Outcomes of Antithymocyte Globulin-Post-Transplantation Cyclophosphamide-Cyclosporine-Based versus Antithymocyte Globulin-Based Prophylaxis for 10/10 HLA-Matched Unrelated Donor Allogeneic Hematopoietic Cell Transplantation

In 2015, dual T cell depletion with antithymocyte globulin (ATG) and post-transplantation cyclophosphamide (PTCy) combined with cyclosporine A (CsA) replaced our prior institutional graft-versus-host disease (GVHD) prophylaxis regimen of 4.5 mg/kg ATG, CsA, and mycophenolate mofetil (MMF) (ATG-based) in 10/10 HLA-matched unrelated donor (MUD) peripheral blood allogeneic hematopoietic stem cell transplantation (allo-HCT). The initial ATG dose of 4.5 mg/kg [ATG(4.5)/PTCy] was reduced to 2 mg/kg [ATG(2)/PTCy] in 2018. This study compares the results obtained from 444 adults undergoing MUD allo-HCT at our institution who received ATG(4.5)/PTCy (n = 127) or ATG(2)/PTCy (n = 223) with those who received ATG-based prophylaxis without PTCy (n = 84). The rates of grade II-IV and grade III-IV acute GVHD (aGVHD) at day +100 and moderate/severe chronic GVHD (cGVHD) at 1 year were 35.7%, 21.6%, and 14.7%, respectively, in patients receiving ATG-based prophylaxis without PTCy; 16.5%, 4.9%, and 4.3% in patients receiving ATG(4.5)/PTCy; and 23.3% (P = .004), 8.0% (P < .001), and 14.1% (P =.006) in patients receiving ATG(2)/PTCy. One-year overall survival (OS), nonrelapse mortality (NRM), and GVHD-free relapse-free survival (GRFS) were 69.8%, 25.3%, and 52.0%, respectively, for patients receiving ATG-based prophylaxis without PTCy; 82.7%, 17.3%, and 59.8% for patients receiving ATG(4.5)/PTCy; and 78.3% (P = .446), 14.7% (P = 101), and 56.2% (P = .448) for patients receiving ATG(2)/PTCy. On univariate analyses, the use of ATG(2)/PTCy was associated with a lower risk of NRM (hazard ratio, .54; P = .023) compared with the use of ATG-based prophylaxis without PTCy. ATG(2)/PTCy prophylaxis effectively prevents GVHD and is associated with comparable relapse risk, OS, and GRFS as seen with ATG(4.5)/PTCy and ATG-based prophylaxis without PTCy.

Pretransplant Blinatumomab Improves Outcomes in B Cell Acute Lymphoblastic Leukemia Patients Who Undergo Allogeneic Hematopoietic Cell Transplantation

BACKGROUND

Blinatumomab, a bispecific monoclonal antibody, effectively controls refractory B cell acute lymphoblastic leukemia (ALL) and promotes measurable residual disease (MRD) negativity. This study investigated the impact of pretransplant blinatumomab on allogeneic hematopoietic cell transplantation (HCT) outcomes in B cell ALL patients.

METHODS

We analyzed the effect of pretransplant blinatumomab on transplant outcomes of 117 adults undergoing allogeneic HCT for B cell ALL at Princess Margaret Hospital, Toronto, between 2010 and 2021. Outcomes assessed included overall survival (OS), graft-versus-host disease and relapse-free survival (GRFS), cumulative incidences of relapse (CIR), and nonrelapse mortality (NRM).

RESULTS

The median follow-up was 36 months. Thirty-one participants (26.5%) received blinatumomab. Blinatumomab group had higher proportions of individuals with high disease risk index, primary induction failure and was more likely to receive dual T cell depletion with antithymocyte globulin and post-transplant cyclophosphamide. Two-year OS, GRFS, NRM, and CIR in the blinatumomab and nonblinatumomab groups were, respectively: 65.4% versus 45.6% (P = .05), 42.2% versus 17.3% (P = .01), 3.2% versus 43.0% (P = .007) and 34.4% versus 14.4% (P = .02). Blinatumomab was associated with a lower incidence of day-100 grade 2 to 4 and grade 3 to 4 acute graft-versus-host disease (aGVHD): 27.5% versus 56.7% (P = .009), and 10.9% versus 34.7% (P = .04), respectively. Multivariate analysis confirmed the association between pretransplant blinatumomab and improved OS and NRM.

CONCLUSIONS

Pretransplant blinatumomab is associated with improved OS and lower risk of NRM in B cell ALL patients undergoing allogeneic HCT, likely reflecting lower burden of treatment-related toxicity in this population. Larger prospective trials are warranted to validate our findings.

Treosulfan- Versus Busulfan-based Conditioning in Allogeneic Hematopoietic Cell Transplantation for Myelodysplastic Syndrome: A Single-center Retrospective Propensity Score-matched Cohort Study

Treosulfan has shown promise in allogeneic hematopoietic cell transplantation (HCT) for its myeloablative properties and low toxicity. In this single-center retrospective propensity score-matched cohort study we compared treosulfan- and busulfan-based conditioning in allogeneic HCT for patients with myelodysplastic syndrome (MDS). This study included 138 adults who underwent allogeneic HCT for MDS or chronic myelomonocytic leukemia at Princess Margaret Hospital, Toronto, from 2015 to 2022. Using propensity score matching, we compared transplant outcomes between 2 well-matched cohorts who received conditioning with either fludarabine-treosulfan (FT) (n = 46) or fludarabine-busulfan with total body irradiation (FBT200) (n = 92). A scoring system based on patient age, Karnofsky performance score, and hematopoietic cell transplant comorbidity index was used to assign patients based on fitness to low-dose (30 g/m2) or high-dose (42 g/m2) treosulfan: 32 (69.6%) received high-dose treosulfan. The racial composition of the 2 groups was similar, with 27.2% and 21.7% of FBT200 and FT recipients, respectively, identifying as non-Caucasian (P = .61). Primary outcomes were analyzed at a median follow-up of 747 days. Of all participants, 116 (84.0%) received graft-versus-host disease (GVHD) prophylaxis with post-transplant cyclophosphamide (PTCY) and antithymocyte globulin (ATG). Patients who received FT had a superior 2-year overall survival (OS) compared to those who received FBT200: 66.9% (95% confidence interval (CI): 46.1 to 81.2) versus 44.5% (95% CI: 34 to 54.4), hazard ratio (HR): 0.43, 95% CI: 0.22 to 0.84 (P = .013). In multivariate analysis (MVA), only the use of fresh grafts (P = .02) and FT (P = .01) were associated with improved OS. FT was associated with superior 2-year relapse-free survival (RFS) compared to FBT200: 63.1% (95% CI: 42.6 to 77.9) versus 39.1% (95% CI: 29.1 to 49.1), HR: 0.44 (95% CI: 0.24 to 0.81), P = .008. In MVA, the use of fresh grafts (P = .03) and FT (P = .009) were associated with improved RFS. Recipients of FT demonstrated superior 2-year graft-versus-host disease relapse-free survival (GRFS) compared to those who received FBT200: 57.4% (95% CI: 37.8 to 72.8) versus 35.1% (95% CI: 25.5 to 45). In MVA, only FT was associated with superior GRFS (P = .02). FT recipients exhibited markedly superior 1-year event-free survival compared to recipients of FBT200 in univariate analysis (40.3% (95% CI: 25.9 to 54.2) versus 9.2% (95% CI: 4.4 to 16.3), HR: 0.47 (95% CI: 0.30 to 0.72), P < .001) and MVA (P = .004). FT was associated with lower 1-year nonrelapse mortality compared to FBT200 in univariate analysis (9.9% (95% CI: 3.0 to 21.8) versus 29.7% (95% CI: 20.6 to 39.3), HR: 0.41 (95% CI: 0.17 to 0.96), P = .04) and MVA (P = .04). Our study utilized propensity score matching to demonstrate superiority of treosulfan- over busulfan-based conditioning in stem cell transplantation of patients with MDS and is the first to evaluate the performance of treosulfan-based conditioning in combination with ATG and PTCY. As such, it contributes to the increasing body of evidence supporting the safety of treosulfan, even at the dose of 42 g/m2.

