Efficacy and safety of outpatient fludarabine, cyclophosphamide, and rituximab based allogeneic hematopoietic cell transplantation in adults with severe aplastic anemia.

The age effect in severe aplastic anemia (SAA) following allogeneic hematopoietic cell transplantation (HCT) favors the use of reduced intensity conditioning (RIC) regimens in older adults. We implemented a non-myeloablative regimen consisting of fludarabine, cyclophosphamide, and rituximab (FCR) to improve HCT outcomes in SAA. Patients who underwent first HCT for SAA utilizing an FCR regimen between January 2016 and May 2022 were included. Outcomes analyzed included time to engraftment, incidence of graft failure, GVHD, viral reactivation, disease recurrence, and GVHD-free, relapse-free survival (GRFS). Among 24 patients included, median age was 43.5 years (22-62) and a variety of donor types and stem cell sources were represented. At median follow-up of 26.9 months (2.4-72.7), no cases of grade III-IV acute (aGVHD) or severe chronic GVHD (cGVHD) were recorded. Viral reactivation was minimal, and there were no cases of graft failure or PTLD, with 100% disease-free and overall survival at last follow up. The estimate of 1-year GRFS was 86.3% (95% CI: 72.8-100%), with moderate cGVHD accounting for all events. The FCR regimen in SAA was well tolerated, even in older adults, with 100% disease-free survival with low GVHD and infection rates. These encouraging findings should be validated in larger prospective trials.

Reduction in the Prevalence of Thrombotic Events in Sickle Cell Disease after Allogeneic Hematopoietic Transplantation.

Thrombosis is a recognized complication in sickle cell disease (SCD). Allogeneic hematopoietic cell transplantation (allo-HCT) remains the sole curative option for patients with severe SCD phenotypes. Data describing the effects of allo-HCT on recurrent thrombotic events (venous and arterial events) are limited, however. We evaluated 31 patients with SCD who underwent allo-HCT with a median follow-up of 34.5 months (range, 13 to 115) post-transplantation. No patient continued anticoagulation or antiplatelet therapy after allo-HCT. There was an absolute difference of 32% (95% confidence interval [CI], 12.3% to 32.2%; P = .002) in the prevalence of venous thromboembolic (VTE) events before and after allo-HSCT. In addition, there was an absolute difference of 38.5% (95% CI, 10.63 to 45.96; P = .006) in the number of ischemic cerebrovascular accidents (CVAs) occurring before and after allo-HSCT. Patients with severe SCD who undergo allo-HCT are less likely to develop recurrent thrombotic events compared with a control cohort of patients matched for age and genotype (odds ratio, 0.22; 95% CI, 0.058 to 0.83; P = .025). Following curative therapy with allo-HCT, there is a reduction in recurrent arterial and venous thrombosis in patients with severe SCD phenotypes.

The use of venetoclax-based salvage therapy for post-hematopoietic cell transplantation relapse of acute myeloid leukemia.

For patients with high risk myeloid disease, allogeneic hematopoietic cell transplantation (HCT) is the only potentially curative therapy. Unfortunately, many of these patients relapse after HCT and have a limited survival. The recent approval of venetoclax, an orally bioavailable BCL-2 inhibitor, resulted in significant responses in treatment naïve acute myeloid leukemia (AML), and off-label use in the relapsed/refractory setting is increasing. We report the outcomes of 21 patients who underwent allogeneic HCT for myeloid disease, relapsed with AML, and were treated with venetoclax. Several patients had poor risk features including antecedent hematologic malignancy (6/21), complex karyotype (6/21), and TP53 mutations (5/21). The median age was 64.5 years and time from HCT to relapse was 5.7 months (range: 0.9 to 44.9 months). Of the 19 patients who were assessed for response, there were meaningful treatment responses seen in eight patients: five CR, three CRi, zero PR, for an ORR of 42.1%. Treatment effect was seen in six additional patients, including four in the morphologic leukemia-free state. Nine patients maintained their response for ≥3 months and eight were receiving therapy at data cut. Post-HCT AML relapse has an exceedingly poor outcome, and venetoclax-based therapy is a potent therapy option that should be studied prospectively in this setting.

