Acid Sphingomyelinase Deficiency: Sharing Experience of Disease Monitoring and Severity in France.

Acid sphingomyelinase deficiency (ASMD) is a rare inherited lipid storage disorder caused by a deficiency in lysosomal enzyme acid sphingomyelinase which results in the accumulation of sphingomyelin, predominantly within cells of the reticuloendothelial system located in numerous organs, such as the liver, spleen, lungs, and central nervous system. Although all patients with ASMD share the same basic metabolic defect, a wide spectrum of clinical presentations and outcomes are observed, contributing to treatment challenges. While infantile neurovisceral ASMD (also known as Niemann-Pick disease type A) is rapidly progressive and fatal in early childhood, and the more slowly progressive chronic neurovisceral (type A/B) and chronic visceral (type B) forms have varying clinical phenotypes and life expectancy. The prognosis of visceral ASMD is mainly determined by the association of hepatosplenomegaly with secondary thrombocytopenia and lung disease. Early diagnosis and appropriate management are essential to reduce the risk of complications and mortality. The accessibility of the new enzyme replacement therapy olipudase alfa, a recombinant human ASM, has been expedited for clinical use based on positive clinical data in children and adult patients, such as improved respiratory status and reduced spleen volume. The aim of this article is to share the authors experience on monitoring ASMD patients and stratifying the severity of the disease to aid in care decisions.

A Cross-Sectional Retrospective Study of Non-Splenectomized and Never-Treated Patients with Type 1 Gaucher Disease.

Patients with type 1 Gaucher disease (GD1) present thrombocytopenia, anemia, organomegaly, and bone complications. Most experts consider that the less aggressive forms do not require specific treatment. However, little is known about the disease course of these forms. The objective of this cross-sectional retrospective study was to compare the clinical, radiological, and laboratory characteristics of patients with less severe GD1 at diagnosis and at the last evaluation to identify features that might lead to potential complications. Non-splenectomized and never-treated patients (19 women and 17 men) were identified in the French Gaucher Disease Registry (FGDR). Their median age was 36.6 years (2.4-75.1), and their median follow-up was 7.8 years (0.4-32.4). Moreover, 38.7% were heterozygous for the GBA1 N370S variant, and 22.6% for the GBA1 L444P variant. From diagnosis to the last evaluation, GD1 did not worsen in 75% of these patients. Some parameters improved (fatigue and hemoglobin concentration), whereas platelet count and chitotriosidase level remained stable. In one patient (2.7%), Lewy body dementia was diagnosed at 46 years of age. Bone lesion onset was late and usually a single event in most patients. This analysis highlights the genotypic heterogeneity of this subgroup, in which disease could remain stable and even improve spontaneously. It also draws attention to the possible risk of Lewy body disease and late onset of bone complications, even if isolated, to be confirmed in larger series and with longer follow-up.

Immunoglobulin Abnormalities in Gaucher Disease: an Analysis of 278 Patients Included in the French Gaucher Disease Registry.

Gaucher disease (GD) is a rare lysosomal autosomal-recessive disorder due to deficiency of glucocerebrosidase; polyclonal gammopathy (PG) and/or monoclonal gammopathy (MG) can occur in this disease. We aimed to describe these immunoglobulin abnormalities in a large cohort of GD patients and to study the risk factors, clinical significance, and evolution. Data for patients enrolled in the French GD Registry were studied retrospectively. The risk factors of PG and/or MG developing and their association with clinical bone events and severe thrombocytopenia, two markers of GD severity, were assessed with multivariable Cox models and the effect of GD treatment on gammaglobulin levels with linear/logarithmic mixed models. Regression of MG and the occurrence of hematological malignancies were described. The 278 patients included (132 males, 47.5%) were followed up during a mean (SD) of 19 (14) years after GD diagnosis. PG occurred in 112/235 (47.7%) patients at GD diagnosis or during follow-up and MG in 59/187 (31.6%). Multivariable analysis retained age at GD diagnosis as the only independent risk factor for MG (> 30 vs. ≤30 years, HR 4.71, 95%CI [2.40-9.27]; p < 0.001). Risk of bone events or severe thrombocytopenia was not significantly associated with PG or MG. During follow-up, non-Hodgkin lymphoma developed in five patients and multiple myeloma in one. MG was observed in almost one third of patients with GD. Immunoglobulin abnormalities were not associated with the disease severity. However, prolonged surveillance of patients with GD is needed because hematologic malignancies may occur.

Intra-monocyte Pharmacokinetics of Imiglucerase Supports a Possible Personalized Management of Gaucher Disease Type 1.

