Two-year safety outcomes of iPS cell-derived mesenchymal stromal cells in acute steroid-resistant graft-versus-host disease.

The first completed clinical trial of induced pluripotent stem cell (iPS cell)-derived cells was conducted in 15 participants with steroid-resistant acute graft-versus-host disease. After intravenous infusion of mesenchymal stromal cells (CYP-001 derived from a clone of human iPS cells), we reported the safety, tolerability and efficacy within the primary evaluation period at day 100. We now report results at the 2-year follow-up: 9 of 15 (60%) participants survived, which compares favorably with previously reported outcomes in studies of steroid-resistant acute graft-versus-host disease. Causes of death were complications commonly observed in recipients of allogeneic hematopoietic stem cell transplantation, and not considered by the investigators to be related to CYP-001 treatment. There were no serious adverse events, tumors or other safety concerns related to CYP-001. In conclusion, systemic delivery of iPS cell-derived cells was safe and well tolerated over 2 years of follow-up, with sustained outcomes up to 2 years after the first infusion. ClinicalTrials.gov registration: NCT02923375 .

Impact of positron emission tomography - computed tomography status on progression-free survival for relapsed follicular lymphoma patients undergoing autologous stem cell transplantation.

The optimum management approach for patients with relapsed or refractory follicular lymphoma remains uncertain. Autologous stem cell transplantation (autoSCT) is considered a standard option in suitable, younger patients with relapsed follicular lymphoma. AutoSCT is associated with very durable remissions in a minority of subjects, but also with significant, well-established toxicities. Although positron emission tomography (PET) status prior to autoSCT is an established prognostic factor in diffuse large B-cell lymphoma and Hodgkin lymphoma, no data exist in follicular lymphoma. We describe survival outcomes according to pre-transplant PET status, classified by the Lugano criteria into complete metabolic remission (CMR) versus non-CMR, in 172 patients with relapsed or refractory follicular lymphoma within a national, multicenter, retrospective British Society of Blood and Marrow Transplantation and Cellular Therapy registry study. The median number of lines of therapy prior to SCT was three (range, 1-6). The median follow-up after SCT was 27 months (range, 3-70). The median progression-free survival for all patients after autoSCT was 28 months (interquartile range, 23- 36). There was no interaction between age at transplantation, sex, number of months since last relapse, Karnofsky performance status or comorbidity index and achieving CMR prior to autoSCT. Superior progression-free survival was observed in 115 (67%) patients obtaining CMR versus 57 (33%) non-CMR patients (3-year progression-free survival 50% vs. 22%, P=0.011) and by pre-SCT Deauville score (continuous variable 1-5, hazard ratio [HR]=1.32, P=0.049). PET status was independently associated with progression-free status (non-CMR HR=2.02, P=0.003), overall survival (non-CMR HR=3.08, P=0.010) and risk of relapse (non-CMR HR=1.64, P=0.046) after autoSCT by multivariable analysis. Our data suggest that pre- SCT PET status is of clear prognostic value and may help to improve the selection of patients for autoSCT.

Production, safety and efficacy of iPSC-derived mesenchymal stromal cells in acute steroid-resistant graft versus host disease: a phase I, multicenter, open-label, dose-escalation study.

