[Manufacturing results of tisagenlecleucel for acute lymphoblastic leukemia: a survey by the CAR-T cell therapy taskforce of the Japan Society of Transfusion Medicine and Cell Therapy].

The frequency of the manufacturing failure of chimeric antigen receptor (CAR)-T cell therapy in clinical practice is unknown. To clarify the current state of how likely CAR-T cell production is to succeed or fail for B-cell acute lymphoblastic leukemia (B-ALL), we analyzed cases in which the production of tisagenlecleucel was performed for patients with B-ALL at 15 facilities in Japan from October 2019 to March 2022. Total 81 patients (47 males and 34 females) were analyzed. The median age at apheresis was 13 years (1-25) with a median number of prior treatments of 4 (1-9). The numbers of patients with histories of allogeneic transplantation, inotuzumab ozogamicin, or blinatumomab treatments were 51 (63.0%), 26 (32.1%), and 37 (45.7%), respectively. The median blast percentage and CD3+ cell counts in peripheral blood were 0% (0-91.5), and 611/µl (35-4,210) at apheresis, and the median number of CD3+ cells shipped was 2.2×109 (0.5-8.3). While cases with a history of heavy prior treatment before apheresis were included, no manufacturing failures were observed. Continuing to monitor the status of manufacturing failures is necessary as the number of B-ALL cases treated with CAR-T cell therapy increases.

Risk factors for CAR-T cell manufacturing failure among DLBCL patients: A nationwide survey in Japan.

For successful chimeric antigen receptor T (CAR-T) cell therapy, CAR-T cells must be manufactured without failure caused by suboptimal expansion. In order to determine risk factors for CAR-T cell manufacturing failure, we performed a nationwide cohort study in Japan and analysed patients with diffuse large B-cell lymphoma (DLBCL) who underwent tisagenlecleucel production. We compared clinical factors between 30 cases that failed (7.4%) with those that succeeded (n = 378). Among the failures, the proportion of patients previously treated with bendamustine (43.3% vs. 14.8%; p < 0.001) was significantly higher, and their platelet counts (12.0 vs. 17.0 × 104 /µL; p = 0.01) and CD4/CD8 T-cell ratio (0.30 vs. 0.56; p < 0.01) in peripheral blood at apheresis were significantly lower than in the successful group. Multivariate analysis revealed that repeated bendamustine use with short washout periods prior to apheresis (odds ratio [OR], 5.52; p = 0.013 for ≥6 cycles with washout period of 3-24 months; OR, 57.09; p = 0.005 for ≥3 cycles with washout period of <3 months), low platelet counts (OR, 0.495 per 105 /µL; p = 0.022) or low CD4/CD8 ratios (

Simultaneous quantification of dasatinib, nilotinib, bosutinib, and ponatinib using high-performance liquid chromatography-Photodiode array detection.

BACKGROUND: Dasatinib, nilotinib, and bosutinib, second-generation tyrosine kinase inhibitors (TKIs), and ponatinib, a third-generation TKI, are approved pharmaceuticals used in the treatment of chronic myeloid leukemia (CML). Although liquid chromatography-tandem mass spectrometry assays for simultaneous quantification of the four TKIs in human serum have been reported in the literature, a high-performance liquid chromatography (HPLC) assay that simultaneously quantifies these compounds has not yet been developed. This study aims to establish and validate an efficient HPLC analytical method using a photodiode array (PDA) detector for the simultaneous quantification of the four TKIs. METHODS: Calibration standards were prepared by serial dilution of serum samples containing the four TKIs, followed by solid-phase extraction. The four TKIs were eluted in order within 10 min using a binary HPLC gradient system. RESULTS: The calibration ranges were 2-500 ng/ml for dasatinib, 100-5000 ng/ml for nilotinib, and 10-500 ng/ml for bosutinib and ponatinib. Intra-day and inter-day precision and accuracy values were found to be in accordance with the U.S. Food and Drug Administration guidelines. The recovery rates were 92.9%-96.0%, 80.7%-86.1%, 91.6%-99.0%, and 86.4%-92.6% for dasatinib, nilotinib, bosutinib, and ponatinib, respectively. CONCLUSION: To the best of our knowledge, this is the first report of an HPLC-PDA analytical method that allows efficient simultaneous quantification of the four TKIs in the serum of patients with CML. We believe that the method developed herein can improve the efficiency of therapeutic drug monitoring in patients with CML in clinical practice.

