Late-onset Pneumocystis jirovecii pneumonia post-allogeneic stem cell transplantation after time-dependent discontinuation of prophylaxis.

INTRODUCTION: Pneumocystis jirovecii pneumonia (PJP) is a rare complication of hematopoietic stem cell transplantation (HSCT). Primary prophylaxis for 6-12 months post-HSCT is the standard approach. However, there is no consensus regarding the optimal duration of prophylaxis. METHODS: We identified patients who developed PJP more than 1-year post-HSCT. All patients had previously received 12 months of PJP prophylaxis. PJP was diagnosed based on clinical findings and the detection of P. jirovecii in bronchoalveolar lavage (BAL) using polymerase chain reaction (PCR). The CD4+ T-cell percentage was determined using flow cytometry. Data expressed as median (interquartile range). RESULTS: Ten patients developed PJP at 17.5 months (16-24 months) post-HSCT. PJP diagnosis occurred 5.5 months (3-15 months) after discontinuing prophylaxis. Eight patients received anti-thymocyte globulin (ATG) as graft versus host disease (GVHD) prophylaxis. At diagnosis, only one patient had lymphopenia; all patients had CD4+ T-lymphocyte counts ≥0.2 × 109 /L (median 0.337 × 109 /L). Three patients had concomitant bacterial infections. The clinical presentation was mild; only three required hospitalization, none of them required intensive care and there were no deaths. CONCLUSION: There is a need to develop risk-adapted prophylactic strategies in the contemporary era using ATG-based GVHD prophylaxis.

Letermovir prophylaxis for cytomegalovirus reactivation in allogeneic hematopoietic cell transplant recipients: Single center Canadian data.

BACKGROUND: Cytomegalovirus (CMV) is associated with morbidity and mortality following allogeneic hematopoietic cell transplantation (alloHCT). Letermovir is a novel antiviral agent that prevents CMV reactivation in alloHCT patients, with limited data regarding influence on post-alloHCT outcomes. METHODS: We retrospectively examined 273 alloHCT recipients, 158 in the non-letermovir cohort (NLC), and 115 in the cohort using letermovir prophylaxis (LC). Patients that received letermovir were CMV-seropositive and met criteria for high risk of CMV reactivation. RESULTS: Median start of letermovir was 21 days post-alloHCT, median duration of prophylaxis was 86 days. Letermovir prophylaxis demonstrated a statistically significant reduction in first CMV reactivation (at 200 days post 63.9% in the NLC vs. 35.7% in the LC; p < .001). On univariate analysis at 1 year, overall survival (OS) for NLC was 79.6% and 79.5% for LC (p = .54). Non relapse mortality (NRM) at 1 year for NLC was 12% and 12.3% for LC (p = .69). Cumulative incidence of relapse (CIR) at 1 year was 13.9% for NLC versus 17.1 for the LC (p = .27). On multivariable analysis, there was no significant difference between the two cohorts for OS, NRM, and CIR. CONCLUSIONS: Letermovir prophylaxis started at day +21 post-alloHCT reduced CMV reactivation, with no impact on posttransplant outcomes.

Impact of cytomegalovirus (CMV) seroconversion pre-allogeneic hematopoietic cell transplantation on posttransplant outcomes.

Cytomegalovirus (CMV) reactivation post-allogeneic hematopoietic cell transplantation (post-alloHCT) increases morbidity and mortality. We sought to determine the frequency of CMV seroconversion in patients pre-alloHCT and to investigate the impact on posttransplant outcomes. We retrospectively investigated 752 adult patients who underwent alloHCT at our center from January 2015 to February 2020 before the adoption of letermovir prophylaxis. CMV serology was assessed at consult and pretransplant. The cohort was divided into four groups based on pretransplant CMV seroconversion: negative to positive (Group 1), positive to negative (Group 2), consistently negative (Group 3), and consistently positive (Group 4). Eighty-nine patients (12%) had seroconverted from negative to positive, 17 (2%) from positive to negative, 151 (20%) were consistently seronegative, and 495 (66%) were consistently seropositive pretransplant. For the four CMV serostatus groups, cumulative incidence of CMV reactivation at 6 months posttransplant was 4.5%, 47.1%, 6.6%, and 76.6% for Groups 1, 2, 3, and 4, respectively (p < .0001). No differences between groups were seen regarding Grade III-IV acute graft-versus-host disease (GVHD) (p = .91), moderate/severe chronic GVHD (p = .41), or graft failure (p = .28). On multivariable analysis, there was no impact of CMV serostatus group on overall survival (p = .67), cumulative incidence of relapse (p = .83) or non-relapse mortality. alloHCT patients who demonstrate CMV seroconversion pretransplant from negative to positive have a very low risk of CMV reactivation posttransplant. The observed seroconversion may be due to passive CMV immunity acquired through blood products. Quantitative CMV immunoglobulin G/immunoglobulin M pretransplant may help differentiate between true seroconversion and passively transmitted CMV immunoglobulin.

