Cryopreservation for Allogeneic Hematopoetic Stem Cell Transplants Is Non-Inferior to Fresh Graft Products

Background: The use of cryopreservation for stem cell grafts for both autologous stem cell and allogeneic cord blood transplant has been utilized for years. For other allogeneic stem cell transplant sources, the use of fresh collected grafts has been preferred due to concerns that cryopreservation may result in impaired graft function. With the onset of the COVID-19 pandemic a shift was made at our institution to exclusive use of cryopreservation Methods: In this retrospective single-center analysis a total of 133 patients undergoing allogeneic stem cell transplant at the University of Minnesota between 1/2018-6/2021 for a variety of malignancies were included, with 62 patients receiving fresh stem cell product and 71 patients receiving frozen stem cell product. Univariate statistical analysis was performed. Result(s): There was no significant difference between the two groups with regards to product type, sex, age, diagnosis (acute leukemia vs other), disease risk index, conditioning regimen, Karnofsky score, co-morbidity index, or cell dose (Table 1). Donor type was notably different between the two groups (p<0.01): matched sibling grafts were more commonly used for fresh products than frozen (85% vs. 35%), while matched unrelated donors were used more frequently for frozen than for fresh products (54% vs. 6%). Use of frozen product was associated with delayed neutrophil and platelet engraftment compared to fresh (median days to engraftment 15 vs 12 for neutrophils, 23 vs 17 for platelets, p<0.01 for both). Two-year relapse rates were significantly lower for frozen products (4%) than fresh (24%) (Table 2). This may be partially attributable to differences in follow up between the groups, as fresh products had a total of 910 days of follow up vs 432 for frozen products (P<0.0001). The difference in follow up remained statistically significant if the data was censored at 730 days (P<0.0001). Of note, the use of frozen products was associated with a lower rate of chronic graft-versus-host disease at one year post-transplant (p<0.01). There was no significant difference in the rates of acute GVHD between the groups. There were significant differences in GVHD prophylaxis regimens between the fresh and frozen groups (p<0.01). (Figure Presented)Two-year overall survival did not differ between groups (p=0.96). Conclusion(s): Use of cryopreserved stem cell products is associated with similar efficacy and outcomes as those seen with the use of fresh stem cell products. Although the data presented here suggest novel finding of decreased risk of relapse and chronic GVHD with the use of frozen stem cell products, additional follow up may abrogate these differences. Regardless, the logistical benefits of cryopreservation make this an attractive option for continued use in allogeneic transplants and our data presented here suggests that cryopreserved products remain an appropriate option for allogeneic stem cell transplant.Copyright © 2023 American Society for Transplantation and Cellular Therapy

Factors Affecting the Need for a Second HPC(A) Collection in Unrelated Allogenic Transplants: Process Improvement Opportunity

Introduction: Matched unrelated donors (MUD) for hematopoietic progenitor cell (HPC) transplantation are facilitated through the National Marrow Donor Program. Most peripheral blood collections (HPC-A) are obtained in a single day apheresis collection. Extensive planning is required to coordinate the mobilization, collection, and shipment of the product with the conditioning and infusing at the transplant center. Typically, these products are infused fresh, although the COVID pandemic has necessitated cryopreservation in many instances. It was perceived that the number of two-day MUD collections was increasing at our institution. This study was performed to determine if this was true and to evaluate potential causes. Method(s): The project was considered a laboratory quality improvement project;IRB approval was not required per institutional guideline. Data was collected retrospectively for 120 HPC(A) MUD from August 2017-November 2020 including donor's age, weight, and sex, along with recipient to donor weight ratio. Each factor was analyzed against CD34 yield per day of collection. Result(s): Of the 120 donors, 5.6% collected over 2 days in 2017(n=1), 3.7 % (n=1, 2018), 3.6 % (n=1, 2019) with highest observation 17% (n=8) in 2020 (Image). Donor age, donor weight, donor sex, and recipient to donor weight ratio were compared to absolute CD34 yield. There was not a correlation seen between CD34 yield and donor age nor weight. However, donor sex along with recipient/donor weight ratio each showed a correlation in the number of collections required. Of those requiring a second day of collection, 73% were female while 27% were male. Two-day collections could be predicted with 83% accuracy in female with >1.09 recipient/donor weight ratio and male with > 1.49 recipient/donor weight ratio.(Figure Presented) Conclusion(s): The observed trend of increased 2-day NMDP collections coincided with an increase in frequency of female donors. Not surprisingly, higher recipient/donor weight was associated with a higher likelihood of 2-day collections. The size and scope of this study do not allow us to determine a definitive cause. However, it was noted these findings coincided with new donor selection guidelines prioritizing HLA-DP match potentially leading to an increase in female donors being selected. Unexpected two-day collection can have significant effects on transplantation. Developing a predictive algorithm with 83% accuracy allows for patient and staff preparation to anticipate the likelihood for additional collections. Having the product collected and received in advance, prior to patient conditioning improves logistics and removes some variability from scheduling. Larger, multicenter studies are required to determine if increased numbers of two-day collection of MUD are occurring at other centers and to the potential causesCopyright © 2023 American Society for Transplantation and Cellular Therapy

