Chemotherapy followed by modified donor lymphocyte infusion as a treatment for relapsed acute leukemia after haploidentical hematopoietic stem cell transplantation without in vitro T-cell depletion: superior outcomes compared with chemotherapy alone and an analysis of prognostic factors

Donor Lymphocyte Infusion in the Treatment of Post-Transplant Relapse of Acute Myeloid Leukemias and Myelodysplastic Syndromes Significantly Improves Overall Survival: A French-Italian Experience of 134 Patients

BACKGROUND

Disease relapse after allogeneic stem cell transplantation (allo-SCT) is the main challenge for curing acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). We investigated the overall survival (OS) after allo-SCT relapse according to different therapeutic approaches.

METHODS

We analyzed 134 patients who relapsed after allo-SCT performed between 2015 and 2021 at Saint-Antoine University Hospital, Paris and Spedali Civili di Brescia, Brescia. Of these, 103 (77%) were treated, comprising 69/103 (67%) who received therapy in overt relapse and 34/103 (33%) who were treated in a pre-emptive manner when molecular/cytogenetics recurrence or mixed chimerism occurred. The treatment was donor lymphocyte infusion (DLI)-based for 40/103 (39%) patients.

RESULTS

The 1-, 2-, and 5-year OS of patients treated with DLI (n = 40) was 67%, 34%, and 34%, respectively, for those treated preventively (n = 20) and 43%, 20%, and 20%, respectively, for those treated in overt relapse (n = 20) (p < 0.01). The 1-, 2-, and 5-year OS of patients treated without DLI (n = 63) was 54%, 40%, and 26%, respectively, for those treated preventively (n = 14) and 17%, 5%, and 0%, respectively, for those treated in overt relapse (n = 49) (p < 0.01).

CONCLUSIONS

Relapse treatment with a pre-emptive strategy was associated with improved outcomes, particularly when DLI was employed.

Prophylactic versus Preemptive modified donor lymphocyte infusion for high-risk acute leukemia after allogeneic hematopoietic stem cell transplantation: a multicenter retrospective study

Donor lymphocyte infusion (DLI) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) has been widely used in preventing post-transplant relapse. We conducted this study to compare the superiority of prophylactic modified DLI (pro-DLI) and preemptive modified DLI (pre-DLI) in patients with high-risk relapse features acute leukemia. Pro-DLI was performed in 95 patients, whereas the pre-DLI cohort included 176 patients. In the pre-DLI cohort, 42 patients relapsed without chance for pre-DLI while 95 patients remained CR without detectable minimal residual disease (MRD). Thirty-nine patients in the pre-DLI cohort became minimal MRD positive/mixed chimerism and received pre-DLI. Pro-DLI cohort had higher 3-year progression-free-survival (PFS) (63.4%vs.53.0%, P = 0.026) and overall survival (OS) (65.2% vs. 57.0%, P = 0.14) compared to the pre-DLI cohort. The 3-year cumulative incidence of relapse (CIR) was 25.3% in the pro-DLI cohort which was significantly lower than 36.7% in the pre-DLI cohort (P = 0.02). The cumulative incidence of grade III-IV aGVHD, cGVHD and non-relapse mortality were comparable between cohorts. Multivariable analysis demonstrated strong protective effect of pro-DLI on OS (hazard ratio (HR) = 0.63, P = 0.04), PFS (HR = 0.54, P = 0.005) and CIR (HR = 0.50, P = 0.005). In high-risk patients with acute leukemia, early scheduled pro-DLI rather than pre-DLI after detectable MRD would reduce post-transplant relapse and improve long-term survival.

Efficacy and safety of venetoclax combined with hypomethylating agents for relapse of acute myeloid leukemia and myelodysplastic syndrome post allogeneic hematopoietic stem cell transplantation: a systematic review and meta-analysis

BACKGROUND

Currently, there is no standard treatment for managing relapse in patients with acute myeloid leukemia and myelodysplastic syndrome (AML/MDS) after allogeneic hematopoietic cell transplantation. Venetoclax-based therapies have been increasingly used for treating post-transplantation relapse of AML. The aim of this systematic review and meta-analysis was to evaluate the efficacy and adverse events of Venetoclax combined with hypomethylating agents (HMAs) for AML/MDS relapse post-transplantation.