The therapeutic potential of donor-derived mesenchymal stromal cells (MSCs) has been investigated in diverse diseases1, including steroid-resistant acute graft versus host disease (SR-aGvHD)2. However, conventional manufacturing approaches are hampered by challenges with scalability and interdonor variability, and clinical trials have shown inconsistent outcomes3,4. Induced pluripotent stem cells (iPSCs) have the potential to overcome these challenges, due to their capacity for multilineage differentiation and indefinite proliferation5,6. Nonetheless, human clinical trials of iPSC-derived cells have not previously been completed. CYP-001 (iPSC-derived MSCs) is produced using an optimized, good manufacturing practice (GMP)-compliant manufacturing process. We conducted a phase 1, open-label clinical trial (no. NCT02923375) in subjects with SR-aGvHD. Sixteen subjects were screened and sequentially assigned to cohort A or cohort B (n = 8 per group). One subject in cohort B withdrew before receiving CYP-001 and was excluded from analysis. All other subjects received intravenous infusions of CYP-001 on days 0 and 7, at a dose level of either 1 × 106 cells per kg body weight, to a maximum of 1 × 108 cells per infusion (cohort A), or 2 × 106 cells per kg body weight, to a maximum dose of 2 × 108 cells per infusion (cohort B). The primary objective was to assess the safety and tolerability of CYP-001, while the secondary objectives were to evaluate efficacy based on the proportion of participants who showed a complete response (CR), overall response (OR) and overall survival (OS) by days 28/100. CYP-001 was safe and well tolerated. No serious adverse events were assessed as related to CYP-001. OR, CR and OS rates by day 100 were 86.7, 53.3 and 86.7%, respectively. The therapeutic application of iPSC-derived MSCs may now be explored in diverse inflammatory and immune-mediated diseases.

Presence of donor-encoded centromeric KIR B content increases the risk of infectious mortality in recipients of myeloablative, T-cell deplete, HLA-matched HCT to treat AML.

The reported influence of donor Killer-cell Immunoglobulin-like Receptor (KIR) genes on the outcomes of haematopoietic cell transplantation (HCT) are contradictory, in part due to diversity of disease, donor sources, era and conditioning regimens within and between different studies. Here, we describe the results of a retrospective clinical analysis establishing the effect of donor KIR motifs on the outcomes of 119 HLA-matched, unrelated donor HCT for adult acute myeloid leukaemia (AML) using myeloablative conditioning (MAC) in a predominantly T-cell deplete (TCD) cohort. We observed that HCT involving donors with at least one KIR B haplotype were more likely to result in non-relapse mortality (NRM) than HCT involving donors with two KIR A haplotypes (p = 0.019). Upon separation of KIR haplotypes into their centromeric (Cen) and telomeric (Tel) motif structures, we demonstrated that the Cen-B motif was largely responsible for this effect (p = 0.001). When the cause of NRM was investigated further, infection was the dominant cause of death (p = 0.006). No evidence correlating donor KIR B haplotype with relapse risk was observed. The results from this analysis confirm previous findings in the unrelated, TCD, MAC transplant setting and imply a protective role for donor-encoded Cen-A motifs against infection in allogeneic HCT recipients.

Allo-HSCT in transplant-naïve patients with Hodgkin lymphoma: a single-arm, multicenter study.

We evaluated the role of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in transplant-naïve patients with relapsed/refractory Hodgkin lymphoma (HL) who failed to attain metabolic complete response (mCR) to 1 to 2 lines of salvage chemotherapyThose with residual but nonprogressive disease assessed by positron emission tomography/computed tomography scanning were eligible. An additional 1 to 2 cycles of salvage therapy were permissible in those with progressive disease or when required to bridge to allo-HSCT, with additional imaging at baseline before transplantation. Conditioning consisted of carmustine, etoposide, cytarabine, melphalan, and alemtuzumab. Donor lymphocyte infusions (DLI) were administered for mixed chimerism or residual or relapsed disease. Eleven patients had sibling donors, 13 had HLA-matched unrelated donors, and 7 had HLA-mismatched unrelated donors. There were no graft failures, and no episodes of grade 4 acute graft-versus-host disease (GVHD); only 19.4% of patients had grade 2 to 3 GVHD, and 22.2% had extensive chronic GVHD. The non-relapse mortality rate was 16.1% (95% confidence interval [CI], 7.1%-34.5%). Relapse incidence was 18.7% (95% CI, 8.2%-39.2%). The study met its primary objective, with a 3-year progression-free survival of 67.7% (95% CI, 48.4%-81.2%). Survival outcomes were equivalent in those with residual metabolically active disease immediately before transplantation (n = 24 [70.8%; 95% CI, 17.2%-83.7%]). Two of the 5 patients who relapsed received DLI and remained in mCR at latest follow-up, with a 3-year overall survival of 80.7% (95% CI, 61.9%-90.8%). We demonstrate encouraging results that establish a potential role for allo-HSCT in selected high-risk patients with HL. This trial was registered at www.clinicaltrials.gov as #NCT00908180.

