Objective To examine the presentation characteristics of patients with Kaposiform hemangioendothelioma (KHE) to describe the spectrum of disease and risk factors for Kasabach-Merritt phenomenon ...(KMP). Study design A retrospective review of 163 patients referred to the Vascular Anomalies Center at Children's Hospital Boston for KHE between 1991 and 2009 identified 107 patients with sufficient data for inclusion. Results The prevalence of KHE in Massachusetts is ∼0.91 case per 100 000 children. KHE manifested in infancy in 93% of cases, with 60% as neonates. Common presenting features included enlarging cutaneous lesion (75%), thrombocytopenia (56%), and musculoskeletal pain or decreased function (23%). Cutaneous KHE favored the extremities, especially overlying joints. In our cohort, 71% developed KMP (11% after initial presentation), and 11% of patients lacked cutaneous findings. Retroperitoneal and intrathoracic lesions, though less common, were complicated by KMP in 85% and 100% of cases, respectively. Compared with superficial lesions, KHE infiltrating into muscle or deeper was 6.3-fold more likely to manifest KMP and 18-fold higher if retroperitoneal or intrathoracic. KHE limited to bone or presenting after infancy did not manifest KMP. Conclusion An enlarging cutaneous lesion is the most common presenting feature of KHE in infancy. Older patients with KHE or those lacking cutaneous manifestations present with musculoskeletal complaints or atypical symptoms. The risk of KMP increases dramatically when tumor infiltrates muscle or when KHE arises in the retroperitoneum or mediastinum.
Therapies engineered to prolong clotting factor protein circulation time, manipulate the balance of pro‐coagulant and anti‐coagulant proteins, or introduce new genetic material to enable endogenous ...factor protein production dominate the clinical trial landscape of hemophilia. The availability of clotting factor concentrates and the establishment of primary prophylaxis have dramatically improved health outcomes for hemophilia patients. But, the burden of hemostatic therapy remains significant, and many barriers to consistent longitudinal use of prophylaxis exist. Several types of emerging therapeutics including engineered factor concentrates, substitutive therapies, rebalancing therapies, and gene transfer/editing all aim to reduce the challenges of current hemophilia treatment. Emerging treatment options may reduce treatment frequency or need for intravenous administration. They may also introduce new challenges in laboratory assessment of hemostasis. These novel therapies must not introduce significant new health risks and continue to support similar or improved outcomes. The potential ramifications of rebalancing the coagulation cascade, particularly in a stress or inflammatory state, or introduction of new genetic material are not trivial. The focus of this review is to provide an overview of active and recently completed clinical trials as well as emerging preclinical data investigating new therapeutic possibilities for hemophilia patients and potentially other rare bleeding disorders.
Objective To describe the clinical and imaging characteristics of a new lymphatic disorder with a unique histological pattern and poor prognosis. Study design An observational, retrospective study ...identified and characterized 20 patients with distinct lymphatic histopathology referred to the Vascular Anomalies Center at Boston Children's Hospital between 1995 and 2011. Results The median age at onset was 6.5 years (range, birth to 44 years). Clinical and radiologic findings suggested a generalized process. The most common presentations were respiratory symptoms (50%), hemostatic abnormalities (50%), and an enlarging, palpable mass (35%). All patients had mediastinal involvement; 19 patients developed pericardial (70%) and/or pleural effusions (85%). Extrathoracic disease manifested in bone and spleen and less frequently in abdominal viscera, peritoneum, integument, and extremities. Despite aggressive procedural and medical therapies, the 5-year survival was 51% and the overall survival was 34%. Mean interval between diagnosis and death was 2.75 years (range, 1-6.5 years). Conclusions We describe a clinicopathologically distinct lymphatic anomaly. We propose the term kaposiform lymphangiomatosis (KLA) because of characteristic clusters or sheets of spindled lymphatic endothelial cells accompanying malformed lymphatic channels. The intrathoracic component is most commonly implicated in morbidity and mortality; however, extrathoracic disease is frequent, indicating that KLA is not restricted to pulmonary lymphatics. The mortality rate of KLA is high despite aggressive multimodal therapy.
The goal of gene therapy for patients with hemophilia A is to safely impart long-term stable factor VIII expression that predictably ameliorates bleeding with the use of the lowest possible vector ...dose.
In this phase 1-2 trial, we infused an investigational adeno-associated viral (AAV) vector (SPK-8011) for hepatocyte expression of factor VIII in 18 men with hemophilia A. Four dose cohorts were enrolled; the lowest-dose cohort received a dose of 5 × 10
vector genomes (vg) per kilogram of body weight, and the highest-dose cohort received 2 × 10
vg per kilogram. Some participants received glucocorticoids within 52 weeks after vector administration either to prevent or to treat a presumed AAV capsid immune response. Trial objectives included evaluation of the safety and preliminary efficacy of SPK-8011 and of the expression and durability of factor VIII.
