Recombinant ADAMTS13 in Congenital Thrombotic Thrombocytopenic Purpura.

BACKGROUND: Congenital thrombotic thrombocytopenic purpura (TTP) results from severe hereditary deficiency of ADAMTS13. The efficacy and safety of recombinant ADAMTS13 and standard therapy (plasma-derived products) administered as routine prophylaxis or on-demand treatment in patients with congenital TTP is not known. METHODS: In this phase 3, open-label, crossover trial, we randomly assigned patients in a 1:1 ratio to two 6-month periods of prophylaxis with recombinant ADAMTS13 (40 IU per kilogram of body weight, administered intravenously) or standard therapy, followed by the alternate treatment; thereafter, all the patients received recombinant ADAMTS13 for an additional 6 months. The trigger for this interim analysis was trial completion by at least 30 patients. The primary outcome was acute TTP events. Manifestations of TTP, safety, and pharmacokinetics were assessed. Patients who had an acute TTP event could receive on-demand treatment. RESULTS: A total of 48 patients underwent randomization; 32 completed the trial. No acute TTP event occurred during prophylaxis with recombinant ADAMTS13, whereas 1 patient had an acute TTP event during prophylaxis with standard therapy (mean annualized event rate, 0.05). Thrombocytopenia was the most frequent TTP manifestation (annualized event rate, 0.74 with recombinant ADAMTS13 and 1.73 with standard therapy). Adverse events occurred in 71% of the patients with recombinant ADAMTS13 and in 84% with standard therapy. Adverse events that were considered by investigators to be related to the trial drug occurred in 9% of the patients with recombinant ADAMTS13 and in 48% with standard therapy. Trial-drug interruption or discontinuation due to adverse events occurred in no patients with recombinant ADAMTS13 and in 8 patients with standard therapy. No neutralizing antibodies developed during recombinant ADAMTS13 treatment. The mean maximum ADAMTS13 activity after recombinant ADAMTS13 treatment was 101%, as compared with 19% after standard therapy. CONCLUSIONS: During prophylaxis with recombinant ADAMTS13 in patients with congenital TTP, ADAMTS13 activity reached approximately 100% of normal levels, adverse events were generally mild or moderate in severity, and TTP events and manifestations were rare. (Funded by Takeda Development Center Americas and Baxalta Innovations; ClinicalTrials.gov number, NCT03393975.).

Platelet RNA Biomarker of Ticagrelor-Responsive Genes Is Associated With Platelet Function and Cardiovascular Events.

BACKGROUND: Identifying patients with the optimal risk:benefit for ticagrelor is challenging. The aim was to identify ticagrelor-responsive platelet transcripts as biomarkers of platelet function and cardiovascular risk. METHODS: Healthy volunteers (n=58, discovery; n=49, validation) were exposed to 4 weeks of ticagrelor with platelet RNA data, platelet function, and self-reported bleeding measured pre-/post-ticagrelor. RNA sequencing was used to discover platelet genes affected by ticagrelor, and a subset of the most informative was summarized into a composite score and tested for validation. This score was further analyzed (1) in CD34+ megakaryocytes exposed to an P2Y12 inhibitor in vitro, (2) with baseline platelet function in healthy controls, (3) in peripheral artery disease patients (n=139) versus patient controls (n=30) without atherosclerosis, and (4) in patients with peripheral artery disease for correlation with atherosclerosis severity and risk of incident major adverse cardiovascular and limb events. RESULTS: Ticagrelor exposure differentially expressed 3409 platelet transcripts. Of these, 111 were prioritized to calculate a Ticagrelor Exposure Signature score, which ticagrelor reproducibly increased in discovery and validation cohorts. Ticagrelor's effects on platelets transcripts positively correlated with effects of P2Y12 inhibition in primary megakaryocytes. In healthy controls, higher baseline scores correlated with lower baseline platelet function and with minor bleeding while receiving ticagrelor. In patients, lower scores independently associated with both the presence and extent of atherosclerosis and incident ischemic events. CONCLUSIONS: Ticagrelor-responsive platelet transcripts are a biomarker for platelet function and cardiovascular risk and may have clinical utility for selecting patients with optimal risk:benefit for ticagrelor use.

Effect of Thromboprophylaxis on Clinical Outcomes After COVID-19 Hospitalization.