Recipients Receiving Better HLA-Matched Hematopoietic Cell Transplantation Grafts, Uncovered by a Novel HLA Typing Method, Have Superior Survival: A Retrospective Study.

HLA matching at an allelic-level resolution for volunteer unrelated donor (VUD) hematopoietic cell transplantation (HCT) results in improved survival and fewer post-transplant complications. Limitations in typing technologies used for the hyperpolymorphic HLA genes have meant that variations outside of the antigen recognition domain (ARD) have not been previously characterized in HCT. Our aim was to explore the extent of diversity outside of the ARD and determine the impact of this diversity on transplant outcome. Eight hundred ninety-one VUD-HCT donors and their recipients transplanted for a hematologic malignancy in the United Kingdom were retrospectively HLA typed at an ultra-high resolution (UHR) for HLA-A, -B, -C, -DRB1, -DQB1, and -DPB1 using next-generation sequencing technology. Matching was determined at full gene level for HLA class I and at a coding DNA sequence level for HLA class II genes. The HLA matching status changed in 29.1% of pairs after UHR HLA typing. The 12/12 UHR HLA matched patients had significantly improved 5-year overall survival when compared with those believed to be 12/12 HLA matches based on their original HLA typing but were found to be mismatched after UHR HLA typing (54.8% versus 30.1%, P = .022). Survival was also significantly better in 12/12 UHR HLA-matched patients when compared with those with any degree of mismatch at this level of resolution (55.1% versus 40.1%, P = .005). This study shows that better HLA matching, found when typing is done at UHR that includes exons outside of the ARD, introns, and untranslated regions, can significantly improve outcomes for recipients of a VUD-HCT for a hematologic malignancy and should be prospectively performed at donor selection.

Allogeneic hematopoietic cell transplantation for primary refractory acute lymphoblastic leukemia: A report from the Acute Leukemia Working Party of the EBMT.

BACKGROUND: Patients with primary refractory acute lymphoblastic leukemia (PREF ALL) who fail to achieve a complete remission (CR) after ≥2 courses of chemotherapy have a dismal prognosis without undergoing allogeneic hematopoietic cell transplantation (HCT). To the authors' knowledge, there currently are no data regarding factors influencing transplantation outcomes. METHODS: The authors retrospectively studied outcomes of transplantation for cases of PREF ALL reported to European Society for Blood and Marrow Transplantation registry. Eligibility criteria for the current analysis included adult patients who underwent their first HCT for PREF ALL between 2000 and 2012. PREF disease was defined as the failure to achieve a morphological CR after ≥2 courses of induction chemotherapy. RESULTS: Data regarding 86 adult patients were analyzed. With a median follow-up of 106 months, the probability of survival was 36% at 2 years and 23% at 5 years. The probability of leukemia-free survival was 28% and 17%, respectively, and the probability of nonrecurrence mortality was 20% and 29%, respectively, at 2 years and 5 years. For 66 patients who achieved a CR (77%), the survival at 2 years and 5 years was 36% and 29%, respectively. In multivariate analysis, use of total body irradiation was found to be associated with improved survival. Total body irradiation and infusion of female hematopoietic cells into male recipients was associated with improved leukemia-free survival. These findings were incorporated into a scoring system that identified 3 groups (those with 2, 1, or no prognostic factors) with survival rates of 57%, 22%, and 8%, respectively. CONCLUSIONS: Although overall these patients would clearly benefit from the introduction of novel antileukemic therapies, the data from the current study support the use of allogeneic HCT in selected patients with PREF ALL. Cancer 2017;123:1965-1970. © 2017 American Cancer Society.

Recent advances in therapy of chronic lymphocytic leukaemia.

