Educational needs of patients, families, and healthcare professionals to support the patient journey in haemophilia gene therapy in the UK.

With the first gene therapies for haemophilia approved by the European Commission, the US Food and Drug Administration, and the Medicines and Healthcare products Regulatory Agency, it is important to consider the remaining unmet needs and challenges that may arise throughout patients' treatment journeys. We discuss existing unmet needs and important considerations prior to, during, and following haemophilia gene therapy treatment in the UK, and propose potential next steps. Key areas for attention are education, psychological support, and guidance on implementation. Strategies are urgently required to fulfil these needs. An immediate priority for information providers should be comprehensive education for people with haemophilia (PWH) and healthcare professionals (HCPs). Greater access to resources and training in psychological services will be required throughout the treatment pathway. More specific guidance is required to define the implementation model, criteria for accreditation, and responsibilities of care centres. Furthermore, PWH may revisit discussions with HCPs multiple times pre-infusion, thus the patient journey is unlikely to be linear. Consideration of these challenges, and of potential strategies to address them, will be integral to optimising the future success of this promising therapy.

RNAi for the Treatment of People with Hemophilia: Current Evidence and Patient Selection.

Severe hemophilia is associated with spontaneous, prolonged and recurrent bleeding. Inadequate prevention and treatment of bleeding can lead to serious morbidity and mortality. Due to the limitations of intravenous clotting factor replacement, including the risk of inhibitory antibodies, innovative novel therapies have been developed that have dramatically changed the landscape of hemophilia therapy. Ribonucleic acid interference (RNAi) has brought the opportunity for multiple strategies to manipulate the hemostatic system and ameliorate the bleeding phenotype in severe bleeding disorders. Fitusiran is a RNAi therapeutic that inhibits the expression of the natural anticoagulant serpin antithrombin. Reduction in antithrombin is known to cause thrombosis if coagulation parameters are otherwise normal and can rebalance hemostasis in severe hemophilia. Reports from late stage clinical trials of fitusiran in hemophilia A and B participants, with and without inhibitory antibodies to exogenous clotting factor, have demonstrated efficacy in preventing bleeding events showing promise for a future "universal" prophylactic treatment of individuals with moderate-severe hemophilia.

Little discrepancy between one-stage and chromogenic factor VIII (FVIII)/IX assays in a large international cohort of persons with nonsevere hemophilia A and B.

BACKGROUND: Accurate measurements of coagulation factor activity form an essential part of hemophilia management and are performed by the one-stage or chromogenic assay. Current literature suggests that approximately one-third of persons with nonsevere hemophilia A exhibit assay discrepancy, albeit with a high variability between studies. Such data are scarce in nonsevere hemophilia B. OBJECTIVES: To investigate the extent of factor VIII/IX one-stage and chromogenic assay discrepancy in moderate and mild hemophilia A and B. METHODS: Persons with previously diagnosed nonsevere hemophilia A and B with a factor level of 2 to 35 IU/dL were included from the international DYNAMO cohort study. Central measurements of the factor VIII and IX activity levels were performed by the one-stage and chromogenic assay. Relative and absolute discrepancy definitions were used, with the International Society on Thrombosis and Haemostasis-Scientific and Standardization Committee proposed ratio of >2.0 or <0.5 being the primary outcome. Discrepancy was also evaluated in a subgroup of 13 persons with mutations previously associated with discrepancy (≥3 cases reported in literature). RESULTS: A total of 220 persons were included, of whom 3 (1%) showed assay discrepancy: 2/175 hemophilia A and 1/45 hemophilia B. Six persons (3%) exhibited an absolute difference >10 IU/dL between the assay results. In addition, with more lenient definitions, over 90% of participants (n = 197) had no discrepant results. Only 1 out of 13 persons with a mutation previously associated with discrepancy had significant assay discrepancy. CONCLUSION: Little assay discrepancy was observed despite the presence of mutations previously associated with discrepancy, suggesting that the presence and magnitude of assay discrepancy are largely determined by laboratory variables.

Desmopressin for bleeding in non-severe hemophilia A: Suboptimal use in a real-world setting.

Background: Desmopressin is an important treatment option in nonsevere hemophilia A because it has several benefits compared with factor (F) concentrates, including no inhibitor risk and much lower costs. Despite these advantages, data are limited on the real-world use of desmopressin in the treatment of bleeds. Objective: To describe the clinical use of desmopressin in relation to other therapeutic modalities in the treatment of bleeding episodes in patients with nonsevere hemophilia A. Methods: Patients with nonsevere hemophilia A aged 12-55 years were included from the DYNAMO cohort study. Data on the desmopressin test response and treated bleeding events in the period January 2009 to July 2020 were retrospectively collected from medical files. An adequate desmopressin test response was defined based on a peak FVIII level of ≥30 IU/dl. Results: A total of 248 patients with a median age of 38 years (interquartile range 25-49) were included. An adequate desmopressin test response was documented in 25% and 73% of patients with moderate and mild hemophilia, respectively. In adequate responders, 51% of bleeds were exclusively treated with FVIII concentrates, 24% exclusively with desmopressin, 21% with a combination of both and 4% with other treatments. In 54% of bleeds treated with a single dose of factor concentrates, the expected FVIII level after desmopressin exceeded the level targeted. Conclusion: Most bleeds in patients with an adequate response to desmopressin are treated with factor concentrates. These findings may indicate a suboptimal use of desmopressin and that barriers to the use of desmopressin should be explored.

