Development of an umbilical cord blood transplantation-specific nonrelapse mortality risk assessment score.

ABSTRACT: Higher rate of nonrelapse mortality (NRM) remains yet to be resolved in umbilical cord blood transplantation (UCBT). Considering that UCBT has some unique features compared with allogeneic hematopoietic cell transplantation from other graft sources, a UCBT-specific NRM risk assessment system is required. Thus, in this study, we sought to develop a UCBT-specific NRM Risk Assessment (CoBRA) score. Using a nationwide registry database, we retrospectively analyzed 4437 recipients who had received their first single-unit UCBT. Using the backward elimination method, we constructed the CoBRA score in a training cohort (n = 2687), which consisted of recipients age ≥55 years (score 2), hematopoietic cell transplantation-specific comorbidity index ≥3 (score 2), male recipient, graft-versus-host disease prophylaxis other than tacrolimus in combination with methotrexate, performance status (PS) 2 to 4, HLA allele mismatch ≥ 2, refined Disease Risk Index high risk, myeloablative conditioning, and CD34+ cell doses < 0.82 × 105/kg (score 1 in each). The recipients were categorized into 3 groups: low (0-4 points), intermediate (5-7 points), and high (8-11 points) groups according to the CoBRA score. In the validation cohort (n = 1750), the cumulative incidence of NRM at 2 years was 14.9%, 25.5%, and 47.1% (P < .001), and 2-year overall survival (OS) was 74.2%, 52.7%, and 26.3% (P < .001) in the low, intermediate, and high groups, respectively. In summary, the CoBRA score could predict the NRM risk as well as OS after UCBT. Further external validation will be needed to confirm the significance of the CoBRA score.

Novel risk assessment for the intensity of conditioning regimen in older patients.

Reduced-intensity conditioning (RIC) regimens have long-term outcomes that are generally comparable with those of myeloablative conditioning (MAC) because of a lower risk of nonrelapse mortality (NRM) but a higher risk of relapse. However, it is unclear how we should select the conditioning intensity in individual cases. We propose the risk assessment for the intensity of conditioning regimen in elderly patients (RICE) score. We retrospectively analyzed 6147 recipients aged 50 to 69 years using a Japanese registry database. Based on the interaction analyses, advanced age (≥60 years), hematopoietic cell transplantation-specific comorbidity index (≥2), and umbilical cord blood were used to design a scoring system to predict the difference in an individual patient's risk of NRM between MAC and RIC: the RICE score, which is the sum of the 3 factors. Zero or 1 implies low RICE score and 2 or 3, high RICE score. In multivariate analyses, RIC was significantly associated with a decreased risk of NRM in patients with a high RICE score (training cohort: hazard ratio [HR], 0.73; 95% confidence interval [CI], 0.60-0.90; P = .003; validation cohort: HR, 0.57; 95% CI, 0.43-0.77; P < .001). In contrast, we found no significant differences in NRM between MAC and RIC in patients with a low RICE score (training cohort: HR, 0.99; 95% CI, 0.85-1.15; P = .860; validation cohort: HR, 0.81; 95% CI, 0.66-1.01; P = .061). In summary, a new and simple scoring system, the RICE score, appears to be useful for personalizing the conditioning intensity and could improve transplant outcomes in older patients.

NPM1-mutation-based measurable residual disease assessment after completion of two courses of post-remission therapy is a valuable clinical predictor of the prognosis of acute myeloid leukemia.

Recent studies have reported that measurable residual disease (MRD) analysis using NPM1 mutations helps determine whether allogeneic hematopoietic stem cell transplantation (allo-HSCT) is indicated in acute myeloid leukemia (AML) patients. However, the optimal timing and cutoff value for measuring MRD using genomic DNA remain undetermined. This study aimed to investigate the optimal timing and cutoff value to ascertain the value of NPM1 mutation in MRD assessment. NPM1-mutated MRD was quantified by real-time polymerase chain reaction of bone marrow samples from 56 patients with NPM1-positive AML who achieved hematological remission. The area under the receiver-operating characteristic curve was greatest when MRD was assessed after two courses of post-remission therapy with a cutoff value of 0.010% (specificity, 68.4%; sensitivity, 87.0%). Patients whose MRD was below the cutoff value throughout the course of treatment had significantly better overall survival and relapse-free survival rates. Of the 33 patients who did not undergo transplantation during the first remission, all of the 11 who were never MRD-negative at any point experienced a relapse. Evaluating MRD with a cutoff value of 0.010% after two courses of post-remission therapy helps predict prognosis and determine the indication for allo-HSCT.

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 (NRM) 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 MUD (8/8 uBMT) or uBMT from a 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 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.

Newly proposed threshold and validation of white blood cell count at diagnosis for Philadelphia chromosome-positive acute lymphoblastic leukemia: risk assessment of relapse in patients with negative minimal residual disease at transplantation-a report from the Adult Acute Lymphoblastic Leukemia Working Group of the JSTCT.

