Donor Lymphocyte Infusion In Patients Research Articles

Mega-dose decitabine conditioning and prophylactic donor lymphocyte infusion for patients with relapsed/refractory AML with active disease at the time of allogeneic haematopoietic cell transplantation: A multicenter prospective phase II study.

Patients with relapsed/refractory acute myeloid leukaemia (R/R AML), especially those who failed in novel target agents are related to dismal survival. We developed a multi-institutional, single-arm, prospective phase II trial, to investigate intensified conditioning with 'Mega-Dose' decitabine (MegaDAC) following allogeneic haematopoietic cell transplantation (allo-HCT) for R/R AML. From 2019 to 2023, 70 heavily treated R/R AML patients in active disease were consecutively enrolled. Significantly, every patient (n = 18) harbouring specific mutations exhibited no response to their best available target agents (BATs). Moreover, 74.3% of the enrolled patients did not reach remission following venetoclax-based regimens. All patients underwent intravenous decitabine (400 mg/m2) along with busulfan and cyclophosphamide. Median follow-up was 26 months (8-65) after HCT. All engrafted patients achieved MRD negativity post-HCT, with a median 3.3-log reduction in recurrent genetic abnormalities. The regimen was well tolerated, without irreversible grades III-IV toxicity peri-engraftment. The estimated 2-year CIR was 29.6% (18.4%-41.7%) and the est-2-year NRM was 15.5% (7.8%-25.5%). The est-2-year LFS, OS, and GRFS were 55.0% (43.5%-69.4%), 58.6% (47.0%-73.0%), and 42.9% (31.9%-57.6%), respectively. Multivariate analysis showed that pre-HCT drug exposures had no significant impact on primary outcomes. MegaDAC is highlighted as an effective and safe option for R/R AML in the new era of targeted therapies.

Second allogeneic stem-cell transplantation or donor lymphocyte infusion in patients who relapse after transplantation?

Second allogeneic stem-cell transplantation or donor lymphocyte infusion in patients who relapse after transplantation?

Donor Lymphocyte Infusion for Relapsed Acute Leukemia or Myelodysplastic Syndrome after Hematopoietic Stem Cell Transplantation: A Single-Institute Retrospective Analysis.

Objective The prognosis of the patients who relapsed after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is poor, and therapeutic options are limited. In the present study, we investigated the efficacy and factors associated with the survival in patients with acute leukemia or myelodysplastic syndrome (MDS) who relapsed following allo-HSCT and were treated with donor lymphocyte infusion (DLI) in real-world practice. Patients Twenty-nine patients with acute myeloid leukemia21, acute lymphoid leukemia4 or MDS4 were enrolled. Eleven patients were diagnosed with hematological relapse, and 18 were diagnosed with molecular or cytogenetic relapse. Results The median injection number and median total number of infused CD3+ T cells were 2 and 5.0×107/kg, respectively. The cumulative incidence of acute graft-versus-host disease (aGVHD) of grade ≥II at 4 months after the initiation of DLI was 31.0%. Extensive chronic graft-versus-host disease (cGVHD) occurred in 3 (10.3%) patients. The overall response rate was 51.7%, including 3 cases of hematological complete remission (CR) and 12 cases of molecular/cytogenetic CR. Cumulative relapse rates at 24 and 60 months following DLI in patients who achieved CR were 21.4% and 30.0%, respectively. The overall survival rates at 1, 2 and 3 years after DLI were 41.4%, 37.9% and 30.3%, respectively. Molecular/cytogenetic relapse, a longer interval from HSCT to relapse, and concomitant chemotherapy with 5-azacytidine (Aza) were significantly associated with a relatively long survival following DLI. Conclusion These results indicated that DLI was beneficial for patients with acute leukemia or MDS who relapsed after allo-HSCT and suggested that DLI in combination with Aza for molecular or cytogenetic relapse might result in favorable outcomes.

On Behalf of the SFGM-TC: Prophylactic Donor Lymphocyte Infusion in Patients Treated with Allogeneic Stem-Cell Transplantation for High-Risk Myelodysplastic Syndrome and Acute Myeloid Leukemia

Introduction: Allogeneic hematopoietic stem-cell transplantation (allo-HSCT) remains the best curative option for high-risk myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Unfortunately, it is still associated with a significant risk of relapse due to mechanisms of escape from the control of alloreactive T cells. Repetitive adjuvant donor lymphocyte infusion (DLI), termed prophylactic DLI (proDLI), as an effective strategy in preventing relapse is still debated. Methods: We performed a retrospective multicenter study to evaluate the efficacy of proDLI in allografted AML and MDS. We identified 56 patients treated with proDLI (DLI planned in full chimeras without any sign of disease relapse) and matched them to 167 patients in control group, (DLI performed for mixed chimerism or positive minimal residual disease) based on similar age, initial disease, cytogenetic prognosis, and conditioning intensity. Results: In univariate analysis, the incidence of severe aGVHD at 100 days and incidence of all grades of chronic GVHD 1 year after allo-HSCT were similar in the two groups. We also observed a trend of higher 3-year RI (52.61% [95% confidence interval 25.99–79.23]) in the proDLI group versus the control group (29.31% [20.28–38.34], p = 0.067). However, 3-year overall survival (p = 0.892), progression-free survival (p = 0.239), and nonrelapse mortality (p = 0.343) were similar between the two groups. In multivariate analysis, the only factor influencing overall and progression-free survival was anti-thymocyte globulin administration during the conditioning regimen. Conclusion: The proDLI strategy had an acceptable toxicity profile but did not improve patient outcomes compared to the pre-emptive strategy.

Prophylactic Donor Lymphocyte Infusion in Patients after Allogeneic Stem Cell Transplantation with Post-Transplant Cyclophosphamide Is Associated with Low Relapse Risk and Excellent Survival in Patients below 65 Years with Acute Myeloid Leukemia and High-Risk Myelodysplasia