METHODS

We searched PubMed, Web of Science, Excerpta Medica Database, Cochrane Library, and Clinical. gov for eligible studies from the inception to February 2022. The Methodological Index for Non-Randomized Studies was used to evaluate the quality of the included literatures. The inverse variance method calculated the pooled proportion and 95% confidence interval (CI).

RESULTS

This meta-analysis included 10 studies involving a total of 243 patients. The pooled complete response and complete response with incomplete blood count recovery rate of Venetoclax combined with HMAs for post-transplantation relapse in AML/MDS was 32% (95% CI, 26-39%, I2 = 0%), with an overall response rate of 48% (95% CI, 39-56%, I2 = 37%). The 6-month survival rate was 42% (95% CI, 29-55%, I2 = 62%) and the 1-year survival rate was 23% (95% CI, 11-38%, I2 = 78%).

CONCLUSION

This study demonstrated a moderate benefit of Venetoclax in combination with HMAs for patients with relapsed AML/MDS post-transplantation (including those who have received prior HMAs therapy), and may become one of treatment options in the future. Large-scale prospective studies are needed to confirm the potential benefit from venetoclax combined with HMAs.

Optimization of Donor Lymphocyte Infusion for AML Relapse After Allo-HCT in the Era of New Drugs and Cell Engineering

Donor lymphocyte infusion (DLI) is a key strategy for the treatment of AML relapse after allogeneic hematopoietic cell transplantation (allo-HCT) and has been used for either prophylactic, pre-emptive, or therapeutic purposes. However, the prognosis of these patients remains dismal even after DLI infusion (2-year overall survival, ~25%), and the efficacy is achieved at the cost of toxicities such as graft-versus-host (GVH) disease. Attempts to optimize DLI efficacy and safety, such as dose/timing modification and the use of cytoreduction, before DLI have been performed previously. Recently, a great number of novel targeted and immunomodulatory agents have emerged. Some of them, such as hypomethylating agents, FLT3 and Bcl-2 inhibitors, have been used in combination with DLI, aiming to enhance the graft-versus-leukemia effect. Moreover, manipulation of the DLI graft through cell selection (e.g., donor NK cells) or cell engineering (donor CAR-T cells) has shown potentially superior anti-tumor effects but less GVH effect than conventional DLI in clinical trials. This review summarizes the recent advances on the use of DLI for the prophylaxis/treatment of AML relapse and discusses future strategies which may further improve the treatment efficacy.

Prevention and Treatment of Acute Myeloid Leukemia Relapse after Hematopoietic Stem Cell Transplantation: The State of the Art and Future Perspectives

Allogeneic hematopoietic stem cell transplantation (HSCT) for high-risk acute myeloid leukemia (AML) represents the only curative option. Progress has been made in the last two decades in the pre-transplant induction therapies, supportive care, selection of donors and conditioning regimens that allowed to extend the HSCT to a larger number of patients, including those aged over 65 years and/or lacking an HLA-identical donor. Furthermore, improvements in the prophylaxis of the graft-versus-host disease and of infection have dramatically reduced transplant-related mortality. The relapse of AML remains the major reason for transplant failure affecting almost 40-50% of the patients. From 10 to 15 years ago to date, treatment options for AML relapsing after HSCT were limited to conventional cytotoxic chemotherapy and donor leukocyte infusions (DLI). Nowadays, novel agents and targeted therapies have enriched the therapeutic landscape. Moreover, very recently, the therapeutic landscape has been enriched by manipulated cellular products (CAR-T, CAR-CIK, CAR-NK). In light of these new perspectives, careful monitoring of minimal-residual disease (MRD) and prompt application of pre-emptive strategies in the post-transplant setting have become imperative. Herein, we review the current state of the art on monitoring, prevention and treatment of relapse of AML after HSCT with particular attention on novel agents and future directions.