White blood cell count (WBC) at diagnosis is the conventional prognostic factor in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL). Nevertheless, little is known about the impact of WBC at diagnosis considering the minimal residual disease (MRD) status at allogeneic hematopoietic cell transplantation (HCT). We evaluated adult patients with Ph+ ALL who achieved negative-MRD and received HCT in first complete remission between 2006 and 2018. The entire cohort was temporally divided into derivation (n = 258) and validation cohorts (n = 366). Using a threshold of 15,000/µL, which was determined by a receiver operating characteristic curve analysis in the derivation cohort, high WBC was associated with an increased risk of hematological relapse in both the derivation cohort (25.3% vs. 11.6% at 7 years, P = 0.004) and the validation cohort (16.2% vs. 8.5% at 3 years, P = 0.025). In multivariate analyses, high WBC was a strong predictor of hematological relapse in the derivation cohort (HR, 2.52, 95%CI 1.32-4.80, P = 0.005) and in the validation cohort (HR, 2.32, 95%CI, 1.18-4.55; P = 0.015). In conclusion, WBC at diagnosis with a new threshold of 15,000/µL should contribute to better risk stratification in patients with negative-MRD at HCT.

Comparison of transplant outcomes and economic costs between biosimilar and originator filgrastim in allogeneic hematopoietic stem cell transplantation.

From January 2012 to September 2015, 49 patients received biosimilar filgrastim (BF) after allogeneic bone marrow transplantation (BMT, n = 31) or peripheral stem cell transplantation (PBSCT, n = 18) in our institution. To evaluate the clinical impact of BF on transplant outcomes of these patients, we compared hematological recovery, overall survival (OS), disease-free survival (DFS), transplantation-related mortality (TRM), cumulative incidence of relapse (CIR), and acute and chronic graft-versus-host disease (GVHD) with those of control patients who received originator filgrastim (OF) after BMT (n = 31) or PBSCT (n = 18). All cases were randomly selected from a clinical database in our institution. In both the BMT and PBSCT settings, neutrophil recovery (17 vs. 19 days in BMT; 13 vs. 15 days in PBSCT) and platelet recovery (27 vs. 31 days in BMT; 17 vs. 28 days in PBSCT) were essentially the same between BF and OF. They were also comparable in terms of OS, DFS, TRM, CIR, and the incidence of acute GVHD and chronic GVHD. On multivariate analysis, the use of BF in both BMT and PBSCT was not a significant factor for adverse transplant outcomes. Although BF significantly reduced filgrastim costs in both BMT and PBSCT, total hospitalization costs were not significantly different between BF and OF.

Retrospective analysis of clinical outcomes of the patients with chronic myeloid leukemia who stopped administration of tyrosine kinase inhibitors: a single institution experience.

We describe herein the clinical outcomes of 16 patients with chronic myeloid leukemia in the chronic phase who stopped the administration of tyrosine kinase inhibitors (TKI) after maintaining undetectable levels of major BCR-ABL1, based on real-time quantitative polymerase chain reaction, for prolonged periods (undetectable MR for a median of 2,100 days (822-4,068). The reasons for discontinuing TKI were enrollments in a clinical trial testing discontinuation of these agents (n=9), adverse effects (n=2) or financial problems (n=5). After TKI discontinuation, patients were followed for a median of 551 days (154-2,446). A total of 8 patients (50%) experienced molecular relapse after a median of 119 days (28-171). Among them, 6 patients who lost major molecular response (MMR) were treated with imatinib (n=2) or dasatinib (n=4), while 2 patients who lost undetectable MR after discontinuing TKI (1 each had taken bostinib and imatinib) but maintained MMR were carefully monitored without re-administration of TKI. Of 6 patients who re-started TKI, 4 (67%) achieved undetectable MR but the other 2 achieved only MMR. The results of this small, retrospective study may support the current understanding of treatment discontinuation, possibly leading to a sustained deep molecular response in some patients.

Posttransplantation bone marrow assessment by quantifying hematopoietic cell-derived mRNAs in plasma exosomes/microvesicles.

BACKGROUND: Bone marrow (BM) aspiration often can be a painful medical procedure. It is unavoidable, however, because hematopoietic precursor cells (HPC) exist only in BM and few escape to peripheral blood (PB). We hypothesized that HPCs might release exosomes and microvesicles (EMV) in BM, and the resulting EMV would penetrate into PB. Such BM-derived EMV might be identified in PB by measuring specific mRNAs produced by HPC. METHODS: Human plasma was applied to an EMV-capture filter plate. After centrifugation, captured EMV were lysed on the filter plate. Resulting lysates were transferred to an oligo(dT)-immobilized microplate for mRNA isolation followed by reverse transcription PCR (RT-PCR). Using this system, myeloid-, erythroid-, and megakaryocyte-lineage-specific poly(A)(+) mRNAs were quantified in plasma obtained from 18 patients who had undergone hematopoietic stem cell transplantation (HSCT). RESULTS: When fluorescent liposomes were applied to the filter plate, more than 95% of applied liposomes were absorbed. When human plasma was applied, a scanning electron microscope showed EMV-like particles on the membrane of the filter plate. After RT-PCR, various HPC-specific mRNAs were detected, and the results were equivalent to those derived from the standard ultracentrifugation method. The levels of these mRNAs were undetectable after HSCT and became detectable 1-2 weeks after HSCT, a substantially earlier time point than with traditional hematological analysis. The recovery of EMV mRNA at day 15 corresponded to the final clinical outcome at day 180. CONCLUSIONS: HPC-derived mRNAs in plasma EMV may represent new biomarkers for the assessment of BM condition and could reduce the necessity for frequent BM aspiration.