European Group for Blood and Marrow Transplantation Risk Score Predicts the Outcome of Patients with Acute Leukemia Receiving Single Umbilical Cord Blood Transplantation

Unrelated cord blood transplantation vs. HLA-matched sibling transplantation for adults with B-cell acute lymphoblastic leukemia in complete remission: superior OS for patients with long-term survival

Background

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an important curative therapy for adult acute lymphoblastic leukemia (ALL). For patients who lack a human leukocyte antigen (HLA)-matched sibling donor, unrelated cord blood (UCB) is an alternative graft option. Previous studies have focused mainly on all T- and B-cell ALL (B-ALL) patients, while data related specifically to adult B-ALL patients after UCB transplantation (UCBT) are scarce.

Methods

We retrospectively compared the outcomes of UCBT and HLA-matched sibling transplantation (MST) in the treatment of adult B-ALL patients in complete remission (CR) at our center. From June 2006 to December 2020, 156 adult B-ALL patients who achieved CR before transplantation were enrolled. The main clinical outcomes of UCBT and MST were analyzed.

Results

Hematopoietic recovery was significantly faster in MST recipients than in UCBT recipients. Higher incidences of grades II-IV and III-IV acute graft-versus host disease (aGVHD) were found in UCBT recipients (P < 0.001 and = 0.03), while a lower incidence of extensive chronic GVHD (cGVHD) was found in UCBT recipients (P < 0.001). The cumulative incidences of 2-year non-relapse mortality (NRM), 2-year relapse, 5-year disease-free survival (DFS) and 5-year GVHD-free relapse-free survival (GRFS) were comparable between MST and UCBT recipients. The overall survival (OS) during the first 700 days was similar between the MST and UCBT groups, while the OS of patients with a survival time of more than 700 days in the UCBT group was better than that in the MST group according to multivariate analysis (P = 0.03).

Conclusions

Our study shows that when treating adult B-ALL patients in CR, UCBT can achieve comparable effects as MST, may provide superior OS for patients with long-term survival, and should be considered a good alternative.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03186-3.

Impact of Consolidative Unrelated Cord Blood Transplantation on Clinical Outcomes of Patients With Relapsed/Refractory Acute B Lymphoblastic Leukemia Entering Remission Following CD19 Chimeric Antigen Receptor T Cells

Background

While chimeric antigen receptor (CAR)-T cell therapy is becoming widely used in hematological malignancies with remarkable remission rate, their high recurrence remains an obstacle to overcome. The role of consolidative transplantation following CAR-T cell-mediated remission remains controversial. We conducted a retrospective study to explore whether bridging to unrelated cord blood transplantation (UCBT) could improve the prognosis of patients entering remission after CAR-T therapy with different characteristics through subgroup analyses.

Methods

We reviewed 53 patients with relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL) successfully infused with CD19 CAR-T cells and achieved complete remission (CR). In this study, 25 patients received consolidative UCBT (UCBT group) and 28 patients did not accept any intervention until relapse (non-UCBT group). Subgroup analysis on prognosis was then performed according to gender, age, number of previous relapses, tumor burden, presence of poor prognostic markers, and structure of CAR.

Results

Compared with the non-UCBT group, patients who underwent consolidative UCBT had better median event-free survival (EFS; 12.3 months vs. 6.2 months; P = 0.035) and relapse-free survival (RFS; 22.3 months vs. 7.2 months; P = 0.046), while no significant difference was found in overall survival (OS; 30.8 months vs. 15.3 months; P = 0.118). Subsequent multivariate analysis revealed that bridging to UCBT was a protective factor for RFS (P = 0.048) but had no significant effect on EFS (P = 0.205) or OS (P = 0.541). In the subgroup analysis, UCBT has an added benefit in patients with specific characteristics. Patients who experienced ≥2 relapses or with sustained non-remission (NR) showed better RFS (P = 0.025) after UCBT. Better EFS was seen in patients with poor prognostic markers (P = 0.027). In the subgroup with pre-infusion minimal residual disease (MRD) ≥5% or with extramedullary disease (EMD), UCBT significantly prolonged EFS (P = 0.009), RFS (P = 0.017), and OS (P = 0.026). Patients with occurrence of acute graft-versus-host disease (aGVHD) appeared to have a longer duration of remission (P = 0.007).