Flow cytometry-based measurable residual disease (MRD) analysis identifies AML patients who may benefit from allogeneic hematopoietic stem cell transplantation

Measurable residual disease (MRD) monitoring independently predicts long-term outcomes in patients with acute myeloid leukemia (AML). Of the various modalities available, multiparameter flow cytometry-based MRD analysis is widely used and relevant for patients without molecular targets. In the transplant (HCT) setting, the presence of MRD pre-HCT is associated with adverse outcomes. MRD-negative remission status pre-HCT was also associated with longer overall (OS) and progression-free survival and a lower risk of relapse. We hypothesize that the combination of disease risk and MRD at the time of first complete remission (CR1) could identify patients according to the benefit gained from HCT, especially for intermediate-risk patients. We performed a retrospective analysis comparing the outcomes of HCT versus non-HCT therapies based on MRD status in AML patients who achieved CR1. Time-dependent analysis was applied considering time-to-HCT as a time-dependent covariate and compared HCT versus non-HCT outcomes according to MRD status at CR1. Among 336 patients assessed at CR1, 35.1% were MRD positive (MRDpos) post-induction. MRDpos patients benefitted from HCT with improved OS and relapse-free survival (RFS), while no benefit was observed in MRDneg patients. In adverse-risk patients, HCT improved OS (HR for OS 0.55; p = 0.05). In intermediate-risk patients, HCT benefit was not significant for OS and RFS. Intermediate-risk MRDpos patients were found to have benefit from HCT with improved OS (HR 0.45, p = 0.04), RFS (HR 0.46, p = 0.02), and CIR (HR 0.41, p = 0.02). Our data underscore the benefit of HCT in adverse risk and MRDpos intermediate-risk AML patients.

Dual T cell depletion for graft versus host disease prevention in peripheral blood haploidentical hematopoietic cell transplantation for adults with hematological malignancies

The ideal immunosuppressive agents to complement post-transplant cyclophosphamide (PTCy) in PBSC-based haploidentical hematopoietic cell transplantation (haplo-HCT) remain debated. This study looks at our experience with ATG-PTCy-Cyclosporine (CsA) prophylaxis in PB haplo-HCT since 2015. Between October 2015 and December 2021, 157 adults underwent haploidentical hematopoietic cell transplantation (haplo-HCT) using a GVHD prophylaxis regimen comprising rabbit-ATG, PTCy, and CsA. Among these patients, 76.4% received a total ATG dose of 4.5 mg/kg, and 23.5% received 2 mg/kg. T-cell replete peripheral blood stem cell (PBSC) grafts were infused on day 0. The study reported a median follow-up of 32 months (range 0.3-61.64) for survivors. The cumulative incidence of grade II-IV and grade III-IV acute GVHD at day +100 was 26.3% and 9.5%, respectively. Moderate/severe chronic GVHD at 1 year was 19.9%. The 2-year overall survival (OS) was 49.4%, with a relapse-free survival (RFS) of 44.6%. In multivariate analysis, older patients, and those with high/very-high disease risk indices (DRI) were at higher risk for worse OS and higher non-relapse mortality (NRM). The study confirms that using PTCy and ATG (4.5 mg/kg), alongside CsA is safe and effective in preventing GVHD when using peripheral blood as the stem cell source in haploidentical hematopoietic cell transplantation (haplo-HCT).

CAR T cells and T cells phenotype and function are impacted by glucocorticoid exposure with different magnitude

BACKGROUND

Chimeric antigen receptor (CAR) T cell therapy is associated with high risk of adverse events. Glucocorticoids (GCs) are cornerstone in the management of high-grade cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). Given the potentially deleterious effects of GCs on CAR T cells anti-tumor activity, increasing our understanding of GCs impact on CAR T cells is crucial.

METHODS

Using several CAR T cells i.e., CD19, mesothelin (MSLN)-CD28 and MSLN-41BB CAR T cells (M28z and MBBz), we compared phenotypical, functional, changes and anti-tumor activity between i) transduced CD19 CAR T cells with untransduced T cells, ii) M28z with MBBz CAR T cells induced by Dexamethasone (Dx) or Methylprednisolone (MP) exposures.

RESULTS

Higher levels of GC receptor were found in less differentiated CAR T cells. Overall, Dx and MP showed a similar impact on CAR T cells. Compared to untreated condition, GCs exposure increased the expression of PD-1 and TIM-3 and reduced the expression of LAG3 and function of T cells and CAR T cells. GC exposures induced more exhausted (LAG3 + PD1 + TIM3 +) and dysfunctional (CD107a-INFγ-TNF-IL2-) untransduced T cells in comparison to CD19 CAR T cells. GC exposure impaired more CD4 + than CD8 + CD19 CAR T cells. GC exposures increased more PD-1 expression associated with reduced proliferative capacity and function of M28z as compared to MBBz CAR T cells. CAR T cells anti-tumor activity was greatly affected by repeated GC exposure but partly recovered within 48h after GCs withdrawal.

CONCLUSIONS

In summary, GCs impacted phenotype and function of untransduced and CAR T cell with different magnitude. The nature of the CAR costimulatory domain influenced the magnitude of CAR T cell response to GCs.