Phase 1-2 Trial of AAVS3 Gene Therapy in Patients with Hemophilia B.

BACKGROUND: FLT180a (verbrinacogene setparvovec) is a liver-directed adeno-associated virus (AAV) gene therapy that uses a synthetic capsid and a gain-of-function protein to normalize factor IX levels in patients with hemophilia B. METHODS: In this multicenter, open-label, phase 1-2 trial, we assessed the safety and efficacy of varying doses of FLT180a in patients with severe or moderately severe hemophilia B (factor IX level, ≤2% of normal value). All the patients received glucocorticoids with or without tacrolimus for immunosuppression to decrease the risk of vector-related immune responses. After 26 weeks, patients were enrolled in a long-term follow-up study. The primary end points were safety and efficacy, as assessed by factor IX levels at week 26. RESULTS: Ten patients received one of four FLT180a doses of vector genomes (vg) per kilogram of body weight: 3.84×1011 vg, 6.40×1011 vg, 8.32×1011 vg, or 1.28×1012 vg. After receiving the infusion, all the patients had dose-dependent increases in factor IX levels. At a median follow-up of 27.2 months (range, 19.1 to 42.4), sustained factor IX activity was observed in all the patients except one, who resumed factor IX prophylaxis. As of the data-cutoff date (September 20, 2021), five patients had normal factor IX levels (range, 51 to 78%), three patients had levels from 23 to 43%, and one had a level of 260%. Of the reported adverse events, approximately 10% were related to FLT180a and 24% to immunosuppression. Increases in liver aminotransferase levels were the most common FLT180a-related adverse events. Late increases in aminotransferase levels occurred in patients who had received prolonged tacrolimus beyond the glucocorticoid taper. A serious adverse event of arteriovenous fistula thrombosis occurred in the patient with high factor IX levels. CONCLUSIONS: Sustained factor IX levels in the normal range were observed with low doses of FLT180a but necessitated immunosuppression with glucocorticoids with or without tacrolimus. (Funded by Freeline Therapeutics; ClinicalTrials.gov numbers, NCT03369444 and NCT03641703; EudraCT numbers, 2017-000852-24 and 2017-005080-40.).

Seroprevalence to adeno-associated virus type 6 in people with hemophilia B from a UK adult cohort.

Background: Gene therapy shows promise as a potential "cure" for hemophilia A and B. Adeno-associated virus (AAV) vectors are the leading platform to deliver modified genetic code of factor VIII or IX to the liver effecting endogenous production. Patient exposure to wild-type AAV leads to the formation of neutralizing factors, which can prevent successful transduction. It is thus important to establish the seroprevalence of the AAV serotypes in people with hemophilia to aid prediction of successful gene transfer. The seroprevalence of AAV6 in UK people with hemophilia B is not yet reported. Objectives: We studied the prevalence of anti-AAV6 neutralizing factors in UK people with hemophilia B (n = 49). We collected data on people's hepatitis C exposure and treatment with plasma-derived factor IX (FIX) to identify if there was correlation with AAV6 exposure. Methods: Serum samples and patient data were collected from 49 people with hemophilia B registered at UK hemophilia comprehensive care centers. The samples were tested for neutralizing factors to AAV6 using a cell-based transduction inhibition assay. Results: Thirty-one percent of patients had serum neutralization against AAV6. There was no correlation between AAV6 seropositivity and previous treatment with plasma-derived FIX products or hepatitis C exposure. Conclusion: Based on limited data, there is no evidence of association between the presence of AAV6 neutralizing factors in people with hemophilia B and exposure to contaminated plasma derivatives. The frequency of AAV6 neutralizing factors in our hemophilia B cohort is similar to UK people with hemophilia A and non-hemophilia populations.

Natural history of PF4 antibodies in vaccine-induced immune thrombocytopenia and thrombosis.