Prognosis and risk factors for central nervous system relapse after allogeneic hematopoietic stem cell transplantation in acute myeloid leukemia

We performed a nested case-control study to investigate the incidence, treatment, and prognosis of central nervous system (CNS) relapse after allogenic hematopoietic stem cell transplantation (allo-HSCT) for acute myeloid leukemia (AML) and compared the outcomes of patients with CNS relapse following haploidentical donor (HID) HSCT versus identical sibling donor (ISD) HSCT. A total of 37 patients (HID-HSCT, 24; ISD-HSCT, 13) developed CNS relapse after transplantation between January 2009 and January 2019, with an incidence of 1.81%. The median time from transplantation to CNS relapse was 239 days. Pre-HSCT CNS involvement (HR 6.940, 95% CI 3.146-15.306, p < .001) was an independent risk factor for CNS relapse after allo-HSCT for AML. The 3-year overall survival (OS) for patients with CNS relapse was 60.3 ± 8.8%, which was significantly lower than that in the controls (81.5 ± 4.5%, p = .003). The incidence of CNS relapse was 1.64% for patients who received HID-HSCT and 2.55% for those who received ISD-HSCT (p = .193). There was no significant difference in OS between the HID-HSCT and ISD-HSCT subgroups among the patients with CNS relapse. In conclusion, CNS relapse is a rare but serious complication after allo-HSCT for AML, and the incidence and outcomes of patients with CNS relapse are comparable following HID-HSCT and ISD-HSCT.

Donor-derived anti-CD19 CAR T cells compared with donor lymphocyte infusion for recurrent B-ALL after allogeneic hematopoietic stem cell transplantation

The efficacy and safety of donor-derived anti-CD19 CAR T cells vs DLI for the management of relapsed B-cell acute lymphoblastic leukemia (B-ALL) after allo-hematopoietic stem cell transplantation (HSCT) remain unclear. Thirteen B-ALL patients with relapsed after allo-HSCT and thus were treated with donor-derived anti-CD19 CAR T-cell (study group). Fifteen B-ALL patients relapsed after allo-HSCT and thus were treated with DLI (DLI group). The rates of MRD-negative complete remission (61.5%) in the study group were significantly higher than those in the DLI group (13.3%) (p = 0.02). The complete remission duration in study group and DLI group were median 8.0 months (range, 3-25 months) and 4.4 months (range, 1-25 months; p = 0.026), respectively. The overall survival of patients in the study group was superior to that of the DLI group: 9.5 months (range,3-25 months) versus 5.5 months (range, 1-25 months; p = 0.030). One patient with grade 1 acute graft-versus-host disease (aGVHD) was identified in the study group. While five (33.3%) patients in the DLI group developed grades III-IV aGVHD. Three patients (23.07%) developed grade 3 or 4 cytokine release syndrome in the study group. This study suggested that donor-derived anti-CD19 CAR T-cell therapy is promising, safe, and potentially effective for relapsed B-ALL after allo-HSCT and may be superior to DLI.

Acute Graft-Versus-Host Disease After Humanized Anti-CD19-CAR T Therapy in Relapsed B-ALL Patients After Allogeneic Hematopoietic Stem Cell Transplant

We studied the acute graft-versus-host disease (GVHD) after humanized anti-CD19-CAR T therapy in relapsed B-acute lymphoblastic leukemia (ALL) patients after allogeneic hematopoietic stem cell transplant (allo-HSCT). Fifteen B-ALL patients were enrolled in our study. Thirteen patients (86.67%) achieved a complete response (CR) or CR with incomplete count recovery. The donor chimerism of the 13 patients reached 99.86 ± 0.21%. The development of aGVHD was observed in 10 patients (66.67%). Six patients developed grade I-II of aGVHD, while the other four patients developed grade III-IV of aGVHD. The notable adverse events were grade 1–2 cytokine release syndrome (CRS) in 10 patients and grade 3–4 CRS in five patients. Two patients died of infection, while another patient died of sudden cardiac arrest. The anti-CD19-CAR T cells were not eliminated in peripheral blood when the patients developed aGVHD. However, we did not observe their expansion peaks again in the process of aGVHD. During the aGVHD, the peaks of IL-6 and TNF-a were correlated with aGVHD levels. By May 31, 2020, the rates of leukemia-free survival (LFS) and overall survival (OS) at 180 days were 53.846 and 61.638%, respectively. All the patients who survived to date experienced aGVHD after humanized anti-CD19-CAR T cell therapy.

