History and Development of Autologous Stem Cell Transplantation for Acute Myeloid Leukemia

Significance of Measurable Residual Disease in Patients Undergoing Allogeneic Hematopoietic Cell Transplantation for Acute Myeloid Leukemia

Allogeneic hematopoietic cell transplantation (HCT) remains an important curative-intent treatment for many patients with acute myeloid leukemia (AML), but AML recurrence after allografting is common. Many factors associated with relapse after allogeneic HCT have been identified over the years. Central among these is measurable ("minimal") residual disease (MRD) as detected by multiparameter flow cytometry, quantitative polymerase chain reaction, and/or next-generation sequencing. Demonstration of a strong, independent prognostic role of pre- and early post-HCT MRD has raised hopes MRD could also serve as a predictive biomarker to inform treatment decision-making, with emerging data indicating the potential value to guide candidacy assessment for allografting as a post-remission treatment strategy, the selection of conditioning intensity, use of small molecule inhibitors as post-HCT maintenance therapy, and preemptive infusion of donor lymphocytes. Monitoring for leukemia recurrence after HCT and surrogacy for treatment response are other considerations for the clinical use of MRD data. In this review, we will outline the current landscape of MRD as a biomarker for patients with AML undergoing HCT and discuss areas of uncertainty and ongoing research.

Auto-hematopoietic stem cell transplantation or chemotherapy? Meta-analysis of clinical choice for AML

For patients with acute myeloid leukemia (AML) who are not candidates for allogeneic stem cell transplantation (SCT) or do not have a human leukocyte antigen (HLA)-matched donor, it is unclear whether autologous SCT (ASCT) has a better prognosis after the first complete response (CR1) compared to further chemotherapy treatment. A meta-analysis evaluating ASCT compared to further chemotherapy for AML patients in CR1 was performed. The Medline, Embase, Cochrane Controlled Trials Registry, Cochrane Library, Web of Science, and National Knowledge Infrastructure of China databases were searched for relevant literature as of May 26, 2023. Eligible studies included prospectively enrolled adults with AML and randomized first-time respondent patients who did not have a matched sibling donor. Fourteen randomized controlled trials were identified and included 4281 participants, of which 1499 patients received ASCT and 2782 underwent chemotherapy and continued follow-up. In patients with AML in CR1, a lower relapse rate was associated with ASCT compared to chemotherapy [odds ratio (OR) = 0.49, 95% confidence interval (CI) = 0.41-0.57]. Significant disease-free survival (DFS; OR = 1.37, 95% CI = 1.02-1.84) and relapse-free survival (RFS; OR = 2.78, 95% CI = 1.28-6.02) ASCT benefits were documented, and there was no difference in the overall survival (OS) when the studies were pooled (OR = 1.12, 95% CI = 0.85-1.48). The study results indicated that after the first remission, AML patients receiving autologous stem cell transplantation had higher DFS and RFS, similar OS, and lower relapse compared to patients undergoing chemotherapy treatment. This indicated that autologous stem cell transplantation may have a better prognosis.

The impact of delayed versus early administration of granulocyte colony-stimulating factor following autologous hematopoietic stem cell transplantation on transplantation outcome

Objectives

Granulocyte colony-stimulating factor (G-CSF) is routinely administered after autologous hematopoietic stem cell transplantation (auto-HSCT) to decrease the duration of neutropenia and diminish the incidence of febrile neutropenia. Nevertheless, the most advantageous timeframe for administering G-CSF in the transplantation setting remains elusive.

Material and Methods

We conducted a cross-sectional study of 200 patients diagnosed with hematological malignancies who underwent auto-HSCT between July 2017 and January 2022. Patients were divided into two groups of 100 individuals based on the timing of G-CSF administration after auto-HSCT. In the first group, G-CSF was administered on post-transplantation day +1, while in the second group, G-CSF was administered on post-transplantation day +5. Patient demographics and clinical outcomes, including time to neutrophil engraftment, time to platelet engraftment, length of hospital stay, duration of fever, and incidence of bacterial and fungal bloodstream infections, were compared between the two groups.

