Prophylactic corticosteroid use prevents engraftment syndrome in patients after autologous stem cell transplantation

Determinants of Interpatient Variability in Treosulfan Pharmacokinetics in AML Patients Undergoing Autologous Stem Cell Transplantation

Limited data on treosulfan pharmacokinetics in adults, particularly regarding autologous stem cell transplantation (ASCT) in acute myeloid leukemia (AML), is available to date. Furthermore, correlations between treosulfan exposure, toxicity, and clinical outcome remain understudied. In this single-center retrospective study, we analyzed data from 55 AML patients who underwent HDCT with treosulfan (14 g/m2) and melphalan (140 mg/m2 or 200 mg/m2) (TreoMel) between August 2019 and November 2023 at the University Hospital of Bern. We assessed treosulfan pharmacokinetics and correlations with several physiological parameters with potential impact on its interpatient variability. We further analyzed how treosulfan exposure correlates with toxicity and clinical outcomes. Women above 55 years showed higher area under the curve (AUC) levels (median: 946 mg*h/L, range: 776-1370 mg*h/L), as compared to women under 55 (median: 758 mg*h/L, range: 459-1214 mg*h/L, p = 0.0487). Additionally, women above 55 showed higher peak levels (median: 387 mg/L, range: 308-468 mg/L), as compared to men of the same age range (median: 326 mg/L, range: 264-395 mg/L, p = 0.0159). Treosulfan levels varied significantly with body temperature, liver enzymes, hemoglobin/hematocrit., and treosulfan exposure correlated with diarrhea severity in women over 55 (p = 0.0076). Our study revealed age- and gender-related variability in treosulfan pharmacokinetics, with higher plasma levels observed in female patients above 55. Moreover, our data suggest that treosulfan plasma levels may vary with several physiological parameters and that higher treosulfan exposure may impact toxicity. Our study underlines the need for further research on treosulfan pharmacokinetics, especially in older patients undergoing HDCT in the ASCT setting.

Ciprofloxacin versus levofloxacin prophylaxis in hematopoietic stem cell transplantation: A randomized trial

OBJECTIVES

We aimed to assess whether there is a difference between ciprofloxacin and levofloxacin as prophylaxis in hematopoietic stem cell transplant (SCT) recipients.

METHODS

This is a prospective, randomized trial in patients receiving SCT at Henry Ford Health in the United States of America. We randomly assigned patients (1:1) to receive ciprofloxacin or levofloxacin. The primary outcome was incidence of bloodstream bacterial infections (BSI) up to day 60 after SCT.

RESULTS

Between June 4, 2018, and May 23, 2022, we randomly assigned 308 consecutive patients to receive ciprofloxacin (154 patients) or levofloxacin (154 patients). BSI was similar in both the ciprofloxacin and levofloxacin groups (18 [11.7%] vs 18 [11.7%]). Pneumonia was more frequent in the ciprofloxacin group compared to the levofloxacin group (18 [18%] vs 7 [23%]; relative risk 2.57, 95% CI 1.11-5.98; p = 0.028). There were no differences in neutrophil engraftment, fever, Clostridium difficile infection, relapse incidence, overall survival, nonrelapse mortality, length of stay post-SCT, or intensive care unit admission.

CONCLUSION

Although both prophylaxis regimens demonstrated the same efficacy in SCT recipients, levofloxacin prophylaxis led to less pneumonia in the first 60 days post-SCT.

TRIAL REGISTRATION

This study is registered on ClinicalTrials.gov, NCT03850379.

Safety and Efficacy of High-Dose Chemotherapy with TreoMel 200 vs. TreoMel 140 in Acute Myeloid Leukemia Patients Undergoing Autologous Stem Cell Transplantation