Conclusion

Consolidative UCBT can, to some extent, improve clinical outcomes of patients with R/R B-ALL entering remission following CD19 CAR-T therapy, especially in patients with more recurrences before treatment, patients with poor prognostic markers, and patients with a higher tumor burden. The occurrence of aGVHD after UCBT was associated with better RFS.

Chimeric Antigen Receptor T Cell Therapy followed by Unrelated Cord Blood Transplantation for the Treatment of Relapsed/Refractory B Cell Acute Lymphoblastic Leukemia in Children and Young Adults: Superior Survival but Relatively High Post-Transplantation Relapse

Several studies have indicated that chimeric antigen receptor (CAR) T cell therapy followed by allogeneic hematopoietic stem cell transplantation is beneficial for treating patients with relapsed or refractory (R/R) B cell acute lymphoblastic leukemia (B-ALL). Whether consolidative unrelated cord blood transplantation (UCBT) is suitable in R/R B-ALL after CAR-T therapy remain uncertain. We aimed to assess the efficacy and safety of CAR-T therapy before UCBT in children and young adults with R/R B-ALL. We retrospectively analyzed 43 patients aged <18 years with R/R B-ALL who underwent single-unit UCBT at the First Affiliated Hospital of the University of Science and Technology of China between February 2012 and November 2020. Among them, 21 patients achieved complete remission (CR) following CAR-T therapy before UCBT (the CAR-T group), and the remaining 22 patients remained in nonremission (NR) without prior CAR-T therapy before UCBT (the NR group). The clinical outcomes in the 2 groups were analyzed. The median time from CAR-T therapy to UCBT was 62 days (range, 42 to 185 days). There were no significant between-group differences in the incidences of grade II-IV acute graft-versus-host disease (GVHD), grade III-IV acute GVHD, and 2-year extensive chronic GVHD. Compared with the NR group, the CAR-T group had a lower 2-year cumulative incidence of transplantation-related mortality and higher probabilities of 2-year overall survival, leukemia-free survival, and GVHD-free relapse-free survival (P = .037, .005, .028, and .017, respectively). However, the 2-year cumulative incidence of relapse (CIR) was comparably high in the 2 groups (26.7% in the CAR-T group and 38.3% in the NR group; P = .41). In the CAR-T group, patients who were minimal residual disease (MRD)-positive before UCBT had a higher CIR compared with those who were MRD-negative before UCBT (66.7% versus 19.2%; P = .006). CAR-T therapy followed by UCBT produces superior survival in R/R B-ALL, but treated patients still have a high post-transplantation relapse rate.

Recombinant human thrombopoietin promotes platelet engraftment after umbilical cord blood transplantation

Delayed platelet engraftment is a common complication after umbilical cord blood transplantation (UCBT) accompanied by increased transplant-related complications or death. This study was designed to determine the safety and efficacy of recombinant human thrombopoietin (rhTPO) in promoting platelet engraftment after UCBT. A total of 120 patients scheduled to receive UCBT were randomly assigned to the rhTPO group (300 U/kg once daily from days 14 to 28 after UCBT, n = 60) or the control group (n = 60). The primary outcome was the 60-day cumulative incidence of platelet engraftment after single-unit cord blood transplantation. The 60-day cumulative incidence of platelet engraftment (platelet count ≥20 × 109/L) and the 120-day cumulative incidence of platelet recovery (platelet count ≥50 × 109/L) were both significantly higher in the rhTPO group than in the control group (83.1% vs 66.7%, P = .020; and 81.4% vs 65.0%, P = .032, respectively). In addition, the number of required platelet infusions was significantly lower in the rhTPO group than in the control group (6 vs 8 units, respectively; P = .026). The cumulative incidence of neutrophil engraftment and the probability of 2-year overall survival, disease-free survival, and graft-versus-host disease-free relapse-free survival did not differ between the 2 groups. Other transplant-related outcomes and complications did not differ between the 2 groups, and no severe adverse effects were observed in patients receiving rhTPO. This study demonstrated that rhTPO is well tolerated in patients and could effectively promote platelet engraftment after UCBT. This study was registered on the Chinese Clinical Trial Registry (http://www.chictr.org.cn/index.aspx) as ChiCTR-IPR-16009357.

