Recombinant Factor VIII Fc Fusion Protein (rFVIIIFc) in Real Life: One-Year Clinical and Economic Outcomes

International audienceBackground: Recombinant factor VIII Fc fusion protein (rFVIIIFc) is the first extended half-life (EHL) recombinant clotting factor with marketing authorization; it has been available in France since October 2016. However, data and literature about rFVIIIFc in clinical practice are scarce.Objective: We propose a 1-year clinical and economic outcome evaluation in patients with hemophilia A taking into consideration treatment adherence.Patients and methods: We reviewed the diaries of all patients treated with rFVIIIFc at Marseille Hemophilia Center for 1 year. All the data were related to the patients' infusion (i.e., annual number of infusions, weekly dose/kg, and annual consumption) and bleeding reports. The clotting factor costs were considered, whereas additional costs (e.g., infusion devices and nurse intervention) were neglected.Results: A total of 34 patients were evaluated. Their median age was 18 years (IQR = 18). Treatment adherence was observed in 62% for FVIII and 66% for rFVIIIFc. The analysis revealed a negligible decrease in the annual clotting factor consumption following the switch (- 2%, p = 0.7339). These data were combined with a significant reduction in the annual number of infusion (- 22.5%, median = 138.5, IQR = 65.8 for FVIII; median = 105, IQR = 24 for rFVIIIFc, p < 0.0001) and bleeding (- 50%, median = 5, IQR = 7.5 for FVIII; median = 1, IQR = 4 for rFVIIIFc, p < 0.0001). With regard to the cost, a decreasing trend was observed (- 8%, p = 0.1300).Conclusion: The analysis in a real-life setting revealed that the input of switches toward rFVIIIFc in different treatment (age of patients and regimen) patterns seems to corroborate previous studies. The results suggest that switches have a beneficial effect in terms of efficacy, clotting factor consumption, and cost

Early changes in bleeding perception and quality of life in children and adolescents receiving emicizumab prophylaxis for severe haemophilia A without inhibitor

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Reinvestigation of unidentified causative variants in FXI-deficient patients: Focus on gene segment deletions

International audienceIntroduction: Data on failure to identify the molecular mechanism underlying FXI deficiency by Sanger analysis and the contribution of gene segment deletions are almost inexistent. Aims and methods: Prospective and retrospective analysis was conducted on FXI-deficient patients’ DNA via Next Generation Sequencing (NGS), or Sanger sequencing and Multiplex Probe Ligation-dependent Assay (MLPA) to detect cryptic causative gene variants or gene segment deletions. Results: Sanger analysis or NGS enabled us to identify six severe and one partial (median activity 41 IU/dl) FXI deficient index cases with deletions encompassing exons 11–15, the whole gene, or both. After Sanger sequencing, retrospective evaluation using MLPA detected seven additional deletion cases in apparently homozygous cases in non-consanguineous families, or in previously unsolved FXI-deficiency cases. Among the 504 index cases with a complete genetic investigation (Sanger/MLPA, or NGS), 23 remained unsolved (no abnormality found [n = 14] or rare intronic variants currently under investigation, [n = 9]). In the 481 solved cases (95% efficiency), we identified F11 gene-deleted patients (14 cases; 2.9%). Among these, whole gene deletion accounted for four heterozygous cases, exons 11–15 deletion for five heterozygous and three homozygous ones, while compound heterozygous deletion and isolated exon 12 deletion accounted for one case each. Conclusion: Given the high incidence of deletions in our population (2.9%), MLPA (or NGS with a reliable bioinformatic pipeline) should be systematically performed for unsolved FXI deficiencies or apparently homozygous cases in non-consanguineous families

Specific therapeutic support and development of the Body Schema in ă bleeding disorders

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Prise en charge néphrologique des patients hémophiles A : difficultés diagnostiques et thérapeutiques illustrées par le cas de 2 patients