Successful matched unrelated donor hematopoietic stem cell transplantation for infantile Wolman disease

Introduction: Wolman disease is a rare genetic disorder with an autosomal recessive inheritance. A mutation in the LIPA gene causes lysosomal acid lipase (LAL) deficiency results in lipid storage and adrenal insufficiency. Death in early infancy is due to liver failure. Patients and methods: We describe the clinical course of a three-month-old infant diagnosed with Wolman disease. A rapid mutational analysis confirmed a LIPA gene defect. Results: He underwent matched unrelated donor peripheral blood stem cell hematopoietic stem cell transplantation (HSCT) at 3 months of age, with a treosulfan-based conditioning, which resulted in engraftment with donor-derived hematopoietic cells. He required supportive care for sinusoidal obstruction syndrome and mucositis. He was administered low dose prednisolone for grade I skin graft versus host disease, and a complete donor chimerism was documented on several occasions. At one year post HSCT, his growth and development were optimal, and there was no hepatosplenomegaly. He is maintained on glucocorticoid and mineralocorticoid supplements for primary hypoaldosteronism. Conclusion: The case emphasizes the timely diagnosis and the potential for successful treatment of Wolman disease by HSCT. © 2022 Pediatric Hematology Oncology Chapter of Indian Academy of Pediatrics

Post-Transplantation Cyclophosphamide for the Prevention of Graft-Versus-Host Disease Should Not Limit Transplantation for Acute Lymphoblastic Leukemia in People with Trisomy 21