(1) Background: Treosulfan and melphalan (TreoMel)-based high-dose chemotherapy (HDCT) has shown promising safety and efficacy as a conditioning regimen for acute myeloid leukemia (AML) patients undergoing autologous stem cell transplantation (ASCT). However, despite intensive first-line induction treatment and upfront consolidation with HDCT and ASCT, AML relapse rates are still high, and further efforts are needed to improve patient outcomes. The aim of this study was to compare two melphalan dose schedules in regard to the safety of TreoMel HDCT and patient outcomes. (2) Methods: We retrospectively analyzed the safety and efficacy of two melphalan dose schedules combined with standard-dose treosulfan in AML patients undergoing HDCT and ASCT at the University Hospital of Bern, Switzerland, between August 2019 and August 2023. Patients received treosulfan 42 g/m2 combined with either melphalan 140 mg/m2 (TreoMel 140) or melphalan 200 mg/m2 (TreoMel 200). Co-primary endpoints were progression-free survival (PFS), overall survival (OS), as well as safety profile. (3) Results: We included a total of 51 AML patients: 31 (60.8%) received TreoMel 140 and 20 (39.2%) TreoMel 200. The patients' basal characteristics were comparable between both cohorts. No significant differences in the duration of hospitalization or the adverse event profile were identified. There were no statistically significant differences in relapse (0.45 vs. 0.30, p = 0.381) and mortality rates (0.42 vs. 0.15, p = 0.064) between the melphalan 140 mg/m2 and 200 mg/m2 cohorts, nor for PFS (HR: 0.81, 95% CI: 0.29-2.28, p = 0.70) or OS (HR: 0.70, 95% CI: 0.19-2.57, p = 0.59) for the TreoMel 140 vs. TreoMel 200 cohort. (4) Conclusions: A higher dose of melphalan (TreoMel 200) was well tolerated overall. No statistically significant differences for patient outcomes could be observed, possibly due to the relatively small patient cohort and the short follow-up. A longer follow-up and prospective randomized studies would be required to confirm the safety profile and clinical benefit.

Early allogeneic immune modulation after establishment of donor hematopoietic cell-induced mixed chimerism in a nonhuman primate kidney transplant model

Background

Mixed lymphohematopoietic chimerism is a proven strategy for achieving operational transplant tolerance, though the underlying immunologic mechanisms are incompletely understood.

Methods

A post-transplant, non-myeloablative, tomotherapy-based total lymphoid (TLI) irradiation protocol combined with anti-thymocyte globulin and T cell co-stimulatory blockade (belatacept) induction was applied to a 3-5 MHC antigen mismatched rhesus macaque kidney and hematopoietic cell transplant model. Mechanistic investigations of early (60 days post-transplant) allogeneic immune modulation induced by mixed chimerism were conducted.

Results

Chimeric animals demonstrated expansion of circulating and graft-infiltrating CD4+CD25+Foxp3+ regulatory T cells (Tregs), as well as increased differentiation of allo-protective CD8+ T cell phenotypes compared to naïve and non-chimeric animals. In vitro mixed lymphocyte reaction (MLR) responses and donor-specific antibody production were suppressed in animals with mixed chimerism. PD-1 upregulation was observed among CD8+ T effector memory (CD28-CD95+) subsets in chimeric hosts only. PD-1 blockade in donor-specific functional assays augmented MLR and cytotoxic responses and was associated with increased intracellular granzyme B and extracellular IFN-γ production.

Conclusions

These studies demonstrated that donor immune cell engraftment was associated with early immunomodulation via mechanisms of homeostatic expansion of Tregs and early PD-1 upregulation among CD8+ T effector memory cells. These responses may contribute to TLI-based mixed chimerism-induced allogenic tolerance.

Early Antibiotic Deescalation and Discontinuation in Patients with Febrile Neutropenia after Cellular Therapy: A Single-Center Prospective Unblinded Randomized Trial

The optimal duration of empiric antimicrobial therapy of febrile neutropenia in patients after cellular therapy is unclear. Early deescalation has been suggested by some authorities; however, data are lacking for cellular therapy recipients. We performed a randomized controlled study of cellular therapy recipients with febrile neutropenia to evaluate the safety and noninferiority of an early deescalation and discontinuation antibiotic strategy (EDD arm) versus standard broad-spectrum antibiotic treatment until recovery of neutropenia (standard duration arm). The primary outcome was the fraction of antibiotic-free neutropenia days. We randomized 110 patients to the standard duration arm (n = 51) or EDD arm (n = 59). The fraction of antibiotic-free neutropenia days was higher in the EDD arm compared to the standard duration arm (median, .8 [interquartile range (IQR), .62 to .86] versus .51 [IQR, .17 to .86]; P = .016). This was true for the per-protocol, allogeneic hematopoietic cell transplantation (HCT), autologous HCT, and anti-CD19 chimeric antigen receptor T cell therapy subgroups. Treatment success rate, subsequent fever, death within 30 days, and other common cellular therapy-related toxicities were all similar between the 2 study arms. An EDD antibiotic strategy in patients after cellular therapy was safe and associated with a substantial reduction in broad-spectrum antibiotic utilization without compromising cellular therapy outcomes.