Multiplex proteomics in the identification of potential biomarkers of very severe sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) in allogeneic hematopoietic cell transplant patients treated with defibrotide.

Introduction Despite well-established clinical criteria for diagnosis of SOS/VOD following allogeneic HCT, there is a lack of established diagnostic protein biomarkers. Methods Prospective samples were collected from patients with very severe SOS/VOD at diagnosis and days +3, +7, +14, and +30 post-initiation of defibrotide. Samples from age-matched controls with no VOD were collected at day +14, +30, +60, +90 and +180 following allogeneic HCT. Serum samples were analyzed for 2925 protein levels by antibody-based proximity extension assay (PEA). Mean differences in the log-transformed abundance values were compared using t-tests in a volcano plot. Results Five patients with very severe SOS/VOD and five control patients were compared. Ten proteins were identified that showed a statistically significant and log-transformed 3-fold increase in concentration. They were CALCA, CCL20, GPR37, IGFBP4, IL1RL1, SLC39A14, SPINK4, FABP3, MYL3, and CHCHD10. Four different proteins, namely CD83, LAIR2, CD7, and HEM6 showed a significant decrease with defibrotide treatment. SOS/VOD resolved in 80% (n=4) of patients, while one patient deceased due to SOS/VOD. Conclusion PEA technology identified 10 proteins that were significantly elevated in patients with very severe SOS/VOD. Prospective studies in a larger cohort using this technology may be able to conclusively identify diagnostic protein biomarkers for SOS/VOD.

Clonal hematopoiesis in the donor does not adversely affect long-term outcomes following allogeneic hematopoietic stem cell transplantation: result from a 13-year follow-up.

Donor clonal hematopoiesis may be transferred to the recipient through allogeneic hematopoietic stem cell transplantation (HSCT), but the potential for adverse long-term impact on transplant outcomes remains unknown. A total of 744 samples from 372 recipients who received HSCT and the corresponding donors were included. Bar-coded error-corrected sequencing using a modified molecular inversion probe capture protocol was performed, which targeted 33 genes covering mutations involved in clonal hematopoiesis with indeterminate potential (CHIP) and other acute myeloid leukemia-related mutations. A total of 30 mutations were detected from 25 donors (6.7%): the most frequently mutated gene was TET2 (n=7, 28%), followed by DNMT3A (n=4, 16%), SMC3 (n=3, 12%) and SF3B1 (n=3, 12%). With a median follow-up duration of 13 years among survivors, the presence of CHIP in the donor was not associated with recipient overall survival (P=0.969), relapse incidence (P=0.600) or non-relapse mortality (P=0.570). Donor CHIP did not impair neutrophil (P=0.460) or platelet (P=0.250) engraftment, the rates of acute (P=0.490), or chronic graft-versus-host disease (P=0.220). No significant difference was noted for secondary malignancy following HSCT between the two groups. The present study suggests that the presence of CHIP in allogeneic stem donors does not adversely affect transplant outcomes after HSCT. Accordingly, further study is warranted to reach a clearer conclusion on whether molecular profiling to determine the presence of CHIP mutations is necessary for the pretransplant evaluation of donors prior to stem cell donation.

Impact of age on hospitalization and outcomes post allogeneic hematopoietic cell transplantation outcome, a single center experience.