Real-world experience with ruxolitinib therapy for steroid-refractory acute graft versus host disease

Acute graft versus host disease (aGVHD) is a complication of allogeneic hematopoietic stem cell transplant (HCT) and is associated with significant morbidity and mortality. Steroid refractory aGVHD (SR-aGVHD) carries a particularly grim prognosis. Ruxolitinib has shown promise for treatment of SR-aGVHD in a phase 3 trial; however, safety and efficacy data outside of the clinical trial setting is lacking. We performed a multicenter retrospective study to examine the response to ruxolitinib and its efficacy in patients with SR-aGVHD. We included 59 patients treated with ruxolitinib for SR-aGVHD between 2015 and 2022. Of these 59 patients, 36 patients (61.0%) achieved a complete (CR) or partial response (PR) at 28 days, while 31 patients (52.5%) obtained a CR/PR at day 56. Patients that achieved a CR or PR at day 28 had a higher rate of overall survival (OS; 69.2%), compared with patients that did not (31.6%; p = 0.037). OS at 12 months was 41.5%, with a median OS duration of 5.3 months. Failure free survival (FFS) at 12 months was 29.1%, with a median FFS of 2.6 months. Overall, this real-world experience data support ruxolitinib as the standard of care for SR-aGVHD in a non-controlled trial population.

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.

Propensity Score Matching Analysis Comparing the Efficacy and Steroid Tapering Benefit of Extracorporeal Photopheresis to Best Available Therapy in Third-Line or Beyond Treatment for Chronic GvHD

Graft-versus host disease (GVHD) is one of the major limitations to allogeneic hematopoietic stem cell transplantation (HCT). Although corticosteroids with calcineurin inhibitors are established first line-therapy for chronic graft-versus-host disease (cGVHD), approximately one-half of cGVHD patients are refractory to corticosteroid therapy. The goal of the present study was to compare treatment outcomes of patients treated with extracorporeal photopheresis (ECP) and best available therapy (BAT) as third-line or beyond treatment for cGVHD. Using propensity score matching (PSM), treatment outcomes were compared between ECP-treated patients (n = 74) and a historical cohort of cGVHD patients treated with BAT (n = 132). By adjusting for unbalanced risk factors between the groups, including GVHD severity at the start of therapy, acute GVHD history, and baseline corticosteroid dose, 62 patients were balanced and selected for PSM. In the PSM cohort, the ECP group showed a 12-month failure-free survival (FFS) rate of 70.1% versus 32.5% in the BAT group (P < .0001; hazard rate [HR], .214), and 93.1% 12 months' overall survival (OS) rate of 93.1% versus 68.1% in the BAT group (P = .0249; HR, .3811); multivariate analysis confirmed ECP's superior FFS and OS compared with BAT. Generalized linear model analysis showed faster tapering of corticosteroids and higher rates of prednisone discontinuation in the ECP versus BAT PSM groups in the first 6 months. The ECP group also had a higher percentage of prednisone discontinuation, by 6% at month 0, by 14.9% at month 3, and by 22.5% at month 6. The current study demonstrates superior FFS, OS, and steroid tapering efficacy for ECP compared with BAT as third-line therapy or beyond in cGVHD patients.

Choosing Between Older Matched Sibling Donor and Younger Matched Unrelated Donor in Allogeneic Hematopoietic Cell Transplantation: Comparison of Clinical Outcomes in Acute Myeloid Leukemia and Myelodysplastic Syndrome

The choice between an older matched sibling donor (MSD) and a younger matched unrelated donor (MUD) in allogeneic hematopoietic cell transplantation (HCT) remains a subject of ongoing debate. In this single-center retrospective study of 377 patients who received peripheral blood stem cell (PBSC) transplants for acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS), we compared outcomes of 85 patients who received grafts from MSDs age >60 years and 292 patients who received grafts from MUDs age <30 years. Compared to recipients of MSD transplants, recipients of MUD transplants were younger and more likely to receive dual T cell depletion (TCD), a higher CD34+ cell dose, and a fresh graft. Recipients of MSD transplants were maintained on immunosuppressive therapy longer than those who received MUD grafts. We found no differences in overall survival, relapse-free survival, graft-versus-host disease (GVHD)-free and relapse-free survival, nonrelapse mortality, relapse, engraftment, graft failure, and acute GVHD between recipients of MSD grafts and recipients of MUD grafts. We report a higher 30-day incidence, but not 1-year incidence, of bloodstream infections among recipients of MUD transplants compared to subjects who received their grafts from a MSD. The incidence of moderate-severe chronic GVHD was higher in MSD graft recipients compared with MUD graft recipients in univariate analysis, but not in multivariate analysis. Although this difference could reflect the greater use of dual TCD, known to be associated with very low rates of chronic GVHD in MUD transplant recipients, the incidence of moderate-severe chronic GVHD was no different between MSD and MUD transplant recipients following propensity score matching, suggesting that other variables could be responsible. Taken together, our data suggest that in patients with AML or MDS who receive PBSC transplants, such factors as convenience, ease of access, and costs should be considered when selecting an older MSD over a younger MUD.

HCT frailty scale for younger and older adults undergoing allogeneic hematopoietic cell transplantation

The HCT Frailty Scale is an easy prognostic tool composed of (a) Clinical Frailty Scale; (b) Instrumental Activities of Daily Living; (c) Timed-up-and-Go test; (d) Grip Strength; (e) Self-Health Rated Questionnaire; (f) Falls tests; (g) Albumin and C-reactive protein levels. This scale was designed to classify allogeneic hematopoietic cell transplant (alloHCT) candidates into fit, pre-frail and frail groups, irrespective of age. This study evaluates the ability of this frailty classification to predict overall survival (OS) and non-relapse mortality (NRM) in adult patients of all ages, in a prospective sample of 298 patients transplanted between 2018 and 2020. At first consultation, 103 (34.6%) patients were fit, 148 (49.7%) pre-frail, and 47 (15.8%) were frail. The 2-year OS and NRM of the three groups were 82.9%, 67.4%, and 48.3% (P < 0.001), and 5.4%, 19.2%, and 37.7% (P < 0.001). For patients younger than 60 years (n = 174), the 2-year OS and NRM of fit, pre-frail, and frail groups were 88.4%, 69.3% and 53.1% (P = 0.002), and 5.8%, 22.8%, and 34.8% (P = 0.005), respectively; and in patients older than 60 (n = 124), OS and NRM were 75.5%, 63.8% and 41.4% (P = 0.006), and 4.9%, 16.4%, and 42.1% (P = 0.001). In conclusion, frailty predicted worse transplant outcomes in both younger and older adults.

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.

Single centre retrospective analysis of extracorporeal photopheresis (ECP) therapy in patients heavily pre-treated for chronic graft-versus-host disease (cGvHD) with steroid failure

BACKGROUND

Extracorporeal photopheresis (ECP) is recommended as a second- or later-line therapy for chronic GvHD (cGvHD). Benefits include reasonable response with avoidance of intense systemic immunosuppression, which can translate into lowering the risk of systemic toxicity and opportunistic infection.

METHODS

We evaluated 75 patients treated with ECP for cGvHD from 2007 to 2021 at Princess Margaret Cancer Centre, and analyzed overall response rate (ORR) and clinical benefit (CB) at 3, 6 and 12 months plus other long-term treatment outcomes.