The last 5 to 10 years have been marked by considerable advances in both our understanding of the biology and treatment of chronic lymphocytic leukaemia (CLL). Fludarabine-based immuno-chemotherapy is the current standard of care for first line therapy in younger fit patients and although this can be highly effective its use in older co-morbid patients is limited by toxicity, and the prognosis for patients with high risk or fludarabine-refractory disease is poor. The introduction of new antibodies has however, facilitated the use of immuno-chemotherapy in co-morbid patients. Beyond this, the recognition that CLL cells are critically dependent on B-cell receptor (BCR) signalling and interactions with the cellular micro-environment for proliferation and survival has led to the investigation of BCR inhibitors in CLL treatment. These have been shown to be highly effective although a number of questions remain about how they should be optimally used in clinical practice.

Impact of Pretransplantation (18)F-Fluorodeoxyglucose-Positron Emission Tomography on Survival Outcomes after T Cell-Depleted Allogeneic Transplantation for Hodgkin Lymphoma.

Pretransplant (18)F-fluorodeoxyglucose (FDG) positron emission tomography status is an important prognostic factor for outcomes after autologous stem cell transplantation (SCT) in Hodgkin lymphoma (HL), but its impact on outcomes after allogeneic SCT remains unclear. We retrospectively evaluated outcomes after T cell-depleted allogeneic SCT of 116 patients with nonprogressive HL according to pretransplant Deauville scores. Endpoints were overall survival (OS), progression-free survival (PFS), relapse rate (RR), and nonrelapse-related mortality (NRM). OS, PFS, and RR did not differ significantly between the Deauville 1 to 2 and Deauville 3 to 5 cohorts (OS: 77.5% versus 67.3%, P = .49; PFS: 59.4% versus 55.7%, P = .43; RR: 20.9% versus 22.6%, P = .28 at 4 years). Differences in PFS remained statistically nonsignificant when comparisons were made between Deauville 1 to 3 and Deauville 4 to 5 cohorts (60.9% versus 51.4%, P = .10), and RR remained very similar (21.5% versus 23.8%, P = .42). Multivariate analyses demonstrated trends toward significance for an effect of Deauville score on PFS (hazard ratio 1.82 for Deauville 4 to 5, P = .06) and for number of lines of prior therapy on OS (hazard ratio 2.34 for >5 lines, P = .10). The latter effect appeared to be driven by higher NRM rather than increased RR. Our findings suggest that Deauville score before allogeneic SCT in patients with nonprogressive HL has a relatively modest impact on survival outcomes in comparison with the impact in autologous SCT and that predictive values for the individual patient remain low, indicating that residual FDG-avid disease should not preclude allogeneic SCT. Furthermore, our findings bring into question the importance of attainment of metabolic complete response in this setting if it is at the expense of increasing NRM risk.

T-cell-depleted reduced-intensity transplantation followed by donor leukocyte infusions to promote graft-versus-lymphoma activity results in excellent long-term survival in patients with multiply relapsed follicular lymphoma.

PURPOSE: Follicular lymphoma (FL) is an indolent disorder that is treatable but considered incurable with chemotherapy alone. The curative potential of allogeneic transplantation using conventional myeloablative conditioning has been demonstrated, but this approach is precluded in the majority of patients with FL because of excessive toxicity. Thus, reduced-intensity conditioning regimens are being explored. PATIENTS AND METHODS: This study reports the outcome of 82 consecutive patients with FL who underwent transplantation using fludarabine, melphalan, and alemtuzumab for in vivo T-cell depletion. Patients were heavily pretreated, having received a median of four lines of prior therapy, and 26% had experienced treatment failure with previous autologous transplantation. Median patient age was 45 years, and 52% of patients received stem cells from unrelated donors. RESULTS: With a median follow-up time of 43 months, the nonrelapse mortality was 15% at 4 years (8% for sibling and 22% for unrelated donor transplantations), acute grade 2 or 3 graft-versus-host disease (GVHD) occurred in 13%, and the incidence of extensive chronic GVHD was only 18%. Although relapse risk was 26%, this was significantly reduced where mixed chimerism had been converted to full donor chimerism by the use of donor lymphocyte infusion (DLI; P = .03). In addition, 10 (77%) of 13 patients given DLI for relapse after transplantation experienced remission, with nine of these responses being sustained. Current progression-free survival at 4 years was 76% for the whole cohort (90% for those with sibling donors and 64% for those with unrelated donors). CONCLUSION: The excellent long-term survival with associated low rates of GVHD and the frequency and durability of DLI responses make this an extremely encouraging strategy for the treatment and potential cure of FL.