The outcomes of allogeneic hematopoietic cell transplantation (HCT) in older patients are not well defined. We retrospectively analyzed the outcomes of 332 patients, with the median age of 65 years (range, 60-76), between 2014 and 2019. We categorized them to 3 age groups (G): G1, 60-65 years (n = 175); G2, > 65-70 years (n = 127); and G3, > 70 years (n = 30). The median length of hospitalization during the initial HCT period was 30 days, with a significant difference when stratified by age (p = 0.049). Overall, 183 (58.7%) patients were re-hospitalized within the first 6 months post HCT, and 60 (21.6%) in the second 6-month period. The 2-year OS was 56% in G1, 53% in G2, and 34% in G3 (p = 0.05). The 2-year event-free survival (EFS) was 54% for G1, 49% for G2, and 31% for G3 (p = 0.04). Non-relapse mortality (NRM) at 2 years was 25% in G1, 36% in G2, and 52% in G3 (p = 0.008). In multivariable analysis, patients aged 60-65 years had significantly better EFS (p = 0.04) and had a trend toward lower NRM (p = 0.05) than those aged > 70 years. Re-admission in the first 6 months post HCT had a significant impact on OS, EFS, and NRM. HCT-specific comorbidity index > 3 had significantly affected NRM. Finally, age had a significant influence on length of hospitalization during HCT. In conclusion, patients aged > 70 years have an inferior EFS and higher NRM. This likely related to higher rate of re-admissions due to infectious complications (84%).

Influence of conditioning regimen intensity on outcomes post-allogeneic hematopoietic cell transplantation for acute myeloid leukemia in complete morphological remission.

INTRODUCTION: The literature comparing outcomes between myeloablative (MAC) and reduced intensity conditioning (RIC) for acute myeloid leukemia (AML) is conflicting. METHODS: We retrospectively analyzed 451 patients who underwent allogenic hematopoietic cell transplantation (alloHCT) for AML in complete remission (CR) with either RIC (n = 331) or MAC (n = 120) with the use of dual T-cell depletion as graft-versus-host disease (GVHD) prophylaxis. RESULTS: Univariate analysis demonstrated nonrelapse mortality (NRM) at 2 years was 19.1% for MAC and 22.5% for RIC (p = .44). Two-year cumulative incidence of relapse (CIR) was 19.8% for MAC and 24.5% for RIC (p = .15). Two-year overall survival (OS) was 61% and 53% for MAC and RIC, respectively (p = .02). Two-year graft-versus-host disease relapse-free survival (GRFS) was 40.8% for MAC and 33.7% for RIC (p = .30). A propensity score-matched analysis was done matching patients for age, HLA match, in vivo T-cell depletion, and Disease Risk Index (DRI). Two-year OS was 67% for MAC, 66% for RIC (p = .95). A subgroup analysis identified that matched related donor transplants benefit from MAC with OS at 2 years 82.6% versus 57.3% for RIC (p = .006). CONCLUSIONS: In the matched-related donor setting, MAC regimens may offer superior survival. Overall, for our cohort of predominantly in vivo T-cell depleted patients the outcomes of MAC and RIC were similar.

Mutational profile, outcomes, and impact of allogeneic hematopoietic stem cell transplantation in adult patients with acute myeloid leukemia and inconclusive cytogenetic analysis.

BACKGROUND: Inconclusive cytogenetic analysis (IC) at baseline has been reported as a predictor of poor prognosis in patients with acute myeloid leukemia (AML). The mutational profile in this group of patients, and its impact on outcomes have not been reported. METHODS: We retrospectively analyzed adult patients (≥18 years) with newly diagnosed AML treated with intensive induction chemotherapy between 2015 and 2019. Patients with any documented cytogenetic abnormalities were excluded. Targeted next generation sequencing (NGS) was performed in all patients. Baseline characteristics, mutation profile, and outcomes were compared between patients with normal cytogenetics(NC) and those with IC. RESULTS: Sixty-one patients (males 39.3%; median age 59 years) had IC at diagnosis. The proportion of patients with mutations in genes with proven prognostic impact were not different between AML patients with IC and NC. AML patients with NC were more likely to harbor the prognostically favorable NPM1mut /FLT3-ITDwt mutational combination conferring "favorable" risk status. As a result, a larger proportion of patients in the IC group underwent allogeneic hematopoietic stem cell transplantation (allo HCT; 54.1% vs. 39.6%; p = .02). The 2-year RFS (55.9% vs. 58.5%; p = .29) and OS (61.9% vs. 66.9%; p = .48) were similar in IC and NC patients. There was no difference in survival of patients who underwent allo HCT when compared with patients who did not (p = .99). CONCLUSIONS: Inconclusive cytogenetic analysis may not be an independent prognostic indicator in AML. In such patients, molecular abnormalities detected through NGS or whole genome sequencing are more likely to be informative.