Comparison of cryoprotectants in hematopoietic cell infusion-related adverse events.

BACKGROUND: The standard cryoprotectant for human cellular products is dimethyl sulfoxide (DMSO), which is associated with hematopoietic cell infusion-related adverse events (HCI-AEs) in hematopoietic stem cell transplantation including peripheral blood stem cell (PBSC) transplantation (PBSCT). DMSO is often used with hydroxyethyl starch (HES), which reduces DMSO concentration while maintaining the postthaw cell recovery. The cryoprotectant medium CP-1 (Kyokuto Pharmaceutical Industrial) is widely used in Japan. After mixture of a product with CP-1, DMSO and HES concentrations are 5% and 6%, respectively. However, the safety profile of CP-1 in association with HCI-AEs has not been investigated. STUDY DESIGN AND METHODS: To compare CP-1 with other cryoprotectants, we conducted a subgroup analysis of PBSCT recipients in a prospective surveillance study for HCI-AEs. Moreover, we validated the toxicity of CP-1 in 90 rats following various dose administration. RESULTS: The PBSC products cryopreserved with CP-1 (CP-1 group) and those with other cryoprotectants, mainly 10% DMSO (non-CP-1 group), were infused into 418 and 58 recipients, respectively. The rate of ≥grade 2 HCI-AEs was higher in the CP-1 group, but that of overall or ≥grade 3 HCI-AEs was not significantly different, compared to the non-CP-1 group. Similarly, after propensity score matching, ≥grade 2 HCI-AEs were more frequent in the CP-1 group, but the ≥grade 3 HCI-AE rate did not differ significantly between the groups. No significant toxicity was detected regardless of the CP-1 dose in the 90 rats. CONCLUSIONS: Infusion of a CP-1-containing PBSC product is feasible with the respect of HCI-AEs.

Clinical Results of a Massive Blood Transfusion Protocol for Postpartum Hemorrhage in a University Hospital in Japan: A Retrospective Study.

Background and objectives: Massive postpartum hemorrhage (PPH) is the most common cause of maternal death worldwide. A massive transfusion protocol (MTP) may be used to provide significant benefits in the management of PPH; however, only a limited number of hospitals use MTP protocol to manage massive obstetric hemorrhages, especially in Japan. This study aimed to assess the clinical outcomes in patients in whom MTP was activated in our hospital. Materials and Methods: We retrospectively reviewed the etiology of PPH, transfusion outcomes, and laboratory findings among the patients treated with MTP after delivery in our hospital. Results: MTP was applied in 24 cases (0.7% of deliveries). Among them, MTP was activated within 2 h of delivery in 15 patients (62.5%). The median estimated blood loss was 5017 mL. Additional procedures to control bleeding were performed in 19 cases, including transarterial embolization (18 cases, 75%) and hysterectomy (1 case, 4.2%). The mean number of units of red blood cells, fresh frozen plasma, and platelets were 17.9, 20.2, and 20.4 units, respectively. The correlation coefficients of any two items among red blood cells, fresh frozen plasma, platelets, blood loss, and obstetrical disseminated intravascular coagulation score ranged from 0.757 to 0.892, indicating high levels of correlation coefficients. Although prothrombin time and activated partial thromboplastin time levels were significantly higher in the <150 mg/dL fibrinogen group than in the ≥150 mg/dL fibrinogen group at the onset of PPH, the amount of blood loss and blood transfusion were comparable between the two groups. Conclusions: Our MTP provides early access to blood products for patients experiencing severe PPH and could contribute to improving maternal outcomes after resuscitation in our hospital. Our study suggests the implementation of a hospital-specific MTP protocol to improve the supply and utilization of blood products to physicians managing major obstetric hemorrhage.

Novel Indicators of Transplant Outcomes for PhALL: Current Molecular-Relapse-Free Survival.

