Andrea Assanelli

Lentiviral haemopoietic stem-cell gene therapy in early-onset metachromatic leukodystrophy: an ad-hoc analysis of a non-randomised, open-label, phase 1/2 trial

BACKGROUND Metachromatic leukodystrophy (a deficiency of arylsulfatase A [ARSA]) is a fatal demyelinating lysosomal disease with no approved treatment. We aimed to assess the long-term outcomes in a cohort of patients with early-onset metachromatic leukodystrophy who underwent haemopoietic stem-cell gene therapy (HSC-GT). METHODS This is an ad-hoc analysis of data from an ongoing, non-randomised, open-label, single-arm phase 1/2 trial, in which we enrolled patients with a molecular and biochemical diagnosis of metachromatic leukodystrophy (presymptomatic late-infantile or early-juvenile disease or early-symptomatic early-juvenile disease) at the Paediatric Clinical Research Unit, Ospedale San Raffaele, in Milan. Trial participants received HSC-GT, which consisted of the infusion of autologous HSCs transduced with a lentiviral vector encoding ARSA cDNA, after exposure-targeted busulfan conditioning. The primary endpoints of the trial are safety (toxicity, absence of engraftment failure or delayed haematological reconstitution, and safety of lentiviral vector-tranduced cell infusion) and efficacy (improvement in Gross Motor Function Measure [GMFM] score relative to untreated historical controls, and ARSA activity, 24 months post-treatment) of HSC-GT. For this ad-hoc analysis, we assessed safety and efficacy outcomes in all patients who had received treatment and been followed up for at least 18 months post-treatment on June 1, 2015. This trial is registered with ClinicalTrials.gov, number NCT01560182. FINDINGS Between April, 2010, and February, 2013, we had enrolled nine children with a diagnosis of early-onset disease (six had late-infantile disease, two had early-juvenile disease, and one had early-onset disease that could not be definitively classified). At the time of analysis all children had survived, with a median follow-up of 36 months (range 18-54). The most commonly reported adverse events were cytopenia (reported in all patients) and mucositis of different grades of severity (in five of nine patients [grade 3 in four of five patients]). No serious adverse events related to the medicinal product were reported. Stable, sustained engraftment of gene-corrected HSCs was observed (a median of 60·4% [range 14·0-95·6] lentiviral vector-positive colony-forming cells across follow-up) and the engraftment level was stable during follow-up; engraftment determinants included the duration of absolute neutropenia and the vector copy number of the medicinal product. A progressive reconstitution of ARSA activity in circulating haemopoietic cells and in the cerebrospinal fluid was documented in all patients in association with a reduction of the storage material in peripheral nerve samples in six of seven patients. Eight patients, seven of whom received treatment when presymptomatic, had prevention of disease onset or halted disease progression as per clinical and instrumental assessment, compared with historical untreated control patients with early-onset disease. GMFM scores for six patients up to the last follow-up showed that gross motor performance was similar to that of normally developing children. The extent of benefit appeared to be influenced by the interval between HSC-GT and the expected time of disease onset. Treatment resulted in protection from CNS demyelination in eight patients and, in at least three patients, amelioration of peripheral nervous system abnormalities, with signs of remyelination at both sites. INTERPRETATION Our ad-hoc findings provide preliminary evidence of safety and therapeutic benefit of HSC-GT in patients with early-onset metachromatic leukodystrophy who received treatment in the presymptomatic or very early-symptomatic stage. The results of this trial will be reported when all 20 patients have achieved 3 years of follow-up. FUNDING Italian Telethon Foundation and GlaxoSmithKline.

BCL2, BCL6, MYC, MALT 1, and BCL10 rearrangements in nodal diffuse large B-cell lymphomas: a multicenter evaluation of a new set of fluorescent in situ hybridization probes and correlation with clinical outcome ☆