International audienceHemophilia A is an X-linked genetic hemorrhagic disorder characterized by a factor VIII deficiency. The availability of secured substitution products has led to a dramatic improvement of life expectancy in hemophiliac patients. Nowadays, adult hemophiliac patients may develop Chronic Kidney Disease (CKD) resulting from age-related comorbidities (hypertension, obesity, diabetes). In addition, the high prevalence of viral infections in this population exposes patients to an increased risk of CKD. The risk of hemorrhage in hemophiliac patients is a challenge for their clinical management, both for diagnostic procedures (kidney biopsy in particular) and for renal replacement therapy (dialysis or renal transplantation) when it is needed. This work provides an update of the literature data concerning the management of hemophiliac patients in nephrology, illustrated by the cases of two patients

Harmful or harmless: biological effects of marennine on marine organisms

Marennine is a water-soluble blue-green pigment produced by the marine diatom Haslea ostrearia. The diatom and its pigment are well known from oyster farming areas as the source of the greening of oyster gills, a natural process increasing their market value in Western France. Blooms of blue Haslea are also present outside oyster ponds and hence marine organisms can be exposed, periodically and locally, to significant amounts of marennine in natural environments. Due to its demonstrated antibacterial activities against marine pathogenic bacteria (e.g. Vibrio) and possible prophylactic effects toward bivalve larvae, marennine is of special interest for the aquaculture industry, especially bivalve hatcheries. The present study aimed to provide new insights into the effects of marennine on a large spectrum of marine organisms belonging to different phyla, including species of aquaculture interest and organisms frequently employed in standardised ecotoxicological assays. Different active solutions containing marennine were tested: partially purified Extracellular Marennine (EMn), and concentrated solutions of marennine present in H. ostrearia culture supernatant; the Blue Water (BW) and a new process called Concentrated Supernatant (CS). Biological effects were meanwhile demonstrated in invertebrate species for the three marennine-based solutions at the highest concentrations tested (e.g., decrease of fertilization success, delay of embryonic developmental stages or larval mortality). Exposure to low concentrations did not impact larval survival or development and even tended to enhance larval physiological state. Furthermore, no effects of marennine were observed on the fish gill cell line tested. Marennine could be viewed as a Jekyll and Hyde molecule, which possibly affects the earliest stages of development of some organisms but with no direct impacts on adults. Our results emphasize the need to determine dosages that optimize beneficial effects and critical concentrations not to be exceeded before considering the use of marennine in bivalve or fish hatcheries

Single-cell analysis of megakaryopoiesis in peripheral CD34⁺ cells: insights into ETV6-related thrombocytopenia

Expansion of human megakaryoblasts from peripheral blood-derived CD34 + cells is commonly used to characterize inherited or acquired thrombocytopenia and evaluate defects in megakaryocyte (MK) differentiation, MK maturation and proplatelet formation. We applied single-cell RNA sequencing to understand local gene expression changes during megakaryopoiesis (days 6 and 11 of differentiation) in peripheral CD34 + cells from healthy controls and patients with ETV6 -related thrombocytopenia. Analysis of gene expression and regulon activity revealed distinct clusters partitioned into seven major cell stages: hematopoietic stem/progenitor cells (HSPC), common-myeloid progenitors (CMP), MK-primed CMP, granulocyte-monocyte progenitors, megakaryocyte-erythroid progenitors (MEP), MK progenitor /mature MK (MKP/MK) and platelets. We observed a subpopulation of MEP that arose directly from HSPC, deviating from the canonical MK differentiation pathway. ETV6 deficiency was characterized by an increase in HSPC, a decrease in MKP/MK, and a lack of platelets. ETV6 deficiency also led to the development of aberrant MEP and MKP/MK cell populations. Genes involved in “mitochondrial” and “DNA repair” pathways were downregulated, while genes involved in “translation” pathways were upregulated. Analysis of patient samples and hematopoietic cell lines transduced with an ETV6 variant revealed increased translation in MK. Ribosomal protein small 6 (RPS6) levels in MK, platelets and peripheral blood mononuclear cells was consistent with the translation findings. Our results provide a framework to understand peripheral CD34 + cell-derived megakaryocytic cultures. Our observations also shed light on ETV6 -variant pathology and reveal potential targets for diagnostic and therapeutic purposes. Key points - scRNAseq gain insight into in vitro megakaryopoiesis, identify MK-primed CMP, and a differentiation trajectory that bypasses the CMP. - ETV6 variants led to the development of aberrant MEP and MK cell populations

