Thiotepa, busulfan and fludarabine compared to busulfan and cyclophosphamide as conditioning regimen for allogeneic stem cell transplant from matched siblings and unrelated donors for acute myeloid leukemia

Lower relapse incidence with haploidentical versus matched sibling or unrelated donor hematopoietic cell transplantation for core-binding factor AML patients in CR2: A study from the Global Committee and the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Allogeneic hematopoietic cell transplantation (allo-HCT) is recommended for core-binding factor mutated (CBF) AML patients achieving second complete remission (CR2). However, approximately 20% of patients may relapse after transplant and donor preference remains unclear. We compared in this EBMT global multicenter registry-based analysis the allo-HCT outcomes using either haploidentical (Haplo), matched siblings donors (MSD), or 10/10 matched unrelated donors (MUD). Data from 865 de novo adult CBF AML patients in CR2 receiving allo-HCT in 227 EBMT centers from 2010 to 2022 were analyzed, in which 329 MSD, 374 MUD, and 162 Haplo-HCTs were included. For the entire cohort, 503 (58%) patients were inv(16)/CBFB-MYH11 and 362 patients (42%) were t(8;21)/RUNX1-RUNX1T1 AML. On multivariate analysis, Haplo-HCT was associated with a lower Relapse Incidence (RI) compared to either MSD (hazard ratio [HR] = 0.56, 95% CI 0.32-0.97; p < .05) or MUD (HR = 0.57, 95% CI: 0.33-0.99, p < .05). No significant difference was observed among the 3 types of donors on LFS, OS and GRFS. CBF-AML with t(8;21) was associated with both higher RI (HR = 1.79, 95% CI 1.3-2.47; p < .01) and higher NRM (HR = 1.58, 95% CI 1.1-2.27; p < .01) than CBF-AML with inv(16), which led to worse LFS, OS and GRFS. To conclude, for CBF-AML patients in CR2, Haplo-HCTs were associated with a lower RI compared to MSD and MUD allo-HCTs. There was no difference on LFS, OS or GRFS. CBF AML patients with inv(16) had a better progonosis than those with t(8;21) after allo-HCT in CR2.

Myeloablative conditioning regimens in adult patients with acute myeloid leukemia undergoing allogeneic hematopoietic stem cell transplantation in complete remission: a systematic review and network meta-analysis

The optimal myeloablative conditioning (MAC) regimens in adult patients with acute myeloid leukemia (AML) undergoing allogeneic hemopoietic stem cell transplantation (allo-HSCT) in complete remission (CR) remain unclear. We performed a systematic review and network meta-analysis to compare the effects of different MAC regimens. Bayesian network meta-analysis was performed using WinBUGS version 1.4.3. The commonly used MAC regimen Bu/Cy (4-day busulfan for toal 16 mg/kg orally or 12.8 mg/kg intravenously, plus 2-day cyclophosphamide for toal 120 mg/kg intravenously) is chosen as the common comparator. Pooled hazard ratios (HRs) with the associated 95% credibility interval (95% CrI) are obtained for all comparisons. We included 19 eligible studies, involving 8104 AML patients and 9 MAC regimens. Compared with Bu/Cy, 3-day busulfan plus fludarabine and thiotepa (Bu3/Flu/TT) is associated with significantly better overall survival (HR, 0.70; 95% CrI, 0.51 to 0.96) and lower risk of relapse (HR, 0.59; 95% CrI, 0.35 to 0.98). Bu3/Flu/TT is also associated with superior overall survival than Cy/TBI (cyclophosphamide plus total body irradiation), and lower risk of relapse than Bu4/Flu (4-day busulfan plus fludarabine). These results suggest that thiotepa-based new MAC regimen Bu3/Flu/TT is associated with improved outcomes in AML patients undergoing allo-HSCT in CR and worth further investigation.