Molecular relapse after allogeneic hematopoietic cell transplantation (allo-HCT) has been thought to predict clinical relapse in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (PhALL). Tyrosine kinase inhibitor (TKI) administration after allo-HCT may dynamically change the status from molecular relapse to molecular remission, but these state changes cannot be accurately represented by conventional survival indicators such as relapse-free survival, where events are usually considered irreversible. We aimed to develop novel indicators of transplant outcomes for allo-HCT recipients with PhALL and to visualize current molecular-relapse-free survival (CMRFS) and current on-TKI status (CTKI), treating molecular relapse or TKI administration after allo-HCT as a reversible event. We retrospectively analyzed 286 patients with PhALL who received allo-HCT between 2000 and 2016 in order to develop the indicators. CMRFS was defined as the probability of molecular remission without clinical relapse or death at any time after allo-HCT. Similarly, CTKI was defined as the probability of TKI administration without clinical relapse or death at any time after allo-HCT. The 1- and 5-year CMRFS rates were 67% and 59%, respectively, whereas the 1- and 5-year conventional molecular relapse-free survival rates were 42% and 37%. The 1- and 5-year CTKI rates were 14% and 8%, respectively. In a post hoc analysis focusing on patients who had achieved a molecular complete remission within 6 weeks (n = 201), the 5-year CMRFS rate (71%) was similar to the 5-year conventional molecular relapse-free survival (molRFS) rate (70%) in the non-TKI group. On the other hand, the 5-year CMRFS rate in the TKI group was 61%, whereas the 5-year conventional molRFS rate was only 38%. CMRFS and CTKI might become useful indicators of transplant success in terms of survival, leukemia-free status, and treatment-free status at any time point. Future extension of these survival models to other clinical situations is warranted.

Impact of Specific Antibody Level on Human Herpesvirus 6 Reactivation after Allogeneic Stem Cell Transplantation.

The majority of adults are seropositive for human herpesvirus 6 (HHV-6). HHV-6 reactivation can occur after allogeneic hematopoietic stem cell transplantation (HSCT) and lead to life-threatening central nervous system disorders. In this prospective study, we evaluated the relationship between HHV-6 reactivation and anti-HHV-6 IgG antibody levels in recipients of allogeneic HSCT. The HHV-6 viral load in the plasma was quantitatively measured weekly after allogeneic HSCT by real-time polymerase chain reaction. The level of anti-HHV-6 IgG antibody was measured by enzyme-linked immunosorbent assay before and serially after transplantation. In 28 of the 56 evaluated patients (50%), HHV-6 reactivation was detected after transplantation. In a multivariate analysis, cord blood as the stem cell source was the only significant factor associated with HHV-6 reactivation (odds ratio, 8.6; 95% confidence interval, 2.3 to 32.6; P < .01). When evaluated in the recipients of cord blood transplantation (CBT), the anti-HHV-6 antibody level before transplantation was significantly lower in the patients with HHV-6 reactivation compared with those without (sample positivity index: median, 2.04 [range, 0.95 to 5.98] versus 4.15 [range, 3.93 to 5.65]; P < .05). The anti-HHV-6 antibody level was significantly decreased at 3 months post-transplantation compared with before transplantation (P < .01). Such differences were not observed in other stem cell sources. Our results demonstrate that the low anti-HHV-6 antibody level before transplantation was associated with the reactivation of HHV-6 after CBT, and that the anti-HHV-6 antibody level was significantly decreased specifically after CBT. These results suggest that HHV-6-specific humoral immunity plays a role in HHV-6 reactivation after CBT.

Phase 1 study of plerixafor in combination with total body irradiation-based myeloablative conditioning for allogeneic hematopoietic stem cell transplantation.