External validation and comparison of multiple prognostic scores in allogeneic hematopoietic stem cell transplantation

Clinical decisions in allogeneic hematopoietic stem cell transplantation (allo-HSCT) are supported by the use of prognostic scores for outcome prediction. Scores vary in their features and in the composition of development cohorts. We sought to externally validate and compare the performance of 8 commonly applied scoring systems on a cohort of allo-HSCT recipients. Among 528 patients studied, acute myeloid leukemia was the leading transplant indication (44%) and 46% of patients had a matched sibling donor. Most models successfully grouped patients into higher and lower risk strata, supporting their use for risk classification. However, discrimination varied (2-year overall survival area under the receiver operating characteristic curve [AUC]: revised Pretransplantation Assessment of Mortality [rPAM], 0.64; PAM, 0.63; revised Disease Risk Index [rDRI], 0.62; Endothelial Activation and Stress Index [EASIx], 0.60; combined European Society for Blood and Marrow Transplantation [EBMT]/Hematopoietic Cell Transplantation-specific Comorbidity Index [HCT-CI], 0.58; EBMT, 0.58; Comorbidity-Age, 0.58; HCT-CI, 0.55); AUC ranges from 0.5 (random) to 1.0 (perfect prediction). rPAM and PAM, which had the greatest predictive capacity across all outcomes, are comprehensive models including patient, disease, and transplantation information. Interestingly, EASIx, a biomarker-driven model, had comparable performance for nonrelapse mortality (NRM; 2-year AUC, 0.65) but no predictive value for relapse (2-year AUC, 0.53). Overall, allo-HSCT prognostic systems may be useful for risk stratification, but individual prediction remains a challenge, as reflected by the scores' limited discriminative capacity.

Predictive value of disease risk comorbidity index for overall survival after allogeneic hematopoietic transplantation

Allogeneic hematologic cell transplantation (alloHCT) is the only curative therapy for many adults with hematological malignancies. However, it can be associated with substantial risks of morbidity and mortality that are dependent on patient comorbidity- or disease risk-related factors. Several pretransplantation prognostic scoring systems have been developed to estimate survival of patients undergoing alloHCT; however, there is significant interstudy variability in the predictive capacity of these assessment tools. We tested the prognostic capability of a composite scoring system including the disease risk index and HCT comorbidity index (DRCI). The DRCI scoring system was applied pretransplantation to determine whether it predicted clinical outcomes of 959 adult patients with hematological malignancies undergoing alloHCT from 2000 to 2013 at the University of Minnesota. The DRCI score categorized patients into 6 risk groups, with 2-year overall survival ranging between 74% for the very low-risk DRCI group and 34% for the very high-risk DRCI group. In multiple regression analyses adjusted for patient age and donor type, the risk of overall mortality independently increased as the DRCI score increased. Additionally, the DRCI score independently predicted risk of relapse, disease-free survival, and graft-versus-host disease-free/relapse-free survival. Our data demonstrate that the pretransplantation DRCI scoring system predicts outcomes after alloHCT and can be used to guide clinical decision making for patients considering alloHCT.

Retrospective cohort study comparing the outcomes of intravenous busulfan vs. total-body irradiation after single cord blood transplantation

Limited to inadequate stem-cell doses, cord blood transplantation (UCBT) is accompanied by increased graft failure and delayed haematopoietic recovery. The conditioning regimen is critically important for engraftment, and numerous trials have been undertaken comparing the outcomes of IV Bu and TBI, but there are no comparative data for UCBT. We conducted a retrospective multicentre study to analyse the outcomes of IV Bu and TBI in UCBT patients with haematologic malignancies. Between 1 May, 2008 and 31 Mar, 31 2018, a total of 331 patients from the China Umbilical Cord Blood Transplantation Corporation (IV Bu, n = 131; TBI, n = 200) were evaluated. The cumulative incidence of neutrophil engraftment was 91.6% in the IV Bu/Cy cohort and 98.0% in the Cy/TBI cohort (P < 0.001). The median times to neutrophil engraftment were 16 and 19 days (P < 0.001), respectively. Multivariate analysis showed no statistical difference for nonrelapse mortality (hazard ratio [HR], 1.11; 95% confidence interval [CI], 0.66 to 1.86; P = 0.695), relapse (HR, 0.90; 95% CI, 0.50 to 1.60; P = 0.713) and overall survival (HR, 0.94; 95% CI, 0.61 to 1.44; P = 0.763) between the two conditioning regimens. Our results show that both IV Bu and TBI are valid myeloablative conditioning regimens for haematologic malignancy patients treated with UCBT.