RESULTS

With a median follow-up of 72 months, a gradual increase in ORR was noted over time: 21% (16 out of 75 patients), 57% (36/63) and 70% (32/46) at month 3, 6 and 12, respectively. Gradual increase in CB was also observed over time with CB rate of 23% (17/75), 62% (39/63), and 76% (35/46) at months 3, 6 and 12, respectively. A total of 27 failures (36%) were noted, due to: 1) ECP resistance requiring switch to other therapy (n = 14, 19%), 2) non-relapse mortality (n = 10, 13%), 3) relapse of primary disease (n = 1, 1%) or 4) ECP procedure-related complication (n = 1, 1%, line infection), with 20 deaths (27%) observed. Failure-free survival (FFS) and overall survival (OS) rates were 68.3% and 85.9% at 12 months, respectively. After starting ECP, the proportions of patients who completely discontinued steroids were 17%, 32%, and 64% at months 3, 6 and 12, respectively.

CONCLUSION

ECP is an effective treatment option for heavily pre-treated cGvHD patients.

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.

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.

Interaction Between High-Dose Intravenous Busulfan and Post-Transplantation Cyclophosphamide on Hemorrhagic Cystitis After Allogeneic Hematopoietic Cell Transplantation

This study investigates the incidence and predictors of hemorrhagic cystitis (HC) in 960 adults undergoing allo- hematopoietic stem cell transplantation. Two hundred fifty-two (26.5%) patients received myeloablative conditioning regimens, and 81.4% received high-dose intravenous busulfan (HD Bu). Six hundred ninety-five (72.4%) patients received post-transplantation cyclophosphamide (PTCY)-based prophylaxis, and 91.4% additionally received anti-thymocyte globulin (ATG) and Cyclosporine A (CsA) (PTCY-ATG-CsA). Two hundred twenty-eight (23.8%) patients developed HC. The day 100 cumulative incidences of grades 2-4 and 3-4 HC were 11.1% and 4.9%. BK virus was isolated in 58.3% of urinary samples. Using HD BU myeloablative regimens increased the risk for grade 2-4 HC (hazard ratio [HR] = 1.97, P = .035), and HD BU combined with ATG-PTCY-CsA increased this 4 times (HR = 4.06, P < .001) for grade 2-4 HC compared to patients who received neither of these drugs. A significant correlation was documented between grade II-IV acute graft-versus-host disease and grade 2-4 HC (HR = 2.10, P < .001). Moreover, patients with BK-POS grade 2-4 HC had lower 1-year overall survival (HR = 1.51, P = .009) and higher non-relapse mortality (HR = 2.31, P < .001), and patients with BK-NEG grade 2-4 HC had comparable post-transplantation outcomes. In conclusion, intravenous HD Bu was identified as a predictor for grade 2-4 HC. Moreover, when HD Bu was combined with PTCY-ATG-CsA, the risk increased 4-fold. Based on the results provided by this study, preventing the onset of HC, especially in high-risk patients, is mandatory because its presence significantly increases the risk for mortality.

Propensity score matching analysis comparing the efficacy of Ruxolitinib to historical controls in second-line or beyond treatment for chronic GvHD after steroid failure

Established first-line therapy for chronic graft-versus-host disease (cGvHD) comprises corticosteroids with/without calcineurin inhibitors, but about half of cGvHD patients are refractory to corticosteroid therapy. The present study retrospectively analyzed treatment outcomes in 426 patients and undertook a propensity-score matching (PSM) analysis between ruxolitinib (RUX) treated group and a historical group of cGvHD patients treated with best available treatment (BAT). PSM process adjusted unbalanced risk factors between the 2 groups, including GvHD severity, HCT-CI score, and treatment line, extracting 88 patients (44 in BAT/RUX groups each) for final analysis. In PSM subgroup, RUX group showed 74.7% 12 months' FFS rate vs 19.1% for BAT group (p < 0.001), whereas 12 months' OS rates were 89.2% and 77.7%, respectively. Multivariate analysis for FFS confirmed RUX superiority over BAT together with HCT-CI score 0-2 vs ≥3. For OS, RUX was superior to BAT, while age ≥60 years and severe grade cGvHD adversely impacted OS. In PSM subgroup, at months 0, 3, and 6, 4.5%, 12.2% and 22.2% more patients in RUX group could discontinue prednisone compared to BAT group, respectively. In conclusion, the current study showed that for FFS, RUX was superior to BAT as second-line therapy or beyond in cGvHD patients after therapy failure.

A Single-center, Real-world Experience of Chronic GVHD Treatment Using Ibrutinib, Imatinib, and Ruxolitinib and its Treatment Outcomes

BACKGROUND

Chronic graft-versus-host disease (cGVHD) is a common cause of morbidity and mortality following allogeneic hematopoietic stem cell transplantation. Tyrosine kinase inhibitors (TKIs), including ruxolitinib, imatinib, and ibrutinib, have shown promising efficacy in cGVHD treatment.

METHOD

A total of 43 patients who developed cGVHD and received at least one line of TKI therapy for cGVHD treatment were evaluated retrospectively. The overall response, clinical benefit (CB), corticosteroid dose reduction, failure-free survival (FFS), and overall survival (OS) were assessed.

RESULT

A total of 62 lines of TKI therapy were evaluated, including ruxolitinib (n = 18), ibrutinib (n = 13), and imatinib (n = 31). With a 12-month median follow-up duration, 19/58 (32.8%), 20/41 (48.7%), and 17/29 (58.6%) responded to TKI therapy at 3, 6, and 12 months, respectively. The CB was observed in 80% of patients over time, allowing prednisone dose reduction in all 3 TKIs. The FFS rate at 12 months was higher in the imatinib (71%) and ruxolitinib groups (67%) than in the ibrutinib group (46%), while the OS rate at 12 months was similar among the three groups at 96%-100% in patients. In the sclerotic GVHD patient subgroup (n = 39), the overall response rate gradually increased over time. Ruxolitinib appeared to be as effective as imatinib and gradually improved the photographic range of motion score in sclerotic GVHD patients.

CONCLUSION

TKI drugs ruxolitinib, imatinib, and Ibrutinib are effective and feasible for cGVHD treatment. Ruxolitinib is as effective as imatinib for sclerotic GVHD.

Post-transplant maintenance therapy in acute myeloid leukemia after allogeneic hematopoietic stem cell transplantation harmonizing multiple therapeutic modalities including targeted therapy, immunotherapy and cellular therapy

Allogeneic hematopoietic stem cell transplant (HCT) has improved survival for patients with acute myeloid leukemia (AML), especially for those at high risk of relapse. However, relapse remains the leading cause of treatment failure post-HCT, occurring in around 35-45% of patients, and leading to dismal outcomes. Strategies to reduce relapse risk are urgently needed, especially in the early post-transplant period before activation of the graft-versus-leukemia (GVL) effect. Maintenance therapy is a course of treatment given post-HCT with the expectation of reducing relapse risk. While there are currently no therapies approved for maintenance therapy for AML after HCT, there are a number of studies and ongoing investigations examining the role of maintenance therapies that include targeted agents against FLT3-ITD, BCL2, or IDH mutations, hypomethylating agents, immunomodulatory therapies and cellular therapies. In this review, we discuss the mechanistic and clinical data for post-transplant maintenance therapies in AML and strategies for maintenance therapy for AML after HCT.

