Fractionated Infusion of Hematopoietic Progenitor Cells Does Not Improve Neutrophil Recovery or Survival in Allograft Recipients.

Allogeneic hematopoietic cell transplantation (HCT) offers a potentially curative therapy in patients with hematologic malignancies; however, nonrelapse mortality (NRM) remains a concern. Strategies to improve neutrophil recovery and immune reconstitution are needed to decrease NRM. Murine models of allogeneic HCT suggest that fractionated hematopoietic progenitor cell (HPC) infusion may improve engraftment through improved access of HPCs to a viable hematopoietic niche. The primary objective of the present study was to determine the impact of fractionated infusion versus unfractionated (bulk) infusion of HPCs on the time to achieve neutrophil engraftment. Secondary objectives included the effect of fractionated versus bulk infusion of HPCs on platelet engraftment, immune reconstitution, the incidence of acute graft-versus-host disease (GVHD) grade II-IV, NRM, and overall survival (OS). In this randomized phase 2 study, patients with hematologic malignancies undergoing allogeneic HCT were randomized to receive HPC infusion as a bulk (bulk arm) or in fractions (fractionated arm): 4 × 106 CD34+ cells/kg recipient weight infused on day 0, with the remaining HPCs CD34+ cell-selected then infused in equally distributed aliquots on days 2, 4, and 6 post-HCT. Randomization was stratified by type of transplant, unmodified (i.e. T cell-replete graft) versus CD34+ cell-selected (T cell-depleted graft). Patients whose donor failed to collect at least 7 × 106 CD34+ cells/kg of recipient weight received bulk HPC infusions regardless of randomization, for safety. These patients continued the HCT process on study but were replaced until each arm reached the prespecified accrual target. Per protocol, these patients were not included in this modified intention-to-treat analysis. A total of 116 patients were enrolled. Donors of 42 patients failed to mobilize the minimum CD34+ cell dose (7 × 106 cells/kg recipient weight) and were excluded from the analysis. The 74 evaluable patients included 38 randomized to the bulk arm and 36 randomized to the fractionated arm. All patients engrafted. The median time to an absolute neutrophil count of ≥0.5 × 109/L was 11 days on both arms. The day +180 median CD4+ cell count was 179 cells/µL in the bulk arm and 111 cells/µL in the fractionated arm (P = .779). The cumulative incidence of grade II-IV acute GVHD on post-transplant day +100 was 32% in the bulk arm and 17% in the fractionated arm (P = .131). Two patients in the bulk arm, but none in the fractionated arm, experienced grade III-IV GVHD. The 4-year OS was 60% in the bulk arm and 62% in the fractionated arm (P = .414), whereas the 4-year cumulative incidences of NRM and relapse were similar in the 2 arms. Fractionated infusion of HPCs in allogeneic HCT recipients did not impact neutrophil or CD4+ cell recovery, NRM, relapse, or OS when compared with bulk HPC infusion. We also observed that with current mobilization techniques, it was unlikely that more than 60% of healthy donors would be able to collect >7 × 106 CD34+ cells/kg recipient weight for adult recipients. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Tamari R ，Brown S ，Devlin SM ，Kosuri S ，Maloy MA ，Ponce DM ，Sauter C ，Shaffer B ，Dahi P ，Young JW ，Jakubowski A ，Papadopoulos EB ，Castro-Malaspina H ，Perales MA ，Giralt SA ，Gyurkocza B ... -  《-》

Universal Engraftment after Allogeneic Hematopoietic Cell Transplantation Using Cryopreserved CD34-Selected Grafts.