BackgroundPost-transplant cyclophosphamide (PTCy) effectively prevents graft-versus-host-disease (GVHD) in allogeneic stem cell transplantation (alloSCT) with matched related and matched unrelated donors resulting in low risk of non-relapse mortality (NRM) (<10%). However, PTCy-alloSCT is associated with high relapse rates of approximately 20-30% after 1 year and 30-40% after 2 years (Gooptu et al. Blood 2021, Ruggeri et al. J Hemat Oncol 2018). Prophylactic donor lymphocyte infusion (DLI) may reduce relapse, although it may increase the risk of GVHD. AimTo provide evidence for reduction of relapse and improvement of survival by combining allogeneic SCT with PTCy and subsequent standardized prophylactic donor lymphocyte infusions (DLI) in a cohort of patients with acute myeloid leukemia (AML) and high risk myelodysplasia (MDS). Patients and MethodsSixty-five patients with AML (n=50) or high risk MDS (n=15) received myeloablative (n=15) or reduced-intensity (n=50) alloSCT with a matched related (n=8) or 9/10 (n=19) or 10/10 (n=38) matched unrelated donor. Based on modified ELN criteria, 10 AML patients were intermediate risk and 40 poor risk. GVHD prophylaxis consisted of PTCy, mycophenolate until day +30, and tacrolimus tapered from +70 (related or 10/10 unrelated) or day +90 (9/10 unrelated). All patients were planned to receive DLI at 6 months after transplantation at a dose of 3 x 10^6 CD3+ cells/kg in related and 1.5 x 10^6 CD3+ cells/kg in unrelated alloSCT. In poor risk patients (poor risk AML and high risk MDS) additional low dose DLI (0.3 or 0.15 x 10^6 CD3+ cells/kg in related and unrelated alloSCT, respectively) was planned one month after tacrolimus tapering (i.e. 3-4 months after alloSCT). In poor risk patients with a sensitive molecular or immunophenotypical minimal residual disease (MRD) marker (<0.1%) low dose DLI was not administered but MRD monitored; only in case of MRD positivity at 2 or 4 months additional low dose DLI was given. ResultsOf the 65 patients, 49 received standard dose DLI at 6 months after alloSCT (75%), either as a first dose at 6 months (40%), or as a second DLI after a low dose DLI at 3-4 months after alloSCT (35%). Reasons for not receiving standard dose DLI were NRM (5%), GVHD (9%), relapse (9%) and donor-related (2%). Of the 22 poor risk patients with a sensitive MRD marker, 15 received the first DLI at 6 months; 6 received both low dose DLI and 6 month DLI because of MRD positivity at 2 or 4 months after alloSCT; one patient did not receive prophylactic DLI because of systemic relapse at day 105. With a median follow up of 400 days (range 183-814), 12 patients developed systemic relapse. Most relapses (67%) occurred very early after transplant (median 110 days, range 63 to 165 days), before low dose DLI could be effectively given. These early relapses occurred significantly more in patients >= 65 years (88%) than <65 years (p=0.01 Fisher's exact). Overall survival at 1 year was 95% (95% CI 89-100%) in patients <65 (n=42), significantly higher than the 68% (95% CI 49-95%) in patients >=65 (n=23) (p=0.01). Relapse rate at 1 year was 5% (95% CI 1-15%) in patients <65, significantly lower than the 37% (95% CI 25-58%) in patients >=65 (p=0.001). Grade 2-4 acute and chronic GVHD incidence at 1 year was low (6% (95% CI 2-14%) and 11% (2.5-25%), respectively). Survival at 1 year was similar (p=0.35) in poor risk patients without MRD marker (80%, 95% CI 67-96%), poor risk with MRD marker (95%, 95% CI 87-100%) and intermediate risk (86%, 95% CI 63-100%). For these groups relapse risk was also similar: 18% (95% CI 7-33%), 16% (95% CI 3-36%) and 11% (95% CI 5-41%), respectively. ConclusionsThis study is the first to demonstrate feasibility of prophylactic DLI after PTCy-alloSCT with a low associated risk of GVHD. The observed low incidence of relapse at 1 year after transplantation (5%) of patients aged <65 years appears to be substantially less than the reported risk without pre-planned DLI (20-30%). Although the value of early DLI administration (around 3-4 months) is still unclear, standard dose DLI administration at 6 months appears feasible in intermediate risk patients and poor risk patients with sensitive MRD markers. Early relapses after alloSCT, at a time point before early DLI could be effective, caused the inferior survival of patients aged >= 65 years. The results of this study can serve as a reference for designing future prophylactic cellular interventions in the PTCy-alloSCT setting. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Muticenter Retrospective Comparable Study of Prophylactic Versus Preemptive Modified Donor Lymphocyte Infusion for Patients with High-Risk Acute Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation

Objective: To compare the efficacy and safety of prophylactic modified DLI (pro-DLI) and preemptive modified DLI (pre-DLI) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with high-risk acute leukemia Method: Patients with high-risk acute leukemia who received myeloablative conditioning and allo-HSCT during August 1, 2014 to August 30, 2020 were eligible for this study. Pro-DLI was scheduled at three months after HSCT for patients in pro-DLI cohort. In the pre-DLI cohort, patients would stop immunosuppressive drugs and receive pre-DLI immediately after MRD turning positive with morphology remission. Result: Pro-DLI was performed in ninty-five patients while two hundred and six patients were included in the pre-DLI cohort. Thirty-eight patients in the pre-DLI cohort became positive MRD and received pre-DLI. Patients in the pro-DLI cohort achieved a lower cumulative incidence of relapse (CIR) (27.6% versus 37.1%, p=0.027) and comparable overall survival (OS) (65.2% versus 59.3%, p=0.303) comparing with patients in the pre-DLI cohort. The 100-days cumulative incidence of grade III-IV acute graft-versus-host-disease (aGVHD) and chronic graft-versus-host-disease (cGVHD) were comparable between cohorts. Further subgroup analysis of patients who received allo-HSCT at CR1, pro-DLI achieved lower 3-year cumulative incidence of relapse (CIR) (27.6% versus 37.1%, p=0.027) while no benefit in OS (72.2% versus 69.2%, p=0.864) comparing with pre-DLI cohort. On the other hand, pro-DLI significantly decreased the CIR (13.25% versus 28.77%, p=0.044) and increased OS (60.7% versus 42.3%, p=0.022) when compared with pre-DLI in patients who received HSCT beyond CR1. Multivariate analysis demonstrated the strong protective effect of pro-DLI on long-term OS and PFS in patients who received HSCT beyond CR1. Conclusion: From these date, pro-DLI was highly recommended for patients with high-risk features who received allo-HSCT beyond CR1 with significantly decreased incidence of relapse and increased survival rates. Pre-DLI could be chosen by those who received allo-HSCT in CR1 in view of comparable survival rates regardless of higher relapse rates compared with pro-DLI.