Diffuse large B-cell lymphoma is the most common type of non-Hodgkin lymphoma. Although it is a curable disease, fewer than half of patients are cured with conventional chemotherapy. The highly variable outcome reflects a heterogeneous group of tumors, with different genetic abnormalities and responses to therapy. We analyzed 74 cases of diffuse large B-cell lymphoma using interphase fluorescent in situ hybridization with commercially available probes for split-signal targeting BCL-2, BCL-6, MYC, BCL-10, and MALT-1. Gene rearrangements were identified in 48 (65%) of 74 cases. BCL-6 was the most rearranged gene (45%), followed by BCL-2 (21%), BCL-10 (18%), and MYC (16%). No MALT-1 rearrangements were found. When diffuse large B-cell lymphoma cases were subdivided into germinal-center B-cell-like and activated B-cell-like groups, an inverse pattern of BCL-2 and BCL-6 rearrangements was observed. Of interest, the presence of chromosome rearrangements was associated with a worse prognosis. The pattern of cytogenetic abnormalities highlighted the fact not only that diffuse large B-cell lymphoma is a heterogeneous entity but also that even individual cases may contain subclones bearing different chromosomal rearrangements. The relevance and the clinical implication of minor clones showing gene rearrangements are poorly understood; however, this first observation suggests that different rearrangements may be involved in the progression of the disease. The fluorescent in situ hybridization analysis with the panel used in this study is useful to detect the heterogeneity of diffuse large B-cell lymphomas and identify alterations with prognostic implications.

Sirolimus-based graft-versus-host disease prophylaxis promotes the in vivo expansion of regulatory T cells and permits peripheral blood stem cell transplantation from haploidentical donors

Hematopoietic stem cell transplantation (HSCT) from human leukocyte antigen (HLA) haploidentical family donors is a promising therapeutic option for high-risk hematologic malignancies. Here we explored in 121 patients, mostly with advanced stage diseases, a sirolimus-based, calcineurin-inhibitor-free prophylaxis of graft-versus-host disease (GvHD) to allow the infusion of unmanipulated peripheral blood stem cell (PBSC) grafts from partially HLA-matched family donors (TrRaMM study, Eudract 2007-5477-54). Conditioning regimen was based on treosulfan and fludarabine, and GvHD prophylaxis on antithymocyte globulin Fresenius (ATG-F), rituximab and oral administration of sirolimus and mycophenolate. Neutrophil and platelet engraftment occurred in median at 17 and 19 days after HSCT, respectively, and full donor chimerism was documented in patients’ bone marrow since the first post-transplant evaluation. T-cell immune reconstitution was rapid, and high frequencies of circulating functional T-regulatory cells (Treg) were documented during sirolimus prophylaxis. Incidence of acute GvHD grade II–IV was 35%, and occurrence and severity correlated negatively with Treg frequency. Chronic GvHD incidence was 47%. At 3 years after HSCT, transpant-related mortality was 31%, relapse incidence 48% and overall survival 25%. In conclusion, GvHD prophylaxis with sirolimus–mycophenolate–ATG-F–rituximab promotes a rapid immune reconstitution skewed toward Tregs, allowing the infusion of unmanipulated haploidentical PBSC grafts.

Human IL2RA null mutation mediates immunodeficiency with lymphoproliferation and autoimmunity.

Cell-surface CD25 expression is critical for maintaining immune function and homeostasis. As in few reported cases, CD25 deficiency manifests with severe autoimmune enteritis and viral infections. To dissect the underlying immunological mechanisms driving these symptoms, we analyzed the regulatory and effector T cell functions in a CD25 deficient patient harboring a novel IL2RA mutation. Pronounced lymphoproliferation, mainly of the CD8+ T cells, was detected together with an increase in T cell activation markers and elevated serum cytokines. However, Ag-specific responses were impaired in vivo and in vitro. Activated CD8+STAT5+ T cells with lytic potential infiltrated the skin, even though FOXP3+ Tregs were present and maintained a higher capacity to respond to IL-2 compared to other T-cell subsets. Thus, the complex pathogenesis of CD25 deficiency provides invaluable insight into the role of IL2/IL-2RA-dependent regulation in autoimmunity and inflammatory diseases.

Central nervous system dissemination in immunocompetent patients with aggressive lymphomas: incidence, risk factors and therapeutic options

Central nervous system (CNS) dissemination is a rare (4–5%) but usually fatal complication of aggressive lymphomas. Prophylaxis modalities to prevent CNS dissemination in aggressive lymphomas cannot be widely applied to every lymphoma patient since it is associated with increased risk of neurotoxicity. Therefore, identification of high‐risk patients as the best candidates to receive CNS prophylaxis constitutes a major endpoint in the management of these malignancies. Various risk factors and models for CNS recurrence have been described. Parameters reflecting the extent and proliferation of the disease, like elevated serum lactate dehydrogenase levels, involvement of multiple extranodal sites, advanced stage and high age‐adjusted International Prognostic Index (IPI) score, as well as the involvement of specific anatomic sites, like testes, orbit, paranasal sinuses, have been identified and confirmed as important to predict CNS dissemination. Management of this complication in aggressive lymphomas with conventional‐dose chemotherapy is associated with disappointing results, while some preliminary but encouraging experiences suggest a potential role of high‐dose chemotherapy and stem cell transplantation. The analysis of recent clinical studies could lead to advancement in the prognosis of aggressive lymphomas, but several questions regarding the optimum chemotherapy combination, the best conditioning regimen and the role of radiation therapy and intrathecal chemotherapy remain still unanswered. The purposes of the present review are to critically analyse current data on the risk of CNS dissemination in aggressive lymphomas, the clinical presentation of secondary CNS lymphomas and the efficacy of CNS prophylaxis as well as to discuss the available therapeutic options for this devastating event. Copyright