Prognostic implication of pre-transplant FEV1 on long-term outcomes following allogeneic hematopoietic stem cell transplantation.

BACKGROUND: Pre-transplant pulmonary function testing (PFT) is essential before allogeneic hematopoietic stem cell transplant (HCT), yet the optimal cutoff value for affecting transplant outcomes remains poorly defined. STUDY DESIGN: Retrospective analysis of pre-HCT PFT data from 605 consecutive patients at the Princess Margaret Cancer Centre between January 1, 2004 and December 31, 2013 used binary recursive partitioning to identify cutoff values for overall survival (OS) as an endpoint of transplant outcomes. These values were compared to HCT comorbidity index (HCT-CI) FEV1 cutoffs for OS, cumulative incidence of relapse and non-relapse mortality. RESULTS: FEV1 ≥ 81% was the identified cutoff point. The OS rate at 3 years showed 49.8% (FEV1 ≥ 81%) vs. 36.6% (<81%, p < .001). For HCT-CI cutoffs, the OS rate at 3 years for FEV1 ≥ 80%, 66%-80% and ≤65% were 49.0%, 38.1% and 37.6% (p = .011), respectively. Multivariate analysis confirmed that FEV1 ≥ 81% predicted reduced mortality (HR 0.682, p = .001). Subgroup analysis showed both FEV1 ≥ 81% and FEV1 by HCT-CI cutoffs may stratify patients according to OS and NRM risk in subgroups receiving myeloablative, but not reduced intensity conditioning. CONCLUSION: FEV1 ≥ 81% can predict OS and NRM in our cohort and is potentially simpler when risk stratifying patients undergoing allogeneic HCT, particularly those receiving myeloablative conditioning.

Multiplex proteomics using proximity extension assay for the identification of protein biomarkers predictive of acute graft-vs.-host disease in allogeneic hematopoietic cell transplantation.

OBJECTIVES: Allogeneic hematopoietic cell transplantation (HCT) is associated with acute graft-vs.-host disease (aGVHD). The presented study applied a novel multiplex antibody-based proximity extension assay (PEA) proteomic platform that can detect thousands of serum proteins simultaneously for the identification of potential biomarkers of aGVHD. METHODS: Serum samples from 28 patients who underwent allogeneic HCT for acute myeloid leukemia (AML) were analyzed; 17 were diagnosed with grade II-IV aGVHD while 11 patients were not. Samples collected on day -6, day 0, +14, +30, +60 and +90 post-HCT were analyzed for the relative concentrations of 552 proteins. The concentration of each protein from baseline to the closest time point before onset of aGVHD, or to the latest time point in control patients, was documented. RESULTS: Individualized analysis identified 26 proteins demonstrating ≥3-fold increase at aGVHD onset compared to baseline, eliminating proteins with a similar increase in controls. Another approach used paired t-testing and logistic regression that identified a four-marker panel, including SLAMF7, IL-1ra, BTN3A2 and DAB2, where individual log-likelihood ratios ranged from 3.99 to 8.15 (logistic regression, p=0.004-0.046). When combined, the four-marker panel demonstrated an area under the curve (AUC) of 0.90 (95% CI: 0.78-1.00; p=0.0006) with high negative predictive value of 81.8% and positive predictive value of 86.7%. All four markers play a physiological role in immune regulation. Among these, three were also present in the individualized analysis (SLAMF7, IL-1ra and BTN3A2). CONCLUSIONS: We conclude that serum proteins identified using multiplex proteomics, particularly SLAMF7, IL-1ra, BTN3A2 and DAB2, may potentially predict aGVHD.

Machine learning for the prediction of survival post-allogeneic hematopoietic cell transplantation: A single-center experience.