Siremadlin Monotherapy and in Combination with Donor Lymphocyte Infusion for Patients with Acute Myeloid Leukemia Post Allogeneic Stem Cell Transplantation Who Are in Complete Remission but at High Risk for Relapse

Background: Relapse post allogeneic stem cell transplantation (SCT) remains the main cause of treatment failure (~40%) for patients (pts) with acute myeloid leukemia (AML). Many pts who ultimately relapse post SCT do so within the first year post transplant, and earlier relapse is associated with poorer survival. Therapeutics that prevent early relapse for these pts are urgently needed. Early cellular or pharmacologic intervention or maintenance strategies that enhance the graft-versus-leukemia (GvL) effect after SCT are of renewed interest as they have the potential to reduce relapse risk post SCT. Siremadlin (HDM201) is a novel investigational MDM2 inhibitor with single-agent, anti-AML activity. MDM2 inhibitors, including siremadlin, possess potent immunomodulatory effects in murine solid tumor and AML models. MDM2 inhibition has been shown to synergize with the allogeneic immune response, increase the vulnerability of AML cells to allogeneic donor T cells, and promote the cytotoxicity and longevity of allogeneic donor T cells in murine models. As such, the post-SCT setting is ideal for investigating the immunomodulatory effects of MDM2 inhibition on enhancing the GvL effect (Ho et al. Blood. 2022). Here we describe the design of a Phase Ib/II, open-label study of siremadlin as monotherapy and in combination with donor lymphocyte infusion (DLI) in pts with AML post SCT who are in complete remission (CR) but at high risk for relapse based on the presence of pre-SCT risk factors (NCT05447663). Study Design: The trial is not yet recruiting but aims to enroll ~38 adult pts with AML who underwent first SCT and are currently between Day 60-120 post SCT. Prior to a patient's SCT, they must have a risk factor that puts them at high risk for relapse, including AML in first CR with adverse risk genetics per 2017 European LeukemiaNet risk stratification, therapy-related AML, or secondary AML; or AML in second or greater CR. The SCT must be from an 8/8 human leukocyte antigen (HLA) matched related or unrelated donor at HLA-A, -B, -C, -DRB1 loci using unmanipulated/T-cell replete bone marrow or peripheral blood stem cells as a stem cell source. Post SCT, pts must have achieved CR or CR with incomplete hematologic recovery (CRi) with no evidence of hematologic relapse. Exclusion criteria include prior exposure to an MDM inhibitor, active graft-vs-host disease (GvHD), past history of grade ≥III acute GvHD (aGvHD) or moderate/severe chronic GvHD (cGVHD), recipient of SCT from a haploidentical family donor or cord blood transplant, and prior systemic AML-directed treatments given at any time after SCT (including DLI). This study contains 2 parts, Part 1 is a dose confirmation of siremadlin monotherapy and will enroll ~12 pts. Siremadlin will be tested at a maximum of 3 dose levels with a starting dose of 30 mg/d on Days 1-5 of a 28-day cycle, dose level +1 at 40 mg/d and dose level -1 at 20 mg/d. The safety and tolerability of these dose levels will be assessed to determine the siremadlin recommended dose (RD) for Part 2. Pts in Part 1 of the study will receive siremadlin monotherapy for the entire duration of the treatment and will not receive DLI. Subsequently, ~26 pts will be enrolled in Part 2 and proceed through a priming phase with siremadlin monotherapy at the RD, followed by a combination phase of siremadlin + DLI, and subsequently a maintenance phase with siremadlin monotherapy (Figure). Primary safety endpoints of the study are incidence of dose-limiting toxicities (DLTs) in Part 1 and time to DLT in Part 2. The primary efficacy endpoint is the proportion of pts in Part 2 who are alive and maintained CR/CRi without hematologic relapse ≥6 months after the start of study treatment. Secondary endpoints include number of pts in Part 1 who are alive and maintained CR/CRi without hematologic relapse ≥6 months after the start of study treatment at the RD for Part 2, time to first documented hematologic relapse or death, incidence of relapse at 1 year and 2 years post study treatment, safety, GvHD-free/relapse-free survival, incidence of and time to treatment-emergent grade ≥III aGvHD or moderate/severe cGvHD, and pharmacokinetics. Conclusions: This Phase Ib/II study investigates siremadlin monotherapy and siremadlin in combination with DLI in pts with AML in remission but at high risk of relapse post SCT. The study will evaluate the unique immunomodulatory potential of siremadlin to reduce risk of relapse in this population with high unmet need. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Azacitidine and donor lymphocyte infusion for patients with relapsed acute myeloid leukemia and myelodysplastic syndromes after allogeneic hematopoietic stem cell transplantation: A meta-analysis.

BackgroundFor patients with relapsed acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) after allogeneic hematopoietic stem cell transplantation (allo-HSCT), azacitidine with donor lymphocyte infusion (DLI) is a feasible option to perform a preemptive or salvage treatment. However, its efficacy lacked comprehensive analysis, and this study aimed to fill this gap.MethodsWe searched potential studies in PUBMED, EMBASE, and the Cochrane Central Register of Controlled Trials. Thirteen studies involving 811 patients were analyzed. The inverse variance method was used to calculate the pooled proportion and 95% confidence interval (CI). Subgroup analysis was performed to explore the source of heterogeneity.ResultsThe rate of pooled complete remission + partial remission (CR + PR), CR, and 2-year overall survival (OS) were 30% (95% CI: 22%–39%), 21% (95% CI: 16%–28%), and 31% (95% CI: 27%–35%), respectively. The pooled acute graft-versus-host disease (GvHD) and chronic GvHD rates were 15% (95% CI: 9%–23%) and 14% (95% CI: 8%–23%), respectively. Adverse cytogenetics and a higher percentage of bone marrow (BM) blasts at relapse were correlated with worse CR + PR and CR (interaction p < 0.05). Higher 2-year OS was found in patients with lower BM blasts at relapse or a longer time from allo-HSCT to relapse (interaction p < 0.05). Furthermore, the preemptive treatment for molecular relapse/minimal residual disease positivity resulted in much better outcomes than that for hematological relapse, both in terms of CR and 2-year OS (interaction p < 0.001).ConclusionThe regimen of azacitidine and DLI could safely improve the outcomes of relapsed AML/MDS after allo-HSCT, especially in those with signs of early relapse. The administration of targeted medicines in azacitidine-based therapies may further improve the outcomes of relapsed AML/MDS.

