BU- vs TBI-based conditioning for adult patients with ALL

A network meta-analysis of the effectiveness of different basic preconditioning regiments in allogeneic hematopoietic stem cell transplantation

OBJECTIVE

To investigate and compare the effects of basic preconditioning regimens Bu/Cy, Cy/TBI and Flu/Bu for the treatment of patients in allogeneic hematopoietic stem cell transplantation.

METHODS

It comprised exploring the published literature in the databases of PubMed, EMBASE, Cochrane Library, and Web of Science, using suitable keywords pertaining to various basic pretreatments Bu/Cy, Cy/TBI, and Flu/Bu, prior to allogeneic hematopoietic stem cell transplantation, and then extracting the searched outcome indicators of Overall Survival (OS) and survival (herein represented as OS and survival). Further, the results were estimated with meta-analysis using R, where the incidence of GVHD was reported in odds ratio (OR) with its 95% confidence interval (95%CI).

RESULTS AND DISCUSSION

A total of 14 papers were included in this study, including 1436 cases were treated with Bu/Cy, 1816 cases with Cy/TBI, and 549 cases with Flu/Bu in the preconditioning regimen. After OS was the outcome pooled, compared with Flu/Bu in the preconditioning group, the results (Cy/TBI HR = 1.12 (95% Cl:1.04,1.61), Bu/Cy HR = 1.24 (95% Cl. 1.13,2.06)) showed that Flu/Bu preconditioning regimen significantly improved the overall survival rate of allogeneic HSCT patients. With the incidence of GVHD as the outcome summary, compared with Flu/Bu in the pretreatment group, the results (Cy/TBI HR = 1.24 (95% Cl:1.12, 1.82), Bu/Cy HR = 1.14 (95% Cl. 1.03, 2.12)) indicated that Flu/Bu in the pretreatment regimen group also significantly reduced the incidence of GVHD after allogeneic HSCT.

CONCLUSION

Patients who received the basal preconditioning regimen Flu/Bu before allogeneic hematopoietic stem cell transplantation had the lowest hazard ratio for overall survival (OS) development. This indicates that the use of the basal preconditioning regimen Flu/Bu for the treatment of patients was the most effective, although the quality of the studies included needs to be confirmed by high-quality randomized controlled trials.

Comparing transplant outcomes in ALL patients after myeloablative conditioning in mismatch-related or unrelated donor settings

The optimal myeloablative conditioning regimen for ALL patients undergoing hematopoietic cell transplant (HCT) with an alternative donor is unknown. We analyzed HCT outcomes ALL patients (n = 269) who underwent HCT at our center from 2010 to 2020 in complete remission (CR) after FTBI-etoposide and CNI-based GvHD prophylaxis for matched donor HCT (ETOP-package; n = 196) or FTBI-Fludarabine and post-transplant cyclophosphamide (PTCy)-based prophylaxis for HLA- mismatched (related or unrelated) donors (FLU-package; n = 64). Patients in FLU-package showed a significant delay in engraftment (p < 0.001) and lower cumulative incidence (CI) of any and extensive chronic GVHD (p = 0.009 and 0.001, respectively). At the median follow up of 4.6 years (range 1-12 years); non-relapse mortality, overall or leukemia-free survival and GVHD-free/relapse-free survival were not significantly impacted by the choice of conditioning. However, in patients at CR2 or with measurable residual disease (MRD+), there was a trend towards higher relapse after FLU-package (p = 0.08 and p = 0.07, respectively), while patients at CR1 regardless of MRD status had similar outcomes despite the package/donor type (p = 0.9 and 0.7, respectively). Our data suggests that FLU-package for alternative donors offers comparable outcomes to ETOP-package for matched donor HCT to treat ALL. Disease status and depth of remission at HCT were independent predictors for better outcomes.

Two Different Transplant Preconditioning Regimens Combined with Irradiation and Chemotherapy in the Treatment of Childhood Leukemia: Systematic Review and Meta-Analysis

Objective

To observe the therapeutic effect and the incidence of adverse reactions of total body irradiation plus cyclophosphamide (TBI/CY) and busulfan plus cyclophosphamide (BU/CY) in the treatment of pediatric hematopoietic stem cell transplantation.

Methods

By searching the Cochrane Library, PubMed, Web of Knowledge, Embase, Chinese Biomedical Literature Database (CBM), and screening randomized controlled trials (RCTs), quality evaluation and data extraction were performed for the included literature, and meta-analysis was performed for RCTs included at using Review Manager 5.2 software.