Individualized busulfan dosing improves outcomes compared to fixed-dose administration in pre-transplant minimal residual disease-positive acute myeloid leukemia patients with intermediate-risk undergoing allogeneic stem cell transplantation in CR

Pre-transplant minimal residual disease (MRD) impacts negatively on post-transplant relapse risk in acute myeloid leukemia (AML). Therapeutic drug monitoring by calculating area under the curve (AUC) was developed to optimize busulfan (Bu) exposure. Here, we compared post-transplant outcomes after individualized versus fixed busulfan dosage in intermediate-risk AML who achieved CR prior to allograft focusing on pre-transplant flow-MRD. Eighty-seven patients (median, 56 years) with intermediate-risk AML and pre-transplant flow-MRD ("different from normal") were included. Thirty-two patients received individualized busulfan; 54 fixed dosages. Individualized dosage was adjusted in 25/32 patients: increased, n = 18/25 (72%); decreased: n = 7/25 (28%). After median follow-up of 27 months, we observed lower 3-year relapses (6%, 2%-19% vs. 35%, 23%-49% p = 0.02), improved 3-year leukemia-free survival (LFS) (78%, 54%-91% vs. 55%, 40%-70% p = 0.009) and - overall survival (OS) (82%, 60%-93% vs. 69%, 54%-81% p = 0.05) after individualized compared to fixed Bu. Non-relapsed mortality (NRM) and acute graft versus host disease (GvHD) were not different. In multivariate analysis, fixed Bu showed unfavorable impact on OS (hazard ratio [HR] 4.6, p = 0.044), LFS (HR 3.6, p = 0.018) and relapses (HR 3.6, p = 0.033). Fixed Bu also had unfavorable impact on LFS (3.6, 1.1-12.6, p = 0.041) in pre-transplant MRD-positive patients. Individualized, AUC-based, busulfan is associated with lower relapses in intermediate-risk AML patients allografted in CR and may overcome pre-transplant MRD-positivity.

A single-center experience of haploidentical stem cell transplantation in hematological malignancies

BACKGROUND

Since well-designed prospective comparative trials are lacking, haploidentical hematopoietic stem cell transplantations approach should be based on the expertise of a particular center. In this study, we aimed to report the results and outcomes of patients who underwent haploidentical hematopoietic stem cell transplantation.

METHODS

: Thirty-nine patients who underwent transplantation in our clinic between 2015 and 2022 were retrospectively analyzed. Primary end point of this study is to find out the survival rates of the patients.

RESULTS

The overall survival of patients was 29.9 ± 4.9 months. The disease-free survival of the patients was 37.8 ± 5.7 months. The 3-year overall survival rate of the patients was %50 and the 3-year disease-free survival rate of the patients was %53. Nineteen patients were nonsurvivors among a total of 39 patients. Busulfan-fludarabine-thiotepa was the most frequently used conditioning regimen for transplantation. Busulfan-fludarabin-antithymocyte globulin regimen is the second preferred conditioning regimen. Cyclosporine- cyclophosphamide-mycophenolate mofetil was the most widely used graft-versus-host disease prophylaxis regimen. Sixteen patients had graft-versus-host disease, 28% of the patients had acute graft-versus-host disease, and 13% had chronic graft-versus-host disease. Gastrointestinal system consists of the most involved organs in graft-versus-host disease since 15% of the patients had gastrointestinal graft-versus-host disease. First-degree relatives (parent/child) were the most frequent donor source for haploidentical hematopoietic stem cell transplantation. Sepsis was the most frequent reason of death among transplant patients.

DISCUSSION

In our center, we prefer to use high dose posttransplantation cyclophosphamide after haploidentical hematopoietic stem cell transplantation for graft-versus-host disease prophylaxis. With this approach, our center's overall survival and disease-free survival rates are comparable and compatible with the literature findings.

Successful Bone Marrow Transplantation With Intensive Post-transplant Intrathecal Chemotherapy for CNS Relapsed AML in 2 Infants

BACKGROUND

Infant acute myeloid leukemia is a rare but aggressive form of leukemia.

OBSERVATION

We report 2 children who presented with hyperleukocytosis, subsequently diagnosed with infant acute myeloid leukemia, and both developed isolated central nervous system relapse while on chemotherapy. Both infants underwent successful bone marrow transplantation with myeloablative conditioning (thiotepa, busulfan, and cyclophosphamide) without radiation, followed by 12 empiric post-transplant lumbar punctures with intrathecal cytarabine. Both patients tolerated these therapies well, and are without infections, chronic graft-versus-host disease, or any post-transplant sequelae.