Minimal residual disease negativity and lenalidomide maintenance therapy are associated with superior survival outcomes in multiple myeloma.

Modern combinations of therapies for multiple myeloma have led to improvement in survival outcomes with near 100% overall response rate and 25% complete response rates, particularly with autologous hematopoietic cell transplant (AHCT). Minimal residual disease (MRD) assessment with multiparameter flow cytometry is a valid prognostic biomarker for progression-free survival (PFS) and overall survival (OS). However, few data exist regarding whether MRD positivity or negativity will meaningfully influence treatment decisions. We evaluated 433 patients who received induction therapy, followed by AHCT. Participants had MRD assessment by multiparameter flow cytometry before and at days +100 and +365 following AHCT. They also received either lenalidomide, bortezomib, or no maintenance therapy following AHCT. Maintenance treatment with lenalidomide improved MRD negativity at day +365 compared to bortezomib (92.9% vs 41.6%, p = 0.01), or no maintenance therapy (92.9% vs 24.4%, p = 0.012). The median PFS for patients who were MRD negative at day + 365 was 42 vs 17.5 months (p < 0.001) and median OS was 80.6 vs 59 months (p = 0.02). Maintenance therapy following AHCT for multiple myeloma improves the depth of response as assessed by MRD.

New-onset post-transplant diabetes mellitus after haploidentical hematopoietic cell transplant with post-transplant cyclophosphamide.

Haploidentical hematopoietic cell transplant (haplo-HCT) with post-transplant cyclophosphamide (PTCY) is utilized for patients with hematological disorders but without conventional donors. The effects of new-onset post-transplant diabetes mellitus (PTDM) following haplo-HCT are unknown. We examined PTDM incidence and outcomes after haplo-HCT with PTCY. Patients without diabetes receiving haplo-HCT (n=64) were analyzed for PTDM diagnosis (defined as blood glucose≥ 200 mg/dL). By day 100, 14 (22%) patients developed PTDM (median, 18 days). Hyperglycemia (blood glucose ≥ 200 mg/dL) preceded corticosteroids in 11 (79%) individuals. PTDM patients had increased death/relapse (p=0.029). PTDM occurs frequently, precedes corticosteroids, and leads to inferior outcomes following haplo-HCT. PTDM prophylaxis/treatment may improve HCT survival.

Differential Interaction of Peripheral Blood Lymphocyte Counts (ALC) With Different in vivo Depletion Strategies in Predicting Outcomes of Allogeneic Transplant: An International 2 Center Experience.

Dosing regimens for antithymocyte globulin (ATG) and anti-CD52 antibody (alemtuzumab) for graft vs. host disease prophylaxis (GVHD) are empiric or weight-based, and do not account for individual patient factors. Recently, it has been shown that recipient peripheral blood absolute lymphocyte count (ALC) on the day of ATG administration interacts with the dose of ATG administered to predict transplantation outcome. Similarly, we wanted to analyze if the recipient ALC interacts with alemtuzumab dosing to predict outcomes. We retrospectively compared 364 patients, 124 patients receiving ATG (anti-thymocyte globulin) for GVHD prophylaxis, and undergoing unrelated first allogeneic transplant for myeloid and lymphoid malignancies (group 1) to 240 patients receiving alemtuzumab (group 2), in similar time period. There was no difference in survival or acute and chronic GVHD between 60 and 100 mg of alemtuzumab dosing. Unlike ATG (where the pre-transplant recipient ALC interacted with ATG dose on day of its administration (day 1) to predict OS and DFS (p = 0.05), within alemtuzumab group, the recipient ALC on second day of alemtuzumab administration (day 2) and its interaction with alemtuzumab dose strongly predicted OS, DFS and relapse (p = 0.05, HR-1.81, 1.1-3.3; p = 0.002, HR-2.41, CI, 1.3-4.2; and p = 0.003, HR-2.78, CI, 1.4-5.2), respectively. ALC (day 2) of 0.08 × 109/lit or higher, had a specificity of 96% in predicting inferior DFS. Like ATG, there is definite but differential interaction between the recipient peripheral blood ALC and alemtuzumab dose to predict OS, DFS, and relapses.

