Ram Malladi

Azacitidine augments expansion of regulatory T cells after allogeneic stem cell transplantation in patients with acute myeloid leukemia (AML)

Strategies that augment a GVL effect without increasing the risk of GVHD are required to improve the outcome after allogeneic stem cell transplantation (SCT). Azacitidine (AZA) up-regulates the expression of tumor Ags on leukemic blasts in vitro and expands the numbers of immunomodulatory T regulatory cells (Tregs) in animal models. Reasoning that AZA might selectively augment a GVL effect, we studied the immunologic sequelae of AZA administration after allogeneic SCT. Twenty-seven patients who had undergone a reduced intensity allogeneic transplantation for acute myeloid leukemia were treated with monthly courses of AZA, and CD8(+) T-cell responses to candidate tumor Ags and circulating Tregs were measured. AZA after transplantation was well tolerated, and its administration was associated with a low incidence of GVHD. Administration of AZA increased the number of Tregs within the first 3 months after transplantation compared with a control population (P = .0127). AZA administration also induced a cytotoxic CD8(+) T-cell response to several tumor Ags, including melanoma-associated Ag 1, B melanoma antigen 1, and Wilm tumor Ag 1. These data support the further examination of AZA after transplantation as a mechanism of augmenting a GVL effect without a concomitant increase in GVHD.

Human induced pluripotent stem cells are capable of B-cell lymphopoiesis.

Induced pluripotent stem (iPS) cells offer a unique potential for understanding the molecular basis of disease and development. Here we have generated several human iPS cell lines, and we describe their pluripotent phenotype and ability to differentiate into erythroid cells, monocytes, and endothelial cells. More significantly, however, when these iPS cells were differentiated under conditions that promote lympho-hematopoiesis from human embryonic stem cells, we observed the formation of pre-B cells. These cells were CD45(+)CD19(+)CD10(+) and were positive for transcripts Pax5, IL7αR, λ-like, and VpreB receptor. Although they were negative for surface IgM and CD5 expression, iPS-derived CD45(+)CD19(+) cells also exhibited multiple genomic D-J(H) rearrangements, which supports a pre-B-cell identity. We therefore have been able to demonstrate, for the first time, that human iPS cells are able to undergo hematopoiesis that contributes to the B-cell lymphoid lineage.

Tolerability and Clinical Activity of Post-Transplantation Azacitidine in Patients Allografted for Acute Myeloid Leukemia Treated on the RICAZA Trial

Disease relapse is the major causes of treatment failure after allogeneic stem cell transplantation (SCT) in patients with acute myeloid leukemia (AML). As well as demonstrating significant clinical activity in AML, azacitidine (AZA) upregulates putative tumor antigens, inducing a CD8+ T cell response with the potential to augment a graft-versus-leukemia effect. We, therefore, studied the feasibility and clinical sequelae of the administration of AZA during the first year after transplantation in 51 patients with AML undergoing allogeneic SCT. Fourteen patients did not commence AZA either because of transplantation complications or withdrawal of consent. Thirty-seven patients commenced AZA at a median of 54 days (range, 40 to 194 days) after transplantation, which was well tolerated in the majority of patients. Thirty-one patients completed 3 or more cycles of AZA. Sixteen patients relapsed at a median time of 8 months after transplantation. No patient developed extensive chronic graft-versus-host disease. The induction of a post-transplantation CD8+ T cell response to 1 or more tumor-specific peptides was studied in 28 patients. Induction of a CD8+ T cell response was associated with a reduced risk of disease relapse (hazard ratio [HR], .30; 95% confidence interval [CI], .10 to .85; P = .02) and improved relapse-free survival (HR, .29; 95% CI, .10 to .83; P = .02) taking into account death as a competing risk. In conclusion, AZA is well tolerated after transplantation and appears to have the capacity to reduce the relapse risk in patients who demonstrate a CD8+ T cell response to tumor antigens. These observations require confirmation in a prospective clinical trial.

A multicentre UK study of GVHD following DLI: Rates of GVHD are high but mortality from GVHD is infrequent

DLIs are frequently used following haematopoietic SCT (HSCT) in patients with risk of relapse but data on GVHD following DLI are scarce. We report on 68 patients who received DLI following HSCT. Most patients developed GVHD following DLI (71%), which was acute in 22 patients (32%) almost half of whom had grade III–IV acute GVHD (aGVHD). Thirty patients (44%) developed cGVHD which followed aGVHD in four patients and was graded severe in nine patients. Corticosteroids were the most common first-line therapy for both acute and chronic GVHD. A wide range of second/third-line agents included cyclosporin, mycophenolate, tacrolimus, imatinib, infliximab and ECP. Relapse of initial malignancy occurred in 37%. Relapse was significantly less frequent in those receiving pre-emptive DLI. Relapse rates were also lower in those with GVHD (31%) than those without GVHD (50%), but this did not reach statistical significance. At 55 months post DLI, 34% of patients had died most commonly from relapse and 22% had on-going GVHD. Although GVHD was an important cause of morbidity post DLI (71%), only 6% died from GVHD. Although most patients develop GVHD post DLI and may require consecutive therapies, mortality from GVHD is infrequent. DLI remains an important option for relapse post transplant and manipulation of the GVT effect needs to be optimised to induce remission without morbidity from GVHD.