CONCLUSION

Nonradiation-based conditioning followed by empiric central nervous system-directed intrathecal chemotherapy may be considered for high-risk infants with leukemia.

Targeting the CD27-CD70 Pathway to Improve Outcomes in Both Checkpoint Immunotherapy and Allogeneic Hematopoietic Cell Transplantation

Immune checkpoint inhibitor therapies and allogeneic hematopoietic cell transplant (alloHCT) represent two distinct modalities that offer a chance for long-term cure in a diverse array of malignancies and have experienced many breakthroughs in recent years. Herein, we review the CD27-CD70 co-stimulatory pathway and its therapeutic potential in 1) combination with checkpoint inhibitor and other immune therapies and 2) its potential ability to serve as a novel approach in graft-versus-host disease (GVHD) prevention. We further review recent advances in the understanding of GVHD as a complex immune phenomenon between donor and host immune systems, particularly in the early stages with mixed chimerism, and potential novel therapeutic approaches to prevent the development of GVHD.

Feasibility and Efficacy of a Pharmacokinetics-Guided Busulfan Conditioning Regimen for Allogeneic Stem Cell Transplantation with Post-Transplantation Cyclophosphamide as Graft-versus-Host Disease Prophylaxis in Adult Patients with Hematologic Malignancies

Busulfan (Bu) is an alkylating agent routinely used for conditioning regimens before allogeneic stem cell transplantation (allo-SCT). Bu shows wide pharmacokinetic (PK) variability among patients. Patients can have a higher systemic exposure (expressed as area under the curve [AUC]) with an increased risk of toxicity or a lower AUC with a higher probability of graft rejection and/or disease relapse. After i.v. administration, an optimal Bu therapeutic window (AUC target of 16,000 to 24,000 μM·minute) has been identified. The use of PK-guided Bu dosing leads to improved overall survival (OS) and progression-free survival (PFS) compared with fixed-dose administration in a variety of hematologic diseases. The aim of this study was to evaluate the outcomes and feasibility of a reduced-toxicity conditioning (RTC) regimen comprising thiotepa, Bu, and fludarabine (TBF) with therapeutic drug monitoring of Bu in patients with hematologic disorders. We report on 41 adult patients with myeloid or lymphoid malignancies who underwent an allo-SCT with a PK-guided Bu-based RTC regimen between January 2019 and October 2020. Patients received a total Bu dose to achieve a target AUC of 16,000 μM·minute in combination with Flu and thiotepa. The median time to absolute neutrophil count recovery and transfusion-independent platelet count recovery was 23 days (range, 15 to 42 days) and 29 days (range, 14 to 97 days), respectively. The cumulative incidence (CI) of nonrelapse mortality was 7% at 100 days and 13% at 1 year. Grade 3 liver toxicity was observed in 6 patients. One patient developed sinusoidal obstruction syndrome at day +27. Grade 3 mucositis occurred in 18 patients. Looking at grade ≥3 infections, the CI was 29% at 30 days, 34% at 60 days, 44% at 100 days, and 56% at 1 year. The 180-day CI of grade II-IV acute graft-versus-host disease (GVHD) was 15%, and the 1-year CI of overall chronic GVHD was 20%. With a median follow-up of alive patients of 14.4 months (range, 3.2 to 24 months), the CI of relapse at 1 year was 6%. The 1-year PFS was 81%, and 1-year OS was 84%. In conclusion, these data support the efficacy of PK-guided Bu dose in the context of a TBF conditioning regimen and the feasibility of therapeutic dosage monitoring of i.v. Bu for patients with hematologic diseases. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Thiotepa-busulfan-fludarabine (TBF) conditioning regimen in patients undergoing allogeneic hematopoietic cell transplantation for myelofibrosis: an outcome analysis from the Chronic Malignancies Working Party of the EBMT