Allogeneic stem cell transplantation in adults 2015-21

BACKGROUND

Allogeneic stem cell transplantation is the only curative treatment for several malignant and non-malignant haematological diseases, and is associated with a risk of serious complications. In recent years, several changes have been introduced with the aim of reducing treatment-related complications. This retrospective study reviews quality indicators for patients who underwent transplantation in the period 2015-21.

MATERIAL AND METHOD

The study included 589 adult patients who were treated with allogeneic stem cell transplantation for the first time at Oslo University Hospital in the period May 2015 to May 2021. Three two-year periods are compared using descriptive methods.

RESULTS

In the period 2015-2021, the number of first-time transplant patients per year increased from 85 to 113. One-year survival increased from 68 % in the first two-year period to 74 % in the second period and 82 % in the last period. Both acute and chronic GVHD were reduced, and one-year GVHD-free and relapse-free survival increased from 42 % to 60 % during the study period.

INTERPRETATION

Since 2015, the number of transplants has increased, while survival has improved and the risk of complications is lower.

Impact of hematopoietic cell transplant frailty scale on transplant outcome in adults

This prospective study designs an HCT Frailty Scale to classify alloHCT candidates into groups of frail, pre-frail, and fit, and to be implemented in the first consultation at no additional cost. The present scale is composed of the following eight variables: Clinical Frailty Scale, Instrumental Activities of Daily Living, Timed Up and Go Test, Grip Strength, Self-Health Rated, Falls, Albumin, and C-Reactive Protein. The Frailty score of a patient is the weighted sum of scores for each item, with weights assigned according to the hazard ratios of a multivariable Cox proportional hazards model estimated and validated with data on OS as the dependent variable, and the scores of the eight variables as explanatory ones, from 298 adults split into training (n = 200) and validation (n = 98) sets. For clinical use, the scale scores were transformed into three categories: scale score ≤1: fit; 1<scale score ≤5.5: pre-frail; scale score >5.5 frail. The estimated probabilities of 1-year OS in each group of frailty, were, respectively: 83.7%, 48.5%, and 16.5% (p < 0.001). In the validation cohort, the respective values were 90.3%, 69.5%, and 46.2% (p < 0.001). Pending further external validations, the HCT Frailty Scale is a low cost-highly informative prognostic signal of outcomes at the pre-transplant stage.

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 NPM1^mut /FLT3-ITD^wt 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.

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

Donor clonal hematopoiesis may be transferred to the recipient through allogeneic hematopoietic stem cell transplantation (HCT), but the potential for adverse long-term impact on transplant outcomes remains unknown. A total of 744 samples from 372 recipients who received HCT and the corresponding donors were included. Bar-coded error-corrected sequencing using a modified molecular inversion probe capture protocol was performed, which targeted 34 genes covering mutations involved in clonal hematopoiesis with indeterminate potential (CHIP) and other AML-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-vs-host disease (p=0.220). No significant difference was noted for secondary malignancy following HCT between the two groups. The present study suggests that the presence of CHIP in allogeneic stem donors does not adversely affect transplant outcomes after HCT. 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 pre-transplant evaluation of donors prior to stem cell donation.

Tuned activation of MSLN-CAR T cells induces superior antitumor responses in ovarian cancer models

BACKGROUND

Limited persistence of functional CAR T cells in the immunosuppressive solid tumor microenvironment remains a major hurdle in the successful translation of CAR T cell therapy to treat solid tumors. Fine-tuning of CAR T cell activation by mutating CD3ζ chain immunoreceptor tyrosine-based activation motifs (ITAMs) in CD19-CAR T cells (containing the CD28 costimulatory domain) has proven to extend functional CAR T cell persistence in preclinical models of B cell malignancies.

METHODS

In this study, two conventional second-generation MSLN-CAR T cell constructs encoding for either a CD28 co-stimulatory (M28z) or 4-1BB costimulatory (MBBz) domain and a novel mesothelin (MSLN)-directed CAR T cell construct encoding for the CD28 costimulatory domain and CD3ζ chain containing a single ITAM (M1xx) were evaluated using in vitro and in vivo preclinical models of ovarian cancer. Two ovarian cancer cell lines and two orthotopic models of ovarian cancer in NSG mice were used: SKOV-3 cells inoculated through microsurgery in the ovary and to mimic a disseminated model of advanced ovarian cancer, OVCAR-4 cells injected intraperitoneally. MSLN-CAR T cell treatment efficacy was evaluated by survival analysis and the characterization and quantification of the different MSLN-CAR T cells were performed by flow cytometry, quantitative PCR and gene expression analysis.

RESULTS

M1xx CAR T cells elicited superior antitumor potency and persistence, as compared with the conventional second generation M28z and MBBz CAR T cells. Ex vivo M28z and MBBz CAR T cells displayed a more exhausted phenotype than M1xx CAR T cells as determined by co-expression of PD-1, LAG-3 and TIM-3. Furthermore, M1xx CAR T cells showed superior ex vivo IFNy, TNF and GzB production and were characterized by a self-renewal gene signature.

CONCLUSIONS

Altogether, our study demonstrates the enhanced therapeutic potential of MSLN-CAR T cells expressing a mutated CD3ζ chain containing a single ITAM for the treatment of ovarian cancer. CAR T cells armored with calibrated activation potential may improve the clinical responses in solid tumors.

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.

Population-based real-world registry study to evaluate clinical outcomes of chronic graft-versus-host disease

INTRODUCTION

Chronic graft-versus-host disease (cGVHD) is a serious immune-mediated complication after allogeneic haematopoietic stem cell transplantation (HSCT), but in patients with malignancy, cGVHD development is associated with superior survival. Lack of reliable biomarkers and clinical underreporting means there is insufficient understanding of cGVHD clinical outcomes and balance between cGVHD treatment and maintaining beneficial graft-versus-tumour effects.

METHODS

We performed a Swedish population-wide registry study following patients who underwent allogeneic HSCT 2006-2015. cGVHD status was retrospectively classified using a real-world method based on the timing and extent of systemic immunosuppressive treatment.

RESULTS

cGVHD incidence among patients surviving ≥6 months post-HSCT (n = 1246) was 71.9%, significantly higher than previously reported. 5-year overall survival in patients surviving ≥6 months post-HSCT was 67.7%, 63.3%, and 65.3%, in non-, mild, and moderate-severe cGVHD, respectively. Non-cGVHD patients had a mortality risk almost five-fold higher compared to moderate-severe cGVHD patients 12-months post-HSCT. Moderate-severe cGVHD patients had greater healthcare utilization compared with mild and non cGVHD patients.