Use of Biosimilar Granulocyte Colony-Stimulating Factor for Mobilization in Autologous and Allogeneic Hematopoietic Stem Cell Transplantation.

The biologic medication filgrastim is approved by the Food and Drug Administration (FDA) to mobilize hematopoietic progenitor cells (HPCs) for collection by leukapheresis for autologous hematopoietic stem cell transplant (HSCT). The FDA-approved biologic tbo-filgrastim is currently used off-label for this indication in both autologous and allogeneic HSCT at the Tennessee Valley Healthcare System. The purpose of this review is to compare the efficacy of filgrastim and tbo-filgrastim for this indication. The primary outcomes were the proportion of autologous patients and allogeneic donors with a CD34+ count ≥15 × 103 cells/uL on day 4 of filgrastim or tbo-filgrastim mobilization. The secondary outcome was the use of plerixafor in the autologous population. A total of 469 subjects were identified for inclusion; 367 underwent mobilization for autologous HSCT and 102 for allogeneic HSCT donation. The primary outcome was achieved in 47.5% of patients who received filgrastim compared to 50.2% who received tbo-filgrastim in the autologous population (p = 0.67). Among donors for allogeneic HSCT, there was no difference between those eligible for collection on day 4 of filgrastim or tbo-filgrastim administration (97.6% vs. 100%, p = 0.41). No significant difference was identified in the number of patients requiring plerixafor use in the autologous HSCT population. The use of the biosimilar tbo-filgrastim for mobilization in either autologous HSCT patients or allogeneic HSCT donors has comparable outcomes to that of the biotherapeutic reference product filgrastim at a reduced cost to the healthcare system.

Risk Score for the Development of Veno-Occlusive Disease after Allogeneic Hematopoietic Cell Transplant.

A risk score identifying patients at high risk for veno-occlusive disease (VOD) may aid efforts to study preventive strategies for this uncommon complication of hematopoietic cell transplantation (HCT). Patients receiving a first allogeneic HCT between 2008 and 2013 as reported to the Center for International Blood and Marrow Transplant Research (N = 13,097) were randomly divided into training and validation sets. Independent prognostic factors for development of VOD by day +100 after HCT were identified with a multivariate logistic regression model. A risk score was constructed in the training set using the significant factors and confirmed in the validation set. Baseline characteristics of the training and validation sets were balanced. In total, 637 patients (4.9%) developed VOD by day +100. Younger age, positive hepatitis B/C serology, lower Karnofsky performance scale score, use of sirolimus, disease, disease status at transplant, and conditioning regimen were independent prognostic factors. Myeloablative conditioning regimens were associated with higher risk of VOD. Busulfan-based myeloablative conditioning regimens guided by pharmacokinetic monitoring were associated with higher risk than those without pharmacokinetic monitoring. Patients were stratified into 4 distinct, statistically significantly different groups by their risk score percentile. This pretransplant risk score successfully stratified allogeneic HCT patients by risk of developing VOD, was validated in an independent set, and demonstrated strong discriminatory ability to identify a high-risk cohort.

Lenalidomide vs bortezomib maintenance choice post-autologous hematopoietic cell transplantation for multiple myeloma.

Maintenance therapy post-autologous hematopoietic cell transplantation (AHCT) with either lenalidomide or bortezomib for multiple myeloma (MM) have separately been shown to improve progression-free survival (PFS), but have never been directly compared. We performed a retrospective study to investigate progression-free and overall survival outcomes and toxicities of lenalidomide maintenance therapy compared with bortezomib maintenance in MM patients post-AHCT. This study included 156 patients who received post-AHCT lenalidomide or bortezomib maintenance therapy for MM. The primary outcome was PFS. Ninety-two patients received lenalidomide maintenance and 64 received bortezomib maintenance post-AHCT. By multivariable analysis, maintenance therapy choice and cytogenetics risk did not impact PFS or OS. Staging by International Staging System and pre-maintenance disease response were the greatest predictors for PFS. Treatment-related toxicities were as anticipated with 5.4% of patients receiving maintenance lenalidomide experiencing secondary primary malignancies (SPMs) compared with 3% for bortezomib. These findings suggest there were no differences in PFS or OS between lenalidomide and bortezomib maintenance therapy options for post-transplantation MM patients. These data should be validated in a larger, prospective cohort to determine if maintenance choice should be guided by side effect profile and patient anticipated tolerance rather than by disease biology alone.