Outcomes After Donor Lymphocyte Infusion in Patients With Hematological Malignancies: Donor Characteristics Matter

In the context of T-cell depletion, failing to achieve full donor chimerism (FDC) entails higher risk of graft loss and disease relapse. Donor lymphocyte infusion (DLI) is an adoptive immunotherapy for mixed chimerism (MC) or relapsed disease after reduced-intensity conditioning allogeneic hematopoietic stem cell transplantation (HSCT). Nevertheless, little is known of factors associated with attaining FDC or disease remission. We carried out a retrospective study with 100 adult patients to identify patient and donor factors that can predict achievement of FDC and disease remission and describe complications after DLI. Indications for DLI were T-cell MC in 61 patients and relapsed disease in 39 patients. Forty patients (65.6%) with MC attained T-full donor chimerism (T-FDC), with higher responses seen in patients whose donors were female (81.5% versus 52.9%, P = .004) and cytomegalovirus negative (76.5% versus 52%, P = .004). However, only patients with younger donors (<30 years old) compared to older donors (94.4% versus 53.5%, P = .013) and those attaining unfractionated whole blood (UWB) FDC after DLI (76.6% versus 28.6%, P < .001) had a survival benefit and subsequently a better graft-versus-host disease (GvHD)–free/relapse-free survival. Nineteen of 39 patients (48.7%) with relapsed disease achieved remission after DLI. In this cohort, attaining T-FDC impacted favorably in disease control (76.7% versus 12.5%, P = .012) and improved survival (45.5% versus 12.5%, P = .007). In the whole population, the cumulative incidence of acute GvHD (aGvHD) at day 100 after DLI was 23%, and chronic GvHD (cGvHD) at 1 year after DLI was 22%. In the whole population, donor age was also a determining factor for aGvHD, because patients with younger donors had a lower incidence of aGvHD (8% versus 36%, P = .021). The cGvHD was more likely to occur in patients who converted to T-FDC (34% versus 10.3%, P = .025). Donor characteristics are increasingly considered when deciding approaches for HSCT. Donor age should be considered when planning HSCT, as well as doses and scheduling of DLI. As per our experience, this should be done alongside T/UWB chimerism to achieve the maximal clinical benefit with less associated toxicity. Selection of younger male donors from stem cell registries can minimize the risk of GvHD and improve survival.

Preemptive Immunotherapy for Minimal Residual Disease in Patients With t(8;21) Acute Myeloid Leukemia After Allogeneic Hematopoietic Stem Cell Transplantation.

In patients with t(8;21) acute myeloid leukemia (AML), recurrent minimal residual disease (MRD) measured by RUNX1-RUNX1T1 transcript levels can predict relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT). This study aimed to compare the efficacy of preemptive interferon (IFN)-α therapy and donor lymphocyte infusion (DLI) in patients with t(8;21) AML following allo-HSCT. We also evaluated the appropriate method for patients with different levels of RUNX1-RUNX1T1 transcripts. In this retrospective study, consecutive patients who had high-risk t(8;21) AML and received allo-HSCT were enrolled. The inclusion criteria were as follows: (1) age ≤65 years; (2) regained MRD positive following allo-HSCT. MRD positive was defined as the loss of a ≥4.5-log reduction and/or <4.5-log reduction in the RUNX1-RUNX1T1 transcripts, and high-level, intermediate-level, and low-level MRDs were, respectively, defined as <2.5-log, 2.5−3.5-log, and 3.5−4.5-log reductions in the transcripts compared with the pretreatment baseline level. Patients with positive RUNX1-RUNX1T1 could receive preemptive IFN-α therapy or DLI, which was primarily based on donor availability and the intentions of physicians and patients. The patients received recombinant human IFN-α-2b therapy by subcutaneous injection twice a week every 4 weeks. IFN-α therapy was scheduled for six cycles or until the RUNX1-RUNX1T1 transcripts were negative for at least two consecutive tests. The rates of MRD turning negative for patients with low-level, intermediate-level, and high-level RUNX1-RUNX1T1 receiving IFN-α were 87.5%, 58.1%, and 22.2%, respectively; meanwhile, for patients with intermediate-level and high-level RUNX1-RUNX1T1 receiving DLI, the rates were 50.0% and 14.3%, respectively. For patients with low-level and intermediate-level RUNX1-RUNX1T1, the probability of overall survival at 2 years was higher in the IFN-α group than in the DLI group (87.6% vs. 55.6%; p = 0.003). For patients with high levels of RUNX1-RUNX1T1, the probability of overall survival was comparable between the IFN-α and DLI groups (53.3% vs. 83.3%; p = 0.780). Therefore, patients with low-level and intermediate-level RUNX1-RUNX1T1 could benefit more from preemptive IFN-α therapy compared with DLI. Clinical outcomes were comparable between preemptive IFN-α therapy and DLI in patients with high-level RUNX1-RUNX1T1; however, they should be further improved.

Alterations of Peripheral Blood T Cell Subsets following Donor Lymphocyte Infusion in Patients after Allogeneic Stem Cell Transplantation

Donor lymphocyte infusion (DLI) after allogeneic stem cell transplantation (alloSCT) is an established method to enhance the Graft-versus-Leukemia (GvL) effect. However, alterations of cellular subsets in the peripheral blood of DLI recipients have not been studied. We investigated the changes in lymphocyte subpopulations in 16 patients receiving DLI after successful alloSCT. Up to three DLIs were applied in escalating doses, prophylactically for relapse prevention in high-risk disease (n = 5), preemptively for mixed chimerism and/or a molecular relapse/persistence (n = 8), or as part of treatment for hematological relapse (n = 3). We used immunophenotyping to measure the absolute numbers of CD4+, CD8+, NK, and CD56+ T cells and their respective subsets in patients’ peripheral blood one day before DLI (d-1) and compared the results at day + 1 and + 7 post DLI to the values before DLI. After the administration of 1 × 106 CD3+ cells/kg body weight, we observed an overall increase in the CD8+ and CD56+ T cell counts. We determined significant changes between day − 1 compared to day + 1 and day + 7 in memory and activated CD8+ subsets and CD56+ T cells. Applying a higher dose of DLI (5 × 106 CD3+ cells/kg) led to a significant increase in the overall counts and subsets of CD8+, CD4+, and NK cells. In conclusion, serial immune phenotyping in the peripheral blood of DLI recipients revealed significant changes in immune effector cells, in particular for various CD8+ T cell subtypes, indicating proliferation and differentiation.