Results

A total of 10160 patients were enrolled in 15 RCTs, including 5211 patients in the TBI/CY group and 4949 patients in the BU/CY group. Meta-analysis showed that there was a statistical difference in transplant failure rate (OR = 1.56, 95% CI (1.23, 1.97), P = 0.0002, I 2 = 56%, Z = 3.69), transplant mortality (OR = 1.45, 95% CI (1.24, 1.68), P < 0.00001, I 2 = 76%, Z = 4.80), transplantation long-term disease-free survival rate (OR = 1.52, 95% CI (1.09, 2.12), P = 0.01, I 2 = 0%, Z = 2.50), and transplantation adverse reactions (OR = 1.28, 95% CI (1.08, 1.52), P = 0.004, I 2 = 0%, Z = 2.85).

Conclusion

Meta-analysis showed that TBI/CY combined pretreatment regimen was more effective than BU/CY regimen alone in the treatment of pediatric hematologic transplantation, with a lower incidence of adverse reactions and significant long-term survival efficacy.

Total Body Irradiation-Based Conditioning Regimen Improved the Survival of Adult Patients With T-Cell Lymphoblastic Lymphoma After Allogeneic Peripheral Blood Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is one of the consolidation modalities for adult patients with T-cell lymphoblastic lymphoma (T-LBL). However, the optimal conditioning regimen needs to be explored. In the present study, 40 patients with T-LBL undergoing allo-HSCT were retrospectively analyzed, including 23/40 (57.5%) with total body irradiation (TBI)–based conditioning regimen and 17/40 (42.5%) with busulfan (BU)-based regimen. TBI–based regimen significantly increased the cumulative incidence (CI) of grade II to IV acute graft-versus-host disease (aGvHD) as compared with BU-based regimen (13.0% vs 0%, P = 0.000). The relapse risk was significantly lowered in TBI-based group with a 2-year CI of relapse (CIR) of 9.1% as compared with that of 49.6% in BU-based group (P = 0.008). The 1-year and 2-year non-relapse mortalities (NRMs) for all patients were 5.0% and 10.3%, respectively. The 1-year and 2-year NRMs were 8.9% and 16.0% in TBI-based group, and 0.00% and 0.00% in BU-based group (P = 0.140). The 2-year probabilities of overall survival (OS) and relapse-free survival (RFS) were 83.0% [95% confidence interval, 63.4%–100%] and 74.0% (95% confidence interval, 54.4%–93.6%) in TBI-based group, which were higher than that of 35.0% (95% confidence interval, 0.0%–72.2%) and 50.0% (95% confidence interval, 24.5%–75.4%) in BU-based group, respectively (P = 0.020 for OS and P = 0.081 for RFS). In multivariate analysis, TBI-based regimen significantly reduced the risk of relapse [subdistribution hazard ratio (SHR) = 0.030, 95% CI, 0.002–0.040, P = 0.000] and improved the OS [hazard ratio (HR) 0.121, 95% CI, 0.021–0.683, P = 0.017] as an independent prognostic factor. These results suggested that TBI-based regimen might be an optimal choice for adult patients with T-LBL undergoing allo-HSCT.

Total body irradiation-based versus busulfan-based myeloablative conditioning for single-unit cord blood transplantation in adults

Comparative studies between total body irradiation (TBI)-based and busulfan-based myeloablative conditioning (MAC) regimens for cord blood transplantation (CBT) have been limited. We retrospectively analyzed the results of single-unit CBT in 333 adult patients who received either TBI-based (n = 258) or busulfan-based (n = 75) MAC regimens at our institute. After adjusting for significant variables in the univariate analysis, there were no significant differences in neutrophil recovery (hazard ratio (HR), 0.88; p = .460), grade III-IV acute graft-versus-host disease (GVHD) (HR: 1.40, p = .410), extensive chronic GVHD (HR: 0.73, p = .380), relapse (HR: 0.61, p = .270), non-relapse mortality (HR: 1.38, p = .420), overall survival (HR: 1.18, p = .637), or event-free survival (HR: 1.08, p = .773), although platelet recovery was lower with marginal significance for the busulfan-based regimen (HR: 0.67, p = .068). In subgroup analysis, TBI-based regimens were superior to busulfan-based regimens in terms of survival for acute lymphoblastic leukemia, but not for myeloid malignancies. Further investigation is warranted even for CBT.