Post-transplantation Cyclophosphamide and Sirolimus after Haploidentical Hematopoietic Stem Cell Transplantation Using a Treosulfan-based Myeloablative Conditioning and Peripheral Blood Stem Cells

Haploidentical hematopoietic stem cell transplantation (HSCT) performed using bone marrow (BM) grafts and post-transplantation cyclophosphamide (PTCy) has gained much interest for the excellent toxicity profile after both reduced-intensity and myeloablative conditioning. We investigated, in a cohort of 40 high-risk hematological patients, the feasibility of peripheral blood stem cells grafts after a treosulfan-melphalan myeloablative conditioning, followed by a PTCy and sirolimus-based graft-versus-host disease (GVHD) prophylaxis (Sir-PTCy). Donor engraftment occurred in all patients, with full donor chimerism achieved by day 30. Post-HSCT recovery of lymphocyte subsets was broad and fast, with a median time to CD4 > 200/μL of 41 days. Cumulative incidences of grade II to IV and III-IV acute GVHD were 15% and 7.5%, respectively, and were associated with a significant early increase in circulating regulatory T cells at day 15 after HSCT, with values < 5% being predictive of subsequent GVHD occurrence. The 1-year cumulative incidence of chronic GVHD was 20%. Nonrelapse mortality (NRM) at 100 days and 1 year were 12% and 17%, respectively. With a median follow-up for living patients of 15 months, the estimated 1-year overall and disease-free survival (DFS) was 56% and 48%, respectively. Outcomes were more favorable in patients who underwent transplantation in complete remission (1-year DFS 71%) versus patients who underwent transplantation with active disease (DFS, 34%; P = .01). Overall, myeloablative haploidentical HSCT with peripheral blood stem cells (PBSC) and Sir-PTCy is a feasible treatment option: the low rates of GVHD and NRM as well as the favorable immune reconstitution profile pave the way for a prospective comparative trial comparing BM and PBSC in this specific transplantation setting.

High-dose chemotherapy supported by autologous stem cell transplantation in patients with primary central nervous system lymphoma: facts and opinions

The standard approach to primary central nervous system lymphomas (PCNSL), that is high-dose methotrexate (HD-MTX)-based chemotherapy followed by whole-brain irradiation (WBRT), is associated with disappointing outcome. Moreover, this strategy is heavily conditioned by increased risk of disabling neurotoxicity, mostly among elderly patients. Several drugs and strategies have been investigated to improve results and neurotolerability. Among others, some investigators focused on the use of high-dose chemotherapy supported by autologous stem cells transplant (HDC/ASCT) as consolidation after primary chemotherapy. This approach has been used as salvage therapy in patients who experienced progressive disease or relapse after conventional chemo-radiotherapy or as consolidation after primary HD-MTX-based chemotherapy, replacing or preceding WBRT. Evidence supporting the role of HDC/ASCT is growing but several questions are still unanswered. The best conditioning regimen, the role of concomitant intrathecal chemotherapy, the neurotoxicity risk of further WBRT after transplant, the best time for response assessment and late effects both on neurological performance and extraneural organs remain to be characterised. This critical review is focused on the analysis of published experiences on HDC/ASCT in PCNSL in order to provide preliminary answers to the most pressing questions in this field.

High Doses of Antimetabolites Followed by High-Dose Sequential Chemoimmunotherapy and Autologous Stem-Cell Transplantation in Patients With Systemic B-Cell Lymphoma and Secondary CNS Involvement: Final Results of a Multicenter Phase II Trial