BACKGROUND AND OBJECTIVES: Intravenous imiglucerase enzyme replacement therapy for Gaucher disease type 1 administered every 2 weeks is at variance with the imiglucerase plasma half-life of a few minutes. We hypothesized that studying the pharmacokinetics of imiglucerase in blood Gaucher disease type 1 monocytes would be more relevant for understanding enzyme replacement therapy responses. METHODS: Glucocerebrosidase intra-monocyte activity was studied by flow cytometry. The pharmacokinetics of imiglucerase was analyzed using a population-pharmacokinetic model from a cohort of 31 patients with Gaucher disease type 1 who either started or were receiving long-term treatment with imiglucerase. RESULTS: A pharmacokinetic analysis of imiglucerase showed a two-compartment model with a high peak followed by a two-phase exponential decay (fast phase half-life: 0.36 days; slow phase half-life: 9.7 days) leading to a median 1.4-fold increase in glucocerebrosidase intra-monocyte activity from the pre-treatment activity (p = 0.04). In patients receiving long-term treatment, for whom the imiglucerase dose per infusion was chosen on the basis of disease aggressiveness/response, imiglucerase clearance correlated with the administered dose. However, the residual glucocerebrosidase intra-monocyte activity value was dose independent, suggesting that the maintenance of imiglucerase residual activity is patient specific. Endogenous pre-treatment glucocerebrosidase intra-monocyte activity was the most informative single parameter for distinguishing patients without (n = 10) and with a clinical indication (n = 17) for starting enzyme replacement therapy (area under the receiver operating characteristic curve: 0.912; 95% confidence interval 0.8-1; p < 0.001), as confirmed also by a factorial analysis of mixed data. CONCLUSION: This study provides novel pharmacokinetic data that support current imiglucerase administration regimens and suggests the existence of a glucocerebrosidase activity threshold related to Gaucher disease type 1 aggressiveness. These findings can potentially improve Gaucher disease type 1 management algorithms and clinical decision making.

Resistance to complement activation, cell membrane hypersialylation and relapses in chronic lymphocytic leukemia patients treated with rituximab and chemotherapy.

The anti-CD20-specific monoclonal antibody rituximab (RTX), in combination with chemotherapy, is commonly used for primary treatment in chronic lymphocytic leukemia (CLL). However, relapses remain important and activation of the complement pathway is one of the mechanisms by which RTX generates the destruction of B cells directly by complement-dependent cytotoxicity (CDC), or indirectly by antibody-dependent cellular phagocytosis. In this study, the RTX capacity to induce CDC was established in 69 untreated CLL patients, this cohort including 34 patients tested before the initiation of RTX-chemotherapy. In vitro CDC-resistance to RTX predicts lower response rates to RTX-chemotherapy and shorter treatment free survival. Furthermore, the predictive value of CDC-resistance was independent from the clinical, cytogenetic and FcγR3A V158F polymorphism status. In contrast, CLL cell resistance to CDC predominates in IGHV unmutated patients and was related to an important α2-6 sialyl transferase activity, which in turn increases cell surface α2-6 hypersialylation. Suspected factors associated with resistance to CDC (CD20, CD55, CD59, factor H, GM1, and sphingomyelin) were not differentially expressed or recruited between the two CLL groups. Altogether, results provide evidence that testing RTX capacity to induce CDC in vitro represents an independent predictive factor of therapeutic effects of RTX, and that α2-6 hypersialylation in CLL cells controls RTX response through the control of the complement pathway. At a time when CLL therapy is moving towards chemo-free treatments, further experiments are required to determine whether performing an initial in vitro assay to appreciate CLL CDC resistance might be useful to select patients.

Non-adherence to treatment with cytoreductive and/or antithrombotic drugs is frequent and associated with an increased risk of complications in patients with polycythemia vera or essential thrombocythemia (OUEST study).

The purpose of this study was to identify the incidence, causes and impact of non-adherence to oral and subcutaneous chronic treatments for patients with polycythemia vera or essential thrombocythemia. Patients receiving cytoreductive drugs for polycythemia vera or essential thrombocythemia were recruited at our institution (Observatoire Brestois des Néoplasies Myéloprolifératives registry). They completed a one-shot questionnaire designed by investigators (Etude de l'Observance Thérapeutique et des Effets Secondaires des Traitements study). Data about complications (thrombosis, transformation and death) at any time in the patient's life (before diagnosis, up until consultation and after the completion of the questionnaire) were collected. Sixty-five (22.7%) of 286 patients reported poor adherence (<90%) to their treatment with cytoreductive drugs and 46/255/18%) also declared non-adherence to antithrombotic drugs. In total, 85/286 patients (29.7%) declared they did not adhere to their treatment. Missing an intake was rare and was mostly due to forgetfulness especially during occupational travel and holidays. Patients who did not adhere to their treatment were characterized by younger age, living alone, having few medications but a high numbers of pills and determining their own schedule of drug intake. Having experienced thrombosis or hematologic evolution did not influence the adherence rate. Non-adherence to oral therapy was associated with a higher risk of phenotypic evolution (7.3 versus 1.8%, P=0.05). For patients treated for polycythemia vera or essential thrombocythemia, non-adherence to cytoreductive and/or antithrombotic therapies is frequent and is influenced by age, habitus and concomitant treatments, but not by disease history or treatment side effects. Phenotypic evolution seems to be more frequent in the non-adherent group.