Results

We identified a significantly shorter platelet engraftment time in the day +5 group than in the day +1 group (P<0.001), though the groups were similar regarding neutrophil engraftment time. The total number of G-CSF injections differed significantly according to the administration schedule. The number of red blood cells and length of hospital stay was greater in the day +1 group (all P<0.001). The incidence of bacterial and fungal bloodstream infections and duration of fever did not differ between the groups.

Conclusion

Delayed administration of G-CSF on day +5 is as effective as early administration and can positively influence platelet engraftment, transfusion support, and hospitalization time.

Multiple small-dose infusions of G-CSF-mobilized haploidentical lymphocytes after autologous haematopoietic stem cell transplantation for acute myeloid leukaemia

This retrospective study analysed 106 acute myeloid leukaemia (AML) patients undergoing autologous haematopoietic stem cell transplantation (ASCT) to assess the impact of multiple small-dose infusions of granulocyte-colony-stimulating factor (G-CSF)-mobilized haploidentical lymphocytes as post-ASCT maintenance therapy. Among them, 50 patients received lymphocyte maintenance therapy, 21 received alternative maintenance therapy, and 35 received no maintenance therapy. Patients receiving lymphocyte maintenance therapy demonstrated significantly higher overall survival (OS) and disease-free survival (DFS) compared to those without maintenance therapy, with 4-year OS and DFS rates notably elevated. While there were no significant differences in recurrence rates among the three groups, lymphocyte maintenance therapy showcased particular benefits for intermediate-risk AML patients, yielding significantly higher OS and DFS rates and lower relapse rates compared to alternative maintenance therapy and no maintenance therapy. The study suggests that multiple small-dose infusions of G-CSF-mobilized haploidentical lymphocytes may offer promising outcomes for AML patients after ASCT, particularly for those classified as intermediate-risk. These findings underscore the potential efficacy of lymphocyte maintenance therapy in reducing disease relapse and improving long-term prognosis in this patient population.

[Chinese consensus on autologous stem cell transplantation for adult acute leukemia (2024)]

Autologous stem cell transplantation (ASCT) emerges as a therapeutic strategy following remission in adult acute leukemia (AL). It offers advantages over allogeneic hematopoietic stem cell transplantation (allo-HSCT), including independence from donor availability, absence of graft-versus-host disease (GVHD), and a reduced risk of transplant-related mortality. Furthermore, when juxtaposed with the extended regimens of consolidation chemotherapy, ASCT stands out by markedly abbreviating treatment duration, alleviating the economic strain on patients, and enhancing their overall quality of life. Despite these benefits, the adoption of ASCT among adult AL patients in China remains disproportionately low. To enhance clinical physicians' understanding of the role and position of ASCT in AL management and to improve the clinical efficacy of ASCT, it is urgent to establish a consensus among experts on ASCT for adult acute leukemia in our nation.

Autologous hematopoietic stem cell transplantation conditioning regimens and chimeric antigen receptor T cell therapy in various diseases

Conditioning regimens employed in autologous stem cell transplantation have been proven useful in various hematological disorders and underlying malig nancies; however, despite being efficacious in various instances, negative consequences have also been recorded. Multiple conditioning regimens were extracted from various literature searches from databases like PubMed, Google scholar, EMBASE, and Cochrane. Conditioning regimens for each disease were compared by using various end points such as overall survival (OS), progression free survival (PFS), and leukemia free survival (LFS). Variables were presented on graphs and analyzed to conclude a more efficacious conditioning regimen. In multiple myeloma, the most effective regimen was high dose melphalan (MEL) given at a dose of 200/mg/m2. The comparative results of acute myeloid leukemia were presented and the regimens that proved to be at an admirable position were busulfan (BU) + MEL regarding OS and BU + VP16 regarding LFS. In case of acute lymphoblastic leukemia (ALL), BU, fludarabine, and etoposide (BuFluVP) conferred good disease control not only with a paramount improvement in survival rate but also low risk of recurrence. However, for ALL, chimeric antigen receptor (CAR) T cell therapy was preferred in the context of better OS and LFS. With respect to Hodgkin's lymphoma, mitoxantrone (MITO)/MEL overtook carmustine, VP16, cytarabine, and MEL in view of PFS and vice versa regarding OS. Non-Hodgkin's lymphoma patients were administered MITO (60 mg/m2) and MEL (180 mg/m2) which showed promising results. Lastly, amyloidosis was considered, and the regimen that proved to be competent was MEL 200 (200 mg/m2). This review article demonstrates a comparison between various conditioning regimens employed in different diseases.

