Luisa Strocchio

Treosulfan-based conditioning regimen for allogeneic haematopoietic stem cell transplantation in children with sickle cell disease

Although allogeneic haematopoietic stem cell transplantation (HSCT) still represents the only consolidated possibility of cure for sickle cell disease (SCD) patients, its use has been limited by the risk of morbidity and mortality associated with conventional myeloablative therapy. The introduction of treosulfan to replace busulfan in conditioning regimens has recently been explored by virtue of its lower toxicity profile. We report our experience with a treosulfan/thiotepa/fludarabine conditioning for human leucocyte antigen (HLA)‐matched sibling or unrelated donor‐HSCT in 15 children with SCD, and compare patient outcomes with those of a historical cohort (15 patients) given a busulfan‐based regimen. Engraftment was achieved in 28 out of 30 patients (93%), with one case of graft failure in either group. The conditioning regimen was well tolerated in both groups, with no cases of grade III‐IV regimen‐related toxicity. The 7‐year overall survival (OS) and disease‐free survival (DFS) for the whole cohort were 100% and 93%, respectively, with a 93% DFS in both busulfan and treosulfan groups. No SCD‐related adverse events occurred after engraftment in patients with complete or mixed donor chimerism. This retrospective analysis suggests that a treosulfan‐based conditioning regimen is able to ensure engraftment with excellent OS/DFS and low regimen‐related toxicity in patients with SCD.

Outcome of children with acute leukemia given HLA-haploidentical HSCT after αβ T-cell and B-cell depletion

Allogeneic hematopoietic stem cell transplantation (HSCT) from an HLA-haploidentical relative (haplo-HSCT) is a suitable option for children with acute leukemia (AL) either relapsed or at high-risk of treatment failure. We developed a novel method of graft manipulation based on negative depletion of αβ T and B cells and conducted a prospective trial evaluating the outcome of children with AL transplanted with this approach. Eighty AL children, transplanted between September 2011 and September 2014, were enrolled in the trial. All children were given a fully myeloablative preparative regimen. Anti-T-lymphocyte globulin from day -5 to -3 was used for preventing graft rejection and graft-versus-host disease (GVHD); no patient received any posttransplantation GVHD prophylaxis. Two children experienced primary graft failure. The cumulative incidence of skin-only, grade 1-2 acute GVHD was 30%; no patient developed extensive chronic GVHD. Four patients died, the cumulative incidence of nonrelapse mortality being 5%, whereas 19 relapsed, resulting in a 24% cumulative incidence of relapse. With a median follow-up of 46 months for surviving patients, the 5-year probability of chronic GVHD-free, relapse-free survival (GRFS) is 71%. Total body irradiation-containing preparative regimen was the only variable favorably influencing relapse incidence and GRFS. The outcomes of these 80 patients are comparable to those of 41 and 51 children given transplantation from an HLA-identical sibling or a 10/10 allelic-matched unrelated donor in the same period. These data indicate that haplo-HSCT after αβ T- and B-cell depletion represents a competitive alternative for children with AL in need of urgent allograft. This trial was registered at www.clinicaltrials.gov as #NCT01810120.

HLA-haploidentical T cell-depleted allogeneic hematopoietic stem cell transplantation in children with fanconi anemia

We report the outcome of 12 consecutive pediatric patients with Fanconi anemia (FA) who had neither an HLA-identical sibling nor an HLA-matched unrelated donor and who were given T cell-depleted, CD34(+) positively selected cells from a haploidentical related donor after a reduced-intensity, fludarabine-based conditioning regimen. Engraftment was achieved in 9 of 12 patients (75%), and the cumulative incidence of graft rejection was 17% (95% confidence interval [CI], 5% to 59%). Cumulative incidences of grades II to IV acute and chronic graft-versus-host disease were 17% (95% CI, 5% to 59%) and 35% (95% CI, 14% to 89%), respectively. The conditioning regimen was well tolerated, with no fatal regimen-related toxicity and 3 cases of grade III regimen-related toxicity. The cumulative incidence of transplant-related mortality was 17% (95% CI, 5% to 59%). The 5-year overall survival, event-free survival, and disease-free survival were 83% (95% CI, 62% to 100%), 67% (95% CI, 40% to 93%), and 83% (95% CI, 62% to 100%), respectively. These data demonstrate that a fludarabine-based conditioning regimen, followed by infusion of high doses of T cell-depleted stem cells, is able to ensure engraftment with good overall survival and disease-free survival, confirming the feasibility of haploidentical hematopoietic stem cell transplantation in FA. To the best of our knowledge, this is the largest series of hematopoietic stem cell transplantation from a haploidentical related donor in FA patients reported to date.