Trial registration: The patients were enrolled in clinical trials of ChiCTR-ONN-16009862 and ChiCTR1800019622.

Benefit-Risk Assessment of Blinatumomab in the Treatment of Relapsed/Refractory B-Cell Precursor Acute Lymphoblastic Leukemia

Blinatumomab is the first-and-only Food and Drug Administration (FDA)-approved cluster of differentiation (CD) 19-directed CD3 bispecific T-cell engager (BiTE^®) immunotherapy. It is currently FDA approved for the treatment of adults and children with Philadelphia chromosome-positive (Ph+) and Philadelphia chromosome-negative (Ph-) relapsed/refractory (R/R) B-cell precursor acute lymphoblastic leukemia (ALL) and B-cell precursor ALL with minimal residual disease. Similarly, initial marketing authorization for blinatumomab in the European Union was granted for the treatment of adults with Ph- R/R B-cell precursor ALL. The benefits of treating R/R B-cell precursor ALL patients with blinatumomab include increased overall survival, more favorable hematologic remission and molecular response rates, and a lower incidence rate of selected adverse events when compared with standard-of-care chemotherapy. The key risks associated with blinatumomab treatment include cytokine release syndrome, neurotoxicity, and medication errors. Here, we review the benefits and risks of blinatumomab treatment and describe how these risks can be mitigated.

Clinical applications of donor lymphocyte infusion from an HLA-haploidentical donor: consensus recommendations from the Acute Leukemia Working Party of the EBMT

Donor lymphocyte infusion has been used in the management of relapsed hematologic malignancies after allogeneic hematopoietic cell transplantation. It can eradicate minimal residual disease or be used to rescue a hematologic relapse, being able to induce durable remissions in a subset of patients. With the increased use of haploidentical hematopoietic cell transplantation, there is renewed interest in the use of donor lymphocytes to either treat or prevent disease relapse post transplant. Published retrospective and small prospective studies have shown encouraging results with therapeutic donor lymphocyte infusion in different haploidentical transplantation platforms. In this consensus paper, finalized on behalf of the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation, we summarize the available evidence on the use of donor lymphocyte infusion from haploidentical donor, and provide recommendations on its therapeutic, pre-emptive and prophylactic use in clinical practice.

Leukemia relapse following unmanipulated haploidentical transplantation: a risk factor analysis on behalf of the ALWP of the EBMT

BACKGROUND

As information on incidence, risk factors, and outcome of acute leukemia (AL) relapse after unmanipulated haploidentical stem cell transplantation (haplo-SCT) is scarce, a retrospective registry study was performed by the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation.

METHODS

Among 1652 transplants performed for lymphoblastic and myeloid AL between 2007 and 2014, 587 patients (acute lymphoblastic leukemia (ALL) 131, acute myeloid leukemia (AML) 456) with detailed information were analyzed aiming to identify risk factors for post-transplant relapse and for overall survival (OS) after relapse.