Incidence and impact of atrial arrhythmias on thrombotic events in MPNs.

Atrial arrhythmias (AA) induce a high rate of thromboses and require vitamin K antagonists (VKA) or direct anticoagulants (DOAC) prescriptions. Essential thrombocythemia (ET) and polycythemia vera (PV) are also pro-thrombotic diseases. The prevention of thromboses is based on the association of cytoreductive drug and low-dose aspirin (LDA). We studied the incidence and complications of AA among patients with ET or PV. We identified 96/713 patients (13.5%) carrying AA. These patients were older (median 72.1 vs. 61.3 years old, p < 0.0001). In a case-control analysis, we observed that patients with AA had a higher frequency of cardiovascular risk factors (77/96, 80% vs. 61/96, 61%; p = 0.01). A higher incidence of thromboses before and after myeloproliferative neoplasm (MPN) diagnosis was seen in this group: 26/96, 27.1% vs. 14/96, 14.6% (p = 0.03) and 34/96, 35% vs. 18/96, 18.8% (p = 0.009). Most of the events were arterial (82 vs. 61%, p = 0.09). This translates into a shorter thrombosis-free survival (11.0 vs. 21.6 years, p = 0.01). Continuation of LDA in this situation exposed patients to more thrombotic events (p = 0.04) but VKA did not seem to be good anticoagulant drugs either. The association of AA and MPN is more frequent than expected. AA clearly increased the thrombotic risk of these patients. Anticoagulant drugs should be carefully managed between cardiologists and hematologists. Association of LDA and VKA or the role of DOAC in such population should be rapidly discussed to reduce the thrombotic rate.

Impact of imiglucerase supply constraint on the therapeutic management and course of disease in French patients with Gaucher disease type 1.

BACKGROUND: In 2009, a worldwide supply constraint of imiglucerase led to treatment modifications or interruptions for patients with Gaucher disease (GD) type 1. In France, joint treatment recommendations were issued to protect the most vulnerable patients. This observational study evaluated the impact of imiglucerase treatment modifications on the clinical and biological course of GD. METHODS: Retrospective data on patients' characteristics, treatment, clinical and biological parameters from 01 June 2009 to 31 October 2010 were collected during a single visit. RESULTS: Ninety-nine GD1 patients, aged 7-84 years, were included (median age 47 years); 10 were children. Patients experienced a median of 4 different treatment modifications. Median change from pre-supply constraint dose (92 U/kg/4-weeks) was -69, -51, -29 and -60 U/kg/4-weeks at 3, 6, 9 and 12 months after first modification, respectively, with imiglucerase discontinuation reported for 70%, 47%, 29% and 55% of patients at these timepoints. Replacement with another ERT was reported for 35 patients. Results show a statistically significant decrease in hemoglobin (-0.8 g/L/month) and platelets (-5905.10(3)/mm(3)/month) and an increase in chitotriosidase (+537 nmol/mL/h/month) and angiotensin-converting enzyme (+4 IU/L/month) in the subgroup of 61 patients who discontinued treatment for at least 3 months; this magnitude of change was not seen in the subgroup (32 patients) treated with reduced imiglucerase for at least 3 consecutive months. GD-related events were spontaneously reported by the study investigators for 39% of the whole study population, including asthenia/fatigue (8%), bone infarction and bone pain (4% each), and hepatomegaly (3%). A Kaplan-Meier estimate of the probability for a patient to present a bone, hematological or visceral event during the constraint was 37% for patients who discontinued the treatment and 10% for patients treated with a reduced imiglucerase dose. CONCLUSION: The release of recommendations and individuals' close follow-up allowed satisfactory management of patients during the imiglucerase supply constraint in France. This study suggests that during this period, lowering the dose of imiglucerase had less impact on the outcomes of patients than interrupting treatment. However, general effects (such as fatigue, bone pain) reported in some patients, emphasize the importance of maintaining appropriate individualized dosing.