As a result of the COVID-19 pandemic, most centers performing allogeneic hematopoietic cell transplantation (allo-HCT) have switched to the use of cryopreserved grafts. Previous investigators have suggested that cryopreserved allografts may heighten risk of nonengraftment. To date, no study has investigated the effect of cryopreservation of CD34-selected hematopoietic progenitor cells (CD34+ HPCs) used as the sole graft source. In this study, we sought to evaluate outcomes after unrelated donor or matched sibling allo-HCT with cryopreserved CD34+ HPCs. This was a single-center analysis of adult patients with hematologic malignancies who underwent allo-HCT with cryopreserved CD34-selected allo-HCT grafts between January 2010 and June 2017. All patients received ablative conditioning and antirejection prophylaxis with rabbit antithymocyte globulin. G-CSF-mobilized leukapheresis products underwent CD34 selection using the CliniMACS Reagent System. Cells were then cryopreserved in DMSO (final concentration 7.5%) to -90 °C using a controlled-rate freezing system before being transferred to vapor-phase liquid nitrogen storage. In internal validation, this method has shown 92% mean CD34+ cell viability and 99.7% mean CD34+ cell recovery. Engraftment was defined as the first of 3 consecutive days of an absolute neutrophil count of ≥0.5. Platelet recovery was recorded as the first of 7 consecutive days with a platelet count ≥20 K/μL without transfusion. Kaplan-Meier methodology was used to estimate overall survival (OS) and relapse-free survival (RFS), and cumulative incidence functions were used to estimate rates of relapse, nonrelapse mortality (NRM), and acute graft-versus-host disease (GVHD). A total of 64 patients received a cryopreserved CD34-selected graft. The median CD34+ cell count before cryopreservation was 6.6 × 106/kg (range, 1.4 to 16.1 × 106/kg), and the median CD3+ cell count was 2.0 × 103/kg (range, 0 to 21.1 × 106/kg). All patients were engrafted, at a median of 11 days post-HCT (range, 8 to 14 days). One patient had poor graft function in the setting of cytomegalovirus viremia, necessitating a CD34-selected boost on day +57. The median time to platelet recovery was 16 days (range, 13 to 99 days). The estimated 2-year OS was 70% (95% confidence interval [CI], 58% to 83%) with cryopreserved grafts versus 62% (95% CI, 57% to 67%) with fresh grafts (hazard ratio [HR], 0.86; 95% CI, 0.54 to 1.35; P = .5). The estimated 2-year RFS in the 2 groups was 59% (95% CI, 48% to 74%) versus 56% (95% CI, 51% to 61%; HR, 1.01; 95% CI, 0.68 to 1.51; P > .9). The cumulative incidence of relapse at 2 years was 29% (95% CI, 17% to 41%) versus 23% (95% CI, 19% to 27%; P = .16), and the cumulative incidence of NRM at 2 years was 17% (95% CI, 9% to 28%) versus 23% (95% CI, 19% to 28%; P = .24). The cumulative incidence of grade II-IV acute GVHD by day +100 was 16% with cryopreserved grafts (95% CI, 8% to 26%) and 16% (95% CI, 13% to 20%; P = .97) with fresh grafts. Moderate to severe chronic GVHD by day +365 occurred in only 1 recipient of a cryopreserved graft (2%). Our data show that in patients with hematologic malignancies who received cryopreserved allogeneic CD34+ HPCs, engraftment, GVHD, and survival outcomes were consistent with those seen in recipients of fresh allogeneic CD34+ HPC grafts at our center. Our laboratory validation and clinical experience demonstrate the safety of our cryopreservation procedure for CD34-selected allografts.

Jacob RP ，Flynn J ，Devlin SM ，Maloy M ，Giralt SA ，Maslak P ，O'Reilly RJ ，Tonon JA ，Perales MA ，Avecilla ST ，Cho C ... -  《-》

Outcomes with allogeneic stem cell transplant using cryopreserved versus fresh hematopoietic progenitor cell products.