RESULTS

The cumulative incidence of relapse at 3 years was 44% (35-53%) for ALL and 32% (27-36%) for AML (p = 0.023). In ALL, risk factors for relapse were disease status different from the first complete remission (CR1) at haplo-SCT (CR2 vs CR1: HR 2.85, p = 0.011; advanced vs CR1: HR 14.28, p < 0.0001) and male donor gender (HR 3.64, p = 0.0002), while in AML, risk factors were advanced disease at haplo-SCT (advanced vs CR1: HR 3.95, p < 0.0001) and comorbidities (HCT-CI) ≥ 3 (HR 1.75, p = 0.014). Transplants performed in more recent years were associated with lower relapse incidence (RI) in AML, but not in ALL (HR 0.91, p = 0.042). After relapse, median follow-up was 13 months (mos). OS at 1-year post relapse was 18%. Prognostic factors for superior OS after relapse were remission at time of haplo-SCT (CR vs advanced: HR 0.71, p = 0.028), time from transplant to relapse (≥ 5 mos vs < 5 mos: HR 0.530, p < 0.0001), and bone marrow as a stem cell source (peripheral blood (PB) vs bone marrow (BM): HR 1.473, p = 0.016).

CONCLUSIONS

Risk factors for relapse after haploidentical transplantation were disease specific. Longer OS after relapse was achieved in particular by patients both in CR at haplo-SCT and relapsing more than 5 months after transplant (1-year OS 33%).

[The comparison of predicting clinical outcomes between immunolophenotype and hematological complete remission before human leukocyte antigen-matched sibling donor transplantation in acute myeloid leukemia]

目的

比较移植前免疫表型缓解（ICR）和血液形态学缓解对急性髓系白血病（AML）患者同胞HLA相合造血干细胞移植（MSDT）疗效的预测价值。

方法

回顾性分析182例接受MSDT的AML患者（除外急性早幼粒细胞白血病），将移植前血液形态学缓解分为血细胞恢复的完全缓解（CR）、血小板未恢复的CR（CRp）、血小板和中性粒细胞均未恢复的CR（CRi），将多参数流式细胞术检测微小残留病阴性定义为ICR。

结果

①全部182例AML患者中，男97例，女85例，中位年龄41（4~62）岁。②移植前CR、CRp+CRi率分别为80.8%（147/182）、19.2%（35/182）；移植前CRp+CRi组、CR组的预期4年累积复发率（CIR）[（11.0±4.3）%对（16.0±7.1）%，χ²=0.274，P=0.600]、非复发死亡率（NRM）[（14.0±4.3）%对（9.0±6.3）%，χ²=0.913，P=0.339]、无白血病生存（LFS）率[（75.0±5.1）%对（75.0±8.3）%，χ²=0.256，P=0.613]、总生存（OS）率[（77.0±5.2）%对（80.0±8.1）%，χ²=0.140，P=0.708]差异均无统计学意义。③移植前ICR组（147例）与非ICR组（35例）比较，4年CIR较低[（11.3±3.4）%对（55.2±8.8）%，χ²=32.687，P<0.001]，LFS率[（76.2±4.7）%对（32.8±8.7）%，χ²=26.234，P<0.001]和OS率[（79.0±4.7）%对（39.0±9.1）%，χ²=25.253，P<0.001]较高，NRM差异无统计学意义[（12.5±4.1）%对（12.0±7.1）%，χ²=1.002，P=0.656]。④多因素分析显示，移植前非ICR是影响AML患者MSDT后复发[HR=11.026（95% CI 4.685~25.949），P<0.001]、LFS[HR=5.785（95% CI 2.974~11.254），P< 0.001]和OS[HR=5.578（95%CI 2.575~27.565），P<0.001]的独立危险因素。

结论

移植前ICR对AML患者MSDT的疗效预测价值优于HCR。

An observational study of Chinese adults with relapsed/refractory Philadelphia-negative acute lymphoblastic leukemia

Aim:

Chinese adults with relapsed/refractory Philadelphia chromosome-negative B-cell precursor acute lymphoblastic leukemia (Ph- ALL) have poor outcomes.

Patients & methods:

We conducted a nationwide, retrospective, observational study to assess outcomes in this patient population.

Results:

Of the 270 enrolled patients, 31% of patients at last salvage achieved complete remission (CR) or CR with partial hematologic recovery (CRh), with median time to CR/CRh of 30 days and median CR/CRh duration of 2.7 months. The CR/CRh rate was more favorable with earlier versus later lines of salvage (41, 24 and 17% at first, second and third or later salvages, respectively).