Characteristics of Engraftment Syndrome following Autologous Stem Cell Transplantation in Light Chain Amyloidosis with Renal Involvement

Engraftment syndrome (ES) is a clinical complication that occurs during the neutrophil recovery phase following hematopoietic stem cell transplantation. The clinical features of ES in light chain (AL) amyloidosis remains to be thoroughly investigated. This study was conducted to better understand the characteristics of ES following autologous stem cell transplantation (ASCT) in AL amyloidosis with renal involvement. We conducted this single-center retrospective study in 302 patients with AL amyloidosis who underwent ASCT between July 2010 and December 2021. Sixty-seven of the 302 patients (22.2%) developed ES, with a median time to the occurrence of ES after stem cell reinfusion of 11 days (range, 7 to 17 days). Among the outcome measures in this study, estimated glomerular filtration rate (eGFR) at baseline and C-reactive protein (CRP) level on the day of granulocyte engraftment were statistically different between the ES patients and non-ES patients. We observed no significant difference between the 2 groups in transplantation-related adverse events (grade ≥ 2), hematologic and organ responses, overall survival, and progression-free survival. Furthermore, CRP level at granulocyte engraftment (odds ratio [OR], 1.012; 95% confidence interval [CI], 1.004 to 1.020; P = .002) and the absence of induction chemotherapy before ASCT (OR, 1.977; 95% CI, 1.047 to 3.731; P = .036) were identified as risk factors for the development of ES, whereas a higher eGFR at baseline (OR, .981; 95% CI, .969 to .993; P = .002) was identified as a protective factor against ES. Our data show a 22.2% incidence of ES in AL amyloidosis patients with renal involvement after ASCT and identify associated risk and protective factors, which can improve the understanding of this clinical complication.

Outcome of Patients with Diffuse Large B-Cell Lymphoma Relapsing after Autologous Transplant before Availability of CAR-T Cell Treatment

Introduction

Autologous stem cell transplantation (ASCT) following high-dose chemotherapy is applied as salvage therapy in patients with relapsed disease or as first-line consolidation in high-risk DLBCL with chemo-sensitive disease. However, the prognosis of relapsing DLBCL post-ASCT remained poor until the availability of CAR-T cell treatment. To appreciate this development, understanding the outcome of these patients in the pre-CAR-T era is essential.

Methods

We retrospectively analyzed 125 consecutive DLBCL patients who underwent HDCT/ASCT.

Results

After a median follow-up of 26 months, OS and PFS were 65% and 55%. Fifty-three patients (42%) had a relapse (32 patients, 60%) or refractory disease (21 patients, 40%) after a median of 3 months post-ASCT. 81% of relapses occurred within the first year post-ASCT with an OS of 19% versus 40% at the last follow-up in patients with later relapses (p=0.0022). Patients with r/r disease after ASCT had inferior OS compared to patients in ongoing remission (23% versus 96%; p<0.0001). Patients relapsing post-ASCT without salvage therapy (n=22) had worse OS than patients with 1-4 subsequent treatment lines (n=31) (OS 0% versus 39%; median OS 3 versus 25 months; p<0.0001). Forty-one (77%) of patients relapsing after ASCT died, 35 of which due to progression.

Conclusions

Additional therapies can extend OS but mostly cannot prevent death in DLBCL relapsing/refractory post-ASCT. This study may serve as a reference to emerging results after CAR-T treatment in this population.