Introduction: Use of hematopoietic cell transplantation (HCT) in patients with trisomy 21 (+21) is infrequent given concerns about increased toxicity with cytotoxic chemotherapy.1 Due to increasing evidence of benefit from post-HCT cyclophosphamide (PTCy) for graft-vs.-host disease (GVHD) prophylaxis and lack of prior descriptions in patients with +21,2-4 we report on 2 patients with +21 and acute lymphoblastic leukemia (ALL) who underwent HCT with PTCy. Method(s): Retrospective data were collected from 2 patients with ALL and +21 who underwent allogeneic HCT with PTCybased GVHD prophylaxis from 2019 to 2021. Data collected included age, disease risk, HCT-CI, GVHD incidence, and survival. Result(s): Patient 1 is a 22-year-old male and patient 2 a 25-year-old female. Both had Ph-negative, B-cell ALL. Patient 1 had ETV6/RUNX1 rearrangement, del 12p, gain of X, and he had recurrence of measurable residual disease (MRD) after initial MRD-negative CR with two lines of therapy pre-HCT. Patient 2 had normal cytogenetics and relapsed disease with 4 prior lines of therapy. Both achieved MRD-negativity pre-HCT. Both received fludarabine and melphalan conditioning, and patient 1 also received thiotepa 2.5 mg/kg. PTCy was given on days +3 and 4 at 50 mg/kg with sirolimus and tacrolimus for GVHD prophylaxis. Patient 1 had a haploidentical donor and received one dose of rabbit ATG (1 mg/kg) on day +5. Patient 2 had a matched unrelated donor. There was no significant delay in engraftment of ANC (day 16-19) or platelets (day 15-16). Patient 2 developed acute GVHD at day 30 (stage I skin, stage II GI) that resolved with steroids which were tapered off by day 96 without recurrence. Sirolimus stopped at day 79 (pt 1) and 103 (pt 2) and tacrolimus was stopped at day 274 (pt 1) and 469 (pt 2). Patient 1 developed a sirolimus-induced pericardial effusion at day 84 which did not recur after sirolimus discontinuation. Patient 2 developed moyamoya 8 months post-HCT during tacrolimus taper without other GVHD symptoms. Response to steroids was noted, so tacrolimus was restarted for residual neurological deficit. Neither patient developed chronic GVHD or left ventricular ejection fraction decline, and neither patient had disease relapse at follow-up of 30 and 16 months respectively. Patient 2 developed COVID pneumonia 16 months post-HCT and died while in CR. Patient 1 remains alive, in CR, and off immunosuppression nearly 3 years post HCT. Conclusion(s): Allogeneic HCT with PTCy at standard doses did not appear prohibitively toxic in patients with +21 when administered after reduced-intensity conditioning. In this case series, GVHD rates seemed consistent with larger series in patients without +21. Moyamoya development is associated with autoimmunity in patients with +21 and hence may have been GVHD-related5. Trisomy 21 should not be a barrier to patients otherwise eligible for HCT, even with PTCy prophylaxis.Copyright © 2023 American Society for Transplantation and Cellular Therapy

Issues Faced by a Resource-Constrained Stem Cell Donor Registry and Impact of Coronavirus Disease 2019 on Their Functioning: A 9-Year Observational Study from a Single Registry in India

Background: Allogeneic hematopoietic stem cell transplantation activity is growing globally as one of the curative treatment options for many hematological diseases. A stem cell transplant registry plays an important role in such treatment. Setting up a functional stem cell donor registry is quite challenging with several issues such as resources, donor recruitment, donor attrition, ethnicity, lack of support, and impact of coronavirus disease 2019 (COVID-19). Aim(s): The aim of the current study was to present the experience of a resource-constrained registry in India as well as the effect of COVID-19 on its operations. Settings and Design: The present study was a descriptive study which was designed to study the functioning of a resource-constrained registry from north India. Material(s) and Method(s): The study data for the period of 2012-2020 pertaining to donor recruitment, number of searches, number of matched donors, number of transplants performed, and donor attrition was collected from the registry software "Prometheus." Statistical Analysis: Descriptive statistics such as frequency and percentage was used. Result(s): During the past 9 years of operation, the registry has faced several issues pertaining to lack of funds, donor recruitment, donor attrition, and COVID-19 has exacerbated their pain points significantly. The registry has recruited a total of 20,093 donors, of which only 7794 have been human leukocyte antigen typed, with the remaining samples awaiting funding. Out of this small number of typed donors, registry has performed 15 matched unrelated donor transplants for Indian and international patients. As a result of COVID-19, donor attrition was on the rise and showed a peak in 2020. During the year 2020, the number of searches, donor recruitment camps, and donors all decreased considerably. Conclusion(s): The establishment and operation of a stem cell transplant registry necessitate extensive planning and resources. The resource-constrained registries face a number of issues pertaining to effective functioning and future developments. The external support and awareness for the cause can help minimize the pain points of these registries. Copyright © 2022 Indian Journal of Transplantation.

Impact of Cryopreservation of Peripheral Blood Stem Cells (PBSC) in Transplantation from Matched Unrelated Donor (MUD).