Conclusion:

This dataset serves as an important reference of real-world outcomes using currently available chemotherapy regimens for high-risk Chinese adults with relapsed/refractory Ph- ALL.

The prognostic role of E2A-PBX1 expression detected by real-time quantitative reverse transcriptase polymerase chain reaction (RQ-PCR) in B cell acute lymphoblastic leukemia after allogeneic hematopoietic stem cell transplantation

The E2A-PBX1 rearrangement is common in B cell acute lymphoblastic leukemia (B-ALL). However, whether this fusion gene can be used as a reliable marker for minimal residual disease (MRD) following allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains unknown. In this study, clinical data were collected from 28 consecutive B-ALL patients who received allo-HSCT. Their MRD was evaluated by E2A-PBX1 and leukemia-associated immunophenotype (LAIP). The median follow-up was 374 days (55-2342 days). Of the enrolled patients, seven (25%) patients died of leukemia relapse. A total of nine (32.1%) patients experienced relapse at a median of 164 days (75-559 days) after transplantation. The median expression level in the first positive sample was 0.14% (0.0071-902.4%). The duration from E2A-PBX1-positive results to hematological relapse was 74 days (30-469 days). E2A-PBX1 expression generally became positive prior to flow cytometry. Patients with positive E2A-PBX1 gene expression pre-transplantation were more likely to have positive E2A-PBX1 expression after transplantation. Taken all together, E2A-PBX1 expression determined by real-time quantitative reverse transcriptase polymerase chain reaction (RQ-PCR) could be used to evaluate MRD status after allo-HSCT. Patients with positive E2A-PBX1 expression after transplant will have a poor prognosis.

Developing T-cell therapies for lymphoma without receptor engineering

T-cell therapy has emerged from the bench for the treatment of patients with lymphoma. Responses to T-cell therapeutics are regulated by multiple factors, including the patient's immune system status and disease stage. Outside of engineering of chimeric antigen receptors and artificial T-cell receptors, T-cell therapy can be mediated by ex vivo expansion of antigen-specific T cells targeting viral and/or nonviral tumor-associated antigens. These approaches are contributing to enhanced clinical responses and overall survival. In this review, we summarize the available T-cell therapeutics beyond receptor engineering for the treatment of patients with lymphoma.

Cell therapies for hematological malignancies: don't forget non-gene-modified t cells!

Cell therapy currently performs an important role in the treatment of patients with various hematological malignancies. The response to the cell therapy is regulated by multiple factors including the patient's immune system status, genetic profile, stage at diagnosis, age, and underlying disease. Cell therapy that does not require genetic manipulation can be mediated by donor lymphocyte infusion strategies, selective depletion in the post-transplant setting and the ex vivo expansion of antigen-specific T cells. For hematologic malignancies, cell therapy is contributing to enhanced clinical responses and overall survival and the immune response to cell therapy is predictive of response in multiple cancer types. In this review we summarize the available T cell therapeutics that do not rely on gene engineering for the treatment of patients with blood cancers.

Graft-versus-Leukemia Effect Following Hematopoietic Stem Cell Transplantation for Leukemia

The success of hematopoietic stem cell transplantation (HSCT) lies with the ability of the engrafting immune system to remove residual leukemia cells via a graft-versus-leukemia effect (GvL), caused either spontaneously post-HSCT or via donor lymphocyte infusion. GvL effects can also be initiated by allogenic mismatched natural killer cells, antigen-specific T cells, and activated dendritic cells of leukemic origin. The history and further application of this GvL effect and the main mechanisms will be discussed and reviewed in this chapter.

Diagnosis and management of AML in adults: 2017 ELN recommendations from an international expert panel

The first edition of the European LeukemiaNet (ELN) recommendations for diagnosis and management of acute myeloid leukemia (AML) in adults, published in 2010, has found broad acceptance by physicians and investigators caring for patients with AML. Recent advances, for example, in the discovery of the genomic landscape of the disease, in the development of assays for genetic testing and for detecting minimal residual disease (MRD), as well as in the development of novel antileukemic agents, prompted an international panel to provide updated evidence- and expert opinion-based recommendations. The recommendations include a revised version of the ELN genetic categories, a proposal for a response category based on MRD status, and criteria for progressive disease.