CONCLUSION

cGVHD incidence was high among HSCT survivors. Non-cGVHD patients had higher mortality during the first 6 months of follow-up; however, moderate-severe cGVHD patients had more comorbidities and healthcare utilization. This study highlights the urgent need for new treatments and real-time methods to monitor effective immunosuppression after HSCT.

A longitudinal multidimensional rehabilitation program for patients undergoing allogeneic blood and marrow transplantation (CaRE-4-alloBMT): Protocol for a phase II feasibility pilot randomized controlled trial

BACKGROUND

Allogeneic blood and marrow transplantation (alloBMT) is a curative treatment for blood cancers associated with various treatment-related adverse events and morbidities. Current rehabilitation programs are limited for patients undergoing alloBMT and research is urgently needed to test the acceptability and effectiveness of these programs. In response, we developed a 6-month multidimensional longitudinal rehabilitation program that spans from pre transplant to 3 months post transplant discharge (CaRE-4-alloBMT).

METHODS

This study is a phase II randomized controlled trial (RCT) conducted at the Princess Margaret Cancer Centre in patients undergoing alloBMT. A total of 80 patients stratified by frailty score will be randomized to receive usual care (n = 40) or CaRE-4-alloBMT plus usual care (n = 40). The CaRE-4-alloBMT program includes individualized exercise prescriptions, access to online education through a dedicated self-management platform, wearable technology for remote monitoring, and remote tailored clinical support. Feasibility will be assessed by examining the recruitment and retention rates and adherence to the intervention. Safety events will be monitored. Acceptability of the intervention will be assessed through qualitative interviews. Secondary clinical outcomes will be collected through questionnaires and physiological assessments at baseline (T0, 2-6 weeks pre-transplant), transplant hospital admission (T1), hospital discharge (T2), and 3 months post-discharge (T3).

CONCLUSION

This pilot RCT study will determine the feasibility and acceptability of the intervention and study design and will inform full-scale RCT planning.

Molecular, cellular and systemic aspects of epithelial ovarian cancer and its tumor microenvironment

Ovarian cancer encompasses a heterogeneous group of malignancies that involve the ovaries, fallopian tubes and the peritoneal cavity. Despite major advances made within the field of cancer, the majority of patients with ovarian cancer are still being diagnosed at an advanced stage of the disease due to lack of effective screening tools. The overall survival of these patients has, therefore, not substantially improved over the past decades. Most patients undergo debulking surgery and treatment with chemotherapy, but often micrometastases remain and acquire resistance to the therapy, eventually leading to disease recurrence. Here, we summarize the current knowledge in epithelial ovarian cancer development and metastatic progression. For the most common subtypes, we focus further on the properties and functions of the immunosuppressive tumor microenvironment, including the extracellular matrix. Current and future treatment modalities are discussed and finally we provide an overview of the different experimental models used to develop novel therapies.

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 patient.

RESULTS

2-year OS was 51% (95%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 to 64, or ≥65, respectively, and 0 to 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 predicts 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. This article is protected by copyright. All rights reserved.

The 17‐gene stemness score associates with relapse risk and long‐term outcomes following allogeneic haematopoietic cell transplantation in acute myeloid leukaemia

A 17‐gene stemness (LSC17) score determines risk in acute myeloid leukaemia patients treated with standard chemotherapy regimens. The present study further analysed the impact of the LSC17 score at diagnosis on outcomes following allogeneic haematopoietic cell transplantation (HCT). Out of 452 patients with available LSC17 score, 123 patients received allogeneic HCT. Transplant outcomes, including overall (OS), leukaemia‐free survival (LFS), relapse incidence (RI) and non‐relapse mortality (NRM), were compared according to the LSC17 scored group. The patients with a low LSC17 score had higher OS (56.2%) and LFS (54.4%) at 2 years compared to patients with high LSC17 score (47.2%, p = 0.0237 for OS and 46.0%, p = 0.0181 for LFS). The low LSC17 score group also had a lower relapse rate at 2 years (12.7%) compared to 25.3% in the high LSC17 score group (p = 0.017), but no difference in NRM (p = 0.674). Worse outcomes in the high LSC17 score group for OS, LFS and relapse were consistently observed across all stratified sub‐groups. The use of more intensive conditioning did not improve outcomes for either group. In contrast, chronic graft‐versus‐host‐disease was associated with more favourable outcomes in both groups. The 17‐gene stemness score is highly prognostic for survival and relapse risk following allogeneic HCT.

Trogocytosis and fratricide killing impede MSLN-directed CAR T cell functionality

Successful translation of chimeric antigen receptor (CAR) T cell therapy for the treatment of solid tumors has proved to be troublesome, mainly due to the complex tumor microenvironment promoting T cell dysfunction and antigen heterogeneity. Mesothelin (MSLN) has emerged as an attractive target for CAR T cell therapy of several solid malignancies, including ovarian cancer. To improve clinical response rates with MSLN-CAR T cells, a better understanding of the mechanisms impacting CAR T cell functionality in vitro is crucial. Here, we demonstrated superior cytolytic capacity of CD28-costimulated MSLN-CAR T cells (M28z) relative to 4–1BB-costimulated MSLN-CAR T cells (MBBz). Furthermore, CD28-costimulated MSLN CAR T cells displayed enhanced cytolytic capacity against tumor spheroids with heterogeneous MSLN expression compared to MBBz CAR T cells. In this study, we identified CAR-mediated trogocytosis as a potential impeding factor for successful MSLN-CAR T cell therapy due to fratricide killing and contributing to tumor antigen heterogeneity. Moreover, we link antigen-dependent upregulation of LAG-3 with reduced CAR T cell functionality. Taken together, our study highlights the therapeutic potential and bottlenecks of MSLN-CAR T cells, providing a rationale for combinatorial treatment strategies.

Acute kidney injury within 100 days post allogeneic hematopoietic cell transplantation is associated with increased risk of post-transplant complications and poor transplant outcomes

Allogeneic hematopoietic cell transplantation (HCT) offers cure for some patients with hematological diseases but is associated with significant risk of morbidity and mortality. We investigated the incidence of AKI and its impact on transplant outcomes among 408 patients transplanted at Princess Margaret Hospital Cancer Centre, Toronto, Canada. The overall incidence of AKI at 100 days was 64.2%. Compared to those with no AKI, patients who developed AKI had inferior 2-y overall survival (OS), 44.7% vs. 62.4% (P = 0.0004), higher 2-y transplant related mortality (TRM) 36.8% vs. 18.7% (P = 0.0003), lower 2-y graft-vs-host disease (GVHD)- and relapse-free survival (GRFS), 21.0% vs. 39.8% (P = 0.0002), and higher 100-day grade 3-4 acute GVHD (aGVHD), 12.4% vs. 6.3% (P = 0.01). There was no difference in 2-y incidence of relapse between the AKI and non-AKI groups, 24.2% vs. 24.3% (P = 0.84), 100-day grade 2-4 aGVHD, 27.7% vs. 25.7 (P = 0.41) or 2-y moderate-severe chronic GVHD, 24.0% vs. 21.6% (P = 0.79). Patients who develop AKI within 100 days of HCT have inferior OS and GRFS with higher rates of TRM and grade 3-4 aGVHD. These results highlight the importance of close monitoring of renal function, multidisciplinary collaboration, and implementation of protective strategies throughout HCT to optimize transplant and kidney outcomes.

