Prospective evaluation of alternative donor from unrelated donor and cord blood in adult acute leukemia and myelodysplastic syndrome

Decision Analysis for Unrelated Bone Marrow Transplantation or Immediate Cord Blood Transplantation for Patients with Philadelphia Chromosome-Negative Acute Lymphoblastic Leukemia in First Complete Remission

An HLA-matched relative is the first-choice donor for patients with Philadelphia chromosome (Ph)-negative acute lymphoblastic leukemia (ALL) in first complete remission (CR1). The most promising alternative donor is thought to be an HLA-matched unrelated donor (MUD) in patients who do not have an HLA-matched related donor. Cord blood transplantation (CBT) is an alternative option. Higher rates of engraftment failure and nonrelapse mortality are significant problems, but the ready availability of cord blood can be an advantage, because patients can immediately undergo transplantation before progression. This study was conducted to identify an appropriate alternative donor in patients with Ph-negative ALL in CR1 who do not have an HLA-matched related donor (MRD). Decision analyses using a Markov model were performed to compare immediate CBT, in which CBT was performed at 1 month after the achievement of CR1, with elective unrelated bone marrow transplantation (uBMT) from an 8/8 HLA-matched unrelated donor (MUD) (8/8 uBMT) or uBMT from 7/8 MUD (7/8 uBMT), in which uBMT was performed at 4 months, in patients age 16 to 55 years with Ph-negative ALL in CR1 who did not have an MRD. We constructed a decision tree. The cycle length was set at 3 months, and analyses were performed for 19 cycles for uBMT and 20 cycles for CBT, resulting in evaluation of the 5-year life expectancy after both decisions. Transition probabilities (TPs) and utilities were estimated from prospective and retrospective Japanese studies and the registry database of Japan. Subgroup analyses were performed according to risk stratification based on WBC count and cytogenetics at diagnosis and according to age stratification, with a cutoff of 25 years. One-way sensitivity analyses for TPs and utilities were performed as well. The baseline analyses showed that 8/8 uBMT or 7/8 uBMT had superior results to CBT, with quality-adjusted life years (QALYs) of 2.86 in 8/8 uBMT, 2.84 in 7/8 uBMT, and 2.75 in CBT. One-way sensitivity analyses showed that the results of the baseline analyses were reversed if the probability of nonrelapse mortality (NRM) in CBT improved. Subgroup analyses showed similar results in younger, older, and high-risk patients. However, QALY was worse in 8/8 uBMT compared with CBT in standard-risk patients. In one-way sensitivity analyses, the probabilities of NRM in uBMT and CBT affected the baseline results in all analyses except for comparisons between 8/8 uBMT and CBT in younger and high-risk patients. In these 2 populations, the superiority of 8/8 uBMT was consistently demonstrated throughout the one-way sensitivity analyses. For patients with Ph-negative ALL in CR1 who decide to undergo transplantation from an alternative donor, elective uBMT from either an 8/8 MUD or a 7/8 MUD is expected to yield a better outcome than immediate CBT. Nonetheless, CBT is a viable option, and improvements to reduce the risk of NRM in CBT may change these results.

A multicenter phase II study of intrabone single-unit cord blood transplantation without antithymocyte globulin

To overcome the delayed or failed engraftment after unrelated cord blood transplantation (CBT), we conducted a multicenter phase II study of intrabone single-unit CBT without antithymocyte globulin (ATG) for adult patients with hematological malignancies (UMIN-CTR, UMIN000020997). Sixty-four patients received an intrabone injection of unwashed (n = 61) or washed (n = 3) cord blood after local anesthesia. All injection-related adverse events were mild and resolved spontaneously. Sixty-two patients were evaluable for the efficacy of intrabone CBT of serological HLA-A, -B, and -DR ≥ 4/6 matched cord blood with a median number of 2.57 × 10⁷/kg cryopreserved total nucleated cells. The probability of survival with neutrophil engraftment on day 28 was 77.4% (95% confidence interval, 67.0-85.8%), which exceeded the threshold value. The cumulative incidences of neutrophils ≥ 0.5 × 10⁹/L on day 60 was 80.6% (68.2-88.6%), with a median time to recovery of 21 days after transplantation. The cumulative incidences of platelets ≥ 20 × 10⁹/L and platelets ≥ 50 × 10⁹/L on day 100 were 75.8% (62.6-84.9%) and 72.6% (59.4-82.1%), respectively, with median time to platelets ≥ 20 × 10⁹/L and platelets ≥ 50 × 10⁹/L of 38 and 45 days after transplantation, respectively. The cumulative incidences of grade II-IV and III-IV acute graft-versus-host disease were 29.0% and 6.5%, respectively. All responded to steroid therapy, and secondary treatments were not required. The present study suggests the efficacy of intrabone single-unit CBT without ATG in terms of early engraftment and controllable acute graft-versus-host disease.