Prophylactic use of low-dose interleukin-2 and the clinical outcomes of hematopoietic stem cell transplantation: A randomized study

Leukemia relapse and chronic graft-versus-host disease (cGVHD) are still major obstacles of allogeneic hematopoietic stem cell transplantation (allo-HSCT). The numbers and activity of natural killer (NK) and T-regulatory cells can be increased post-transplantation by exposure to interleukin-2 (IL-2). We tested whether administering low-dose IL-2 would decrease leukemia relapse while reducing cGVHD after allotransplantation. This controlled, open-label randomized trial included 90 recipients of allotransplants. Subjects were randomized in a 1:1 ratio to either receive or not receive low-dose IL-2 during the early post-transplantation period. Patients in the IL-2 arm received a subcutaneous injection of low-dose IL-2 (1×10⁶ U/d) on day 60 after allo-HSCT. IL-2 was administered daily for 14 d followed by a 14-d hiatus. The primary endpoint was the cumulative incidence of leukemia relapse (CIR). Three-year CIRs for the IL-2 arm and control arm were 23% (range 16-30%) and 11% (range 6-15%; p = 0.20), respectively. Minimal residual disease-positive (MRD+) tests were more common in the IL-2 arm compared to the control arm (36% [range 29-44%] vs. 15% [range 10-20%], p = 0.03). The cumulative incidence of moderate-to-severe chronic GVHD (cGVHD) was lower in the IL-2 arm compared to the control arm (33% [range 26-39%] vs. 57% [range 49-64%), p = 0.02). Therefore, the 3-y GVHD-free and GVHD progression-free survival (GPFS) rates were significantly higher in the IL-2 arm compared to the control arm (47% [range 39-55%] vs. 31% [range 25-38%], p = 0.048). Blood Tregs, NK cells, and NK-cell cytotoxicity were increased in subjects in the IL-2 arm between 3 mo and 6 mo post-transplantation. Administration of low-dose IL-2 during the immediate post-transplantation period was associated with a higher GPFS but did not decrease the CIR.

Minimal residual disease- and graft-vs.-host disease-guided multiple consolidation chemotherapy and donor lymphocyte infusion prevent second acute leukemia relapse after allotransplant

BACKGROUND

Persons with acute leukemia relapsing after allotransplant and who respond to anti-leukemia interventions are at high risk of a second relapse. We studied the impact of minimal residual disease (MRD)- and graft-vs.-host disease (GvHD)-guided multiple consolidation chemotherapy and donor lymphocyte infusions (DLIs) to prevent second relapse in patients with acute leukemia relapsing post-transplant and who achieved complete remission after induction chemotherapy and DLI.

METHODS

Forty-seven subjects with acute leukemia relapsing after an allotransplant and who achieved complete remission after post-relapse induction chemotherapy and DLI were eligible. The use of consolidation chemotherapy and DLI was guided by the results of MRD testing and whether or not DLI caused acute and/or chronic GvHD. Outcomes were compared with those of 34 similar historical controls who did not receive consolidation chemotherapy and DLIs after induction chemotherapy and DLI.

RESULTS

One-year cumulative incidence of relapse (CIR; 22 % 95 % confidence interval (10, 35 %) vs. 56 % (39, 73 %); P < 0.0001), leukemia-free survival (LFS; 71 % (57, 84 %) vs. 35 % (19, 51 %); P < 0.0001), and survival (78 % (66, 90 %) vs. 44 % (27, 61 %); P < 0.0001) was significantly better in subjects than controls. In multivariate analyses, no chronic GvHD after therapy (hazard ratio (HR) = 3.56 (1.09, 11.58); P = 0.035) and a positive MRD test after therapy (HR = 21.04 (4.44, 94.87); P < 0.0001) were associated with an increased CIR.