INTRODUCTION: Prediction of outcomes following allogeneic hematopoietic cell transplantation (HCT) remains a major challenge. Machine learning (ML) is a computational procedure that may facilitate the generation of HCT prediction models. We sought to investigate the prognostic potential of multiple ML algorithms when applied to a large single-center allogeneic HCT database. METHODS: Our registry included 2697 patients that underwent allogeneic HCT from January 1976 to December 2017, 45 pre-transplant baseline variables were included in the predictive assessment of each ML algorithm on overall survival (OS) as determined by area under the curve (AUC). Pre-transplant variables used in the EBMT machine learning study (Shouval et al, 2015) were used as a benchmark for comparison. RESULTS: On the entire dataset, the random forest (RF) algorithm performed best (AUC 0.71±0.04) compared to the second-best model, logistic regression (LR) (AUC=0.69±0.04) (p<0.001). Both algorithms demonstrated improved AUC scores using all 45 variables compared to the limited variables examined by the EBMT study. Survival at 100 days post-HCT using RF on the full dataset discriminated patients into different prognostic groups with different 2-year OS (p<0.0001). We then examined the ML methods that allow for significant individual variable identification, including LR and RF, and identified matched related donors (HR=0.49, p<0.0001), increasing TBI dose (HR=1.60, p=0.006), increasing recipient age (HR=1.92, p<0.0001), higher baseline Hb (HR=0.59, p=0.0002) and increased baseline FEV1 (HR=0.73, p=0.02), among others. CONCLUSION: The application of multiple ML techniques on single center allogeneic HCT databases warrants further investigation and may provide a useful tool to identify variables with prognostic potential.

Weight loss post-allogeneic stem cell transplant is associated with increased transplant-related mortality.

PURPOSE: Allogeneic stem cell transplant (allo-HSCT) patients are at risk of malnutrition and weight loss from impaired oral intake resulting from gastrointestinal toxicities, dysgeusia, and psychological effects. METHODS: A retrospective review of 264 adult patients transplanted at Princess Margaret Cancer Centre who achieved relapse-free survival up to 3 months after allo-HSCT was performed. RESULTS: Overall incidence of patients who experienced WL (WL) ≥ 10% from HSCT to 3-month post-transplant was 45.9% and from HSCT to 6 months was 56.6%. Patients with ≥ 10% WL from allo-HSCT at 3 months and 6 months had similar 2-year overall survival (OS) compared to those with < 10% WL, 55.7% vs 62.8% (HR = 1.38, p = 0.11) and 71.1% vs 77.2% (HR = 1.37, p = 0.27), respectively. Patients with ≥ 10% WL 3 and 6 months from allo-HSCT also had similar 2-year relapse-free survival (RFS) compared to those with < 10% WL, 48.1% vs 55.8% (HR = 1.26, p = 0.22), and 62.7% vs 69.8% (HR = 1.29, p = 0.31), respectively. The 2-year transplant-related mortality (TRM) was higher for those with ≥ 10% WL from allo-HSCT to 3 months, 35.4% vs 16.9% (HR = 2.39, p = 0.0007) and 6 months, 22% vs 8% (HR = 3.1, p = 0.0034). Although statistical significance was not observed for OS or RFS, patients who experienced ≥ 10% WL 3- and 6-months post allo-HSCT experienced higher 2-year TRM. These results highlight the importance of early intervention and close monitoring of weight post allo-HSCT. CONCLUSION: Approaches to WL post allo-HSCT should be multifaceted and include members of the interdisciplinary team in order to decrease TRM.

Patient age and donor HLA matching can stratify allogeneic hematopoietic cell transplantation patients into prognostic groups.