High response rate to donor lymphocyte infusion after allogeneic stem cell transplantation for indolent non-Hodgkin lymphoma.

The role of donor lymphocyte infusion (DLI) in the management of lymphoid malignancies after allogeneic stem cell transplantation (SCT) has not been clearly characterized. There is emerging evidence pointing to the effectiveness of this approach, particularly in patients with low-grade disease, although to date this has been reported only in small numbers of patients, and thus the utility of this treatment remains uncertain. A total of 28 patients with low-grade lymphoid malignancies previously treated with allogeneic SCT received a total of 68 infusions of donor lymphocytes. The diagnoses were indolent non-Hodgkin lymphoma (NHL; n = 23) and transformed NHL (n = 5), and the indications for DLI were progressive disease with or without mixed chimerism (MC) (n = 17) and persistent MC alone (n = 11). Escalating doses of cells were administered in the absence of graft-versus-host disease (GVHD) or continued disease progression, until stable full donor chimerism or disease response were achieved. The cumulative response rates after DLI to treat progressive disease and persistent MC were 76.5% and 91.6%, respectively. The major toxicity resulting from the use of donor lymphocytes was GVHD. The cumulative incidence of acute grade II-IV disease was 15%, and that of extensive chronic disease was 31%; there were no deaths resulting from GVHD. Seven patients had graft-versus-lymphoma responses without significant GVHD. These data support the existence of a clinically significant graft-versus-tumor effect in indolent NHL and suggest that this is an effective treatment for progressive disease after allogeneic SCT.

RFP represses transcriptional activation by bHLH transcription factors.

Basic helix-loop-helix (bHLH) transcription factors play a pivotal role in the regulation of tumorigenesis, and also in a wide range of other developmental processes in diverse species from yeast to humans. Here we demonstrate for the first time that Ret finger protein (RFP), a member of the TRIM family of proteins initially identified as a recombined transforming gene from a human lymphoma, is a novel interaction partner for four different bHLH proteins (SCL, E47, MyoD and mASH-1), but does not interact with GATA-1 or PU.1. Interaction with SCL required the B-box and first coiled-coil region of RFP together with the bHLH domain of SCL. RFP was able to repress transcriptional activation by E47, MyoD and mASH-1, but not by members of several other transcription factor families. Transcriptional repression by RFP was trichostatin A sensitive and did not involve an Id-like mechanism or ubiquitination with subsequent degradation of bHLH proteins. Instead, our results suggest that bHLH transcription factors are regulated by a previously undescribed interaction with RFP, which functions to recruit HDAC and/or Polycomb proteins and thus repress target genes of bHLH proteins. These results reveal an unexpected link between the bHLH and TRIM protein families.

The role of the stem cell leukemia (SCL) gene in hematopoietic and endothelial lineage specification.

Anatomical observations made at the beginning of the twentieth century revealed an intimate association between the ontogeny of blood and endothelium and led to the hypothesis of a common cell of origin termed the hemangioblast. However, the precise nature of the cellular intermediates involved in the development of both lineages from uncommitted precursors to mature cell types is still the subject of ongoing studies, as are the molecular mechanisms driving this process. There is clear evidence that lineage-restricted transcription factors play a central role in the genesis of mature lineage committed cells from multipotent progenitors. Amongst these, the basic helix-loop-helix (bHLH) family is of key importance for cell fate determination in the development of the hematopoietic system and beyond. This article will review the current evidence for the common origin of blood and endothelium, focusing on the function of the bHLH protein encoded by the stem cell leukemia (SCL) gene, and its role as a pivotal regulator of hematopoiesis and vasculogenesis.