Integrating CAR T-Cell Therapy and Transplantation: Comparisons of Safety and Long-Term Efficacy of Allogeneic Hematopoietic Stem Cell Transplantation After CAR T-Cell or Chemotherapy-Based Complete Remission in B-Cell Acute Lymphoblastic Leukemia

Patients often undergo consolidation allogeneic hematopoietic stem cell transplantation (allo-HSCT) to maintain long-term remission following chimeric antigen receptor (CAR) T-cell therapy. Comparisons of safety and efficacy of allo-HSCT following complete remission (CR) achieved by CAR-T therapy versus by chemotherapy for B-cell acute lymphoblastic leukemia (B-ALL) has not been reported. We performed a parallel comparison of transplant outcomes in 105 consecutive B-ALL patients who received allo-HSCT after achieving CR with CAR-T therapy (n=27) or with chemotherapy (n=78). The CAR-T-allo-HSCT group had more patients in second CR compared to the chemotherapy-allo-HSCT group (78% vs. 37%; p<0.01) and more with complex cytogenetics (44% vs. 6%; p<0.001) but the proportion of patients with pre-transplant minimal residual disease (MRD) was similar. The median follow-up time was 49 months (range: 25-54 months). The CAR-T cohort had a higher incidence of Grade II-IV acute graft-versus-host disease (aGVHD 48.1% [95% CI: 46.1-50.1%] vs. 25.6% [95%CI: 25.2-26.0%]; p=0.016). The incidence of Grade III-IV aGVHD was similar in both groups (11.1% vs.11.5%, p=0.945). The overall incidence of chronic GVHD in the CAR-T group was higher compared to the chemotherapy group (73.3% [95%CI: 71.3-75.3%] vs. 55.0% [95%CI: 54.2-55.8%], p=0.107), but the rate of extensive chronic GVHD was similar (11.1% vs.11.9%, p=0.964). Efficacy measures 4 years following transplant were all similar in the CAR-T vs. the chemotherapy groups: cumulative incidences of relapse (CIR; 11.1% vs.12.8%; p=0.84), cumulative incidences of non-relapse mortality (NRM; 18.7% vs. 23.1%; p=0.641) leukemia-free survival (LFS; 70.2% vs. 64.1%; p=0.63) and overall survival (OS; 70.2% vs. 65.4%; p=0.681). We found that pre-transplant MRD-negative CR predicted a lower CIR and a higher LFS compared with MRD-positive CR. In conclusion, our data indicate that, in B-ALL patients, similar clinical safety outcomes could be achieved with either CD19 CAR T-cell therapy followed by allo-HSCT or chemotherapy followed by allo-HSCT. Despite the inclusion of more patients with advanced diseases in the CAR-T group, the 4-year LFS and OS achieved with CAR T-cells followed by allo-HSCT were as remarkable as those achieved with chemotherapy followed by allo-HSCT. Further confirmation of these results requires larger, randomized clinical trials.

Impact of Total Body Irradiation-Based Myeloablative Conditioning Regimens in Patients with Acute Lymphoblastic Leukemia Undergoing Allogeneic Hematopoietic Stem Cell Transplantation: Systematic Review and Meta-Analysis