The combination of bortezomib with chemotherapy to treat relapsed/refractory acute lymphoblastic leukaemia of childhood

Achieving complete remission (CR) in childhood relapsed/refractory acute lymphoblastic leukaemia (ALL) is a difficult task. Bortezomib, a proteasome inhibitor, has in vitro activity against ALL blasts. A phase I‐II trial, reported by the Therapeutic Advances in Childhood Leukaemia and Lymphoma (TACL) consortium, demonstrated that bortezomib with chemotherapy has acceptable toxicity and remarkable activity in patients with relapsed ALL failing 2–3 previous regimens. We evaluated bortezomib in combination with chemotherapy in 30 and 7 children with B‐cell precursor (BCP) and T‐cell ALL, respectively. Bortezomib (1·3 mg/m2/dose) was administered intravenously on days 1, 4, 8, and 11. Chemotherapy agents were the same as those used in the TACL trial, consisting of dexamethasone, doxorubicin, vincristine and pegylated asparaginase. Three patients (8·1%) died due to infections. Twenty‐seven patients (72·9%) achieved CR or CR with incomplete platelet recovery (CRp). Fourteen had minimal residual disease (MRD) lower than 0·1%. Twenty‐two of 30 BCP‐ALL patients (73·3%) and 5/7 patients (71%) with T‐cell ALL achieved CR/CRp. The 2‐year overall survival (OS) is 31·3%; CR/CRp patients with an MRD response had a remarkable 2‐year OS of 68·4%. These data confirm that the combination of bortezomib with chemotherapy is a suitable/effective option for childhood relapsed/refractory ALL.

Successful T-cell-depleted Haploidentical Hematopoietic Stem Cell Transplantation in a Child with Dyskeratosis Congenita after a Fludarabine-based Conditioning Regimen

Allogeneic hematopoietic stem cell transplantation (HSCT) is the only cure for marrow failure associated with dyskeratosis congenita (DC). Data on transplants from alternative donors are limited. We describe a boy with DC and severe aplastic anemia who underwent haploidentical T-cell depleted HSCT using a reduced-intensity conditioning regimen. He underwent engraftment without toxicity or GVHD. His posttransplant course was complicated by EBV reactivation, treated with rituximab and EBV-specific T lymphocytes. After 26 months, he is in complete chimerism, with normal blood count and no sign of GVHD or pulmonary dysfunction. To the best of our knowledge, this is the first report of DC successfully treated with allogeneic HSCT from a haploidentical family donor.

Comprehensive characterization of mesenchymal stromal cells from patients with Fanconi anaemia

Fanconi anaemia (FA) is an inherited disorder characterized by pancytopenia, congenital malformations and a predisposition to develop malignancies. Alterations in the haematopoietic microenvironment of FA patients have been reported, but little is known regarding the components of their bone marrow (BM) stroma. We characterized mesenchymal stromal cells (MSCs) isolated from BM of 18 FA patients both before and after allogeneic haematopoietic stem cell transplantation (HSCT). Morphology, fibroblast colony‐forming unit (CFU‐F) ability, proliferative capacity, immunophenotype, differentiation potential, ability to support long‐term haematopoiesis and immunomodulatory properties of FA‐MSCs were analysed and compared with those of MSCs expanded from 15 age‐matched healthy donors (HD‐MSCs). FA‐MSCs were genetically characterized through conventional karyotyping, diepoxybutane‐test and array‐comparative genomic hybridization. FA‐MSCs generated before and after HSCT were compared. Morphology, immunophenotype, differentiation potential, ability in vitro to inhibit mitogen‐induced T‐cell proliferation and to support long‐term haematopoiesis did not differ between FA‐MSCs and HD‐MSCs. CFU‐F ability and proliferative capacity of FA‐MSCs isolated after HSCT were significantly lower than those of HD‐MSCs. FA‐MSCs reached senescence significantly earlier than HD‐MSCs and showed spontaneous chromosome fragility. Our findings indicate that FA‐MSCs are defective in their ability to survive in vitro and display spontaneous chromosome breakages; whether these defects are involved in pathophysiology of BM failure syndromes deserves further investigation.