Allogeneic hematopoietic cell transplantation (allo-HCT) remains the only curative option in MF. There is no consensus on the optimal conditioning regimen. We report outcomes of 187 patients with MF transplanted between 2010 and 2017 conditioned with TBF. Median age was 58 years. Median interval from diagnosis to allo-HCT was 44 months. Donors were haploidentical (41%), unrelated (36%) or HLA-identical siblings (23%). Stem cell source was PB in 60%. Conditioning was myeloablative in 48% of cases. Antithymocyte globulin (ATG) was used in 41% of patients. At 100 days, neutrophil and platelet engraftment were 91% and 63% after a median of 21 and 34 days, respectively. Grade II-IV and III-IV acute GVHD occurred in 24% and 12%, while at 3 years, all grade chronic GVHD and chronic extensive GVHD had been diagnosed in 38% and 11%. At 3 years, OS, RFS and GRFS were 55%, 49% and 43%, respectively. RI and NRM were 17% and 33%. On multivariate analysis, poor KPS and the use of unrelated donors were associated with worse GRFS and a higher grade II-IV acute GVHD, respectively. Neither donor type nor intensity of the conditioning regimen influenced survival outcomes. TBF is a feasible conditioning regimen in allo-HCT for MF in all donor settings although longer term outcomes are required.

Adverse Effects of Busulfan Plus Cyclophosphamide versus Busulfan Plus Fludarabine as Conditioning Regimens for Allogeneic Bone Marrow Transplantation

BACKGROUND

The side effects of conditioning regimens on the success rate of allogeneic transplantation around the world have been challenging. In this study, we aimed to investigate the side effect of Bu/Cy and Bu/Flu regimens on our patients who underwent allogeneic bone marrow transplantation.

METHODS

We analyzed 180 patients receiving bone marrow transplantation in Taleghani Hospital, in Tehran, Iran between April 2016 and December 2019. Patients in group A received a combination of intravenous busulfan 0.8 mg/kg QID over two hours for 4 consecutive days (12.8 mg/kg in total)(Savani et al., 2006) and cyclophosphamide 60 mg/kg per day for two consecutive days. Patients in group B received busulfan the same as the first group in combination with fludarabine equal to 40 mg/m² per day. Patients were followed up at regular intervals up to two years after transplantation.

RESULT

Various items were evaluated for patients, including cardiopulmonary function, psychological disorders, GVHD, and endocrine disorders such as hypothyroidism, fertility, or gonad dysfunction.  Primary hypothyroidism developed in 13.3% and 11.1% of the Bu/Cy and Bu/Flu groups, respectively (p=0.230). None of the patients in either group experienced infertility or gonad dysfunction. In group A versus group B, pulmonary diseases were detected in  4.4% versus 6.6% of BMT recipients, respectively (p = 0.223). In both groups, mitral and tricuspid regurgitation were observed in patients (8.9% vs. 11.1%; p = 0.189). Incidence of Psychological disorders was no significant difference between the two groups. 32.2% of group A versus 34.45%  of group B had skin and liver GVHD, respectively (p = 0.235).

CONCLUSION

The therapeutic-related adverse effects of the two conditioning regimens in patients who underwent allogeneic bone marrow transplant were almost similar. To improve quality of life and overall survival among BMT patients, careful evaluation of treatment-related complications should be part of the regular follow-up of them.

Structural insights of human N-acetyltransferase 10 and identification of its potential novel inhibitors

N-acetyltransferase 10 (NAT10), is an acetyltransferase that regulates RNA stability and translation processes. Association of NAT10 with several diseases including cancer, makes it a promising therapeutic target. Remodelin is the only known NAT10 inhibitor, but the structural information related to its binding with NAT10 is still obscure. Here, we predicted the human NAT10 structure using homology modeling that was not available previously and used human NAT10 to identify the novel binding site(s) of Remodelin. The alignment of the modeled human NAT10 showed 24% identity and 37% positivity with crystal structure of tRNA (Met) cytidine acetyltransferase. Molecular docking showed binding of Remodelin with NAT10 in acetyl-CoA binding pocket. Additionally, we screened a library of FDA-approved drugs for the identification of novel inhibitors of NAT10 activity. Binding score showed that four drugs namely, Fosaprepitant (- 11.709), Leucal (- 10.46), Fludarabine (- 10.347) and Dantrolene (- 9.875) bind to NAT10 and have better binding capability when compared with Acetyl-CoA (- 5.691) and Remodelin (- 5.3). Acetyl-CoA, Remodelin, and others exhibit hits for hydrophobic, hydrophilic and hydrogen interactions. Interestingly, Remodelin and others interact with the amino acid residues ILE629, GLY639, GLY641, LEU719, and PHE722 in the Acetyl-CoA binding pocket of NAT10 similar to Acetyl-CoA. Our findings revealed that Fosaprepitant, Leucal, Fludarabine, and Dantrolene are promising molecules that can be tested and developed as potential inhibitors of NAT10 acetyltransferase activity.