Allogeneic hematopoietic cell transplantation (allo-HCT) is a curative treatment option for patients with acute lymphoblastic leukemia (ALL). Both total body irradiation (TBI)-based and chemotherapy only-based myeloablative transplantation conditioning regimens have been applied, but the optimal regimen remains unclear. We performed a systematic review to assess the efficacy of TBI-based versus chemotherapy only-based myeloablative conditioning regimens. We searched PubMed, Embase, and Cochrane databases and meeting abstracts for all studies comparing TBI-based and chemotherapy only-based conditioning regimens in patients who underwent allo-HCT for ALL. Two authors independently reviewed all studies for inclusion and extracted data related to overall survival (OS), progression-free survival (PFS), nonrelapse mortality (NRM), relapse, and acute and chronic graft-versus-host disease (GVHD). Eight studies were included in the final analysis. The overall methodological quality of the included studies was optimal. TBI-based regimens showed evidence of benefit compared with chemotherapy only-based conditioning regimens in terms of relapse (relative risk [RR], 0.82; 95% confidence interval [CI], 0.72 to 0.94; 6 studies, 5091 patients), OS (hazard ratio [HR], 0.76; 95% CI, 0.64 to 0.89; 7 studies, 4727 patients), and PFS (HR, 0.74; 95% CI, 0.63 to 0.85; 7 studies, 4727 patients). The TBI-based regimen did not increase the likelihood of grade II-IV acute GVHD (RR, 1.12; 95% CI, 0.92 to 1.36; 5 studies, 4996 patients) or chronic GVHD (RR, 1.10; 95% CI, 1.00 to 1.21; 5 studies, 4490 patients), or NRM (RR, 0.94; 95% CI, 0.69 to 1.28; 6 studies, 4522 patients). However, TBI-based regimens were associated with an increased risk of grade III-IV acute GVHD (RR, 1.29; 95% CI, 1.01 to 1.63; 3 studies, 3675 patients). A subgroup comparison of patients age ≥16 years showed similar results. This systematic review represents evidence supporting the use of TBI-based conditioning regimen in patients undergoing allo-HCT for ALL who are candidates for myeloablative conditioning, as it offers better OS, PFS, and less relapse with acceptable NRM.

Haematopoietic Stem Cell Transplantation in Adolescents and Young Adults With Acute Lymphoblastic Leukaemia: Special Considerations and Challenges

Adolescents and young adults (AYAs) represent a challenging group of acute lymphoblastic leukaemia (ALL) patients with specific needs. While there is growing evidence from comparative studies that this age group profits from intensified paediatric-based chemotherapy, the impact and optimal implementation of haematopoietic stem cell transplantation (HSCT) in the overall treatment strategy is less clear. Over recent years, improved survival rates after myeloablative allogeneic HSCT for ALL have been reported similarly for AYAs and children despite differences in transplantation practise. Still, AYAs appear to have inferior outcomes and an increased risk of treatment-related morbidity and mortality in comparison with children. To further improve HSCT outcomes and reduce toxicities in AYAs, accurate stratification and evaluation of additional or alternative targeted treatment options are crucial, based on specific molecular and immunological characterisation of ALL and minimal residual disease (MRD) assessment during therapy. Age-specific factors such as increased acute toxicities and poorer adherence to treatment as well as late sequelae might influence treatment decisions. In addition, educational, social, work, emotional, and sexual aspects during this very crucial period of life need to be considered. In this review, we summarise the key findings of recent studies on treatment approach and outcomes in this vulnerable patient group after HSCT, turning our attention to the different approaches applied in paediatric and adult centres. We focus on the specific needs of AYAs with ALL regarding social aspects and supportive care to handle complications as well as fertility issues. Finally, we comment on potential areas of future research and concisely debate the capacity of currently available immunotherapies to reduce toxicity and further improve survival in this challenging patient group.

Irradiation free conditioning regimen is associated with high relapse rate in Egyptian patients with acute lymphoblastic leukemia following allogeneic hematopoietic stem cell transplantation

Background

Allogeneic hematopoietic stem cell transplantation (Allo-HSCT) is a curative treatment for adult patients with acute lymphoblastic leukemia (ALL). Cyclophosphamide plus total body irradiation (TBI/Cy) or plus busulfan (Bu/Cy) is a widely used pre-transplant conditioning regimen for ALL. We retrospectively compared the overall survival (OS), disease-free survival (DFS), and other transplant outcomes of allo-HSCT in 119 adult patients with ALL who received an HLA-matched sibling allo-HSCT using TBI-based versus non-TBI-based conditioning regimens. Patients were divided into two groups by their conditioning regimen: TBI/Cy or Bu/Cy.

Results

Median OS was 11 months in the TBI/Cy group and 6.2 months in the Bu/Cy group. Median DFS was 11.1 months in the TBI group versus 6.8 months in the Bu group, without a statistically significant difference. A higher risk of relapse was observed with the Bu/Cy regimen (HR 2.709, CI 95% 1.106 to 6.638, p = 0.029). Patients who received a transplant in ≥ CR2 were associated with poor DFS.

Conclusion

Despite the high relapse rate in the non-TBI regimen (Bu/Cy), both regimens had no statistically significant differences in OS, DFS, and NRM. Additional prospective studies are indeed warranted to evaluate the long-term outcomes of radiation-free regimens, including oral and intravenous busulfan, and compare these regimens with TBI-based ones.