Background: Cryopreservation of PBSC for allogenic hematopoietic stem cell transplantation (allo-HSCT) was implemented due to the current Coronavirus 2019 pandemic. The impact of match unrelated donor (MUD) graft freezing on the outcome of allo-HSCT in terms of hematological recovery, graft versus host disease (GVHD), and survival are still controversial. Methods: In this study, we compared graft composition, clinical characteristics, and outcome of 31 allo-HSCT from MUD cryopreserved PBSC (Cryo Group) with 23 matched-pair allo-HSCT from fresh MUD PBSC (Fresh Group) performed in our center between January 2020 and July 2021. Results: No significant differences were recognized in clinical characteristics of patients, donors, and transplants between the Cryo and Fresh groups except for a better prognostic comorbidity index (HCT-CI) of the Cryo group. In the Cryo Group, the median time from apheresis to cryopreservation was 46.0 h (range 23.8-53.5), while the median time from cells collection and reinfusion was 13.9 days (range 5.8-28.1). In the Fresh Group, median time from apheresis to reinfusion was 35.6 h (range 21.4-51.2). The number of viable (7-AAD negative) CD34+ cells per kg patient infused was significantly lower in the Cryo Group (5.2 ± 1.9 × 106/kg vs. 7.0 ± 1.3 × 106/kg; p < 0.001). Indeed, there was a 36% (11-70) median loss of viable CD34+/kg cells after freezing. All patients engrafted: median time to neutrophil engraftment (>0.5 × 109/L) was 13.5 days (range 12-15) for Cryo Group and 14 days (range 13-16) days for Fresh Group (p = 0.522), while the median time to platelet engraftment (>20 × 109/L) was, respectively, 14 (range 12-18) and 15 (range 12-17) days (p = 0.904). The incidence of grade ≥ 2 acute GVHD was similar in the two groups (56.5% Cryo Group vs. 60.0% Fresh Group; p = 0.832) and no differences in terms of OS (p = 0.090), PFS (p = 0.200) and TRM (p = 0.970) were observed between the Cryo and Fresh groups. Conclusions: In our series, no differences between the Cryo and Fresh groups were found in engraftment, grade ≥ 2 acute GVHD incidence, OS, PFS, and TRM despite a lower CD34+ infused dose in the Cryo Group. Frozen PBSCs could be considered a safe option also for allo-HSCT from MUD but a higher amount of PBSC should be collected to warrant an adequate viable CD34+ post-thawing.

A prospective phase 2 study testing high dose post-transplant cyclophosphamide as sole GHVD prophylaxis after matched allotransplant using baltimore-based reducedintensity conditioning regimens and PBSC as source of graft