Plerixafor, a CXCR4 inhibitor, has the potential to mobilize leukemic cells, which may contribute to their chemosensitization. This phase 1 study evaluated the safety of myeloablative conditioning combined with plerixafor for allogeneic hematopoietic stem cell transplantation (HSCT). Patients with high-risk leukemia undergoing allogeneic HSCT after total body irradiation (TBI, 12 Gy)-based myeloablative conditioning were eligible; 9 patients were enrolled. The study was performed using a 3 + 3 design with an escalating total dose of plerixafor. Plerixafor was given subcutaneously 8 h before TBI and chemotherapeutic agents. Plerixafor was successfully escalated to the maximum dose (0.72 mg/kg) without dose-limiting toxicities. Underlying diseases were acute myelogenous and lymphoblastic leukemia, chronic myeloid leukemia, and myelodysplastic syndrome. As adverse events, plerixafor administration was associated with transient Grades 2-3 diarrhea (n = 7) and abdominal pain (n = 4). In 6 patients, leukemic cell mobilization into the peripheral blood by plerixafor was confirmed by a morphological or molecular method. All patients achieved neutrophil engraftment and 5 were alive in remission at a follow-up after 30-40 months. Plerixafor-combined myeloablative conditioning for allogeneic HSCT was well tolerated. Leukemic-cell mobilization into peripheral blood was observed in half of the patients. Further study is required to evaluate the efficacy and safety of this concept.

[Spontaneous remission of relapsed skin lesions of ALK-positive anaplastic large cell lymphoma after autologous stem cell transplantation].

A 44-year-old woman was diagnosed with anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) with clinical stage IVA (nodal and bladder involvement). Complete response (CR) was achieved after the CHOP chemotherapy; however, 12 months after the last course of chemotherapy, ALCL relapsed in the form of skin lesions without nodal involvement. After achieving a second CR with chemotherapy, autologous stem cell transplantation was performed. Two months after transplantation, the disease again relapsed as multiple skin lesions. Electron beam irradiation was performed; however, other skin lesions appeared thereafter and spontaneously disappeared. At present, 3.4 years after the transplantation, the patient is free from disease. ALK-positive ALCL relapsing as skin lesions may behave differently from the nodal relapse. An accumulation of cases is required to elucidate ALCL characteristics relapsing as skin lesions.

Cytomegalovirus retinitis after allogeneic hematopoietic stem cell transplantation under cytomegalovirus antigenemia-guided active screening.

Although cytomegalovirus (CMV) remains a leading cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT), the incidence of CMV retinitis is considered to be lower than the incidence of CMV infection in other organs following allogeneic HSCT. In this study, the incidence and characteristics of CMV retinitis were retrospectively evaluated in recipients of allogeneic HSCT. Ophthalmological screening was performed at the development of ocular symptoms or positive CMV infection using peripheral blood evaluated by pp65 antigenemia or polymerase chain reaction. Of the 514 patients, 13 patients developed CMV retinitis. The median onset of CMV retinitis was day 34 (range, 21-118) post transplant, and the cumulative incidence was 2.5% (95% CI, 1.6-4.2) at 6 months after transplantation. Five patients presented ocular symptoms at the onset. In the remaining eight asymptomatic patients, the diagnosis of CMV retinitis was made by the screening guided by positive CMV infection. All evaluable patients responded to antiviral treatment but three showed incomplete improvement with ocular sequela. Our results suggest that the incidence of CMV retinitis after allogeneic HSCT is not negligible and active ophthalmological screening based not only on symptoms but also positive CMV infection monitoring contributes to the early diagnosis of CMV retinitis.

Toxoplasmosis after allogeneic hematopoietic stem cell transplantation: Impact of serostatus-based management.

Toxoplasmosis caused by Toxoplasma gondii (T. gondii) is a serious infectious complication after allogeneic hematopoietic stem cell transplantation (HSCT). The incidence of toxoplasmosis varies widely because of the variabilities of seroprevalence among patient populations. The incidence and the optimal management of toxoplasmosis after allogeneic HSCT in a patient population with a low seroprevalence have not been fully evaluated. We conducted a single-center retrospective study evaluating toxoplasmosis in Japanese patients who underwent allogeneic HSCT. Of the 728 evaluable patients, only 5 developed toxoplasmosis with a median onset of day 60 post-transplant (range, day 55-393). The cumulative incidence was 0.7% (95% CI: 0.3%-1.5%) at day 500 post-transplant. Four of the five patients succumbed due to toxoplasmosis. The more recently treated 220 patients (not the earlier 508 patients) were screened for the T. gondii serostatus, and prophylactic treatment with trimethoprim/sulfamethoxazole was applied. All five patients with toxoplasmosis were in the unscreened group, and there was no case of toxoplasmosis after the introduction of the screening and prophylactic treatment. Our results suggest that toxoplasmosis after allogeneic HST is rare but can develop as a life-threatening complication even in the populations with low seroprevalence, and that prophylactic treatment for seropositive patients could effectively prevent toxoplasmosis.