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 HLA alleles and the risk of cytomegalovirus (CMV) reactivation following allogeneic HSCT (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 was available for recipient and donor. 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% CI 50.8%-59.2%). Mismatched donor, increasing recipient age, occurrence of AGVHD and recipient CMV seropositivity were associated with increased risk of CMV reactivation. HLA B*07:02 (HR 0.59, 95% CI 0.40-0.83) was associated with 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) compared to 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 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 transplant related mortality. This article is protected by copyright. All rights reserved.

Targeting of Nrf2 improves antitumoral responses by human NK cells, TIL and CAR T cells during oxidative stress

Background

Adoptive cell therapy using cytotoxic lymphocytes is an efficient immunotherapy against solid and hematological cancers. However, elevated levels of reactive oxygen species (ROS) in the hostile tumor microenvironment can impair NK cell and T cell function. Auranofin, a gold (I)-containing phosphine compound, is a strong activator of the transcription factor Nrf2. Nrf2 controls a wide range of downstream targets important for the cells to obtain increased resistance to ROS. In this study, we present a strategy using auranofin to render human cytotoxic lymphocytes resistant toward oxidative stress.

Methods

Melanoma patient-derived tumor infiltrating lymphocytes (TIL) and healthy donor-derived NK cells and CD19-directed CAR T cells were pretreated with a low dose of auranofin. Their resistance toward oxidative stress was assessed by measuring antitumoral responses (killing-assay, degranulation/CD107a, cytokine production) and intracellular ROS levels (flow cytometry) in conditions of oxidative stress. To confirm that the effects were Nrf2 dependent, the transcription level of Nrf2-driven target genes was analyzed by qPCR.

Results

Pretreatment of human TIL and NK cells ex vivo with a low-dose auranofin significantly lowered their accumulation of intracellular ROS and preserved their antitumoral activity despite high H₂O₂ levels or monocyte-derived ROS. Furthermore, auranofin pretreatment of CD19 CAR-T cells or TIL increased their elimination of CD19 +tumor cells or autologous tumor spheroids, respectively, especially during ROS exposure. Analysis of Nrf2-driven target genes revealed that the increased resistance against ROS was Nrf2 dependent.

Conclusion

These novel findings suggest that Nrf2 activation in human cytotoxic lymphocytes could be used to enhance the efficacy of adoptive cell therapy.

Comparison of Outcomes After Second Allogeneic Hematopoietic Cell Transplantation Versus Donor Lymphocyte Infusion in Allogeneic Hematopoietic Cell Transplant Patients

BACKGROUND

Allogeneic hematopoietic cell transplantation (HCT) is potentially curative for hematological disease however can be complicated by relapse or graft failure (GF), for which second-HCT and donor lymphocyte infusions (DLI) are performed. This study aimed to compare outcomes following the two interventions.

METHODS

We retrospectively investigated 89 patients with relapse or GF after first-HCT, 50 (56%) underwent second HCT and 39 (44%) received (DLI), from June 2011 to September 2020.

RESULTS

Median age at intervention was 55 years (19-72). Second-HCT was performed for relapse in 19 patients and for GF in 31 patients (primary GF in 11 and secondary in 20 patients), same donor was used in 25 (50%) patients. DLI was performed for relapse in 20 and for secondary GF in 19 patients. Median number of DLI administered was 2 (range 1-11). Univariate analysis demonstrated 2 year overall survival (OS) for second-HCT was superior when performed for relapse (65%) compared to GF (44%) (P = .03). For DLI patients, 2 year OS was 49% for GF and 45% for relapse patients (P = .49). For relapse as an indication, second-HCT demonstrated borderline superiority compared to DLI (P = .07). Multivariable analysis demonstrated for OS for the entire cohort demonstrated donor mismatch (HR 0.50, 95% CI 0.26%-0.94%, P = .03), KPS at time of intervention (HR 2.10, 95% CI 1.14%-3.85%, P = .02) and time from first-HCT to intervention (HR 0.51, 95% CI 0.28%-0.93%, P = .03) as significant variables.

CONCLUSION

Second-HCT may improve outcomes when performed for relapse post-transplant if patients achieve remission again, while DLI may be reserved for patients with active disease.

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.

Chronic kidney disease, survival and graft-versus-host-disease/relapse-free survival in recipients of allogeneic hematopoietic stem cell transplant

Background

Advances in allogeneic hematopoietic stem cell transplant (HSCT) have increased patient survival, although substantial treatment-related toxicity remains, including chronic kidney disease (CKD). We assessed the association between CKD and survival and transplant-specific outcomes in HSCT recipients.

Methods

We conducted a retrospective study of all 408 adult patients with allogenic HSCT at Princess Margaret Cancer Centre (Toronto, Canada, 2015–18). We used logistic regression to identify risk factors for CKD at 1 year post-transplant. Associations between CKD at 1 year and overall survival, relapse-free survival, graft-versus-host-disease (GVHD)-free/relapse-free survival, relapse and transplant-related mortality were examined using extended time-varying Cox models. In a sensitivity analysis, we restricted the cohort to survivors at 1 year, using standard Cox proportional hazard models to examine associations between CKD and overall survival, relapse-free survival and GVHD-free/relapse-free survival, and Fine and Gray's competing risk models to determine associations between CKD and relapse/transplant-related mortality.

Results

The prevalence of CKD at 1 year was 19% (46 patients) with median follow-up of 23 months. Multivariable regression identified age at transplant [adjusted OR (aOR) 1.09, 95% confidence interval (95% CI) = 1.05–1.14; P < 0.0001), female gender (aOR 2.83, 95% CI = 1.34–5.97; P = 0.006) and acute kidney injury during the first 100 days (aOR 3.86, 95% CI = 1.70–8.73; P = 0.001) as risk factors for CKD at 1 year. Patients with CKD at 1 year had significantly poorer overall survival than those without CKD, when adjusted for relevant covariates [adjusted HR (aHR) 1.93, 95% CI = 1.02–3.66; P = 0.04 in the time-varying Cox model, and aHR 2.06, 95% CI = 1.04–4.07; P = 0.04 using the standard Cox model]. CKD at 1 year was also associated with worse GVHD-free/relapse-free survival (aHR 1.65, 95% CI = 1.04–2.61; P = 0.03).