Women's Sexual Dysfunctions Following Stem Cell Transplant and the Impact on Couple Relationship

Stem cell transplant proved its efficacy in increasing the survival rate among young patients diagnosed with hematological malignancies. A transplant conditioning regimen is particularly destructive on the genital system, often determining premature ovarian failure, accompanied by vulvovaginal atrophy and sexual dysfunctions. The aims of the present study were, first, to evaluate sexual dysfunctions among transplanted women, using clinical examination and the female sexual function index (FSFI), and second, to determine their impact on a couple's relationship. A prospective observational comparative study was performed and included 38 patients who underwent allogenic stem cell transplant (SCT) procedures for different hematological malignancies and 38 healthy patients (control group). This study included baseline evaluation, one-year, and three-year follow-up visits. In addition to anamnesis and medically obtained information, FSFI was evaluated to determine the impact of gynecological damage in a subjective manner. In the study group, vulvovaginal atrophy was diagnosed in 76.32%, with subsequent sexual dysfunctions in 92.10% of patients, based on FSFI scoring. Even though the results improved throughout the study, at the last visit, mild vulvovaginal atrophy was diagnosed in 81.58% of patients, and the FSFI score was abnormal for 21.05%. When compared to the control group, both sexual dysfunctions and FSFI results were considerably impaired, with statistical significance. There is a confirmed negative impact of sexual dysfunctions and self-declared FSFI on couple/marital status and couple relationships, with statistical significance, at the last visit. In conclusion, anatomical, functional, and psychological difficulties are a reality of long-term survivors after a stem cell transplant. They should be addressed and assessed equally to other medical conditions, as they may determine serious consequences and impact the sexual quality of life and the couple's relationship.

Autologous stem cell transplantation in adult patients with intermediate-risk acute myeloid leukemia in first complete remission and no detectable minimal residual disease. A comparative retrospective study with haploidentical transplants of the global committee and the ALWP of the EBMT

In patients with acute myeloid leukemia (AML) of intermediate-risk (IR) in first remission (CR1) with no measurable residual disease (MRD negative), the choice of the best consolidation is questionable. 1122 adult patients from 196 centers, transplanted in 2010-21 were analyzed: 547 received an autologous stem cell transplantation (ASCT) and 575 a Haploidentical donor transplant. Because of a significant interaction, comparisons were done separately for patients with wild-type FLT3 (FLT3-wt) and FLT3-ITD mutation (FLT3-ITD). In FLT3-wt patients, haploidentical transplants had two year lower relapse incidence (RI) (16.9% versus 32.6%; HR = 0.40, p < 0.001), higher NRM higher (17.2% vs 3.5%; HR = 7.02, p < 0.001), similar LFS (65.9% vs 63.8%; p = 0.37) and lower OS (73.2% vs 80.6%; HR = 1.69, p = 0.018). In FLT3-ITD patients, haploidentical transplants had two year lower RI (8.2% vs 47.8%; HR = 0.14, p < 0.001) higher NRM (20.2% vs 5.6%; HR = 3.43, p = 0.002), better LFS (71.5% vs 46.6%; HR = 0.53, p = 0.007) and similar OS (73.5% vs 61.9%; p = 0.44). In IR AML patients with FLT3-wt in MRD negative CR1, autologous stem cell transplantation is a valid option, while in patients with FLT3-ITD, haploidentical transplant is better. Whether autologous transplantation is superior to chemotherapy in FLT3-wt patients and the role of maintenance therapy with FLT3 inhibitors remain to be studied.