Comparison of Prophylactic and Preemptive Donor Lymphocyte Infusion in Patients with Very High Risk Acute Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation

Relapse remains to be the biggest problem for patients with very high risk acute leukemia after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Donor lymphocyte infusion (DLI) has been widely applied to the prevention and preemptive intervention of relapse post-transplantation. However, the optimal time to implement DLI in patients with a high risk of relapse remains controversial. During August 1, 2014 and August 30, 2020, four hundred and thirty-one consecutive acute leukemia patients with very high-risk features underwent allo-HSCT in our center. Ninety-five patients received prophylactic DLI (pro-DLI) while one hundred and fifty-five patients received preemptive DLI (pre-DLI). Patients were stratified into five risk groups by the disease-risk stratification system (DRSS) which recently introduced by European Society for Blood and Marrow Transplantation: low risk (N=44), intermediate-1 (N=67), intermediate-2 (N=60), high (N=36), and very high (N=43). In the very high group, patients who received pro-DLI achieved higher 3-year overall survival (OS) (50.8% versus 31.8%, P=0.05), leukemia-free survival (LFS) (52.5% versus 31.6%, P=0.03) and graft-versus-host disease (GVHD)-free and relapse-free survival (GRFS) (47.9% versus 31.6%, P=0.04) compared with pre-DLI. Pro-DLI cohort was associated with a trend of lower 3-year cumulative rates of relapse (42.8% versus 57.9%, P=0.12) and non-relapse mortality (NRM) (4.6% versus 10.5%, P=0.43). In the subgroup of intermediate-2 and high (N=96), pro-DLI cohort was associated with superior survival and relapse rate, though without statistical significance. Further analysis was conducted separately between patients with positive minimal residual disease (MRD) and negative MRD pre-transplant in intermediate-2/high subgroup. In the patients with positive MRD before all-HSCT, pro-DLI achieved significant higher 3-year OS (66.7 % versus 26.2%, P=0.028), PFS (68.6 % versus 24.7%, P=0.015) and GRFS (68.6 % versus 14.4%, P=0.007), along with lower cumulative of relapse (31.4 % versus 59.3%, P=0.1) and NRM (0 versus 16%, P=0.1) compared with pre-DLI. However, pro-DLI patients was associated with inferior OS (52.7 % versus 77.8%, P=0.046), PFS(54.8 % versus 75.3%, P=0.247) and NRM (25% versus 3%, P=0.02) in patients with negative MRD. In addition, no difference was found in patients in the group of low and intermediate-1 risk. Taken together, we recommend early pro-DLI in patients of very-high risk group and positive MRD of intermediate-2/high group. Pre-DLI given timely after MRD turning positive achieved better outcome in the remaining patients. DisclosuresNo relevant conflicts of interest to declare.

Treatment of Relapse of MDS, AML and CMML after Allogeneic Blood Stem Cell Transplantation with Azacitidine, Lenalidomide and Donor Lymphocyte Infusions - Results from the First Interim Analysis of the Azalena-Trial (NCT02472691)

Background:Azacitidine (Aza) and donor lymphocyte infusions have become a standard treatment of myeloid malignancies relapsing after allo-SCT. Studies so far showed response rates ranging from 10% to 75% following treatment with Aza with or without donor lymphocyte infusions (DLI) and particularly patients (pts) with MDS and AML with low disease burden seem to benefit most. Lenalidomide (Len), due to its immunomodulatory and antileukemic properties, may act synergistically with Aza and DLI.Design/Methods:We initiated a prospective, multicenter, single-arm phase-II trial combining Aza, Len and DLI in patients with MDS, AML or CMML as first salvage treatment for relapse after allo-SCT. Pts were envisaged to receive up to 8 cycles Aza (75 mg/m2/d d1-7, every 28 days) and 3 DLI with increasing dosages (0.5×106 - 1.5×107 cells/kg) after cycles 4, 6 and 8. Concomitantly, eight cycles of Len were administered with a daily dose of 2.5 mg for the first 21 days of a 28 day-cycle each.To cope with the potential risk of GvHD induction by Len after allo-SCT the primary endpoint is safety and the study incorporates two interim analyses scheduled after the first 10 and 20 patients respectively. If no dose limiting toxicity (DLT) defined as steroid refractory acute GvHD grade III/IV, chronic GvHD NIH score severe or any unexpected hematologic and non-hematological toxicity grade ≥ III is observed in more than 3 patients in the first interim analysis, the dose of Len will be increased to 5 mg/day for the next 10 patients. Otherwise the study will be stopped.Results:Here we present the results of the first interim analysis (data lock February 20th 2017), which includes 10 patients (median age: 64 years, range 43 to 73) who experienced molecular (70%) or hematological (30%) relapse of MDS (70%), AML (20%) or CMML (10%) after median of 275 days (range: 91 to 937) following allo-SCT. So far, these 10 patients have received a total of 54 cycles of Len corresponding to median of 7 cycles per patient (range: 1 to 8). In addition, patients received a median of 7 courses of Aza (range 1-8) and 7 of 10 pts (70%) received at least one DLI (median: 1, range: 0-5).No DLT was observed. Two patients either developed acute GvHD (20%, overall grade I and III) and chronic GvHD (20%, NIH score mild and moderate). Treatment-associated neutropenia, thrombocytopenia or anemia CTC grade III/IV occurred in 75%, 50% and 0% of the patients, respectively. Common adverse events were gastrointestinal side effects, elevation of liver enzymes as well as infections. Nevertheless, during the treatment period only 2 patients needed to be hospitalized. Although efficacy was not the major scope of this first interim analysis, of 7 evaluable patients (early drop-out of 3 patients) 4 (57%) achieved complete remission and 1 patient (14%) achieved partial remission resulting in overall response rate of 71%.Conclusion:This interim-analysis shows that the combination of Aza, Len (21x2.5 mg/cycle) and DLI as first salvage therapy for relapse after allo-SCT is safe and feasible and not associated with excess GvHD. According to the protocol, the dose of Lena will now be increased to 21x5 mg/cycle for the next 10 patients. Furthermore, due to the label extension of Aza, the inclusion criteria will also be amended to AML patients with >30% BM blasts. DisclosuresSchroeder:Celgene: Consultancy, Honoraria, Other: travel support. Rautenberg:Celgene: Other: travel support. Scheid:BMS: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Nachtkamp:Celgene: Other: Travel Support. Germing:Janssen: Honoraria; Novartis: Honoraria, Research Funding; Celgene: Honoraria, Research Funding. Kröger:RIEMSER Pharma: Research Funding; Novartis AG: Research Funding; Amgen Inc.: Speakers Bureau; Janssen Global Services, LLC: Speakers Bureau; Neovii Pharmaceuticals AG: Speakers Bureau; Novartis AG: Speakers Bureau; Sanofi: Speakers Bureau. Kobbe:Celgene: Other: Advisory Board, Research Funding.

Haematologic malignancies with unfavourable gene mutations benefit from donor lymphocyte infusion with/without decitabine for prophylaxis of relapse after allogeneic HSCT: A pilot study.

