Planned Granulocyte Colony-Stimulating Factor Adversely Impacts Survival after Allogeneic Hematopoietic Cell Transplantation Performed with Thymoglobulin for Myeloid Malignancy

Impact of Granulocyte Colony-Stimulating Factor (G-CSF) on Clinical Outcomes in Allogeneic Hematopoietic Cell Transplantation: Does Speeding Up Neutrophil Engraftment Make a Difference?

Background

Despite decades of post-allogeneic hematopoietic cell transplantation (HCT) growth factor utilization, its role remains undefined, leading to ongoing debates and research. The theoretical impacts of growth factors have been challenged in numerous studies.

Methods

In this retrospective cohort study conducted at the Princess Margaret Cancer Centre, we analyzed the clinical outcomes of 509 patients who underwent allogeneic HCT between May 1, 2019, and May 31, 2022. This study aimed to assess the impact of granulocyte colony-stimulating factor (G-CSF) administration posttransplantation on neutrophil and platelet engraftment, incidence of bloodstream infections (BSIs), graft-versus-host disease, engraftment syndrome (ES), and survival metrics including overall survival, nonrelapse mortality, and graft-versus-host disease-free/relapse-free survival.

Results

Our findings indicate that G-CSF administration expedited neutrophil engraftment (16 versus 18 d, P = 0.009) and was associated with a decreased incidence of BSI (9.4% versus 31.3%, P = 0.014). However, this benefit was counterbalanced by a significant delay in platelet engraftment (21 versus 17 d, P < 0.001). Multivariate logistic regression analysis identified mismatched donors (odds ratio, 1.72; 95% confidence interval, 1.03-2.88; P = 0.038) and the duration of G-CSF therapy (odds ratio, 1.04; 95% confidence interval, 1.00-1.09; P = 0.038) as independent predictors for the development of ES. Despite these hematological impacts, there was no observed advantage in overall survival, nonrelapse mortality, or graft-versus-host disease-free/relapse-free survival among patients who received G-CSF compared with those who did not.

Conclusions

Although G-CSF post-HCT expedited neutrophil engraftment and reduced BSI risk, it did not result in a survival advantage. The association with ES necessitates careful consideration.

Different impacts of granulocyte colony-stimulating factor administration on allogeneic hematopoietic cell transplant outcomes for adult acute myeloid leukemia according to graft type

We retrospectively evaluated the impacts of using granulocyte colony-stimulating factor (G-CSF) and its timing on posttransplant outcomes for 9766 adults with acute myeloid leukemia (AML) between 2013 and 2022 using a Japanese database. We separately evaluated three distinct cohorts based on graft type: 3248 received bone marrow transplantation (BMT), 3066 received peripheral blood stem cell transplantation (PBSCT), and 3452 received single-unit cord blood transplantation (CBT). Multivariate analysis showed that G-CSF administration significantly accelerated neutrophil recovery after BMT, PBSCT, and CBT. However, it was associated with a higher risk of grades II-IV acute graft-versus-host disease (GVHD) across all graft types. Moreover, an increased incidence of overall chronic GVHD was observed with G-CSF administration in BMT and CBT patients, but not in PBSCT patients. G-CSF administration significantly improved overall survival (OS) and leukemia-free survival (LFS) only following CBT. Regarding the timing of G-CSF, in comparison with late initiation of G-CSF (Days 5-10), early initiation (Days 0-4) did not provide benefits for hematopoietic recovery regardless of graft type. In contrast, late initiation was significantly associated with a lower risk of grades II-IV acute GVHD and better OS and LFS in CBT patients. These data demonstrated that G-CSF administration accelerated neutrophil recovery and increased the risk of grades II-IV acute GVHD across all graft types, but significantly improved survival outcomes but only following CBT. Therefore, routine use of G-CSF should be considered for CBT in adult patients with AML.

Haplo-cord transplant. Realizing the potential of umbilical cord blood grafts. - A review of techniques and analysis of outcomes

The combination of cord blood transplant with progenitor cells from partially HLA-matched adult donors (haplo-cord transplant) has been used over the past two decades. In Europe and the US the adult donor graft is CD34 selected and provides early hematopoiesis, but durable engraftment derives from the cord blood graft (CD34 selected haplo-cord). Neutrophil recovery is prompt and rates of acute and chronic GVHD are low. Recent Chinese studies combine cord blood grafts with T-replete haplo-identical grafts (unmodified haplo-cord). The haplo graft usually establishes dominance and UCB chimerism is rarely detected. Comparison studies suggest considerably decreased rates of relapse and improved outcomes, compared with either haplo-identical transplant or CBU transplant, particularly in patients with advanced leukemia. A recent prospective randomized study confirms this. Haplo-cord mitigates the engraftment delay of UCB transplant. The unique biology of UCB grafts results in low GVHD and improved GVL especially beneficial in high-risk disease.

