher TRM (RR = 1.52, P < .0001), and lower DFS (RR = 1.12, P = .0015) and OS (RR = 1.25, P = .0001), with no difference in relapse or chronic GVHD. In subgroup analysis, inferior transplant outcomes were noted regardless of the HLA allele mismatched. Previously reported permissive mismatches at HLA-C (C*03:03/C*03:04) and HLA-DP1 (based on T cell-epitope matching) were not associated with better outcomes. Although feasible, single-locus mismatch in RIC URD HCT is associated with inferior outcomes.