Total Body Irradiation Forever? Optimising Chemotherapeutic Options for Irradiation-Free Conditioning for Paediatric Acute Lymphoblastic Leukaemia

Total-body irradiation (TBI) based conditioning prior to allogeneic hematopoietic stem cell transplantation (HSCT) is generally regarded as the gold-standard for children >4 years of age with acute lymphoblastic leukaemia (ALL). Retrospective studies in the 1990's suggested better survival with irradiation, confirmed in a small randomised, prospective study in the early 2000's. Most recently, this was reconfirmed by the early results of the large, randomised, international, phase III FORUM study published in 2020. But we know survivors will suffer a multitude of long-term sequelae after TBI, including second malignancies, neurocognitive, endocrine and cardiometabolic effects. The drive to avoid TBI directs us to continue optimising irradiation-free, myeloablative conditioning. In chemotherapy-based conditioning, the dominant myeloablative effect is provided by the alkylating agents, most commonly busulfan or treosulfan. Busulfan with cyclophosphamide is a long-established alternative to TBI-based conditioning in ALL patients. Substituting fludarabine for cyclophosphamide reduces toxicity, but may not be as effective, prompting the addition of a third agent, such as thiotepa, melphalan, and now clofarabine. For busulfan, it's wide pharmacokinetic (PK) variability and narrow therapeutic window is well-known, with widespread use of therapeutic drug monitoring (TDM) to individualise dosing and control the cumulative busulfan exposure. The development of first-dose selection algorithms has helped achieve early, accurate busulfan levels within the targeted therapeutic window. In the future, predictive genetic variants, associated with differing busulfan exposures and toxicities, could be employed to further tailor individualised busulfan-based conditioning for ALL patients. Treosulfan-based conditioning leads to comparable outcomes to busulfan-based conditioning in paediatric ALL, without the need for TDM to date. Future PK evaluation and modelling may optimise therapy and improve outcome. More recently, the addition of clofarabine to busulfan/fludarabine has shown encouraging results when compared to TBI-based regimens. The combination shows activity in ALL as well as AML and deserves further evaluation. Like busulfan, optimization of chemotherapy conditioning may be enhanced by understanding not just the PK of clofarabine, fludarabine, treosulfan and other agents, but also the pharmacodynamics and pharmacogenetics, ideally in the context of a single disease such as ALL.

Improved Outcomes of Haploidentical Hematopoietic Cell Transplantation with Total Body Irradiation-Based Myeloablative Conditioning in Acute Lymphoblastic Leukemia

The optimal myeloablative conditioning (MAC) for patients undergoing haploidentical hematopoietic cell transplantation (haplo-HCT) is unknown. We studied the outcomes of total body irradiation (TBI)-based versus chemotherapy (CT)-based MAC regimens in patients with acute lymphoblastic leukemia (ALL). The study included 427 patients who underwent first haplo-HCT with post-transplantation cyclophosphamide (PTCy), following TBI-based (n = 188; 44%) or CT-based (n = 239; 56%) MAC. The median patient age was 32 years. Fludarabine-TBI (72%) and thiotepa-busulfan-fludarabine (65%) were the most frequently used TBI- and CT-based regimens, respectively. In the TBI and CT cohorts, 2-year leukemia-free survival (LFS) was 45% versus 37% (P = .05), overall survival (OS) was 51% versus 47% (P = .18), relapse incidence (RI) was 34% versus 32% (P = .44), and nonrelapse mortality (NRM) was 21% versus 31% (P < .01). In the multivariate analysis, TBI was associated with lower NRM (hazard ratio [HR], 0.53; 95% confidence interval [CI], 0.33 to 0.86; P = .01), better LFS (HR, 0.71; 95% CI, 0.52 to 0.98; P =.04), and increased risk for grade II-IV acute graft-versus-host disease (GVHD) (HR, 1.59; 95% CI, 1.08 to 2.34; P = .02) compared with CT-based MAC. The type of conditioning regimen did not impact RI, chronic GVHD, OS, or GVHD-free, relapse-free survival after adjusting for transplantation-related variables. TBI-based MAC was associated with lower NRM and better LFS compared with CT-based MAC in patients with ALL after haplo-HCT/PTCy.