Cyclophosphamide versus etoposide in combination with total body irradiation as conditioning regimen for adult patients with Ph-negative acute lymphoblastic leukemia undergoing allogeneic stem cell transplant: On behalf of the ALWP of the European Society for Blood and Marrow Transplantation

Allogeneic hematopoietic cell transplantation (alloHCT) with myeloablative conditioning based on total body irradiation (TBI) is widely used for the treatment of adults with acute lymphoblastic leukemia (ALL). TBI is most frequently administered in combination with either cyclophosphamide (Cy/TBI) or etoposide (Vp/TBI). The goal of this study was to retrospectively compare these two regimens. Adult patients with Ph-negative ALL treated with alloHCT in first or second complete remission who received Cy/TBI (n = 1346) or Vp/TBI (n = 152) conditioning were included in the analysis. In a univariate analysis, as compared to Cy/TBI, the use of Vp/TBI was associated with reduced incidence of relapse (17% vs. 30% at 5 years, P = .007), increased rate of leukemia-free survival (60% vs. 50%, P = .04), and improved "graft versus host disease (GVHD) and relapse-free survival" (GRFS, 43% vs. 33%, P = .04). No significant effect could be observed in terms of the incidence of nonrelapse mortality or acute or chronic GVHD. In a multivariate model, the use of Vp/TBI was associated with reduced risk of relapse (HR = 0.62, P = .04) while the effect on other study end-points was not significant. In conclusion, conditioning regimen based on Vp combined with TBI appears more effective for disease control than the combination of Cy with TBI for adult patients with Ph-negative ALL treated with alloHCT.

Hematopoietic stem cell transplant in adults with acute lymphoblastic leukemia: the present state

INTRODUCTION

Allogeneic hematopoietic stem cell transplant (allo-HSCT) has an important role in management of acute lymphoblastic leukemia (ALL). Proper patient selection is central to ensure optimal outcomes. Areas covered: This review covers various aspects of HSCT in ALL patients, including indications, donor selection, conditioning regimens, and post-transplant management. Expert commentary: Allo-HSCT is important in post-remission management of ALL but proper risk-stratification is a major challenge. Incorporation of minimal residual disease (MRD) and molecular testing will improve patient allocation. Patients receiving pediatric-inspired induction who achieve molecular remission might not need allo-HSCT in first remission. Allo-HSCT should be considered in patients who don't achieve MDR negativity, didn't receive intensive induction, or have high risk cytogenetic and molecular features. Despite improved responses with tyrosine kinase inhibitors (TKIs) in Philadelphia positive (Ph+) ALL, allo-HSCT remains standard. Matched sibling donors are the optimal graft source, but other sources are valid alternatives. There is no single optimal conditioning regimen and retrospective studies found myeloablative and reduced intensity regimens to be comparable. Following allo-HSCT, there is no role for maintenance therapy in Philadelphia-negative ALL. In Ph+ ALL, maintenance TKIs improve outcomes. The integration of targeted and immunotherapies in the peri-transplant period holds potential for improved outcomes.

Refining the Role of Hematopoietic Cell Transplantation for Acute Lymphoblastic Leukemia as Novel Therapies Emerge

Acute lymphoblastic leukemia (ALL) is a rare adult neoplasm. The disorder consists of precursor B or T phenotypes. In the pediatric population, ALL was a success story in that 80% of children with ALL enjoy long-term survival. In adults, similar complete remission rates are achieved with current induction regimens; however, less than 50% of patients are alive at 5 years, with most deaths due to relapsed disease. Accordingly, optimizing post remission consolidation therapy might improve in outcomes. Such strategies may include chemotherapy and autologous or allogeneic transplant. Moreover, the ability to modify such therapy based on better disease risk stratification while taking into account patient characteristics such as performance status and presence of comorbidities is necessary to tailor treatment accordingly. Here, we review available medical literature on the use of hematopoietic cell transplantation as a consolidation modality in the treatment of adult ALL.

Haploidentical versus Matched-Sibling Transplant in Adults with Philadelphia-Negative High-Risk Acute Lymphoblastic Leukemia: A Biologically Phase III Randomized Study

PURPOSE

Although matched-sibling donor (MSD) hematopoietic stem-cell transplantation (HSCT) has an established role in the management of adults with acute lymphoblastic leukemia (ALL) in first complete remission (CR1), the effect of haploidentical donor (HID) HSCT as post-remission treatment for this portion of patients is not defined.