Relapse is the main cause of treatment failure for leukaemia patients with unfavourable gene mutations who receive allogeneic haematopoietic stem cell transplantation (allo‐HSCT). There is no consensus on the indication of donor lymphocyte infusion (DLI) for prophylaxis of relapse after allo‐HSCT. To evaluate the tolerance and efficacy of prophylactic DLI in patients with unfavourable gene mutations such as FLT3‐ITD, TP53, ASXL1, DNMT3A or TET2, we performed a prospective, single‐arm study. Prophylactic use of decitabine followed by DLI was planned in patients with TP53 or epigenetic modifier gene mutations. The prophylaxis was planned in 46 recipients: it was administered in 28 patients and it was not administered in 18 patients due to contraindications. No DLI‐associated pancytopenia was observed. The cumulative incidences of grade II–IV and III–IV acute graft‐versus‐host disease (GVHD) at 100 days post‐DLI were 25.8% and 11.0%, respectively. The rates of chronic GVHD, non‐relapse mortality and relapse at 3 years post‐DLI were 21.6%, 25.0% and 26.1%, respectively. The 3‐year relapse‐free survival and overall survival (OS) rates were 48.9% and 48.2%, respectively. Acute GVHD (HR: 2.30, p = 0.016) and relapse (HR: 2.46, p = 0.003) after DLI were independently associated with inferior OS. Data in the current study showed the feasibility of prophylactic DLI with/without decitabine in the early stage after allo‐HSCT in patients with unfavourable gene mutations.

Effect of Salvage Chemotherapy Before Donor Lymphocyte Infusion in Patients With Relapse After Allogeneic Hematologic Stem Cell Transplantation

ObjectivesAllogeneic hematopoietic stem cell transplantation (AHSCT) is an important treatment option in hematologic malignancies. Relapse after AHSCT is an indicator of poor prognosis. These patients may be treated with donor lymphocyte infusion (DLI). The chemotherapy given before DLI increases the success of the treatment by reducing the burden of disease. The aim of this study is to investigate post-DLI graft vs host disease (GvHD) and survival based on the course of chemotherapy given before DLI. MethodsA total of 23 patients who received DLI because of relapsed disease after AHSCT were enrolled. All of the patients received 1 or more courses of cytoreductive chemotherapy before DLI. ResultsComplete remission (CR) after DLI remained in 78.2% of all patients. There is no difference between 1 or multiple courses of chemotherapy in terms of CR (55.6% vs 44.4%; P = .21). During follow-up after DLI, although it did not reach statistical significance (P = .09), the patients receiving single-course chemotherapy tended to have longer survival (36.1 vs 4.3 months, respectively). Four patients who received multiple courses of chemotherapy were lost because of infection-related disease (pneumonia, sepsis) while they were in CR. GvHD development was more frequent in patients receiving multiple courses of chemotherapies (60% of all GvHD patients). ConclusionIt has been demonstrated that reducing the tumor burden by multiple-cycle chemotherapy does not have any advantage in terms of CR and does not improve the overall survival.

Analysis of Decitabine Therapeutic Effeicacy for Patients with Relapsed MDS/AML and High-Risk AML Patients after HSCT

To investigate the therapeutic efficacy of using decitabine as maintenance therapy for patients with relapsed MDS/AML and as prophylactic therapy for patients with high-risk AML after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Clinical data of 10 patients with MDS/AML from November 2016 to May 2018 were analyzed retrospectively. Among 10 patients there were 4 cases of AML, 2 cases of MDS, and 4 cases of AML transformed from MDS (t-AML). The 10 patients were devided into 2 groups: the relapsed group (n=8) and the prophylactic group (n=2). In relapsed group the decitabine was used as maintenance therapy after achieved complete remission (CR) with decitabine chemotherapy. In prophylactic group the decitabine was used as prophylactic therapy if the patients didn't appear the symptom of graft-versus- host-disease (GVHD) during 30 to 45 d after allo-HSCT. Eight patients received G-CSF-mobilized donor lymphocyte infusion (DLI). The dosage of decitabine for maintenance therapy and prophylactic therapy was 5 mg/m2 for 7 to 10 days every 4 to 6 weeks, as 1 cycle, amount to 3 to 7 cycles. The dosage was adjusted by the endurance of patients. Until Nov 30, 2018, 7 out of 10 patients survived. The average survival time was 15.5±1.9 months. 1-year OS rate was 64.0%. Six patients appeared aGVHD, and four patients appeared cGVHD. The usage of decitabine combined with DLI in patients with relapsed MDS/AML and high-risk AML after allo-HSCT can prolong lives of patients, reduce relapsed rate, and provide the probability for long time survival.

Donor Lymphocyte Infusions for Relapsed Hematological Malignancies after Allogeneic Hematopoietic Stem Cell Transplantation: Single Center Experience

Abstract Introduction:Donor lymphocyte infusion (DLI) is one of the therapeutic options for patients with relapsed or refractory hematologic malignancies after allogeneic hematopoietic stem cell transplantation (allo-HSCT). DLI can augment the graft-versus-tumor (GVT) effect; however, it can sometimes induce severe graft-versus-host disease (GVHD) and infectious complications induced by bone marrow aplasia or immunosuppressive therapy. In this study, we wanted to assess the risk factors for GVHD and transplant-related mortality (TRM) as well as disease outcomes according to the reason for DLI in patients who received DLI after allo-HSCT. Patients and Methods:We retrospectively analyzed 152 patients with various hematological malignancies who received a total of 250 DLI in our center between March 1991 and July 2018 for disease relapse and at different intervals after allo-HSCT. We used our institutional database to evaluate details and characteristics of patients and DLI outcomes. The probabilities of overall survival were calculated from the day of transplantation with Kaplan-Meier analysis using SPSS (IBM SPSS Statistics 21; IBM Corp., Chicago, IL) statistical tool kit. Results:Median patient age was 34 years (range, 14-67 years); the patient cohort included 96 males (63.2%) and 36.8 female (56%). Patients evaluated in this study were adult patients with acute myeloid leukemia (n=64), chronic myeloid leukemia (n=36), multiple myeloma (n=6), non-hodgkin lymphoma (4), primary myelofibrosis (n=6), myelodisplastic syndrome (n=3), and severe aplastic anemia (n=3). One hundred thirty-six (10.5%) and sixteen (10.5%) patients had sibling (SD) and unrelated donors (UD), respectively. The stem cell source was peripheral blood stem cells (PBSC) in 116 patients (76.3%) and the other 36 patients (23.8%) received bone marrow stem cells (BMSC). Patients underwent an allo-HSCT with a MAC (n= 109) or RIC (n=43) regimens at a median of 12.5 months from diagnosis. Cyclosporine and methotrexate were used as the main graft versus host disease (GVHD) prophylaxis in our cohort. All patients received DLI for relapse or progression. Median number of DLI was 1 (range, 1-5), the median interval between transplant and first DLI was 6 months (range, 3-86 months), median number of infused CD3+cells x 106/kg of recipient body weight was 1.5x107(range, 0.5x107- 11.1x107). The median time from relapse to the first DLI was 1.9 months (range, 0.1-32.7 months). Thirty-one patients (21%) developed acute grade II to IV GVHD and 10 patients (7%) developed extensive chronic GVHD. We could not demonstrate the higher CD3+ cell dose of DLI associated with an increased risk of GVHD. Furthermore, none of our patients presented graft hypoplasia after DLI. At a median follow-up from transplantation interval of 16.3 months (range, 0.5-188.2 months), 35 patients were still alive (%60). The OS at 1 and 3 years was 63.4±0.4 and 28.2±0.4, respectively (Figure 1). The primary cause of death was relapse of the original disease in most of the patients, whereas 14 patients died of TRM (15.3%). Discussion:Various modifications of DLI have been investigated in combination with molecular-targeted agents to enhance the antitumor effect while minimizing GVHD. Therefore, further studies of larger randomized cohorts with high quality data management are required to clarify the role of DLI in relapsed hematological malignancies. Figure. Figure. Disclosures Civriz Bozdag: TAKEDA: Consultancy; MSD: Research Funding; NOVARTIS: Consultancy. Özcan:MSD: Other: travel support, Research Funding; Jazz: Other; Janssen: Other: Travel Support, Research Funding; Novartis: Research Funding; Archigen: Research Funding; Jazz: Other: Travel support; Bayer: Research Funding; Abbvie: Other: Travel payment; Celgene: Other: Travel support, Research Funding; BMS: Honoraria; Roche: Honoraria, Research Funding; Takeda: Honoraria, Other: Travel payment, Research Funding; MSD: Research Funding. Ilhan:Roche: Speakers Bureau; Celgene: Speakers Bureau; BMS: Speakers Bureau; Alexion: Speakers Bureau. Beksac:Takeda: Membership on an entity's Board of Directors or advisory committees; Amgen,Janssen-Cilag,Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