Fludarabine-treosulfan compared to thiotepa-busulfan-fludarabine or FLAMSA as conditioning regimen for patients with primary refractory or relapsed acute myeloid leukemia: a study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation (EBMT)

Background

Limited data is available to guide the choice of the conditioning regimen for patients with acute myeloid leukemia (AML) undergoing transplant with persistent disease.

Methods

We retrospectively compared outcome of fludarabine-treosulfan (FT), thiotepa-busulfan-fludarabine (TBF), and sequential fludarabine, intermediate dose Ara-C, amsacrine, total body irradiation/busulfan, cyclophosphamide (FLAMSA) conditioning in patients with refractory or relapsed AML.

Results

Complete remission rates at day 100 were 92%, 80%, and 88% for FT, TBF, and FLAMSA, respectively (p = 0.13). Non-relapse mortality, incidence of relapse, acute (a) and chronic (c) graft-versus-host disease (GVHD) rates did not differ between the three groups. Overall survival at 2 years was 37% for FT, 24% for TBF, and 34% for FLAMSA (p = 0.10). Independent prognostic factors for survival were Karnofsky performance score and patient CMV serology (p = 0.01; p = 0.02), while survival was not affected by age at transplant. The use of anti-thymocyte globulin (ATG) was associated with reduced risk of grade III–IV aGVHD (p = 0.02) and cGVHD (p = 0.006), with no influence on relapse.

Conclusions

In conclusion, FT, TBF, and FLAMSA regimens provided similar outcome in patients undergoing transplant with active AML. Survival was determined by patient characteristics as Karnofsky performance score and CMV serology, however was not affected by age at transplant. ATG appears able to reduce the incidence of acute and chronic GVHD without influencing relapse risk.

Electronic supplementary material

The online version of this article (10.1186/s13045-019-0727-4) contains supplementary material, which is available to authorized users.

Haploidentical transplantation is associated with better overall survival when compared to single cord blood transplantation: an EBMT-Eurocord study of acute leukemia patients conditioned with thiotepa, busulfan, and fludarabine

Background

Thiotepa-busulfan-fludarabine (TBF) is a widely used conditioning regimen in single umbilical cord blood transplantation (SUCBT). More recently, it was introduced in the setting of non-T cell depleted haploidentical stem cell transplantation (NTD-Haplo). Whether TBF based conditioning provides additional benefit in transplantation from a particular alternative donor type remains to be established.

Methods

This was a retrospective study based on an international European registry. We compared outcomes of de-novo acute myeloid leukemia patients in complete remission receiving NTD-Haplo (n = 186) vs. SUCBT (n = 147) following myeloablative conditioning (MAC) with TBF. Median follow-up was 23 months. Treatment groups resembled in baseline characteristics.

Results

SUCBT was associated with delayed engraftment and higher graft failure. In multivariate analysis no statistically significant differences were observed between the two groups in terms of acute or chronic graft-versus-host disease (GvHD) (HR = 1.03, p = 0.92 or HR = 1.86, p = 0.21) and relapse incidence (HR = 0.8, p = 0.65). Non-relapse mortality (NRM) was significantly higher in SUCBT as compared to NTD-Haplo (HR = 2.63, p = 0.001); moreover, SUCBT did worse in terms of overall survival (HR = 2.18, p = 0.002), leukemia-free survival (HR = 1.94, p = 0.007), and GvHD relapse-free survival (HR = 2.38, p = 0.0002).

Conclusions

Our results suggest that TBF-MAC might allow for a potent graft-versus-leukemia, regardless of the alternative donor type. Furthermore, in patients receiving TBF-MAC, survival with NTD-Haplo may be better compared to SUCBT due to decreased NRM.

Electronic supplementary material

The online version of this article (10.1186/s13045-018-0655-8) contains supplementary material, which is available to authorized users.