Fiorina Giona

Pivotal trial with plant cell-expressed recombinant glucocerebrosidase, taliglucerase alfa, a novel enzyme replacement therapy for Gaucher disease

Taliglucerase alfa (Protalix Biotherapeutics, Carmiel, Israel) is a novel plant cell-derived recombinant human β-glucocerebrosidase for Gaucher disease. A phase 3, double-blind, randomized, parallel-group, comparison-dose (30 vs 60 U/kg body weight/infusion) multinational clinical trial was undertaken. Institutional review board approvals were received. A 9-month, 20-infusion trial used inclusion/exclusion criteria in treatment-naive adult patients with splenomegaly and thrombocytopenia. Safety end points were drug-related adverse events: Ab formation and hypersensitivity reactions. Primary efficacy end point was reduction in splenic volume measured by magnetic resonance imaging. Secondary end points were: changes in hemoglobin, hepatic volume, and platelet counts. Exploratory parameters included biomarkers and bone imaging. Twenty-nine patients (11 centers) completed the protocol. There were no serious adverse events; drug-related adverse events were mild/moderate and transient. Two patients (6%) developed non-neutralizing IgG Abs; 2 other patients (6%) developed hypersensitivity reactions. Statistically significant spleen reduction was achieved at 9 months: 26.9% (95% confidence interval [CI]: -31.9, -21.8) in the 30-unit dose group and 38.0% (95% CI: -43.4, -32.8) in the 60-unit dose group (both P < .0001); and in all secondary efficacy end point measures, except platelet counts at the lower dose. These results support safety and efficacy of taliglucerase alfa for Gaucher disease.

Low bone density and decreased inhibin-B/FSH ratio in a boy treated with imatinib during puberty

A 9-year-old boy was diagnosed in June, 2000, with BCR-ABL-positive chronic myeloid leukaemia (CML) in the chronic phase. In December, 2002, because of a cytogenetic relapse during interferon therapy, he was switched to imatinib 400 mg daily. Complete cytogenetic, haematological, and mole cular remission was attained and per sisted during follow-up. During 53 months of therapy, the dose of imatinib was unvaried, the patient took no other medications, and only a minor side-eff ect consisting of one episode of skin photosensitivity was reported. At the beginning of imatinib ad ministration, the patient was 11·7 years old, his height 142 cm, weight 32 kg, Tanner pubertal stage 2, and testicular volume 5 mL. During the fi rst 2 years on imatinib, his longitudinal growth, which had been 4·3 cm per year from 8·0 years to 11·7 years, slowed to 1·5 cm per year, with a modest attenuation of weight gain. Thereafter, concomitant with pubertal maturation, the patient’s growth rate increased (7·5 cm per year), and the boy reached the midparental target height. Up until the age of 14 years, testicular volume, Tanner stage, and con centrations of serum androgens were pre pubertal. 1 year later, these con centrations rose in parallel with the appearance of signs of puberty (table). In the following months, andro gens, testis volume, and Tanner staging reached adult values. In parallel, however, a progressive in crease of follicle-stimulating hor mone (FSH) and a decrease of inhibin-B, outside the normal range, were seen (table). This eff ect led to a strong reduction in the inhibin-B/FSH ratio to levels predictive of the failure of spermatogenesis and reduction of fertility. At age 14·6 years, the boy developed bilateral gynaecomastia, which persisted during follow-up. Serum calcium and phosphate con centrations were in the upper limits of normal and urinary calcium was higher than normal; serum para thyroid hormone, 25-hydroxyvitamin-D, urinary phos phate, bonespeci fi c alkaline phos phatase, and osteo calcin were within the expected ranges. How ever, con centra tions of the bone resorption markers C-terminal telo peptides of type I collagen were up to 2·6 times higher than the highest reference range for age-matched healthy boys (table), sug gesting a pre valence of bone resorption over forma tion. Accordingly, bone mineral density (BMD) measured by dual-energy X-ray absorptiometry of the lumbar spine (L1–L4) at 15 and at 15·9 years revealed low BMD for chrono logical age (0·556 g/cm2 and 0·557 g/cm2, respectively)—a condition that pre disposes to an increased risk of fracture. Imatinib inhibits the tyrosine kinase functions of BCR-ABL, platelet-derived growth factor receptor (PDGFR), and KIT receptor associated with diseases such as CML and gastrointestinal stromal tumour. Inhibition of PDGFR and KIT can also occur, and the presumed clinical consequences—altered Age in years (months on imatinib) Reference range

A novel heterozygous HIF2AM535I mutation reinforces the role of oxygen sensing pathway disturbances in the pathogenesis of familial erythrocytosis

This report shows that two members of a family with idiopathic erythrocytosis carried a mutation in the hypoxia-inducible factor-2A (HIF2A) gene. See related perspective article on page 963. HIF2A transcription factor plays a central role in the regulation of the hypoxia responding pathway in mammalian cells, by modulating erythropoiesis and angiogenesis. Molecular alterations of oxygen sensing pathway constituents are implicated in hereditary erythrocytosis. Here we show that 2 members of a family with idiopathic erythrocytosis exhibited a new heterozygous G to A mutation at base 1605 of the exon 12 of hypoxia-inducible factor-2A (HIF2A) gene. This mutation determines the replacement of methionine by isoleucine at the position 535, very close to the position 531, where the hydroxyl acceptor prolyne is located. In addition, we found that mRNA expression of erythropoietin receptor, vascular endothelial growth factor, transferrin receptor, adrenomedullin and N-myc downstream regulated gene 1, up-regulated by HIF2A or hypoxia, were significantly higher in patients carrying the mutation than in normal controls. These results suggest that the HIF2AM535I gene mutation could induce hereditary erythrocytosis at a young age.