Allogeneic hematopoietic stem cell transplant (alloHSCT) is a mainstay of treatment for hematologic malignancies such as acute leukemias and aggressive lymphomas. Historically, fresh hematopoietic progenitor cell (HPC) products have been preferred to cryopreserved products (cryo-HPC) due to concerns of loss of stem cell viability and number with the cryopreservation procedure. We aimed to analyze the outcomes of patients who received cryo-HPCs during the COVID-19 pandemic and compare this against historical cohorts that received fresh HPC. A retrospective chart review was conducted on all adult patients who received a peripheral blood alloHSCT in British Columbia, Canada between June 2017 and November 2021. Baseline characteristics, Kaplan-Meier (KM) overall survival (OS), engraftment, and incidences of acute and chronic graft versus host disease were compared between patients who received cryo-HPCs and fresh HPCs. Univariable analysis followed by multivariable analysis was performed using a backward stepwise selection procedure to generate predictors of OS, cumulative incidence of relapse (CIR), nonrelapse mortality (NRM), and primary and secondary graft failure. Three hundred eighty-three patients were included in the analysis, with cryo-HPC representing 40%. Median viability was higher in the fresh-HPC group at 99.2% (IQR 98.3-99.5) versus cryo-HPCs at 97.0% (96.0, 98.6) (P < 0.01). The 12-month actuarial survivals were 77% in the fresh HPC and 75% in the cryo-HPC groups (P = 0.21). There were no differences between cryo-HPCs and fresh HPCs on univariable analysis of OS, CIR, or NRM. There was a shorter median time to platelet engraftment in patients receiving fresh HPC at 17 days (IQR 16, 20) versus cryo-HPC at 21 days (IQR 18, 29), P < 0.001. There was a shorter median time to neutrophil engraftment in the fresh HPC group at 17 days (IQR 14, 20) versus 20 days (17, 23), P < 0.001. Cryo-HPC accounted for 5 out of 6 cases of primary graft failure (P = 0.04), and 3 out of five cases of secondary graft failure (P = 0.39). There were no significant differences in acute GVHD between the fresh HPC and cryo-HPC groups (P = 0.34). The incidence of moderate or severe chronic GVHD was 32% in the fresh-HPC group and 17% in the cryo-HPC group (P < 0.001). In multivariable analysis, cryopreservation did not emerge as an independent predictor of OS, CIR, NRM, primary GF or secondary GF. However, viability <90% on arrival at our center was a significant predictor of OS (HR 5.3, 2.3-12.3, P < 0.01), primary graft failure (OR 36.3, 5.4-210.2, P < 0.01), and secondary graft failure (OR 18.4, 1.7-121.1, P < 0.01). Patients who received cryo-HPCs had similar OS and relapse rates to those who received fresh-HPCs but typically took 2-3 days longer to achieve engraftment of platelets or neutrophils and were associated increased primary graft failure. However, after accounting for multiple variables, cryopreservation was no longer a significant predictor of survival or engraftment while viability <90% emerged as an important predictor of OS, primary graft failure, and secondary graft failure. If confirmed, this suggests that viability on arrival at the infusion center may be a good quality control indicator used to identify HPC products that may warrant recollection if the risk of graft failure is sufficiently increased.

Wan BA ，Lindo L ，Mourad YA ，Chung S ，Forrest D ，Kuchenbauer F ，Nantel S ，Narayanan S ，Nevill T ，Power M ，Rodrigo J ，Sanford D ，Song K ，Stubbins RJ ，Sutherland H ，Toze CL ，White J ，Roy C ，Hay KA ... -  《-》

Post-Transplantation Cyclophosphamide for Graft-versus- Host Disease Prophylaxis in Multiple Myeloma Patients Who Underwent Allogeneic Hematopoietic Cell Transplantation: First Comparison by Donor Type. A Study from the Chronic Malignancies Working Party

Graft-versus-host disease (GVHD) remains among the major causes of treatment failure in patients with multiple myeloma (MM) undergoing allogeneic hematopoietic cell transplantation (allo-HCT). The use of post-transplantation cyclophosphamide (PT-Cy) is now a well-established and widely used method for GVHD prophylaxis after HLA haploidentical HCT. However, the rationale for using PT-Cy in the setting of matched donor transplantation is less apparent, given the lesser degree of bidirectional alloreactivity. In this retrospective study, we investigated the role of PT-Cy as GVHD prophylaxis in patients with multiple myeloma underoing allo-HCT, among different donor types, to determine cumulative incidence of acute and chronic GVHD and impact on engraftment, progression-free survival (PFS), GVHD-free/relapse- free survival (GRFS), overall survival (OS), and NRM A total of 295 patients with MM underwent allo-HCT using grafts from a matched related donor (MRD; n = 67), matched unrelated donor (MUD; n = 72), mismatched related or unrelated donor (MMRD/MMUD, 1 antigen; n = 27), or haploidentical donor (haplo; n = 129) using PT-Cy between 2012 and 2018. In addition to PT-Cy, agents used in GVHD prophylaxis included calcineurin inhibitors in 239 patients (81%), with mycophenolate mofetil in 184 of those 239 (77%). For grade II-IV acute GVHD, the cumulative incidence at day +100 was 30% (95% confidence interval [CI], 25% to 36%), 9% (95% CI, 5% to 12%) for grade III-IV acute GVHD, and 27% (95% CI, 21% to 32%) for chronic GVHD (limited, 21%; extensive, 6%), with no differences by donor type. The median time to neutrophil engraftment was 19d (95% CI, 18-19), with no significant difference by donor type. The median time to platelet engraftment was delayed in haploidentical donor graft recipients (27 days versus 21 days; P < .001). Two-year OS, PFS, GRFS, and NRM were 51% (95% CI, 45% to 58%), 26% (95% CI, 20% to 32%), 24% (95% CI, 18% to 30%), and 19% (95% CI, 14% to 24%), respectively, with no significant difference between different donor types. In multivariable analyses, compared with the haplo donors, the use of MRDs was associated with significantly better OS (hazard ratio [HR], 0.6; 95% CI, 0.38 to 0.95; P = .029), and the use of MUDs was associated with a significantly higher GRFS (HR, 0.63; 95% CI, 0.42 to 0.97; P = .034). There was a trend toward improved PFS with use of MUDs (HR, 0.69; 95% CI, 0.46 to 1.04; P = .08). Our data show that PT-Cy in MM patients undergoing allo-HCT resulted in low rates of acute and chronic GVHD and led to favorable survival, especially in the matched related donor setting. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Sahebi F ，Eikema DJ ，Koster L ，Kroger N ，Meijer E ，van Doesum JA ，Rovira M ，Koc Y ，Angelucci E ，Blaise D ，Sammassimo S ，McDonald A ，Arroyo CH ，Sanchez JF ，Forcade E ，Castagna L ，Stölzel F ，Sanz J ，Tischer J ，Ciceri F ，Valcarcel D ，Proia A ，Hayden PJ ，Beksac M ，Yakoub-Agha I ，Schönland S ... -  《-》