The COVID-19 pandemic has resulted in the rapid development of a range of vaccines against SARS-CoV-2. Vaccine-induced immune thrombocytopenia and thrombosis (VITT) is a rare but life-threatening complication of primarily adenoviral-based vaccines associated with the presence of antibodies to a PF4/polyanion neoepitope and measured by using enzyme-linked immunosorbent assays. Presented are serial anti-PF4/polyanion antibody, platelet, and D-dimer measurements in a large cohort of patients and their relation to relapse. Overall, 51% of patients using the Stago assay had persistently positive anti-PF4/polyanion levels 100 days' postdiagnosis, whereas 94% of patients monitored by using the Immucor assay remain positive. The median duration of positivity of the PF4 assay is 87 days, with 72% of patients remaining positive after a median follow-up of 105 days. The use of plasma exchange seemed to reduce anti-PF4/polyanion levels and increase platelet counts in the acute setting more rapidly than other therapies. The rate of relapse in this study was 12.6%, with all relapsed cases exhibiting persistently positive PF4 antibodies and falling platelet counts. Only one patient had extension of their thrombosis. Overall, despite the persistence of PF4 antibodies in 72% of patients, the rate of relapse was low and did not seem to result in recrudescence of the aggressive clinical picture seen at index presentation. Monitoring of these patients in the UK cohort is ongoing and will aid in definition of the natural history of this novel condition.

Malignant middle cerebral artery syndrome with thrombotic thrombocytopenia following vaccination against SARS-CoV-2.

Cases of thromboses at unusual sites with thrombocytopenia have been reported following vaccination against Sars-CoV-2. This new syndrome, christened vaccine-induced thrombotic thrombocytopenia (VITT), mainly results in venous thromboses. We report the case of a young woman with a right middle cerebral artery stroke following vaccination with ChAdOx1 nCoV-19. A diagnosis of VITT was made and platelet counts began to recover shortly after commencing treatment with argatroban, intravenous immunoglobulins and corticosteroids. On day 6 following admission, the patient deteriorated neurologically and decision made to proceed with decompressive hemicraniectomy. There were no perioperative complications and anticoagulation with argatroban was reinitiated on the first postoperative day. VITT is a rare condition resembling auto-immune heparin-induced thrombocytopenia. All critical care staff should be aware of the rare link between vaccination against SARS-CoV-2 and VITT and the need to rapidly commence both anticoagulation, using heparin alternatives, and immunomodulation.

Acquired Bernard-Soulier syndrome and hypodysfibrinogenaemia because of multiple myeloma.

We describe a case of a patient with multiple myeloma with initial presentation simulating a bleeding disorder. Detailed coagulation work-up showed hypodysfibrinogenaemia along with a platelet function defect consistent with acquired Bernard-Soulier syndrome (BSS). Multiple plasma exchanges led to significant improvement in his bleeding symptoms. To the best of our knowledge, this is the first described case of simultaneous presentation of hypodysfibrinogenaemia and BSS secondary to multiple myeloma.

Homeostasis of Hemostasis: The Role of Endothelium.

Forming an interface with virtually every other organ, endothelium has a strategic role in modulating vascular homeostasis. While its miscellany of functions includes regulation of vasomotor tone, promotion, and prevention of vascular growth, and modulation of inflammatory and hemostatic processes, it functions critically in maintaining the balance of hemostasis in health. Whereas endothelium has been recognized to influence all stages of hemostasis, new evidence suggests it to have a primary role for thrombin generation. Endothelial dysfunction is being increasingly appreciated in several pathological states and particularly, by virtue of its critical role in hemostasis, in causing thrombosis in a multitude of diseases.

The Activation of Complement and Its Role in the Pathogenesis of Thromboembolism.

It is well established that inflammation and thrombosis are intricately linked processes, and there is increasing evidence of the importance of their roles in activated complement in the pathogenesis of thromboembolism. The two systems are activated by similar stimuli simultaneously and interact, either directly or through biochemical mediators, to protect the host from microbial invasion. Diseases characterized by complement hyperactivity such as paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome have high rates of thrombosis. This review describes how disease processes where there is excessive complement activation leads to thrombosis, and the specific interactions between the complement and coagulation systems that lead to pathological thrombus formation.

A still image of a transient rash captured by a mobile phone.

The diagnosis of adult onset Still's disease (AOSD) can be difficult as the differential diagnosis is broad, it is based on clinical criteria and the signs, for example rash, can be transient. Clinical photography has an obvious role, and with modern technology, is now in the hands of physicians. We report a case of AOSD where an image of a transient rash taken with a camera phone allowed the diagnosis to be established. Further, we discuss the controversies around hospital bans on mobile phones (due to potential incompatibility with medical devices) and the reality of their widespread use. We conclude that, providing safeguards of consent and data storage are in place, the camera phone is a useful tool in rheumatology practice.

Lupus and leg ulcers--a diagnostic quandary.

Leg ulcerations can occur in systemic lupus erythematosus (SLE) patients with antiphospholipid (aPL) antibodies and/or vasculitis, and it has been suggested that aPL antibodies may play a pathogenetic role in skin manifestations of SLE. To our knowledge, there is only one report of an aPL antibody-negative patient who developed pyoderma gangrenosum (PG) several years before the diagnosis of SLE. We describe a case of a young male affected by SLE who developed leg ulcers diagnosed as PG in the absence of aPL antibodies, where the onset of PG was associated with reactivation of SLE. Effective treatment led to significant improvement in skin lesions and SLE activity.