Characterization of medulloblastoma in Fanconi Anemia: a novel mutation in the BRCA2 gene and SHH molecular subgroup

AbstractFanconi Anemia (FA) is an inherited disorder characterized by the variable presence of multiple congenital somatic abnormalities, bone marrow failure and cancer susceptibility. Medulloblastoma (MB) has been described only in few cases of FA with biallelic inactivation in the tumor suppressor gene BRCA2/FANCD1 or its associated gene PALB2/FANCN. We report the case of a patient affected by Fanconi Anemia with Wilms tumor and unusual presentation of two medulloblastomas (MB1 and MB2). We identified a new pathogenetic germline BRCA2 mutation: c.2944_2944delA. Molecular analysis of MBs allowed us to define new features of MB in FA. MBs were found to belong to the Sonic Hedgehog (SHH) molecular subgroup with some differences between MB1 and MB2. We highlighted that MB in FA could share molecular aspects and hemispheric localization with sporadic adult SHH-MB. Our report provides new findings that shed new light on the genetic and molecular pathogenesis of MB in FA patients with implications in the disease management.

Transplantation for thalassemia major: alternative donors

Purpose of reviewLack of a human leukocyte antigen (HLA)-matched family donor is a major obstacle limiting the use of allogeneic hematopoietic stem cell transplantation (HSCT) to cure thalassemia major. Use of alternative donors, if found well tolerated enough, may be a viable option for transplantation in this setting, allowing to expand the number of patients treatable by HSCT. This review will provide an overview of alternative HSCT approaches in thalassemia major. Recent findingsWith the introduction of high-resolution molecular HLA-typing techniques, the outcome of matched unrelated donor HSCT recipients has become comparable with that of patients given matched family donor HSCT. On the contrary, the use of unrelated cord blood transplantation has been limited by the risk of graft failure and slow hematopoietic recovery, although novel techniques of ex vivo graft manipulation are emerging as promising strategies for overcoming these obstacles. Although experience with haploidentical HSCT in thalassemia major is still limited, currently explored platforms hold the potential to extend the access to HSCT to thalassemia major patients lacking an HLA-matched either related or unrelated donor. SummaryThe significant advances achieved in transplantation techniques, both in the matched unrelated and in the haploidentical setting, are expected to significantly broaden the applicability of HSCT to patients with thalassemia major.

Eltrombopag for treatment of thrombocytopenia-associated disorders

Introduction: Eltrombopag is an orally bioavailable, non-peptide thrombopoietin receptor agonist capable of stimulating platelet production through the differentiation of CD34+ hematopoietic progenitor cells into committed CD41+ megakaryocyte precursors and proliferation of megakaryocyte progenitor cells. Areas covered: This drug has been tested in several clinical trials in adult patients with chronic immune thrombocytopenia (ITP), demonstrating the ability of the drug to reduce the burden of thrombocytopenia and its associated side effects. Two multicenter trials on eltrombopag in chronic ITP of childhood have been recently completed, showing that the drug is effective also in pediatric patients. Recent studies have suggested a potential role of eltrombopag in the treatment of thrombocytopenia associated with hepatitis-C virus infection. These studies have documented that adjunct treatment with eltrombopag can help avoid either dose reductions or withdrawal of pegylated interferon due to development of thrombocytopenia. Eltrombopag has shown efficacy also in patients with acquired severe aplastic anemia and myelodysplastic syndromes. Expert opinion: Eltrombopag plays an important therapeutic role in many different conditions characterized by persistent thrombocytopenia. A more comprehensive definition of both long-term safety and benefits deriving from the use of eltrombopag will be obtained through prolonged observation of patients already enrolled in the different studies conducted so far and from future prospective controlled trials.

Che‐1 is targeted by c‐Myc to sustain proliferation in pre‐B‐cell acute lymphoblastic leukemia

Despite progress in treating B‐cell precursor acute lymphoblastic leukemia (BCP‐ALL), disease recurrence remains the main cause of treatment failure. New strategies to improve therapeutic outcomes are needed, particularly in high‐risk relapsed patients. Che‐1/AATF (Che‐1) is an RNA polymerase II‐binding protein involved in proliferation and tumor survival, but its role in hematological malignancies has not been clarified. Here, we show that Che‐1 is overexpressed in pediatric BCP‐ALL during disease onset and at relapse, and that its depletion inhibits the proliferation of BCP‐ALL cells. Furthermore, we report that c‐Myc regulates Che‐1 expression by direct binding to its promoter and describe a strict correlation between Che‐1 expression and c‐Myc expression. RNA‐seq analyses upon Che‐1 or c‐Myc depletion reveal a strong overlap of the respective controlled pathways. Genomewide ChIP‐seq experiments suggest that Che‐1 acts as a downstream effector of c‐Myc. These results identify the pivotal role of Che‐1 in the control of BCP‐ALL proliferation and present the protein as a possible therapeutic target in children with relapsed BCP‐ALL.