Immune Reconstitution Following TCRαβ/CD19-Depleted Hematopoietic Cell Transplantation for Hematologic Malignancy in Pediatric Patients.

TCRαβ/CD19-depleted HCT has been used with excellent outcomes in pediatric patients with hematologic malignancies, and several studies have demonstrated rapid immune reconstitution in the nonmalignant setting. However, immune recovery following TCRαβ/CD19-depleted hematopoietic cell transplantation (HCT) for malignancy remains incompletely elucidated. Furthermore, the majority of studies to date have used haploidentical and matched unrelated donors. Here we report results of immune reconstitution following TCRαβ/CD19-depleted HCT for hematologic malignancy in 51 pediatric patients with hematologic malignancies, the majority of whom received grafts from unrelated donors. Grafts were from matched unrelated (n = 20), mismatched unrelated (n = 20), and haploidentical (n = 11) donors. The median CD34+ cell dose was 10.2 × 106/kg (range, 4.54 to 20 × 106/kg), and the median TCRαβ+ cell dose was 2.53 × 104/kg (range, 0 to 44.9 × 104/kg). Conditioning was myeloablative with either busulfan or total body irradiation, cyclophosphamide, and thiotepa. Thirty-three patients also received rabbit antithymocyte globulin. No prophylactic post-transplantation immune suppression was routinely given. Forty-three patients received rituximab on day +1 for recipient positive Epstein-Barr virus serology. Forty-nine patients (96%) engrafted with a median time to neutrophil recovery of 13 days (range, 8 to 30 days). Thirty-seven patients (73%) are alive at a median follow-up of 25 months (range, 6 to 50 months). Nine patients (18%) developed grade II-IV acute graft-versus-host disease (GVHD), and 5 patients (11%) developed extensive chronic GVHD. Twenty-six patients (51%) experienced viral reactivation. T cell reconstitution was rapid with significant numbers of CD3+, CD4+, and CD8+ T cells present on first assessment at 4 months post-HCT, and significant numbers of naïve CD4+ T cells were present by 8 months post-HCT. Chronic GVHD was associated with delayed T cell recovery; however, T cell reconstitution was not affected by underlying diagnosis, donor source, TCRαβ+ T cell dose, conditioning regimen, or use of antithymocyte globulin. B cell recovery mirrored T cell recovery, and i.v. Ig was discontinued at a median of 8 months (range, 4 to 22 months) post-HCT in patients alive and relapse-free at last follow-up. Immune reconstitution is rapid following TCRαβ/CD19-depleted HCT in pediatric patients with hematologic malignancies. Donor graft source, haploidentical or unrelated, did not affect immune reconstitution. Viral reactivation is common in the first 100 days post-HCT, indicating that improved T cell defense is needed in the early post-HCT period.

Arnold DE ，MacMath D ，Seif AE ，Heimall JR ，Wang Y ，Monos D ，Grupp SA ，Bunin NJ ... -  《-》