Conclusions

CKD adversely affects the long-term prognosis for allogeneic HSCT recipients, with increased mortality risk and worse GVHD-free/relapse-free survival.

A novel CD34-specific T-cell engager efficiently depletes acute myeloid leukemia and leukemic stem cells in vitro and in vivo

Less than a third of patients with acute myeloid leukemia (AML) are cured by chemotherapy and/or hematopoietic stem cell transplantation, highlighting the need to develop more efficient drugs. The low efficacy of standard treatments is associated with inadequate depletion of CD34⁺ blasts and leukemic stem cells, the latter a drug-resistant subpopulation of leukemia cells characterized by the CD34⁺CD38^- phenotype. To target these drug-resistant primitive leukemic cells better, we have designed a CD34/CD3 bi-specific T-cell engager (BTE) and characterized its anti-leukemia potential in vitro, ex vivo and in vivo. Our results show that this CD34-specific BTE induces CD34-dependent T-cell activation and subsequent leukemia cell killing in a dose-dependent manner, further corroborated by enhanced T-cell-mediated killing at the singlecell level. Additionally, the BTE triggered efficient T-cell-mediated depletion of CD34⁺ hematopoietic stem cells from peripheral blood stem cell grafts and CD34⁺ blasts from AML patients. Using a humanized AML xenograft model, we confirmed that the CD34-specific BTE had in vivo efficacy by depleting CD34⁺ blasts and leukemic stem cells without side effects. Taken together, these data demonstrate that the CD34-specific BTE has robust antitumor effects, supporting development of a novel treatment modality with the aim of improving outcomes of patients with AML and myelodysplastic syndromes.

Intrathecal cytomegalovirus immunoglobulin for CMV encephalitis post allogeneic stem cell transplantation

We report the outcome of a 43 year old man who developed fatal ventriculoencephalitis due to cytomegalovirus (CMV) infection 7 months post allogeneic stem cell transplant. He failed multiple lines of treatment, including intravenous ganciclovir, foscarnet, and CMV-specific immunoglobulins, without improvement in CSF CMV copies. Novel intrathecal administration of CMV immunoglobulins was given but did not lead to clearance of CMV from CSF. No adverse effects related to intrathecal CMV immunoglobulins were observed. Notably, throughout this period, CMV in blood remained undetectable. This case highlights the difficulty in treating CMV encephalitis, and that novel therapeutic approaches are needed.

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.

Outcomes of patients diagnosed with chronic lymphocytic leukemia after allogeneic hematopoietic stem cell transplantation: Results from a tertiary care center

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (allo-HCT) is currently the only curative treatment for patients with chronic lymphocytic leukemia (CLL).

METHODS

We analyzed the outcomes of 93 patients (median age: 52 years) who underwent allo-HCT at our center between 1989 and 2019.

RESULTS

After a median follow-up of 35 months, relapse was observed in 15.1% (n = 14) patients. The estimated 2-year non-relapse mortality, relapse-free survival, and overall survival (OS) were 38.1%, 54.2%, and 58.7%, respectively. The ECOG performance status ≥ 2 (hazard ratio [HR]: 4.1; p = .001) and use of total body irradiation (in a myeloablative conditioning regimen; HR: 2.64; p = .005) were predictive of poor OS after multivariable analysis. The occurrence of sinusoidal obstruction syndrome/veno-occlusive disease post-transplant was associated with poor survival (p = .001).

CONCLUSION

Although the use of kinase and bcl2 inhibitors may result in a decrease in the number and need of transplants, allo-HCT remains a viable option in selected patients with high-risk CLL and good performance status.

Validation of a clinicopathological and gene expression profile model to identify patients with cutaneous melanoma where sentinel lymph node biopsy is unnecessary

BACKGROUND

In patients with cutaneous melanoma, sentinel lymph node biopsy (SLNB) serves as an important technique to asses disease stage and to guide adjuvant systemic therapy. A model using clinicopathologic and gene expression variables (CP-GEP; Merlin Assay) has recently been introduced to identify patients that may safely forgo SLNB. Herein we present data from an independent validation cohort of the CP-GEP model in Swedish patients.

METHODS

Archival histological material (primary melanoma tissue) from a prospectively collected cohort of 421 consecutive patients with pT1-T4 melanoma undergoing SLNB between 2006 and 2014 was analyzed using the CP-GEP model. CP-GEP combines Breslow thickness and patient age with the expression levels of eight genes from the primary melanoma. Stratification is based on their risk for nodal metastasis: CP-GEP Low Risk or CP-GEP High Risk.

RESULTS

The SLNB positivity rate was 13%. Of 421 primary melanomas, the CP-GEP model identified 86 patients as having a low risk for nodal metastasis. In patients with pT1-2 melanomas, the SLNB reduction rate was 35.4% (95% CI: 29.4-41.8) with a negative predictive value (NPV) of 96.5% (95% CI: 90.0-99.3). Among patients with pT1-3 melanomas, CP-GEP suggested a SLNB reduction rate of 24.0% (95% CI: 19.7-28.8) and a NPV of 96.5% (95% CI: 90.1-99.3). Only one of 118 pT3 tumors was classified as CP-GEP Low Risk, and all pT4 tumors were classified as being high risk for nodal metastasis.

CONCLUSION

This study demonstrates that CP-GEP can identify patients with a low risk for nodal metastasis. Patients with pT1-2 melanomas have the highest clinical benefit from using the test, where 35% of the patients could forgo a SLNB procedure.

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.

Lower dose of ATG combined with post-transplant cyclophosphamide for HLA matched RIC alloHCT is associated with effective control of GVHD and less viral infections

This study compares the outcomes before and after reducing the ATG dose from 4.5 to 2 mg/kg, in a combination of PTCy and CsA for GVHD prevention, in 250 patients treated with HLA matched RIC PB-alloHCT (70% received 4.5 mg/kg and 30% received 2 mg/kg). The incidences of grade II-IV and III-IV aGVHD at day +100, and moderate/severe cGVHD at 1-year were 12.6% vs. 20% (p = 0.431), 3.6% vs. 4.5% (p = 0.935), and 10.9% vs. 26.1% (p = 0.480), respectively. PTLD (9.1% vs. 1.3%, p = 0.026) and viral infections (30.3% vs. 12%; p = 0.001) were lower for those treated with 2 mg/kg of ATG. The reduction of the ATG dose resulted in a comparable OS (2-year: 64.7% vs. 64.7%), GRFS (2-year: 48.0% vs. 44.5%), RFS (2-year: 57.0% vs. 62.0%), and NRM (2-year: 17.8 vs. 14.9). The use of (2 mg/kg) ATG-PTCy-CsA for HLA matched RIC alloHCT results in lower viral infections, and incomparable GVHD preventive effect and survival rates.