Treatment of MDS, AML and CMML Relapse after Allogeneic Blood Stem Cell Transplantation with Azacitidine, Lenalidomide and Donor Lymphocyte Infusions Results from the Second Interim Analysis of the Prospective Azalena-Trial (NCT02472691)

BackgroundDuring the last years Azacitidine (Aza) in combination with donor lymphocyte infusions (DLI), has proven to be a valuable treatment option for pts with relapse of MDS or AML after allo-SCT. Reasoning that Lenalidomide (Len) may further improve response rate and outcome due to its immunomodulatory and antileukemic properties, we initiated a prospective, multicenter, single-arm phase-II trial evaluating the combination of Aza, Len and DLI in patients with MDS, AML or CMML who had relapsed after allo-SCT. To acknowledge the risk of triggering GvHD with Len this study comprises two safety interim analyses. Results from the interim analysis I on the first 10 pts did not reveal a dose limiting toxicity (DLT) enabling an increase in the daily Len dosage from 2.5 mg to 5 mg in next cohort.Design/Methods:This planned second interim safety analysis (data lock March 2018) was performed in the next 10 pts who were treated with a daily dose of 5 mg Len for 21 days of a 28-day cycle in combination with up to 8 cycles Aza (75 mg/m2/d d1-7, every 28 days) and 3 DLI with increasing T cell dosages (0.5×106 - 1.5×107 cells/kg). In addition, we here present efficacy and safety results of all 24 pts included in this trial so far. The protocol demands a dose reduction of Len to 2.5 mg/day for the remaining 30 patients in case of DLT defined as steroid refractory aGvHD grade III/IV, cGvHD NHI score severe or any unexpected hematologic and non-hematological toxicity grade ≥III in more than 3 pts. In the absence of DLT in more than 3 pts the study will be continued with 5 mg/day.Results:Overall, 24 pts, who had suffered from molecular (54%) or hematological (46%) relapse of MDS (58%), AML (38%) or CMML (4%) after median of 260 days (range, 61-2659) following allo-SCT, were treated with a median of 5.5 cycles of Len per patient (range, 1 to 8; total no. of cycles 121; 83 cycles 2.5 mg/day, 38 cycles 5 mg/day). Concomitantly, pts received a median of 7 courses Aza (range 2-8) and 17 pts (71%) received at least one DLI (median: 2, range: 1-12).No DLT was seen in the cohort of 10 pts treated with a Len dosage of 5mg/day. Furthermore, the increased Len dose did neither result in a higher frequency of dose reductions and treatment interruptions in this cohort, nor to a higher number of AE per cycle (2.5 mg/day: 5.45 AE vs. 5 mg/day: 3.15 AE).We observed an overall response rate of 68% (CR 58%, PR 10%). CR rate was by trend higher in pts with molecular than in those with hematological relapse (67% vs. 43%) and all pts with CR remained in remission for a median of 183 days (range, 113-513) so far. Four pts (17%) developed acute GvHD (overall grade II, II, III, III) and 5 pts (21%) chronic GvHD (mild n=2; moderate n=2; severe n=1). While therapy-related CTC grade III/IV neutropenia (90%), thrombopenia (71%) or anemia (29%) occurred frequently, non-hematological adverse events (AE) >grade II were rare and mainly consisted of gastrointestinal toxicity, laboratory findings and infections.Conclusion:This 2nd interim-analysis of the AZALena-trial shows, that an increase in the Len dosage to 5 mg/day is feasible, safe and not associated with excess GvHD and toxicity. Consequently, 5 mg/day Len will be used in the remaining pts who will be included in this trial (total no. of pts planned, n=50). Furthermore, results from all 24 pts suggest that the combination of Aza, Len and DLI has promising clinical activity and can induce durable responses in a substantial proportion of pts with MDS and AML who relapse after allo-SCT. DisclosuresSchroeder:Celgene: Consultancy, Honoraria, Research Funding. Rautenberg:Celgene: Honoraria. Stelljes:MSD: Consultancy; Pfizer: Consultancy, Honoraria, Research Funding; JAZZ: Honoraria; Amgen: Honoraria; Novartis: Honoraria. Scheid:Celgene: Honoraria; Janssen: Honoraria; Novartis: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; BMS: Honoraria; Amgen: Honoraria. Beelen:Medac: Consultancy, Other: Travel Support. Germing:Janssen: Honoraria; Celgene: Honoraria, Research Funding; Novartis: Honoraria, Research Funding. Kobbe:Celgene: Honoraria, Other: Travel Support, Research Funding; Amgen: Honoraria, Research Funding; Roche: Honoraria, Research Funding.