BACKGROUND: Mixed results surround the accuracy of commonly used prognostic risk scores to predict overall survival (OS) and non-relapse mortality (NRM) in allogeneic hematopoietic stem cell transplant (allo-HCT) recipients. We hypothesize that a simple prognostic score performs better than conventional scoring systems. PATIENTS AND METHODS: OS risk factors, HCT-CI, age-HCT-CI, and augmented-HCT-CI were studied in 299 patients who underwent allo-HCT for myeloid and lymphoid malignancies. A scoring system was developed based on results and validated in a different cohort of 455 patients. RESULTS: Two-year OS was 51% (95% confidence interval (CI) 0.45-0.56); 2-year NRM was 34% (95% CI 0.29-0.39). HCT-CI and associated scores were grouped into 0-2 and ≥3. Age and HLA mismatch status were the only risk factors to affect OS in multivariate analysis (p = 0.02 and 0.05, respectively). HCT-CI and associated scores were not informative for OS prediction. The weighted scoring system assigned 0 to 2 points for age < 50, 50-64, or ≥65, respectively, and 0-1 points for no HLA mismatch versus any mismatch (except HLA-DQ). Distinct 2-year OS (62%, 53%, and 38% [p = <0.001]) and NRM (24%, 34%, and 43% [p = 0.02]) groups were characterized. The scoring system was validated in a second independent cohort with similar results on OS and NRM (p < 0.001). CONCLUSIONS: A simple scoring system based on recipient's age and mismatch status accurately predict OS and NRM in two distinct cohorts of allo-HCT patients. Its simplicity makes it a helpful tool to aid clinicians and patients in clinical decision-making.

Allogeneic hematopoietic stem cell transplantation in patients with therapy-related hematologic malignancies developing after multiple myeloma.

INTRODUCTION: Increasing survival of patients with multiple myeloma (MM) has resulted in an increased recognition of therapy-related hematological malignancies (t-MDS/AML, t-ALL, and t-CMML). There are limited data on the role of allogeneic hematopoietic stem cell transplantation (HCT) in this patient population. PATIENTS AND METHODS: We retrospectively reviewed patients who underwent HCT for t-MDS/AML, t-ALL, and t-CMML developing after receiving treatment for MM at our center. Patients were analyzed for myeloma characteristics and therapy, time to diagnosis of therapy-related hematological neoplasms, clinical, laboratory characteristics, transplant details, relapse-free survival (RFS), and overall survival (OS). RESULTS: Twenty patients underwent HCT for therapy-related hematological malignancies after MM (t-MDS/AML = 13, t-ALL = 6, t-CMML = 1). Median(range) age at time of transplant was 62.5 (49-73) years and 70% (n = 14) were male. The most common cytogenetic abnormality was complex/monosomal karyotype in 30% (n = 6) followed by monosomy/deletion of chromosome 5 or 7 in 15% (n = 3) of patients each. Donors were human leukocyte antigen matched (10/10 or 6/6) siblings in 30% (n = 6), unrelated in 60% (n = 12) and haploidentical in 10% (n = 2) patients. Estimated 2-year OS and RFS for the whole cohort were 53.1% and 47.2% respectively. There was a trend toward better survival in patients with t-ALL when compared to t-MDS/AML; however, the difference was not statistically significant. We did not find any pre-transplant or post-transplant factors that were predictive of survival outcomes after multivariate analysis. CONCLUSIONS: Allogeneic HCT provides substantial long-term disease-free survival in a proportion of patients with MM-associated therapy-related hematological malignancies. Multicenter studies with more patients and longer follow-up may provide additional information about factors affecting outcomes.

Anti-thymocyte globulin and post-transplant cyclophosphamide predisposes to inferior outcome when using cryopreserved stem cell grafts.

During 2020, the concurrent novel COVID-19 pandemic lead to widespread cryopreservation of allogeneic hematopoietic cell transplant grafts based on National Marrow Donor Program and European Society of Blood and Marrow Transplantation recommendations, in order to secure grafts before the start of conditioning chemotherapy. We sought to examine the impact of this change in practice on patient outcomes. We analyzed the outcomes of 483 patients who received hematopoietic stem cell transplantation (HSCT) between August 2017 and August 2020, at Princess Margaret Cancer Centre, Canada, in the retrospective study, comparing the outcomes between those who received cryopreserved or fresh peripheral blood stem cell grafts. Overall compared with those who received fresh grafts (n = 348), patients who received cryopreserved grafts (n = 135) had reduced survival and GRFS, reduced incidence of chronic graft-versus-host disease (GvHD), delay in neutrophil engraftment, and higher graft failure (GF), with no significant difference in relapse incidence or acute GvHD. However, recipients of cryopreserved matched-related donor HSCT showed significantly worse OS, NRM, GRFS compared with fresh grafts. Multivariable analysis of the entire cohort showed significant impact of cryopreservation on OS, relapse, cGvHD, GF, and GRFS. We conclude that cryopreservation was associated with inferior outcomes post-HSCT, possibly due to the combination of ATG and post-transplant cyclophosphamide impacting differential tolerance to cryopreservation on components of the stem cell graft; further studies are warranted to elucidate mechanisms for this observation.