The median safety observation period was 36.6 months (range, 5.5 to 50.3). A total of 33 treatment-related adverse events occurred in 8 participants; 17 events were vector-related, including 1 serious adverse event, and 16 were glucocorticoid-related. Two participants lost all factor VIII expression because of an anti-AAV capsid cellular immune response that was not sensitive to immune suppression. In the remaining 16 participants, factor VIII expression was maintained; 12 of these participants were followed for more than 2 years, and a one-stage factor VIII assay showed no apparent decrease in factor VIII activity over time (mean ±SD factor VIII activity, 12.9±6.9% of the normal value at 26 to 52 weeks when the participants were not receiving glucocorticoids vs. 12.0±7.1% of the normal value at >52 weeks after vector administration; 95% confidence interval CI, -2.4 to 0.6 for the difference between matched pairs). The participants had a 91.5% reduction (95% CI, 88.8 to 94.1) in the annualized bleeding rate (median rate, 8.5 events per year range, 0 to 43.0 before vector administration vs. 0.3 events per year range, 0 to 6.5 after vector administration).
Sustained factor VIII expression in 16 of 18 participants who received SPK-8011 permitted discontinuation of prophylaxis and a reduction in bleeding episodes. No major safety concerns were reported. (Funded by Spark Therapeutics and the National Heart, Lung, and Blood Institute; ClinicalTrials.gov numbers, NCT03003533 and NCT03432520.).
Introduction
Over the last decades progress in haemophilia treatment has been remarkable and prophylaxis with clotting factor concentrates in haemophilia A and B has been established as the standard ...of care in individuals with haemophilia and a severe bleeding phenotype. Besides clotting factor products with prolonged half‐life non‐factor therapies were developed which enable prophylaxis via subcutaneous administration. Factor VIIIa mimetics like emicizumab facilitate the coagulation pathway and are used in routine clinical practice for indivdiduals with haemophilia A. Rebalancing therapeutic agents like fitusiran, concizumab, marstacimab and serpin PC block the anticoagulant pathway and clinical trials using these products in individuals with haemophilia A and B are ongoing.
Aim and Methods
A narrative review to asess the benefits and risks of non‐factor therapies taking in to account re‐defined haemophilia treatment goals.
Results
Prophylaxis for prevention of bleeds using non‐factor products by subcutaneous administration is effective and results in reductions of bleeding episodes in individuals with haemophilia A or B with and without inhibitors. The treatment with emicizumab showed tolerable safety both in clinical trials and long‐term real‐world observations with few thrombotic events. In some clinical trials with rebalancing therapies (fitusiran and concizumab) thrombotic events occurred. Monitoring of the haemostatic function of novel therapies especially with concomitant haemostatic treatment is not yet established.
Conclusion
With the advent of novel therapeutic agents including factor concentrates with ultra‐long half‐life and improved FVIIIa mimetics aimed at raising the bar of protection into the non‐hemophilic range redefinition of haemophilia treatment goals is eagerly needed.
Low von Willebrand factor (VWF) poses diagnostic and therapeutic challenges for predicting bleed risk and need for empiric hemostatic therapy, particularly in children. Retrospective review ...identified 293 low VWF pediatric patients and investigated clinical and laboratory features. Low activity to antigen ratio was observed in 142 patients. When evaluation included VWF activity with gain‐of‐function glycoprotein Ib fragments (VWF:GPIbM) assay or VWF exon 28 sequencing, low VW was excluded in the majority (62%) of these patients. Application of a condensed bleeding assessment tool to quantify bleeding symptoms and use of the VWF:GPIbM assay may reduce the number of patients with bleed risk anxiety and unnecessary hemostatic management plans.
Clinical coagulation assays are an integral part of diagnosing and managing patients with hemophilia; however, in this new era of bioengineered factor products and nonfactor therapeutics, problems ...have arisen with use of traditional coagulation tests for the quantification of several of these new products. Discussion over the use of one‐stage clotting assays versus chromogenic substrate assays for clinical decision making and potency labeling has been ongoing for many years. Emerging factor concentrates have heightened concern over assay selection and availability. Emicizumab interferes with all aPTT based assays, rendering them unreliable and potentially falsely reassuring to the unaware provider. This review explores considerations for coagulation assays in the clinical setting and highlights how awareness of institutional coagulation assays and potential limitations have never been more critical for providers caring for patients with bleeding disorders.
Gene therapy has the potential to overcome many of the limitations of prophylactic hemophilia therapies. Several clinical trials evaluate investigational adeno-associated virus (AAV)-mediated gene ...transfer approaches for the treatment of hemophilia A and B. The practical application of these approaches is nuanced by differences in AAV serotypes, transgene modifications, manufacturing, dosing, administration, and approach to follow-up. This guide explores mechanisms of AAV gene transfer, identification of appropriate candidates for clinical trial participation, anticipated trial events that follow infusion of an investigational gene therapy including outcomes to be monitored, and future considerations. Patient-accessible infographic summaries of these topics are included to serve as potential visual aids that healthcare providers may choose to utilize or adapt to guide informed consultation. The fundamentals of AAV-mediated, liver-directed gene transfer for hemophilia are reviewed, to facilitate discussion between healthcare providers, patients, and their families and advocates if considering a trial of investigational gene therapy.
PDF