EXPERIMENTAL DESIGN

Transplantation outcomes from HIDs or MSDs were compared in a disease-specific, biologically phase III randomized, multicenter study. Between July 2010 and December 2013, 210 patients with Philadelphia-negative high-risk ALL in CR1 were assigned to undergo unmanipulated HIDs (121 patients) or MSDs HSCT (89 patients) according to donor availability on an intent-to-treat (ITT) basis.

RESULTS

Overall, 24 of the 210 patients had lost transplant eligibility. Therefore, 186 of 210 (88%) patients were finally transplanted from MSD (n = 83) or HID (n = 103). Based on the ITT principle, the 3-year disease-free survival (DFS) did not differ between HID and MSD groups [61%, 95% confidence interval (CI), 52%-70%; vs. 60%, CI, 49%-71%; P = 0.91] from CR, neither did DFS differ between the two groups (68%, CI, 58%-78%; vs. 64%, CI, 52%-76%; P = 0.56) from time of the graft, with cumulative incidence of nonrelapse mortality of 13% (CI, 7%-19%) and 11% (CI, 4%-18%; P = 0.84) and relapse rates of 18% (CI, 10%-26%) and 24% (CI, 14%-34%; P = 0.30), respectively.

CONCLUSIONS

Haploidentical HSCT achieves outcomes similar to those of MSD-HSCT for Philadelphia-negative high-risk ALL patients in CR1. Such transplantation could be a valid alternative as post-remission treatment for high-risk ALL patients in CR1 lacking an identical donor. Clin Cancer Res; 22(14); 3467-76. ©2016 AACR.

Low Dose Total Body Irradiation Combined With Recombinant CD19-Ligand × Soluble TRAIL Fusion Protein is Highly Effective Against Radiation-Resistant B-Precursor Acute Lymphoblastic Leukemia in Mice

In high-risk remission B-precursor acute lymphoblastic leukemia (BPL) patients, relapse rates have remained high post-hematopoietic stem cell transplantation (HSCT) even after the use of very intensive total body irradiation (TBI)-based conditioning regimens, especially in patients with a high “minimal residual disease” (MRD) burden. New agents capable of killing radiation-resistant BPL cells and selectively augmenting their radiation sensitivity are therefore urgently needed. We report preclinical proof-of-principle that the potency of radiation therapy against BPL can be augmented by combining radiation with recombinant human CD19-Ligand × soluble TRAIL (“CD19L–sTRAIL”) fusion protein. CD19L–sTRAIL consistently killed radiation-resistant primary leukemia cells from BPL patients as well as BPL xenograft cells and their leukemia-initiating in vivo clonogenic fraction. Low dose total body irradiation (TBI) combined with CD19L–sTRAIL was highly effective against (1) xenografted CD19⁺ radiochemotherapy-resistant human BPL in NOD/SCID (NS) mice challenged with an otherwise invariably fatal dose of xenograft cells derived from relapsed BPL patients as well as (2) radiation-resistant advanced stage CD19⁺ murine BPL with lymphomatous features in CD22ΔE12xBCR-ABL double transgenic mice. We hypothesize that the incorporation of CD19L–sTRAIL into the pre-transplant TBI regimens of patients with very high-risk BPL will improve their survival outcome after HSCT.

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CD19L–sTRAIL plus low dose radiation kills leukemia-initiating cells.

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CD19L–sTRAIL plus low dose TBI is very well tolerated in mice.

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CD19L–sTRAIL plus low dose TBI is very effective in mouse models of BPL.

Total body irradiation and cyclophosphamide plus antithymocyte globulin regimen is well tolerated and promotes stable engraftment as a preparative regimen before T cell-replete haploidentical transplantation for acute leukemia