Anti-thymocyte Globulin and Post-Transplant Cyclophosphamide do not abrogate the inferior outcome risk conferred by human leukocyte antigen-A and -B mismatched donors.

In donor selection for allogeneic stem cell transplant, several factors are considered for potential impact on transplant outcome. Previous publications suggested single HLA-mismatched unrelated donors (MMUD) may be equivalent to 10/10 matched unrelated donors (MUDs). We retrospectively examined factors affecting outcome in a single-center study using ATG followed by post-transplant cyclophosphamide, termed ATG-PTCy, GvHD prophylaxis. Fifty-two patients who received grafts from MMUD and 188 patients transplanted from MUD between January 2015 and December 2019, at Princess Margaret Cancer Centre, Canada, were enrolled. All patients received reduced-intensity conditioning. Overall survival for 9/10 recipients at 2 years was significantly worse, 37.2% versus 68.5% for 10/10 MUDs, p < .001, as were NRM at 1 year 39.5% versus 11.7%, p < .001, and GRFS at 2 years 29.8% versus 58.8%, p < .001, respectively, potentially due to higher incidence of infections including CMV. By multivariable analysis, factors correlating with survival negatively were DRI, and MMUD, whereas for NRM MMUD and increasing age were unfavorable. For GRFS significant unfavorable factors included donor age ≤32 years, female donor to male recipient, DRI high-very high and MMUD. These data suggest that MMUD, primarily HLA-A and HLA-B MMUD, confer significantly inferior outcome despite use of ATG-PTCy. Further development of novel conditioning regimens and GvHD prophylaxis is needed to mitigate these risks.

Relationship between certain HLA alleles and the risk of cytomegalovirus reactivation following allogeneic hematopoietic stem cell transplantation.

INTRODUCTION: Evidence is emerging to support an association between certain human leukocyte antigen (HLA) alleles and the risk of cytomegalovirus (CMV) reactivation following allogeneic hematopoietic stem cell transplant (allo-HSCT). The primary aim of this study was to identify HLA alleles associated with resistance or susceptibility to CMV reactivation. METHODS: We studied 586 adults who underwent allo-HSCT for high-risk hematological malignancies. High-resolution HLA typing data were available for recipients and donors. HLA class I and II alleles observed at a frequency of >5% in our population were included in the analysis. A CMV viremia level of more than 200 IU/ml on weekly monitoring was considered to be indicative of CMV reactivation. RESULTS: The median follow-up time in surviving patients was 21 months (range 4-74 months). The cumulative incidence of CMV reactivation at 6 months in the entire cohort was 55% (95% confidence interval [CI] 50.8%-59.2%). Mismatched donors, increasing recipient age, occurrence of acute graft versus host disease and recipient CMV seropositivity were associated with an increased risk of CMV reactivation. HLA B*07:02 (hazard ratio 0.59, 95% CI 0.40-0.83) was associated with a decreased risk of CMV reactivation. Patients who developed CMV reactivation had a lower incidence of relapse, higher transplant-related mortality (TRM) and lower overall survival (OS) than those without CMV reactivation. There was an adverse correlation of OS and TRM with increasing numbers of CMV reactivations. CONCLUSION: We observed that HLA B*07:02 was associated with a decreased risk of CMV reactivation. CMV reactivation was associated with lower relapse post-transplant, but this did not translate into a survival benefit due to higher TRM.

Post-transplant ferritin level predicts outcomes after allogeneic hematopoietic stem cell transplant, independent from pre-transplant ferritin level.