Detection of residual disease in chronic myeloid leukemia utilizing genomic next generation sequencing reveals persistence of differentiated Ph+ B cells but not bone marrow stem/progenitors.

Persistence of leukemic stem cells (LSCs) results in the recurrence of chronic myeloid leukemia (CML) after the administration of tyrosine kinase inhibitors (TKIs). Thus, the detection of minimal residual disease (MRD) with LSC potential can improve prognosis. Here, we analyzed 115 CML patients and found that CD25 was preferentially expressed on the phenotypic stem and progenitor cells (SPCs), and TKI therapy decreased the number of CD25-positive cells in the SPC fraction. To detect MRD harboring BCR-ABL1 fusion DNA, we developed a highly-sensitive method using patient-specific primers and next-generation sequencing. By using this method, we identified that in patients who achieved molecular remission, almost all residual CD25-positive SPCs were BCR-ABL1-negative. Moreover, in some patients BCR-ABL1 was detectable in peripheral B cells but not in SPCs. We conclude that CD25 marks LSCs at diagnosis but does not mark MRD following TKI treatment and that analysis of peripheral B cells can allow sensitive detection of MRD.

[Two serial events of delayed hemolytic transfusion reactions due to different primary immune response-induced irregular antibodies].

A 74-year-old woman with a history of pregnancies, but without previous transfusions, received a red blood cell transfusion for aplstic anemia. She lost consciousness due to severe anemia two weeks later and was transported by ambulance to our hospital. Delayed hemolytic transfusion reaction (DHTR) was diagnosed based on the detection of anti-E antibody and positive E antigen of the previously transfused product. A transfusion of E antigen-negative red cell products was performed. However, DHTR due to anti-c antibody developed 16 d after the transfusion of a c antigen-positive product. Based on the onset of ≥14 d after the transfusions and the detection of a causative IgM-type antibody, DHTR due to a primary immune response was diagnosed. Because the incidence of DHTR is low, physicians rarely experience it in clinical practice. However, in our case, DHTR due to a primary immune response, which is even rarer in DHTR cases, developed twice within a short period. A history of transfusion and pregnancy as well as preexisting irregular antibodies have been identified as risk factors for DHTR. Thus, more attention should be paid to the risk of DHTR redevelopment by repeated transfusions.

Clinical characteristics of human herpesvirus-6 myelitis after allogeneic hematopoietic stem cell transplantation and its favorable outcome by early intervention.

After allogeneic hematopoietic stem cell transplantation (HSCT), human herpesvirus-6 (HHV-6) can cause serious central nervous system (CNS) disorder and typically presents as encephalitis. Another manifestation of HHV-6 is myelitis, which has not been fully evaluated. In this study, we retrospectively analyzed 19 patients who developed HHV-6 myelitis after allogeneic HSCT. Median onset was 20 days after transplantation (range, 13-31), with a cumulative incidence of 4.1% at day 40 after transplantation. Median age at transplant was 50 years (range, 17-61). Median copy number of HHV-6 DNA was 3000 copies/ml in cerebrospinal fluid (CSF; range, 200-100,000). The most common symptoms were pruritus, pain of the extremities/back, and numbness. Three patients subsequently developed encephalitis in the clinical course of myelitis; their HHV-6 copy numbers in CSF had been higher than 10,000 copies/ml at the onset of myelitis. Antiviral agents were initiated shortly after onset in all patients, resulting in recovery. These results suggest that myelitis would be an important subtype of HHV-6-associated CNS disorders after allogeneic HSCT, whose prognosis could be favorable by an early intervention. Transplant physicians should recognize early posttransplant neurological symptoms such as pruritus, pain, or numbness as possible signs of HHV-6 myelitis, which could also progress to encephalitis.