Alemtuzumab markedly reduces chronic GVHD without affecting overall survival in reduced-intensity conditioning sibling allo-SCT for adults with AML

By retrospective analysis of 88 patients from the British Society of Blood and Marrow Transplantation registry, we investigated the effect of in vivo T-cell depletion in HLA-identical sibling reduced-intensity conditioning (RIC) allografts for adult AML by comparing patients who received alemtuzumab with those without alemtuzumab conditioning. Both groups were equivalent for age, sex, karyotype and disease status at transplant. With a median follow-up of 27 months (3–72 months) and 48 months (7–72 months), the 2- and 5-year overall survival, with or without alemtuzumab, is 60 and 60% (P=0.80) and 61 and 53%, respectively (P=0.85). The 2-year non-relapse mortality is 12% with alemtuzumab, and 17% without alemtuzumab (P=0.49). The 2-year relapse rate is 35% with alemtuzumab compared with 19% without alemtuzumab (P=0.28). Grades II–IV acute GVHD occurred in 22% (8/37) without alemtuzumab compared with 14% (7/51) given alemtuzumab (P=0.25). Extensive chronic GVHD occurred in 47% (14/30) not given alemtuzumab compared with 4% (2/45) who were given alemtuzumab (P=0.001). Among evaluable patients, the risk of infections was higher in those treated with alemtuzumab compared with those not treated with alemtuzumab (79 vs 57%, respectively, P=0.02). In conclusion, alemtuzumab has a beneficial effect by reducing chronic GVHD without affecting overall survival. Further studies are warranted before alemtuzumab can be recommended as standard in RIC allografts for AML.

Post-transplant T cell chimerism predicts graft versus host disease but not disease relapse in patients undergoing an alemtuzumab based reduced intensity conditioned allogeneic transplant

In this multicentre retrospective study we have studied the impact of T cell chimerism on the outcome of 133 patients undergoing an alemtuzumab based reduced intensity conditioning allograft (RIC). The median age of the patients was 50 years (range 42-55 years). 77 patients were transplanted using an HLA identical sibling donor while 56 patients received a fully matched volunteer unrelated donor graft. 64 patients had a lymphoid malignancy and 69 were transplanted for a myeloid malignancy. 38 patients (29%) relapsed with no significant difference in risk of relapse between patients developing full donor and mixed donor chimerism in the T-cell compartment on D+90 and D+180 post transplant. Day 90 full donor T cell chimerism correlated with an increased incidence of acute GVHD according to NIH criteria (p=0.0004) and the subsequent development of chronic GVHD. Consistent with previous observations, our results confirmed a correlation between the establishment of T cell full donor chimerism and acute GVHD in T deplete RIC allografts. However our study failed to identify any correlation between T cell chimerism and relapse risk and challenge the use of pre-emptive donor lymphocyte infusions (DLI) in patients with mixed T cell chimerism transplanted using an alemtuzumab based RIC regimen.

The role of extracorporeal photopheresis in the management of cutaneous T-cell lymphoma, graft-versus-host disease and organ transplant rejection: a consensus statement update from the UK Photopheresis Society

Extracorporeal photopheresis (ECP) has been used for over 35 years in the treatment of erythrodermic cutaneous T‐cell lymphoma (CTCL) and over 20 years for chronic and acute graft‐versus‐host disease (GvHD) and solid organ transplant rejection. ECP for CTCL and GvHD is available at specialised centres across the UK. The lack of prospective randomised trials in ECP led to the development of UK Consensus Statements for patient selection, treatment schedules, monitoring protocols and patient assessment criteria for ECP. The recent literature has been reviewed and considered when writing this update. Most notably, the national transition from the UVAR XTS® machine to the new CELLEX machine for ECP with dual access and a shorter treatment time has led to relevant changes in these schedules. This consensus statement updates the previous statement from 2007 on the treatment of CTCL and GvHD with ECP using evidence based medicine and best medical practise and includes guidelines for both children and adults.

Autologous stem cell transplantation for relapsed/refractory diffuse large B-cell lymphoma: efficacy in the rituximab era and comparison to first allogeneic transplants. A report from the EBMT Lymphoma Working Party.