Allogeneic hematopoietic stem cell transplantation (HCT) is associated with significant morbidity and mortality. Elevated pre-transplant ferritin level (ferritinPre-HCT) is reported to be associated with increased mortality following HCT. The present study attempted to determine whether post-transplant ferritin level (ferritinPost-HCT) is associated with outcomes post-HCT, especially in the subgroups which developed acute or chronic graft-versus-host disease (GVHD). Out of 229 patients with serum ferritin level measured post-HCT, median ferritinPost-HCT was 2178 ng/mL. Patients were stratified into low- or high-risk groups using recursive partitioning, based on ferritinPost-HCT (≤ 3169 vs > 3169 ng/mL) and ferritinPre-HCT (≤ 669 vs > 669 ng/mL). Compared to the low ferritinPost-HCT group, the high ferritinPost-HCT group had lower 3-year overall survival (OS) (40.0% vs 66.7%, p < 0.001) and higher non-relapse mortality (NRM) (48.6% vs 17.8%, p < 0.001), but no difference in relapse (10.5% vs 19.7%, p = 0.079). Multivariate analysis confirmed ferritinPost-HCT as an independent prognostic factor for OS (p = 0.001, HR = 2.323) and NRM (p < 0.001, HR = 3.905). However, ferritinPre-HCT did not stratify well for OS or NRM. FerritinPost-HCT was also found to be an independent prognostic marker for OS and NRM in the subgroups which developed GVHD. In our cohort, high ferritinPost-HCT levels were significantly associated with decreased OS and increased NRM independent of ferritinPre-HCT or GVHD. Additional studies including larger sample sizes and prospective investigation are warranted to clarify the prognostic significance and pathophysiology of pre- and post-transplant hyperferritinemia.

Moderate-severe grade of chronic graft versus host disease and younger age (less than 45 years old) are risk factors for avascular necrosis in adult patients undergoing allogeneic hematopoietic cell transplantation.

Avascular necrosis (AVN) is a debilitating complication of allogeneic hematopoietic cell transplantation (HCT). A retrospective review of 845 patients who underwent HCT was conducted. Cumulative incidence of AVN was 6.3% at 4 years. The following risk factors were significantly associated with AVN risk on univariate analysis: age < 45 (p=0.004), moderate to severe chronic GvHD (p<0.001), reduced intensity conditioning (p=0.02), and a diagnosis of acute leukemia (p=0.045). Multivariate analysis confirmed two risk factors: younger age (<45 years), 9.0% vs 4.4% (p=0.011, hazard ratio (HR) 2.134), and moderate-severe chronic GvHD, 15.4% vs 2.1% (p<0.001, HR 4.950). A risk score model was generated assigning a score to each risk factor. A score of 1 was assigned to moderate-severe GvHD or those with age <45. Total score was calculated, thus dividing patient into three groups: low (score 0, n=349, 41.3%), intermediate (score 1, n=379, 44.9%), and high risk (score 2; n=116, 13.7%). This risk score could stratify the patients according to AVN risk (p<0.001). The risk of AVN was 1.5% in the low risk, 6.2% in the intermediate risk, and 20.8% in the high risk groups. Moderate-severe chronic GvHD and younger age (<45 years) are key risk factors for AVN following allogeneic HCT.

Comorbidity profile of adult survivors at 20 years following allogeneic hematopoietic cell transplantation.

Numerous chronic medical conditions and complications can arise following allogeneic hematopoietic cell transplantation (HCT) that may have a negative impact on survival and quality of life. OBJECTIVE: The purpose of the present study was to review the comorbidities of a single-center cohort of allogeneic HCT recipients that survived 20 years postallogeneic transplantation. METHODS: We retrospectively investigated 172 patients that underwent allogeneic HCT at the Princess Margaret Cancer Centre between 1979 and 1998 and who survived at least 20 years post-HCT. RESULTS: The most frequent individual comorbidities documented were dyslipidemia (29%), hypertension (31%), osteoporosis (15%), hypothyroidism (15%), and depression/anxiety (13%). Follow-up data following the 20-year mark were available for 135 patients, overall survival (OS) of that group at 5 and 10 years was 94% and 90%, respectively. When grouped by the number of concurrent comorbidities, there was a significant difference in OS between the groups with 0-1, 2-3, and ≥4 comorbidities (P = .01). CONCLUSIONS: Evidently, long-term allogeneic HCT recipients may develop a number of comorbidities that negatively influence survival even past the 20-year post-transplant mark. These findings warrant the continuous long-term medical follow-up of allogeneic transplant patients, regardless of age or time that has lapsed post-HCT.