We compared total body irradiation (TBI, 700 cGy)/cyclophosphamide (Cy, 3.6 g/m(2))/simustine (250 mg/m(2)) plus antithymocyte globulin (ATG) (TBI/Cy plus ATG) with cytarabine (8 g/m(2))/i.v. busulfan (Bu, 9.6 mg/kg)/Cy (3.6 g/m(2))/simustine (250 mg/m(2)) plus ATG (modified Bu/Cy plus ATG) as preparative therapy in T cell-replete haploidentical hematopoietic stem cell transplantation (haplo-HSCT) for acute leukemia. From August 2009 to August 2013, 38 consecutive patients using TBI/Cy plus ATG regimen for T cell-replete haplo-HSCT (TBI group) at our center were eligible, which contained 28 high-risk and 10 standard-risk patients. A nested case-control study was designed. Seventy-seven patients using modified Bu/Cy plus ATG regimen (Bu group) were randomly selected in a 1 to 3:1 ratio matching for age, disease and status, year of HSCT (±2 years), and length of follow-up. Only 1 graft failure occurred in the TBI group. The incidence and time of neutrophil and platelet engraftment were comparable between the 2 groups. Severe grades III/IV graft-versus-host disease was observed in 13.4% of Bu group and only 2.6% of TBI group (P = .083). More toxicity of the liver (37.7% versus 10.5%; P = .002) and more hemorrhagic cystitis occurred in the Bu group (49.3% versus 23.7%, P = .008). Diarrhea was more common in the TBI group (44.7% versus 22.1%; P = .031). No significant differences were found in the 2-year incidences of relapse (26.5% for TBI group versus 32.3% for Bu group, P = .742), 1-year transplant-related mortality (12.6% versus 16.2%, P = .862), 2-year overall survival (60.2% versus 57.0%, P = .937), and 2-year incidence of disease-free survival (57.9% versus 56.6%, P = .845) between the 2 groups. We conclude that the TBI/Cy plus ATG regimen seems to be feasible in T cell-replete haplo-HSCT, which promotes stable engraftment and a lower incidence of liver toxicity and hemorrhagic cystitis. However, longer follow-up is necessary to determine the late relapse rate and late toxicity.

Comparison of total body irradiation plus cyclophosphamide with busulfan plus cyclophosphamide as conditioning regimens in patients with acute lymphoblastic leukemia undergoing allogeneic hematopoietic stem cell transplant

Conditioning regimens used during stem cell transplant provide prolonged control or cure of the disease in patients with acute lymphoblastic leukemia (ALL). In this study, we present a comparison of treatment results for 95 patients with ALL who underwent allogeneic hematopoietic stem cell transplant (AHSCT) with total body irradiation plus cyclophosphamide (TBI + Cy) or busulfan plus cyclophosphamide (Bu + Cy) as conditioning regimen. Median age was 25 (range: 9-54) years. Median follow-up was 24 (range: 3-107) months. Median overall survival (OS) was found to be 29 months. Median event-free survival (EFS) was 9 months. Median OS was 37 months in the TBI + Cy arm, while it was 12 months in the Bu + Cy arm, suggesting a significant advantage favoring the TBI + Cy arm (p = 0.003). Median EFS was 13 months in the TBI + Cy arm, while it was 4 months in the Bu + Cy arm, indicating a significant difference (p = 0.006). In univariate and multivariate analysis, it was found that high OS and EFS were significantly correlated with TBI + Cy conditioning regimen and lack of transplant-related mortality (p < 0.05). The TBI + Cy conditioning regimen was found to be superior to the Bu + Cy regimen in patients with ALL undergoing AHSCT regarding both OS and EFS.

Pharmacokinetically-targeted BU and fludarabine as conditioning before allogeneic hematopoietic cell transplantation for adults with ALL in first remission

Allogeneic hematopoietic cell transplantation offers improved survival in patients with ALL, but with regimens containing TBI, the nonrelapse mortality is 20-40%. Efforts to lessen transplant toxicities by reducing conditioning regimen intensity have led to increased relapse risk. Therefore, there is a need for less toxic regimens that maintain an anti-leukemia effect. We report here a retrospective review of 65 patients with ALL in first remission receiving grafts from allogeneic donors after fludarabine 40 mg/m(2)/day for 4 days and i.v. BU targeted to a median daily area under the concentration-time curve below 6000 μmoles min/L. At 2 years after transplantation, OS was 65% (95% confidence interval (CI): 52-77%), relapse-free survival was 61% (95% CI: 48-73%), cumulative incidence of relapse was 26% (95% CI: 17-39%) and cumulative incidence of nonrelapse mortality was 14% (95% CI: 8-26%). Age over 35 years, Ph chromosome positivity and minimal residual disease at transplant did not adversely affect outcomes. Pharmacokinetically targeted BU and fludarabine can provide intensive pre-transplant conditioning for adults with ALL in first remission, with promising relapse-free and OS rates.