Phase I clinical trial of intra-bone marrow cotransplantation of mesenchymal stem cells in cord blood transplantation

Mesenchymal stem cells (MSCs) have immunomodulatory properties and support hematopoiesis in the bone marrow (BM). To develop a new strategy to not only prevent graft‐vs‐host disease (GVHD) but also to enhance engraftment, a phase I trial of cord blood transplantation (CBT) combined with intra‐BM injection of MSCs (MSC‐CBT) was designed. Third‐party BM‐derived MSCs were injected intra‐BM on the day of CBT. The conditioning regimen varied according to patient characteristics. GVHD prophylaxis was tacrolimus and methotrexate. The primary endpoint was toxicity related to intra‐BM injection of MSCs. Clinical outcomes were compared with those of six controls who received CBT alone. Five adult patients received MSC‐CBT, and no adverse events related to intra‐BM injection of MSCs were observed. All patients achieved neutrophil, reticulocyte, and platelet recoveries, with median times to recoveries of 21, 35, and 38 days, respectively, comparable with controls. Grade II‐IV acute GVHD developed in three controls but not in MSC‐CBT patients. No patients developed chronic GVHD in both groups. At 1 year after transplantation, all MSC‐CBT patients survived without relapse. This study shows the safety of MSC‐CBT, and the findings also suggest that cotransplantation of MSCs may prevent GVHD with no inhibition of engraftment. This trial was registered at the University Hospital Medical Information Network Clinical Trials Registry as number 000024291.

Randomised controlled trial of conditioning regimen for cord blood transplantation for adult myeloid malignancies comparing high-dose cytarabine/cyclophosphamide/total body irradiation with versus without G-CSF priming: G-CONCORD study protocol

INTRODUCTION

A better long-term quality of life after umbilical cord blood transplantation (CBT) is observed compared with transplants from other alternative donors, whereas graft failure and relapses after CBT are still major issues. To minimise graft failure and relapse after CBT, intensification of conditioning by the addition of high-dose cytosine arabinoside (CA) and concomitant continuous use of granulocyte-colony stimulating factor (G-CSF) are reported to convey a significantly better survival after CBT in some retrospective studies. To confirm the effect of G-CSF plus CA combination, in addition to the standard conditioning regimen, cyclophosphamide (CY)/total body irradiation (TBI), we design a randomised controlled study comparing CA/CY/TBI with versus without G-CSF priming (G-CSF combined conditioned cord blood transplantation [G-CONCORD] study).

METHODS AND ANALYSIS

This is a multicentre, open-label, randomised phase III study that aimed to compare G-CSF+CA/CY/TBI as a conditioning regimen for CBT with CA/CY/TBI. Patients with acute myeloid leukaemia or myelodysplastic syndrome, aged 16-55 years, are eligible. The target sample size is 160 and the registration period is 4 years. The primary endpoint is the 2-year disease-free survival rate after CBT. The secondary endpoints are overall survival, relapse, non-relapse mortality, acute and chronic graft-versus-host disease, engraftment rate, time to neutrophil recovery, short-term adverse events, incidence of infections and causes of death.This study employs a single one-to-one web-based randomisation between the with-G-CSF versus without-G-CSF groups after patient registration. Combination of high-dose CA and CY/TBI in both groups is used for conditioning.

ETHICS AND DISSEMINATION

The study protocol was approved by the central review board, Nagoya University Certified Review Board, after the enforcement of the Clinical Trials Act in Japan. The manuscripts presenting data from this study will be submitted for publication in quality peer-reviewed medical journals. Study findings will be disseminated via presentations at national/international conferences and peer-reviewed journals.

TRIAL REGISTRATION NUMBERS

UMIN000029947 and jRCTs041180059.

Updated Comparison of 7/8 HLA Allele-Matched Unrelated Bone Marrow Transplantation and Single-Unit Umbilical Cord Blood Transplantation as Alternative Donors in Adults with Acute Leukemia

The outcomes of 7/8 allele-matched unrelated bone marrow transplantation (7/8 UBMT) and umbilical cord blood transplantation (UCBT) have been improving. We retrospectively analyzed adults with acute leukemia who underwent their first 7/8 UBMT or UCBT in Japan. Between January 2008 and December 2017, a total of 4150 patients were recorded, including 488 who underwent 7/8 UBMT and 3662 who underwent UCBT. Only 32 patients with 7/8 UBMT had graft-versus-host-disease (GVHD) high-risk HLA mismatched pairs. Overall survival at 3 years was 54% for 7/8 the UBMT group and 46% for the UCBT group, a nonsignificant difference in multivariate analysis (hazard ratio [HR], 1.01; 95% confidence interval [CI], .88 to 1.17; P = .89). The 7/8 UBMT and UCBT groups showed a similar nonrelapse mortality rate (HR, 1.16; 95% CI, .96 to 1.45; P = .16) and relapse rate (HR, .85; 95% CI, .71 to 1.02; P = .08). However, the UCBT group had a lower risk of grade II-IV acute GVHD (HR, .76; 95% CI, .65 to .88; P < .001) and chronic GVHD (HR, .77; 95% CI, .66- .91; P = .002) compared with the 7/8 UBMT group. In stratified analyses combining disease risk with conditioning intensity, 7/8 UBMT showed superior overall survival to UCBT in standard risk and myeloablative conditioning (HR, .72; 95% CI, .56 to .93; P = .014). Both 7/8 UBMT and UCBT are appropriate alternative donor procedures. The stem cell source can be selected on the basis of disease risk, patient tolerability, or concerns regarding GVHD.

Which lower risk myelodysplastic syndromes should be treated with allogeneic hematopoietic stem cell transplantation?

Indications of allogeneic hematopoietic stem cell transplantation (HSCT) remain controversial in patients with lower risk myelodysplastic syndrome. We review prognostic factors in lower risk MDS, delineating patients with relatively poor risk who may potentially benefit from HSCT during the disease course. Results of HSCT in those patients, and main efforts to decrease non-relapse mortality (NRM) are detailed. Prospective studies are needed to determine more precisely which lower risk MDS patients may benefit from transplantation.