BeEAM High-Dose Chemotherapy with Polatuzumab (Pola-BeEAM) before ASCT in Patients with DLBCL—A Pilot Study

(1) Introduction: BEAM is a high-dose chemotherapy (HDCT) frequently administered before autologous stem cell transplantation (ASCT) in diffuse large B-cell lymphoma (DLBCL). Bendamustine replacing BCNU (BeEAM) is similarly effective at lower toxicities. However, relapse remains the major cause of death in DLBCL. (2) Methods: This is a 12-patient pilot study of the BeEAM preparative regimen with additional polatuzumab vedotin (PV, targeting CD79b) aiming to establish feasibility and to reduce toxicity without increasing the early progression rate. PV was given once at the standard dose of 1.8 mg/kg at day −6 together with BeEAM-HDCT (days −7 to −1) before ASCT. (3) Results: 8/12 patients (67%) received PV with BeEAM as a consolidation of first-line treatment, and 4/12 patients (33%) received PV with BeEAM after relapse treatment. All patients experienced complete engraftment (neutrophils: median 11 days; platelets: 13 days). Gastrointestinal toxicities occurred in 7/12 patients (58%, grade 3). All patients developed neutropenic infections with at least one identified pathogen (bacterial: 10/12 patients; viral: 2/12; and fungal: 1/12). The complete remission rate by PET-CT 100 days post-ASCT was 92%, with one mortality due to early progression. Eleven out of twelve patients (92%) were alive without progression after a median follow-up of 15 months. (4) Conclusions: Our study with 12 patients suggests that combining PV with BeEAM HDCT is feasible and safe, but the limited cohort prevents definite conclusions regarding efficacy. Larger cohorts must be evaluated.

Comparison of Melphalan Combined with Treosulfan or Busulfan as High-Dose Chemotherapy before Autologous Stem Cell Transplantation in AML

Simple Summary

Different consolidation strategies are available for acute myeloid leukemia (AML) patients fit for intensive treatment. For favorable- or intermediate-risk AML, high-dose chemotherapy (HDCT) followed by autologous stem cell transplantation (ASCT) is one of these options. Busulfan plus melphalan is a frequently used and efficient HDCT regimen, but it bears neurotoxic potential and may cause irreversible alopecia, amongst other toxicities. Thus, improving HDCT regimens with lesser toxicity, albeit at comparable anti-leukemic efficacy, is wishful. We combined treosulfan with its more favorable toxicity profile with melphalan for HDCT and compared these patients with a group receiving busulfan/treosulfan. Whereas disease-free and overall survival did not differ significantly, the treosulfan regimen compared favorably, with the absence of neurotoxicity and irreversibly alopecia. Treosulfan serum levels by mass cytometry demonstrated considerable interindividual biovariability. Further studies should explore treosulfan/melphalan for HDCT/ASCT in AML, aiming to improve the quality of life of AML survivors and offer safer consolidation strategies.

Abstract

(1) Background: High-dose chemotherapy (HDCT) before autologous stem cell transplantation (ASCT) in acute myeloid leukemia (AML) patients predominantly combines busulfan with cyclophosphamide or melphalan. Treosulfan compares favorably regarding lower inter-individual bioavailability and neurotoxicity, but so far, had not been studied before ASCT in AML. (2) Methods: This single-center study investigated AML patients undergoing ASCT in CR1 between November 2017 and September 2020. The first 16 patients received busulfan 16 mg/kg b.w. (days −5 to −2) and melphalan 140 mg/m² (day −1) (BuMel). In a subsequent (TreoMel) cohort, 20 patients received treosulfan 14 g/m² (days −4 to −2) and melphalan. Plasma concentrations of busulfan and treosulfan were determined by mass spectrometry. (3) Results: Neutrophil engraftment and platelet recovery were similar, and PFS and OS were comparable. In only the BuMel cohort, patients reported central nervous toxicities, including seizures (6%) and encephalopathy (12%). The mean AUC for busulfan was 1471.32 μM*min, and for treosulfan it was 836.79 mg/L*h, with ranges of 804.1–2082 μM*min and 454.2–1402 mg/L*h. The peak values for busulfan ranged between 880.19–1734 μg/L and for treosulfan between 194.3–489.25 mg/L. (4) Conclusions: TreoMel appears to be safe and effective for pre-ASCT treatment in AML patients. Due to considerable interindividual biovariability, pharmacologic monitoring may also be warranted for the use of treosulfan.