In the era of chemoimmunotherapy, the optimal treatment paradigm for relapsed and refractory diffuse large B-cell lymphoma has been challenged. We reviewed the outcome of standard salvage therapy with an autologous stem cell transplant (autoSCT) over the last two decades and the outcome of allogeneic SCT (alloSCT) in the most recent decade. AutoSCT recipients diagnosed between 1992 and 2002 (n=2737) were compared with those diagnosed between 2002 and 2010 (n=3980). Patients diagnosed after 2002 had a significantly lower non-relapse mortality (NRM) and relapse incidence (RI) and a superior PFS and overall survival (OS). A total of 4210 patients diagnosed between 2002 and 2010 underwent either an autoSCT or an alloSCT as their first transplant procedure. Two-hundred and thirty patients received an alloSCT (myeloablative (MACalloSCT) n=132, reduced intensity (RICalloSCT) n=98). The 4-year NRM rates were 7%, 20% and 27% for autoSCT, RICalloSCT and MACalloSCT, respectively. The 4-year RI was 45%, 40% and 38% for autoSCT, RICalloSCT and MACalloSCT, respectively (NS). The 4-year PFS were 48%, 52% and 35% for autoSCT, RICalloSCT and MACalloSCT, respectively. The 4-year OS was 60%, 52% and 38% for autoSCT, RIC alloSCT and MACalloSCT, respectively. After adjustment for confounding factors NRM was significantly worse for patients undergoing alloSCT whilst there was no difference in the RI.

Myeloablative versus reduced intensity allogeneic stem cell transplantation for relapsed/refractory Hodgkin's lymphoma in recent years: a retrospective analysis of the Lymphoma Working Party of the European Group for Blood and Marrow Transplantation

BACKGROUND To evaluate long-term outcome of myeloablative allogeneic stem cell transplantation (allo-SCT) (MAC) versus reduced-intensity allo-SCT (RIC) in patients with relapsed/refractory Hodgkins lymphoma (HL) in recent years. PATIENTS AND METHODS A total of 312 patients (63 MAC and 249 RIC) with relapsed/refractory HL who received allo-SCT between 2006 and 2010 and were reported to the EBMT Database were included in the study. RESULTS With a median follow-up for alive patients of 56 (26-73) months, there were no significant differences in non-relapse mortality (NRM) between MAC and RIC. Relapse rate (RR) was somewhat lower in the MAC group (41% versus 52% at 24 months, P = 0.16). This lower RR translated into a marginal improvement in event-free survival (EFS) for the MAC group (48% versus 36% at 24 months, P = 0.09) with no significant differences in overall survival (73% for MAC and 62% for RIC at 24 months, P = 0.13). Multivariate analysis after adjusting for disease status at the time of allo-SCT showed that the use of MAC was of borderline statistical significance for predicting a lower RR and EFS [HR 0.7, 95% CI (0.5-1.0), P = 0.1] and [HR 0.7, 95% CI (0.5-1.0), P = 0.07], respectively, after allo-SCT. CONCLUSIONS With modern transplant practices, the NRM associated with MAC for HL has strongly decreased, resulting into non-significant improvement of EFS because of a somewhat better disease control compared with RIC transplants. The intensity of conditioning regimens should be considered when designing individual allo-SCT strategies or clinical trials in patients with relapsed/refractory HL.

Cryopreservation of allogeneic PBSC from related and unrelated donors is associated with delayed platelet engraftment but has no impact on survival.

Cryopreservation of PBSC for allo-SCT offers potential advantages; however, its impact on engraftment and outcomes remains unclear. A total of 76 allo-SCT performed using cryopreserved PBSC from HLA identical related (n=57) and unrelated donors (n=19) were compared with 123 fresh PBSC allo-SCT. Median neutrophil engraftment was on day 12 for both cryopreserved and fresh PBSC; in multivariate analysis, there was a slight but significant delay in neutrophil engraftment after the median date (hazard ratio (HR)=1.44, P=0.003). Platelet engraftment was significantly delayed in cryopreserved PBSC recipients (median time 19 vs 14 days). In multivariate analysis cryopreservation (HR=1.85, P<0.001), earlier date of transplant and lower CD34+ cell dose were associated with delayed platelet engraftment. Two-year OS and relapse and 1-year TRM rates did not differ significantly. Acute GVHD incidence was comparable, and extensive chronic GVHD at 1 year was higher in cryopreserved PBSC recipients (40.3 vs 28.3%), but not significantly so (P=0.13). Cryopreservation of related and unrelated donor allogeneic PBSC is safe and effective where its benefits outweigh the risks of delayed platelet engraftment; its impact on chronic GVHD incidence requires further assessment.