Long-Term Results of Prophylactic Donor Lymphocyte Infusions for Patients with Multiple Myeloma after Allogeneic Stem Cell Transplantation

The major reason for treatment failure after allografting in multiple myeloma (MM) is relapse. Donor lymphocyte infusions (DLIs) are considered a valuable post-transplant strategy mainly for relapsed patients but using them to prevent relapse in MM has been reported rarely. In the present study, we examined the efficacy of prophylactic DLIs after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in myeloma patients with a long-term follow-up of more than 5 years. A total of 61 patients with MM who did not relapse or develop disease progression after allo-HSCT were treated with prophylactic DLI in an escalating fashion (overall 132 DLI procedures) to deepen remission status and prevent relapse. Overall response rate to DLI was 77%. Thirty-three patients (54%) upgraded their remission status, 41 patients (67%) achieved or maintained complete remission, and 26% achieved a molecular remission. Incidence of acute graft-versus-host disease (GVHD) grade II to IV was 33% and no DLI-related mortality was noted. After a median follow-up of 68.7 months from first DLI the estimated 8-year progression-free survival (PFS), and overall survival (OS) in a landmark analysis was 43% (95% confidence interval [CI], 28% to 57%) and 67% (95% CI, 53% to 82%), respectively, with best outcome for patients who acquired molecular remission (8-year PFS was 62% and 8-year OS was 83%). Prophylactic escalating DLI in a selected cohort of MM patients to prevent relapse after allograft resulted in a low incidence of severe GVHD and encouraging long-term results, especially if molecular remission is achieved.

Outcomes and Impact of Donor Lymphocyte Infusion after Reduced Intensity Conditioned-Alemtuzumab Allogeneic Hematopoietic Stem Cell Transplantation for Patients with Mature Lymphoid Malignancies

Allogeneic hematopoetic stem cell transplantation (allo-HSCT) offers long-term remission for patients with lymphoid malignancies. In particular, reduced intensity conditioned (RIC) protocols with Alemtuzumab T-cell depletion lead to durable engraftment and reduced graft versus host disease (GvHD). However, such regimens may be associated with reduced graft-versus-lymphoma (GvL) effect and higher incidence of disease progression, leading to increased use of donor lymphocyte infusion (DLI). This study examined transplant outcomes and use of DLI in a large UK RIC-Alemtuzumab conditioned HSCT cohort.288 consecutive adult patients from three UK transplant centres (Birmingham, Glasgow, Oxford) undergoing first Alemtuzumab-based RIC HSCT for Hodgkin's lymphoma (57%), Non-Hodgkin's lymphoma (24%) and chronic lymphocytic leukemia (19%) between 2000 and 2012 were included. Overall survival (OS), current progression-free survival (CPFS), relapse incidence (RI), transplant-related mortality (TRM), incidence of GvHD and effects of DLI were analyzed.Median age was 49y (range 17-68) and 60% were male. Patients were heavily pre-treated with 58% having received ≥3 prior lines of treatment and 49% having failed a previous autograft. 55% received stem cells from an HLA-matched unrelated donor and 94% received a peripheral blood stem cell harvest. The most frequent conditioning regimen was Fludarabine, Melphalan and Alemtuzumab (FMC) (70%) and the median total Alemtuzumab dose was 50mg (range 30-100). Median duration of follow-up for survivors was 64 months.3y OS and CPFS were 53% and 50%, respectively. Factors negatively associated with OS in univariate (UV) analysis were previous autograft (p=0.01), no requirement for DLI (p=0.05), disease status not CR (p=0.05), previous treatment number ≥3 (p=0.007) and failure to engraft plts (p=0.001). On multivariate (MV) analysis, only previous autograft (HR 1.58 p=0.01) and failure to engraft plts (HR 2.3 p=0.0001) retained significance. Factors negatively associated with CPFS on UV analysis were no requirement for DLI (p=0.006), failure to engraft plts (p=0.0003) and previous treatment lines ≥3 (p=0.04). On MV analysis, no DLI remained a significant predictor of adverse CPFS (HR 1.8 p=0.01), as did failure to engraft plts (HR 1.77 p=0.005) and ≥3 treatment lines (HR 1.46 p=0.04).At 3y, the cumulative incidence of relapse and TRM was both 27%. The incidence of grade 2-4 acute GvHD (aGvHD) and extensive chronic GvHD (cGvHD) was 22% and 18%, respectively. UV predictors of RI were unrelated donor (p=0.0009), HLA mismatch (p=0.04), age > median (p=0.04) and lack of aGvHD (p=0.04). The presence of cGvHD may have been protective against relapse (p=0.08). No variables retained significance on MV modelling. UV predictors of TRM were failure to engraft plts (p=0.001), HLA mismatch (p=0.005), age > median (p=0.004), previous autograft (p=0.02), FMC conditioning (p=0.03), ≥3 previous lines of treatment (p=0.001) and development of aGvHD (p=0.04). On MV modelling, failure to engraft plt (p=0.001), HLA mismatch (p=0.03), age > median (p=0.003) and treatment number ≥3 (p=0.04) retained significance.62/288 patients received DLI; 37 receiving prophylactic DLI (pDLI) for mixed chimerism and 25 receiving therapeutic DLI (tDLI) for disease relapse. The median dose of DLI was 1x 10^6 CD3+ cells/kg (range 0.1 - 10 x 10^6). Median time from HSCT to first DLI was 10.5 months (range 3-30), to 2nd DLI 15 months (6-51) and to 3rd DLI 19 months (9-30). At 3y, OS after pDLI was 75% and after tDLI was 29%. 29/37 (78%) of pDLI and 14/25 (56%) of tDLI recipients achieved full or stable mixed chimerism. 3y RI after pDLI was 29% and after tDLI was 59% (p=0.02). Overall, the incidence of GvHD post-DLI was 32% (48% tDLI, 22% pDLI, p=ns). Median time to GvHD after last DLI was 46 days (range 17-249). There was no significant impact of post-DLI GvHD on RI (RI at 1y post DLI 18% in GvHD cohort vs 21% with no GvHD, p=ns), but GvHD increased TRM at 1y post DLI (17% in the GvHD cohort vs 3% with no GvHD, p=0.05).This is the largest series to date with long-term follow-up examining outcomes after Alemtuzumab-based RIC HSCT for mature lymphoid malignancy. Our data indicate that allo-HSCT is effective and is associated with good long term outcomes. Use of pDLI for was associated with excellent outcomes and supports use of DLI in patients developing mixed chimerism following allo-HSCT for lymphoid malignancies. DisclosuresNo relevant conflicts of interest to declare.