Introduction: The use of high-dose post-transplant cyclophosphamide (PTCY) has revolutionized graft-versus-host disease (GVHD) prophylaxis and allowed to successfully reconsider haplotransplant in recent years. As this strategy significantly reduces the incidence of both acute and chronic GVHD, PTCY has been thereafter considered not only in matched settings but also as sole GVHD prophylaxis, at least when considering myeloablative allotransplant using matched sibling (MSD) or unrelated (MUD) donors and bone marrow as source of graft. Here, PTCY, as a sole GVHD prophylaxis, was tested in a reduced-intensity conditioning (RIC) setting, using peripheral blood stem cells (PBSC) as source of graft considering that this platform is currently broadly used worldwide in adults. Methods: This prospective monocentric phase 2 study was designed with the main objective to demonstrate the feasibility and safety of using only PTCY (without cyclosporine A nor mycophenolate mofetyl after transplant) in adults (18-70 years old) eligible for a RIC PBSC transplant with MSD or MUD. The Baltimore platform with 2 days of PTCY 50mg/kg/day on days 3 and 4 post infusion was considered as conditioning regimen, using fludarabine for lymphoid disease or clofarabine for myeloid disease. The primary objective was to appreciate the incidence of corticosteroid-resistant acute grade 3-4 GVHD (CR 3-4 GVHD) within 100 days post-transplant. According to statistical rules, patients have to be included in a step by step fashion (3, 3, 6, 15, 15 and 17 patients) for a total of 59 evaluable patients (meaning having received PTCY), in order to stop the protocol soon enough in case of excessive rate of deleterious severe acute GVHD (graded according to Mount Sinai International Consortium). Thus, the trial had to be stopped in case of documentation of > 2 CR 3-4 GVHD for the first 3 patients, >3 CR 3-4 GVHD for the first 6 patients, > 4 CR 3-4 GVHD for the first 12 patients, > 6 3-4 CR GVHD for the first 27 patients, > 8 CR 3-4 GVHD for the first 42 patients and finally as soon as > 9 CR 3-4 GVHD for the last included patients. All patients gave informed consent. The trial was registered at ClinicalTrials.gov Identifier: NCT03263767. Results: The results of the first 27 first patients (males n=17 and female n=10;median age: 59 years old (yo), range: 26-70) are reported here. They were included between February 2018 and November 2020. Diagnoses were AML (N=8), MDS (N=5), CMML (N=2), myelofibrosis (N=5), CML (N=1), DLBCL (N=1), T-cell lymphoma (N=1), Philadelphia positive B-ALL (N=1), CLL (N=1), lymphoblastic lymphoma (N=1) and mixed phenotype acute leukemia (N=1). Donors were MSD in 10 cases and MUD in 17. Only one primary graft failure was documented in a 61 yo MDS patient with active disease at transplant. He is however still alive in response after autologous reconstitution. With a median follow-up of 17.6 months (range: 10-42) for alive patients at the time of analysis (July 2021), 1-year and 2-year survivals were 80.9+7% and 74.7+9%, respectively, for both OS et DFS. GVHD-free/relapse-free survival (GRFS) at 1-year and 2-year was 58.7+9% and 52.2+10%, respectively. Three relapses (11%) and 6 deaths occurred. Deaths were due to acute GVHD in 4 patients (including 1 with sepsis and 1 with SARS-COVID 19 infection) and relapse in 2. Grade 2, 3 and 4 acute GVHD occurred in 11, 1 and 4 patients, respectively, for a total of 59% of grade 2-4 acute GVHD. CR 3-4 GVHD was observed in all of 5 patients with acute grade 3-4 GVHD and 4 died related to GVHD. Moderate/severe chronic GVHD occurred in 5/22 (22.7%) evaluable patients, including 4 still on immunosuppressive therapy at 40, 28, 25 and 16 months post-transplant. Overall non-relapse mortality (NRM) was 14.8% and related to acute GVHD. However, the number of cases conducting to stop the protocol was not reached. Conclusion: PTCY as a sole GVHD prophylaxis is here demonstrated as possible and relatively safe for adults receiving a matched PBSC Baltimore-based RIC allograft. The very good survivals reported he e may be related to a strong GVL effect associated with the high incidence of acute GVHD. However, because of this high incidence and the fact that NRM was related to GVHD after this first analysis, we have now made an amendment to test the addition to PTCY of one day of anti-thymoglobulin (ATG) 2.5 mg/kg on day-2 for the next 32 patients to be included. This second cohort receiving PTCY+ATG as a sole prophylaxis is ongoing.

ATG and Post-Transplant Cyclophosphamide Predisposes to Inferior Outcome When Using Cryopreserved Stem Cell Grafts