Impact of rabbit anti-thymocyte globulin (ATG) exposure on outcomes after ex vivo T-cell-depleted hematopoietic cell transplantation in pediatric and young adult patients

BACKGROUND AIMS

Traditional weight-based dosing of rabbit anti-thymocyte globulin (rATG) used in allogeneic hematopoietic cell transplantation (HCT) to prevent graft-versus-host disease (GVHD) and graft rejection leads to variable exposures. High exposures induce delayed CD4+immune reconstitution (CD4+IR) and greater mortality. We sought to determine the impact of rATG exposure in children and young adults receiving various types of EX-VIVO T-cell-depleted (EX-VIVO-TCD) HCT.

METHODS

Patients receiving their first EX-VIVO-TCD HCT (CliniMACS CD34+, Isolex or soybean lectin agglutination), with removal of residual T cells by E-rosette depletion (E-) between 2008 and 2018 at Memorial Sloan Kettering Cancer Center were retrospectively analyzed. rATG exposure post-HCT was estimated (AU*d/L) using a validated population pharmacokinetic model. Previously defined rATG-exposures, <30, 30-55, ≥55 AU*d/L, were related with outcomes of interest. Cox proportional hazard and cause-specific models were used for analyses.

RESULTS

In total, 180 patients (median age 11 years; range 0.1-44 years) were included, malignant 124 (69%) and nonmalignant 56 (31%). Median post-HCT rATG exposure was 32 (0-104) AU*d/L. Exposure <30 AU*d/L was associated with a 3-fold greater probability of CD4+IR (P < 0.001); 2- to 4-fold lower risk of death (P = 0.002); and 3- to 4-fold lower risk of non-relapse mortality (NRM) (P = 0.02). Cumulative incidence of NRM was 8-fold lower in patients who attained CD4+IR compared with those who did not (P < 0.0001). There was no relation between rATG exposure and aGVHD (P = 0.33) or relapse (P = 0.23). Effect of rATG exposure on outcomes was similar in three EX-VIVO-TCD methods.

CONCLUSIONS

Individualizing rATG dosing to target a low rATG exposure post-HCT while maintaining total cumulative exposure may better predict CD4+IR, reduce NRM and increase overall survival, independent of the EX-VIVO-TCD method.

Graft-versus-host disease: teaching old drugs new tricks at less cost

Graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality after allogeneic stem cell transplantation (SCT). Currently, more patients can receive SCT. This is attributed to the use of reduced intensity regimens and the use of different GVHD prophylaxis that breaks the barrier of human leukocyte antigen, allowing an increase in the donor pool. Once an area with relatively few clinical trial options, there has been an increase in interest in GVHD prophylaxis and treatment, which has led to many US Food and Drug Administration (FDA) approvals. Although there is considerable excitement over novel therapies, many patients may not have access to them due to geographical or other resource constraints. In this review article, we summarize the latest evidence on how we can continue to repurpose drugs for GVHD prophylaxis and treatment. Drugs covered by our review include those that have been FDA approved for other uses for at least 15 years (since 2008); thus, they are likely to have generic equivalents available now or in the near future.

Allogeneic haematopoietic cell transplants as dynamical systems: influence of early-term immune milieu on long-term T-cell recovery

Objectives

Immune recovery following haematopoietic cell transplantation (HCT) functions as a dynamical system. Reducing the duration of intense immune suppression and augmenting antigen presentation has the potential to optimise T-cell reconstitution, potentially influencing long-term outcomes.

Methods

Based on donor-derived T-cell recovery, 26 patients were adaptively randomised between mycophenolate mofetil (MMF) administered for 30-day post-transplant with filgrastim for cytokine support (MMF30 arm, N = 11), or MMF given for 15 days with sargramostim (MMF15 arm, N = 15). All patients underwent in vivo T-cell depletion with 5.1 mg kg^-1 antithymocyte globulin (administered over 3 days, Day -9 through to Day -7) and received reduced intensity 450 cGy total body irradiation (3 fractions on Day -1 and Day 0). Patients underwent HLA-matched related and unrelated donor haematopoietic cell transplantation (HCT).

Results

Clinical outcomes were equivalent between the two groups. The MMF15 arm demonstrated superior T-cell, as well as T-cell subset recovery and a trend towards superior T-cell receptor (TCR) diversity in the first month with this difference persisting through the first year. T-cell repertoire recovery was more rapid and sustained, as well as more diverse in the MMF15 arm.

Conclusion

The long-term superior immune recovery in the MMF15 arm, administered GMCSF, is consistent with a disproportionate impact of early interventions in HCT. Modifying the 'immune-milieu' following allogeneic HCT is feasible and may influence long-term T-cell recovery.