Single-cell analysis of megakaryopoiesis in peripheral CD34+ cells: insights into ETV6-related thrombocytopenia

ETV6-related thrombocytopenia mechanisms remain poorly understood Megakaryopoiesis was studied by single-cell RNA sequencing and defects were confirmed ex-vivo ETV6 deficiency led to the development of aberrant haemopoietic cells as early as the MEP stage Upregulation of ribosome biogenesis were documented in patient megakaryocytes and platelet

Relationship between plasma tissue Factor Pathway Inhibitor (TFPI) levels, thrombin generation and clinical risk of bleeding in patients with severe haemophilia A or B

International audienceAbstract Introduction Bleeding severity in severe haemophilic patients, with low thrombin generation (TG) capacity, can vary widely between patients, possibly reflecting differences in tissue factor pathway inhibitor (TFPI) level. Aim To compare free TFPI (fTFPI) levels in patients with severe haemophilia A (sHA) and severe haemophilia B (sHB) and to investigate in these patients as a whole the relationships between bleeding and TG potential, between TG potential and fTFPI level and between fTFPI level and bleeding tendency. Methods Data on bleeding episodes retrospectively recorded during follow‐up visits over 5–10 years were collected and used to calculate the annualised joint bleeding rate (AJBR). fTFPI levels and basal TG parameters were determined in platelet‐poor plasma (PPP) and platelet‐rich plasma (PRP) using calibrated automated tomography (CAT). Results Mean fTFPI levels did not differ significantly between sHA ( n = 34) and sHB ( n = 19) patients. Mean values of endogenous thrombin potential (ETP) and thrombin peak (peak) in PPP and PRP were two‐fold higher when fTFPI levels &lt; 9.4 versus &gt; 14.3 ng/mL. In patients treated on demand, ETP and peak in PRP were doubled when AJBR was , AJBR being halved in patients with a low fTFPI level (9.4 ng/mL). In patients on factor prophylaxis, no association was found between TG parameters and either fTFPI level or AJBR. Conclusion In patients treated on demand, bleeding tendency was influenced by fTFPI levels, which in turn affected basal TG potential. In patients on prophylaxis, bleeding tendency is probably determined primarily by the intensity of this treatment

Association of laboratory test results with the bleeding history in patients with inherited platelet function disorders (the Bleeding Assesment Tool - LABoratory tests substudy): communication from the Platelet Physiology ISTH-SSC

International audienceBackground: In hemophilia and von Willebrand disease, the degree of alteration of laboratory assays correlates with bleeding manifestations. Few studies have assessed the predictive value for bleeding of laboratory assays in patients with inherited platelet function disorders (IPFDs). Objectives: To assess whether there is an association between platelet function assay results and bleeding history, as evaluated by the International Society on Thrombosis and Haemostasis (ISTH) bleeding assessment tool (BAT). Methods: Centers participating in the international ISTH-BAT validation study were asked to provide results of the diagnostic assays employed for the patients they enrolled, and the association with the individual patients' bleeding score (BS) was assessed. Results: Sixty-eight patients with 14 different IPFDs were included. Maximal amplitude of platelet aggregation was significantly lower in patients with a pathologic BS and correlated inversely with the BS, a finding largely driven by the subgroup of patients with Glanzmann thrombasthenia and CalDAG-GEFI deficiency; after their exclusion, TRAP -induced aggregation remained significantly lower in patients with a pathologic BS. Bleeding time was significantly more prolonged in patients with a high BS than in those with a normal BS (27.1 +/- 6.2 minutes vs 15.1 +/- 10.6 minutes; P < .01). Reduced alpha-granule content was significantly more common among patients with a pathologic BS than among those with a normal BS (80% vs 20%; P < .05). Receiver operating characteristic curve analysis revealed a significant discriminative ability of all the aforementioned tests for pathologic BS (P < .001), also after exclusion of patients with Glanzmann thrombasthenia and CalDAG-GEFI deficiency. Conclusion: This study shows that altered platelet laboratory assay results are associated with an abnormal ISTH-BAT BS in IPFD