Epigenetic alteration of SOCS family members is a possible pathogenetic mechanism in JAK2 wild type myeloproliferative diseases

In polycythemia vera (PV) and essential thrombocythemia (ET) specific JAK2 mutations constitutively activate the JAK‐STAT pathway, explaining biologic findings such as endogenous erythroid colony (EECs) growth or PRV‐1 RNA overexpression. Since these markers are detected also in JAK2 wild type patients, we hypothesized that, in these cases, the activation of the JAK‐STAT pathway could be produced by a deregulation of the suppressor of cytokine signaling (SOCS) protein system. Eighty‐one patients with PV and ET (53 adults and 28 children) were investigated for the methylation status of the SOCS‐1, SOCS‐2 and SOCS‐3 CpG islands and for several myeloproliferative markers (including JAK2 and MPL mutations and clonality of hematopoiesis). SOCS‐1 or SOCS‐3 hypermethylation was identified in 23 patients and was associated with a significant decrease of SOCS‐1 or SOCS‐3 RNA and protein levels. The gene expression was restored by exposing cells to the demethylating agent 2‐deoxyazacytidin. Interestingly, SOCS‐1 or SOCS‐3 hypermethylation was detected in 6 female patients, proved negative for JAK2 or MPL mutations and exhibiting monoclonal hematopoiesis. In conclusion, SOCS‐1 or SOCS‐3 hypermethylation can activate the JAK‐STAT signaling pathway in alternative or together with JAK2 mutations. These alterations might represent a potential therapeutic target.

A new severity score index for phenotypic classification and evaluation of responses to treatment in type I Gaucher disease

Gaucher disease is the first lysosomal storage disease for which specific therapy became available. This study reports a reliable method for staging the severity of adult type I Gaucher disease, and for monitoring the response to treatment. Background Gaucher disease is the first lysosomal storage disease for which specific therapy became available. Over 4800 patients have been treated with enzyme replacement therapy. Analysis of Gaucher disease registry data has outlined the clinical heterogeneity of the disease and the different responses to treatment from patient to patient, and for different organs. This variability in clinical response justifies the development of a severity score index to assess disease activity, stage and prognosis, and to quantify the effects of treatment. Design and Methods The new scoring system proposed here, the “Gaucher Disease Severity Score Index – Type I” (GauSSI-I), is based on the clinical experience of the authors and an extensive literature review, including data from the International Gaucher Registry. In particular for skeletal disease, all the available scoring systems have been reviewed and compared in order to provide a skeletal scoring system that allows use of any of the different methods on an equivalent basis. Results The new scoring system, GauSSI-I, was developed. Six specific domains, in which different items were scored according to their impact on morbidity, were characterized. GauSSI-I was evaluated in 53 type I Gaucher patients treated with imiglucerase, and it was compared to the Zimran score, the only severity index score so far available. Conclusions The GauSSI-I is a reliable method for staging the severity of adult type I Gaucher disease, and it is more sensitive than the Zimran score for monitoring the response to treatment.

Evidence for a founder effect of the MPL-S505N mutation in eight Italian pedigrees with hereditary thrombocythemia

Hereditary thrombocythemia is a rare disease characterized by increased megakaryopoiesis and overproduction of platelets. Germline mutations have been identified in the genes for thrombopoietin (THPO) and its receptor, MPL. This study suggests that the recurrent MPL (S505N) mutation found in eight Italian families with hereditary thrombocythemia is likely due to a founder effect. Background Hereditary thrombocythemia is a rare disease characterized by increased megakaryopoiesis and overproduction of platelets. Germ line mutations have been identified in the genes for thrombopoietin (THPO) and its receptor, MPL. A clustering of familial cases with the MPL-G1073A mutation that results in a serine to asparagine substitution (S505N) has been recently reported in Italy. Here we performed haplotype analysis in nine families (eight Italian and one Japanese) with hereditary thrombocythemia carrying the MPL-S505N mutation in the MPL gene. Design and Methods The MPL gene was examined by genomic DNA sequencing. Haplotype analysis was performed using microsatellites and single nucleotide polymorphisms. Results Analysis of microsatellite markers and single nucleotide polymorphisms in the eight Italian families with hereditary thrombocythemia revealed the presence of a common haplotype compatible with a founder effect, which may have originated 23 generations ago. This haplotype was rarely observed in 132 unrelated individuals and was absent in a Japanese family with the MPL-S505N mutation. Conclusions The recurrent MPL-S505N mutation found in the eight Italian families with hereditary thrombocythemia is likely due to a founder effect.