Optimizing Antithymocyte Globulin Dosing for Unrelated Donor Allogeneic Hematopoietic Cell Transplantation Based on Recipient Absolute Lymphocyte Count.

Antithymocyte globulin (ATG) is used as prophylaxis against graft-versus-host disease (GVHD). Current dosing regimens for ATG are empiric and weight-based, and do not account for patient-specific factors. Furthermore, the target of ATG, recipient T cells post-cytotoxic chemotherapy, is not a function of recipient weight. We hypothesized the recipient peripheral blood absolute lymphocyte count (ALC) on the day of ATG administration would interact with the dose of ATG administered to predict transplantation outcomes. We retrospectively analyzed 135 patients who received ATG for GVHD prophylaxis for unrelated allogeneic hematopoietic cell transplantation at 3 different doses: 10 mg/kg, 7.5 mg/kg, and 5 mg/kg. There was no difference in 2-year overall survival (OS) among ATG dosing groups; however, deaths from infectious complications were significantly higher with higher doses of ATG (3.7% versus 19% versus 26.7%; P = .02). Severity of chronic GVHD was lower with higher doses of ATG (28% versus 24% versus 4%; P = .03). In multivariate analysis, the median peripheral blood ALC on day of ATG administration and the total amount of ATG interacted to predict OS (hazard ratio, .09; P = .03). For low recipient ALC (10th percentile, or .56 × 102/µL), a higher total ATG dose was associated with a greater risk of death, whereas for high recipient ALC (90th percentile, or 24.96 × 102/µL), a higher ATG dose was associated with a lower risk of death. Our findings suggest that the interaction between ATG and its target, the recipient lymphocyte, could represent a new paradigm for ATG dosing.

Metabolic Complications Precede Alloreactivity and Are Characterized by Changes in Suppression of Tumorigenicity 2 Signaling.

New-onset post-transplantation diabetes mellitus (PTDM) occurs commonly after allogeneic hematopoietic cell transplantation (HCT) and is associated with inferior survival. We hypothesize that PTDM and nonrelapse mortality (NRM) are related to IL-33/suppression of tumorigenicity 2 (ST2) signaling and that soluble ST2 (sST2) levels will predict PTDM diagnosis. sST2 was measured at engraftment and day +30 in 36 euglycemic HCT recipients followed prospectively for PTDM (cohort 1). Results were confirmed in a validation cohort of 26 patients without pre-existing diabetes analyzed retrospectively for PTDM (cohort 2). Twelve patients with established diabetes before HCT were analyzed in cohort 3. When compared with recipients without PTDM, patients developing PTDM (n = 24) from cohort 1 had elevated sST2 levels at engraftment (P = .02) and at day +30 (P < .01). Cohort 2 confirmed this finding at engraftment (P = .01). Cohort 3 patients with pretransplantation diabetes had higher sST2 at engraftment than patients maintaining euglycemia after HCT from cohort 2 (P = .03). Multivariate analysis of cohorts 1 and 2 showed high engraftment sST2 predicted increased PTDM and NRM risk, independent of conditioning and grades 3 to 4 acute graft-versus-host-disease. sST2 was elevated in PTDM, indicating a relationship between glucose homeostasis and the IL-33/ST2 axis after transplantation. Correction of metabolic complications may decrease sST2 and improve NRM.

Reduced-Intensity Conditioning with Fludarabine, Cyclophosphamide, and Rituximab Is Associated with Improved Outcomes Compared with Fludarabine and Busulfan after Allogeneic Stem Cell Transplantation for B Cell Malignancies.