Seasonal changes in indoor airborne fungal concentration in a hematology ward.

Invasive fungal disease (IFD) is an important infectious complication of hematological disorders, especially in hematopoietic stem cell transplantation recipients. Evidences suggest seasonal and/or geographical variations in the airborne fungal counts and a relationship between those counts and the incidence of IFD. We evaluated the concentrations of indoor airborne fungi quantitated over the course of one year in a hematology ward in Japan. In January, April, July, and October, fixed volumes of air samples were obtained by an air sampler in a hematology ward not equipped with a high-efficiency particulate air filter and incubated in fugal cultures. Samples were also obtained from a protective environment in the same ward and were evaluated. The number of fungal colonies per 50 L of sampled air was highest in October (median 2.25 (range, 0.2-7.0)), which was significantly higher than those in the other three months (0.1 (range, 0-1.0) in January; 0 (0-0) in April; 0.55 (0-2.5) in July; P < 0.01)). Commonly identified pathogens included Penicillium and Cladosrporium species, but Aspergillus species was detected only in July and October samples. These results suggest a seasonal variation in indoor airborne fungal concentrations in Japan, which could affect the epidemiology of IFD.

Human Herpesvirus 6 Reactivation Evaluated by Digital Polymerase Chain Reaction and Its Association With Dynamics of CD134-Positive T Cells After Allogeneic Hematopoietic Stem Cell Transplantation.

BACKGROUND: Human herpesvirus 6 (HHV-6) causes life-threatening central nervous system disorders after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Recent studies implicated CD134 as a specific receptor of HHV-6B and demonstrated that its expression levels in CD4-positive T cells after allo-HSCT could be related to the reactivation of HHV-6. We prospectively evaluated the relationship between HHV-6 reactivation and CD134+ T cells in the recipients of allo-HSCT. METHODS: HHV-6 viral load in plasma was quantitatively measured weekly after allo-HSCT by digital polymerase chain reaction in 34 patients. The ratio of CD134 in CD4+ T cells (CD134/CD4 ratio) was serially measured by flow cytometry before and after transplantation. RESULTS: HHV-6 reactivation was detected in 23 patients (68%). The CD134/CD4 ratio before conditioning was significantly higher in patients with HHV-6 reactivation than in those without (median, 3.8% vs 1.5%, P < .01). In multivariate analysis, a higher CD134/CD4 ratio before conditioning was significantly associated with the incidence of HHV-6 reactivation (odds ratio, 10.5 [95% confidence interval, 1.3-85.1], P = .03). CONCLUSIONS: A higher CD134/CD4 ratio before conditioning was associated with a higher risk of HHV-6 reactivation, suggesting that the rate may be a promising marker for predicting HHV-6 reactivation after allo-HSCT.

Impact of immunoglobulin G2 subclass level on late-onset bacterial infection after allogeneic hematopoietic stem cell transplantation.

BACKGROUND: Immunoglobulin (Ig) G2 subclass deficiency is known to be associated with recurrent bacterial respiratory infections caused by capsulated bacteria and is found mostly in pediatric patients. However, its impact after allogeneic hematopoietic stem cell transplantation (HSCT) has not been fully assessed. METHODS: We retrospectively evaluated the relationship between IgG2 subclass levels and bacterial pneumonia in 74 adult patients who survived longer than 2 years after allogeneic HSCT. RESULTS: During the evaluation period, nine patients developed bacterial pneumonia. The median IgG2 level was significantly lower in patients with an infectious episode than in those without (143 mg/dL vs 287 mg/dL; P < 0.01). In multivariate analysis, a history of rituximab therapy and cord blood as a stem cell source were significantly associated with decreased levels of both IgG2 and IgG2/IgG ratios (P < 0.05). CONCLUSIONS: Suboptimal serum IgG2 levels could increase susceptibility to late-onset bacterial pneumonia after allogeneic HSCT. IgG2 levels should be considered carefully, especially in patients receiving cord blood transplantation and/or rituximab treatment.