Treatment of primary refractory and relapsed acute lymphoblastic leukaemia in children and adults: the GIMEMA/AIEOP* experience

One hundred and forty‐seven patients aged <55 years with advanced acute lymphoblastic leukaemia (ALL) were enrolled in an Italian cooperative study (ALL R‐87), This protocol consists of an induction phase with idarubicin (IDA) plus intermediate‐dose cytarabine (IDARA‐C), followed by a consolidation phase and bone marrow transplant (BMT). Complete remission (CR) was achieved in 97/147 patients (66%) with a CR rate of 77% in children versus 51% in adults (P<0·01), 48 responders (50%) underwent BMT.

Platelet size for distinguishing between inherited thrombocytopenias and immune thrombocytopenia: a multicentric, real life study

The most frequent forms of inherited thrombocytopenia (IT) are characterized by platelet size abnormalities and it has been suggested that this parameter is useful for their differentiation from immune thrombocytopenia (ITP). Recently, a monocentric study identified cut‐off values for mean platelet volume (MPV) and mean platelet diameter (MPD) with good diagnostic accuracy in this respect. To validate these cut‐off values in a different and larger case series of patients, we enrolled 130 subjects with ITP and 113 with IT in six different centres. The platelet count and MPV was each measured by the instrument routinely used in each institution. In some centres, platelet count was also measured by optical microscopy. MPD was evaluated centrally by image analysis of peripheral blood films. The previously identified cut‐off value for MPV had 91% specificity in distinguishing ITP from inherited macrothrombocytopenias (mono and biallelic Bernard‐Soulier, MYH9‐related disease), while its sensitivity was greatly variable depending on the instrument used. With an appropriate instrument, specificity was 83%. The diagnostic accuracy of MPD was lower than that obtained with MPV. We concluded that MPV is a useful parameter for differentiating ITP from IT provided that it is measured by appropriate cell counters.

Thrombocythemia and polycythemia in patients younger than 20 years at diagnosis: clinical and biologic features, treatment, and long-term outcome

Sixty-four patients < 20 years of age, investigated for a suspicion of Philadelphia-negative myeloproliferative disease (MPD), were retrospectively evaluated to characterize the different forms and to examine the treatments used and long-term outcome. JAK2 mutations, endogenous erythroid colony growth, and clonality were investigated in 51 children. Mutations of thrombopoietin, the thrombopoietin receptor (MPL), and the erythropoietin receptor and mutations of other genes involved in the pathogenesis of MPD were investigated in JAK2 wild-type patients. Based on our criteria for childhood MPD, we identified 34 patients with sporadic thrombocythemia (ST), 16 with hereditary thrombocytosis (HT), 11 with sporadic polycythemia (SP), and 3 with hereditary polycythemia (HP). JAK2(V617F) mutations were present in 47.5% of ST and in no HT. The MPL(S505A) mutation was detected in 15/16 HT patients and in no ST (P < .00001). The JAK2(V617F) mutation occurred in 27% of SP patients diagnosed according to the Polycythemia Vera Study Group or World Health Organization 2001 criteria. Children with ST received more cytoreductive drugs than those with HT (P = .0006). After a median follow-up of 124 months, no patient had developed leukemia or myelofibrosis and 5% had thrombosis; the miscarriage rate in thrombocythemic patients was 14%. The low complication rate in our population suggests that children with MPD may be managed by tailored approaches.

Pre-transplant prognostic factors for patients with high-risk leukemia undergoing an unrelated cord blood transplantation

Summary:From July 1995 to December 2001, 42 patients with leukemia aged 1–42 years underwent cord blood transplant (CBT) from unrelated, ⩽2 antigen HLA mismatched donors. In all, 26 patients were in ⩽2nd complete remission and 16 in more advanced phase. Conditioning regimens, graft-versus-host disease (GVHD) prophylaxis and supportive policy were uniform for all patients. The cumulative incidence of engraftment was 90% (95% CI: 0.78–0.91). The cumulative incidence of III–IV grade acute- and chronic-GVHD was 9% (95% CI: 0.04–0.24) and 35% (95% CI: 0.21–0.60), respectively. The 4-year cumulative incidence of transplant-related mortality (TRM) and relapse was 28% (95% CI: 0.17–0.47) and 25% (95% CI: 0.14–0.45), respectively. The 4-year overall survival (OS), leukemia-free survival (LFS) and event-free survival (EFS) were 45% (95% CI: 0.27–0.63), 47% (95% CI: 0.30–0 .64) and 46% (95% CI: 0.30–0.62), respectively. In multivariate analysis, the most important factor affecting outcomes was the CFU-GM dose, associated with CMV serology (P=0.003 and 0.04, respectively) in influencing OS and with patient sex (P=0.008 and 0.03, respectively) in influencing LFS. Finally, CFU-GM dose was the only factor that affected EFS significantly (P=0.02). In conclusion, the infused cell dose expressed as in vitro progenitor cell growth is highly predictive of outcomes after an unrelated CBT and should be considered the main parameter in selecting cord blood units for transplant.