Reduced-intensity conditioning (RIC) has been used increasingly for allogeneic hematopoietic cell transplantation to minimize transplant-related mortality while maintaining the graft-versus-tumor effect. In B cell lymphoid malignancies, reduced-intensity regimens containing rituximab, an antiCD20 antibody, have been associated with favorable survival; however, the long-term outcomes of rituximab-containing versus nonrituximab-containing regimens for allogeneic hematopoietic cell transplantation in B cell lymphoid malignancies remain to be determined. We retrospectively analyzed 94 patients who received an allogeneic transplant for a B cell lymphoid malignancy. Of these, 33 received RIC with fludarabine, cyclophosphamide, and rituximab (FCR) and graft-versus-host disease (GVHD) prophylaxis with a calcineurin inhibitor and mini-methotrexate, and 61 received RIC with fludarabine and busulfan (FluBu) and GVHD prophylaxis with a calcineurin inhibitor and mycophenolate mofetil. The 2-year overall survival was superior in patients who received FCR versus FluBu (72.7% versus 54.1%, P = .031), and in multivariable analysis adjusted for Disease Risk Index and donor type, only the conditioning regimen (FluBu versus FCR: HR, 2.06; 95% CI, 1.04 to 4.08; P = .037) and Disease Risk Index (low versus intermediate/high: HR, .38; 95% CI, .17 to .86; P = .02) were independent predictors of overall survival. The 2-year cumulative incidence of chronic GVHD was lower in patients who received FCR versus FluBu (24.2% versus 51.7%, P = .01). There was no difference in rate of relapse/progression or acute GVHD. Our results demonstrate that the use of RIC with FCR and GVHD prophylaxis with a calcineurin inhibitor and mini-methotrexate is associated with decreased chronic GVHD and improved overall survival.

New allergies after cord blood transplantation.

BACKGROUND AIMS: Umbilical cord blood transplantation (CBT) is an effective treatment for benign and malignant diseases. Late effects of CBT are not well described in the literature. In the present study, we present our experience of new-onset allergies in long-term survivors after CBT. METHODS: After an initial patient had a severe peanut allergic reaction after CBT, all CBT patients were prospectively followed for new allergy development. Fifty patients received CBT between March 2006 and June 2011. RESULTS: The median follow-up after CBT was 447 days (range, 12-2022). At the time of analysis, 30 patients were alive, with 3-year survival of 55.5%; median follow-up of surviving patients was 910 days (range, 68-2022). The allergic syndrome developed in five patients, with the cumulative incidence of new allergies at 2 years of 18.4% (95% confidence interval, 10.8-26). The median time to onset of new allergy after transplantation was 298 days (range, 250-809). CONCLUSIONS: Allergy development has been linked to a delayed maturation of the immune system in several studies. We present the first case series of patients who had new allergies after CBT. Further study of this novel complication as well as counseling of patients after CBT would be important.

Immunomodulatory nonablative conditioning regimen for B-cell lymphoid malignancies.

Twenty-six patients with recurrent CD20(+) B-cell lymphoid malignancies received fludarabine, cyclophosphamide, and rituximab-based nonablative conditioning followed by either matched related (n = 18) or unrelated (n = 8) donor allogeneic stem cell transplantation (allo-SCT) between March 2008 and May 2011. Median age of patients at transplantation was 59 years (range, 41-64 years). At diagnosis, 20 (77%) had stage IV disease; 23 (88%) received ≥3 regimens, 14 (54%) received ≥4 regimens, and 4 (15%) had earlier autologous-SCT. All patients had either chemosensitive or stable disease and nine (35%) were in complete remission before transplantation. At the time of analysis, 17 patients were alive with an estimated 2-year overall survival and progression-free survival rate of 63% and nonrelapse mortality of 25%. Grade II to IV acute graft-vs-host-disease occurred in 8 (31%) and chronic graft-vs-host-disease in 6 (23%) patients (extensive, n = 3). Causes of death include progressive disease in four, acute graft-vs-host-disease in two (both after receiving donor lymphocyte infusion for mixed chimerism with residual disease), infection in one, and other (e.g., substance abuse, leukoencephalopathy) in two. Six patients required rehospitalization within 100 days of SCT (mean = 10 days; range, 3-18 days). Our data support fludarabine, cyclophosphamide, and rituximab-based nonablative conditioning allo-SCT in CD20(+) B-cell lymphoid malignancies and it is time to compare this regimen with an alternative reduced-intensity conditioning regimen in B-cell malignancies.