PURPOSE Treatment of secondary CNS dissemination in patients with aggressive lymphomas remains an important, unmet clinical need. Herein, we report the final results of a multicenter phase II trial addressing a new treatment for secondary CNS lymphoma based on encouraging experiences with high doses of antimetabolites in primary CNS lymphoma and with rituximab plus high-dose sequential chemoimmunotherapy (R-HDS) in relapsed aggressive lymphoma. PATIENTS AND METHODS HIV-negative patients with aggressive B-cell lymphoma and secondary CNS involvement at diagnosis or relapse, age 18 to 70 years, and Eastern Cooperative Oncology Group performance status ≤ 3 were enrolled and treated with high-doses of methotrexate and cytarabine, followed by R-HDS (cyclophosphamide, cytarabine, and etoposide) supported by autologous stem-cell transplantation (ASCT). Treatment included eight doses of rituximab and four doses of intrathecal liposomal cytarabine. The primary end point was 2-year event-free survival; the planned accrual was 38 patients. RESULTS Thirty-eight patients were enrolled; CNS disease was detected at presentation in 16 patients. Toxicity was usually hematologic and manageable, with grade 4 febrile neutropenia in 3% of delivered courses and grade 4 nonhematologic toxicity in 2% of delivered courses. Four patients died because of toxicity. Autologous stem cells were successfully collected in 24 (89%) of 27 patients (median, 10 × 10(6)/kg); 20 patients underwent ASCT. Complete response was achieved in 24 patients (complete response rate, 63%; 95% CI, 48% to 78%). At a median follow-up of 48 months, 17 patients remained relapse free, with a 2-year event-free survival rate of 50% ± 8%. At 5 years, 16 patients were alive, with a 5-year overall survival rate of 41% ± 8% for the whole series and 68% ± 11% for patients who received transplantation. Systemic (extra-CNS) and/or meningeal disease did not affect outcome. CONCLUSION The combination of high doses of antimetabolites, R-HDS, and ASCT is feasible and effective in patients age 18 to 70 years old with secondary CNS lymphoma, and we propose it as a new standard therapeutic option.

Role of 18FDG-PET/CT in detecting relapse during follow-up of patients with Hodgkin’s lymphoma

The role of 18FDG-PET/CT during follow-up of patients affected by Hodgkin’s lymphoma (HL) in complete remission after treatment is not fully elucidated, since a wide use of 18F fluorodeoxyglucose positron emission tomography/computed tomography (18FDG-PET/CT) in this setting could be limited by a relative high rate of false-positive results. Herein, we summarize a retrospective analysis of 27 patients with Hodgkin’s lymphoma in complete remission after the first-line (n = 20) or salvage (n = 7) therapy receiving serial 18FDG-PET/CT scans during follow-up. Out of 165 scans, 13 were suspected for relapse, which was confirmed in seven patients. All relapses were correctly identified by 18FDG-PET/CT positivity, with a 100% sensitivity; false-positive rate was 46% and negative predictive value was 100%. True-positive findings were mostly associated with multiple sites, subdiaphragmatic involvement, and/or previous sites of disease. According to our results, we conclude that performing routine PET/CT scan during follow-up of those patients who are at high risk of relapse would be advisable, although caution must be adopted when interpreting PET/CT results due to the relatively high rate of false-positive findings. If FDG abnormal uptake is present at multiple nodal sites, subdiaphragmatic lymph nodes, or previous sites of disease, histological verification of PET abnormal findings is warranted.

Incidence, risk factors and clinical outcome of leukemia relapses with loss of the mismatched HLA after partially incompatible hematopoietic stem cell transplantation

Genomic loss of the mismatched human leukocyte antigen (HLA) is a recently described mechanism of leukemia immune escape and relapse after allogeneic hematopoietic stem cell transplantation (HSCT). Here we first evaluated its incidence, risk factors and outcome in 233 consecutive transplants from partially HLA-mismatched related and unrelated donors (MMRD and MMUD, respectively). We documented 84 relapses, 23 of which with HLA loss. All the HLA loss relapses occurred after MMRD HSCT, and 20/23 in patients with acute myeloid leukemia. Upon MMRD HSCT, HLA loss variants accounted for 33% of the relapses (23/69), occurring later than their ‘classical’ counterparts (median: 307 vs 88 days, P<0.0001). Active disease at HSCT increased the risk of HLA loss (hazard ratio (HR): 10.16; confidence interval (CI): 2.65–38.92; P=0.001), whereas older patient ages had a protective role (HR: 0.16; CI: 0.05–0.46; P=0.001). A weaker association with HLA loss was observed for graft T-cell dose and occurrence of chronic graft-versus-host disease. Outcome after ‘classical’ and HLA loss relapses was similarly poor, and second transplantation from a different donor appeared to provide a slight advantage for survival. In conclusion, HLA loss is a frequent mechanism of evasion from T-cell alloreactivity and relapse in patients with myeloid malignancies transplanted from MMRDs, warranting routine screening in this transplantation setting.