Background During 2020, the novel COVID-19 pandemic lead to cryopreservation of allogeneic hematopoietic stem cell (HSCT) grafts based on NMDP and EBMT recommendations, to secure grafts before start of conditioning chemotherapy. We examined the impact of this change in practice on patient outcomes. Methods We retrospectively analyzed the outcomes of 483 patients who received HSCT between Aug 2017 and Aug 2020, at Princess Margaret Cancer Centre, Canada, comparing the outcomes between those who received cryopreserved (CRYO, n=135) or fresh peripheral blood stem cell grafts (FRESH, n=348). Median follow-up: 12.3 months. Probability of overall survival (OS) was calculated using the Kaplan-Meier product-limit method and heterogeneity of time-to-event distribution functions were compared by the log-rank test. Cumulative incidences of aGvHD and cGvHD, relapse, and non-relapse mortality (NRM) were estimated using the cumulative incidence method considering competing risk, and groups were compared using Gray's test. Death was considered as a competing event for relapse, aGvHD and cGvHD, and relapse was considered a competing event for NRM, aGvHD and cGvHD. Results Median age was 58y;54.5% were males. Acute myeloid leukemia was commonest HSCT indication (n=248, 49.1%). Donors: MUD 10/10 n=233;MUD 9/10 (MMUD) n=48, matched related donor (MRD) n=112, Haploidentical n=88. Transplant conditioning: 79 (23%) and 23 (17%) patients received myeloablative conditioning (MAC) in the FRESH and the CRYO groups, respectively (p ns). In the FRESH group, 253 (73%) patients and 114 (84%) patients in the CRYO group received ATG followed by posttransplant cyclophosphamide (PTCy) and Cylosporine GvHD prophylaxis. OS at the 2y timepoint, FRESH group (n=348), was 67.0% (61.1-72.3%), compared to 48.7% (38.1-58.4%) for patients in the CRYO group (n=135), p=0.002, Figure 1a. This was mainly due to MRD cohort outcomes: 2y OS in MRD FRESH group (n=65), was 85.2% (73.3-92.0%), compared to 45.1% (29.9-59.1%) in MRD CRYO group (n=47), p<0.001, Figure 2a. Multivariate analysis (MVA) for OS, significant factors were increasing patient age, DRI high/v.-high, HCT-CI ≥ 3, Donors: Haplo and MMUD, cryopreservation, Table 1. NRM at 1y for FRESH (n=348) 17% (13.2-21.2) vs CRYO (n=135) 22.1 % (14.8-30.4), p ns. However, in the MRD cohort, NRM at 1y for FRESH group (n=65), was 1.5% (0.1-7.4%), compared to 15.4% (6.6-27.4%) for CRYO group (n=47), p=0.003, Figure 2b. On MVA, NRM adverse significant factors were patient age, DRI high/v.-high, Donors: Haplo and MMUD, Table 1. Cumulative incidence (CI) of relapse at 2y for FRESH 22.4% (17.5-27.7) vs CRYO 27.0 % (18.8-35.9) p=0.07. The CI of moderate-severe cGvHD at 1y for FRESH group (n=315) was 21.5% and 10.8% in the CRYO group, p=0.027, Figure 1c. Patients with FRESH 10/10 MUDs (n=180), had CI of moderate-severe cGvHD at 1y of 20.6%, compared to CRYO 10/10 MUDs (n=35), 6.0% p ns for MUDs;FRESH MRD (n=64) CI was 30.1%;and CRYO MRD (n=43) 10.3%, p=0.008 for MRD, Figure 1d. On MVA, significant adverse factors for chronic GvHD were increasing donor age, male recipient/female donor, whilst graft CRYO was protective, Table 1. GvHD-and Relapse free Survival (GRFS) at 2y for FRESH 54.0% (47.9-59.6) vs CRYO 43.4% (33.4-53.0) p<0.05, Figure 1b. However, in the MRD cohort, GRFS at 2y in FRESH group (n=65), was 74.2% (61.3-83.4%), compared to 40.7% (26.3-54.6%) for CRYO group (n=47), p=0.001;other donor types no difference, Figure 1c. On MVA, significant factors correlated with worse GRFS were: DRI high and very-high, cryopreservation, Donors: Haplo and MMUD, Table 1. Compared to FRESH group, CRYO group experienced reduced cGvHD, delay in neutrophil engraftment, higher graft failure and increased CMV reactivation, with no difference in relapse incidence or acute GvHD. Conclusion Cryopreservation was associated with inferior outcomes post-HSCT particularly in the MRD cohort, possibly due to combination ATG and post-transplant cyclophosphamide impacting differential tolerance to cryopreservation on components of the stem ce l graft;further studies are warranted to elucidate mechanisms for this observation. [Formula presented] Disclosures: Law: Novartis: Consultancy;Actinium Pharmaceuticals: Research Funding. Lipton: Bristol Myers Squibb, Ariad, Pfizer, Novartis: Consultancy, Research Funding. Kim: Bristol-Meier Squibb: Research Funding;Paladin: Honoraria, Research Funding;Pfizer: Honoraria, Research Funding;Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Mattsson: MattssonAB medical: Current Employment, Current holder of individual stocks in a privately-held company.