CONCLUSION

These data suggest MRD- and GvHD-guided multiple consolidation chemotherapy and DLIs reduce CIR and increase LFS and survival compared with controls in persons relapsing after allotransplant for acute leukemia.

TRIAL REGISTRATION

ChiCTR-ONC-12002912 . Donor lymphocyte infusion for the treatment of leukemia relapse following allogeneic hematopoeitic stem cell transplant.

Lymphodepleting chemotherapy with donor lymphocyte infusion post-allogeneic HCT for hematological malignancies is associated with severe, but therapy-responsive aGvHD

Donor lymphocyte infusion (DLI) is an option for relapsed hematologic malignancies or incomplete chimerism of non-malignant diseases following allogeneic hematopoietic cell transplantation (HCT). We analyzed the incidence of acute graft versus host disease (aGVHD) in patients treated with DLI. From 1995-2013, 171 DLIs were given to 120 patients. The cumulative incidence of post-DLI grade II-IV aGVHD was 31.6% (CI 25-42%, n=40; 12 grade II); grade III-IV 23.3% (CI 16-32%, n=28). GVHD after DLI (n=46) involved the skin in 70% (n=32), lower gastrointestinal (GI) 65% (n=30), upper GI 43% (n=20), and liver 35% (n=16). Patients receiving chemotherapy accompanying the DLI (chemo-DLI)(n=37) had more frequent aGVHD and particularly lower GI GVHD. Risk factors for grade II-IV aGVHD included: age > 40, chemo-DLI, malignant disease, and time from HCT to DLI < 200 days. aGVHD response to treatment at 8 weeks was complete in 40% and complete/partial (CR/PR) in 52%.

We observed frequent, yet therapy-responsive aGVHD following DLI. Gastrointestinal GVHD in particular is a significant risk when giving chemotherapy prior to DLI. Improvements in DLI efficacy and GVHD management are still needed.

New strategies of DLI in the management of relapse of hematological malignancies after allogeneic hematopoietic SCT

DLI is an effective strategy for patients with recurrent hematological malignancies after allogeneic hematopoietic SCT (allo-HSCT). DLI has been widely applied to boost the graft vs tumor (GVT) or GVL effects. However, given the potentially severe complications associated with conventional DLI and transient GVL effect, new strategies for DLI are emerging. In this review, we have discussed the recent important studies on DLI as a prophylactic or therapeutic modality for relapsed hematological disorders after allo-HSCT. The strategies to separate GVL from GVHD have also been discussed. Leukemia-targeting therapy and lymphodepletion combined with DLI, and prophylactic DLI after allo-HSCT are often employed for patients with high risk of relapse, which has been reviewed as well. In addition, we have also discussed the issues on DLI to be further addressed, such as the doses, timing and frequency of DLI in different clinical settings, leukemic antigen-specific DLI as well as how to augment GVL effect while attenuating GVHD.

Haploidentical hematopoietic transplantation without T-cell depletion: current status and future perspectives

Human leukocyte antigen (HLA)-haploidentical hematopoietic stem cell transplantation (HLA-haplo HSCT) without T-cell depletion has tremendously progressed over the past 20 years and has become a feasible treatment option for leukemia patients without an HLA-identical sibling donor. Advances in conditioning regimens, graft manipulation, and pharmacological graft-versus-host disease (GVHD) prophylaxis have reduced the risk of fatal graft failure and severe GVHD, two of the most serious complications of traversing the HLA barrier. According to clinical observations, killer immunoglobulin-like receptor (KIR) mismatch and donor-specific anti-HLA (DSA) antibodies-negative status play potential roles in reducing the risk of GVHD and graft failure following HLA-haploidentical SCT. New strategies to improve transplant outcomes include donor lymphocyte, NK cell and selected T-cell subset infusion, mesenchymal stem cell (MSC) co-transplantation and interleukin-2 (IL-2) application. Future challenges remain in improving post-transplant immune reconstitution and finding the best approach to reduce the incidence and severity of GVHD while simultaneously preserving the graft-versus leukemia effect to prevent the recurrence of underlying malignancy.