BACKGROUND: Patients hospitalized with COVID-19 have an increased incidence of thromboembolism. The role of extended thromboprophylaxis after hospital discharge is unclear. OBJECTIVE: To determine whether anticoagulation is superior to placebo in reducing death and thromboembolic complications among patients discharged after COVID-19 hospitalization. DESIGN: Prospective, randomized, double-blind, placebo-controlled clinical trial. (ClinicalTrials.gov: NCT04650087). SETTING: Done during 2021 to 2022 among 127 U.S. hospitals. PARTICIPANTS: Adults aged 18 years or older hospitalized with COVID-19 for 48 hours or more and ready for discharge, excluding those with a requirement for, or contraindication to, anticoagulation. INTERVENTION: 2.5 mg of apixaban versus placebo twice daily for 30 days. MEASUREMENTS: The primary efficacy end point was a 30-day composite of death, arterial thromboembolism, and venous thromboembolism. The primary safety end points were 30-day major bleeding and clinically relevant nonmajor bleeding. RESULTS: Enrollment was terminated early, after 1217 participants were randomly assigned, because of a lower than anticipated event rate and a declining rate of COVID-19 hospitalizations. Median age was 54 years, 50.4% were women, 26.5% were Black, and 16.7% were Hispanic; 30.7% had a World Health Organization severity score of 5 or greater, and 11.0% had an International Medical Prevention Registry on Venous Thromboembolism risk prediction score of greater than 4. Incidence of the primary end point was 2.13% (95% CI, 1.14 to 3.62) in the apixaban group and 2.31% (CI, 1.27 to 3.84) in the placebo group. Major bleeding occurred in 2 (0.4%) and 1 (0.2%) and clinically relevant nonmajor bleeding occurred in 3 (0.6%) and 6 (1.1%) apixaban-treated and placebo-treated participants, respectively. By day 30, thirty-six (3.0%) participants were lost to follow-up, and 8.5% of apixaban and 11.9% of placebo participants permanently discontinued the study drug treatment. LIMITATIONS: The introduction of SARS-CoV-2 vaccines decreased the risk for hospitalization and death. Study enrollment spanned the peaks of the Delta and Omicron variants in the United States, which influenced illness severity. CONCLUSION: The incidence of death or thromboembolism was low in this cohort of patients discharged after hospitalization with COVID-19. Because of early enrollment termination, the results were imprecise and the study was inconclusive. PRIMARY FUNDING SOURCE: National Institutes of Health.

2023 ACR/EULAR antiphospholipid syndrome classification criteria.

OBJECTIVE: To develop new antiphospholipid syndrome (APS) classification criteria with high specificity for use in observational studies and trials, jointly supported by the American College of Rheumatology (ACR) and EULAR. METHODS: This international multidisciplinary initiative included four phases: (1) Phase I, criteria generation by surveys and literature review; (2) Phase II, criteria reduction by modified Delphi and nominal group technique exercises; (3) Phase III, criteria definition, further reduction with the guidance of real-world patient scenarios, and weighting via consensus-based multicriteria decision analysis, and threshold identification; and (4) Phase IV, validation using independent adjudicators' consensus as the gold standard. RESULTS: The 2023 ACR/EULAR APS classification criteria include an entry criterion of at least one positive antiphospholipid antibody (aPL) test within 3 years of identification of an aPL-associated clinical criterion, followed by additive weighted criteria (score range 1-7 points each) clustered into six clinical domains (macrovascular venous thromboembolism, macrovascular arterial thrombosis, microvascular, obstetric, cardiac valve, and hematologic) and two laboratory domains (lupus anticoagulant functional coagulation assays, and solid-phase enzyme-linked immunosorbent assays for IgG/IgM anticardiolipin and/or IgG/IgM anti-ß2-glycoprotein I antibodies). Patients accumulating at least three points each from the clinical and laboratory domains are classified as having APS. In the validation cohort, the new APS criteria vs the 2006 revised Sapporo classification criteria had a specificity of 99% vs 86%, and a sensitivity of 84% vs 99%. CONCLUSION: These new ACR/EULAR APS classification criteria were developed using rigorous methodology with multidisciplinary international input. Hierarchically clustered, weighted, and risk-stratified criteria reflect the current thinking about APS, providing high specificity and a strong foundation for future APS research.

Vaccine-induced immune thrombotic thrombocytopenia: what we know and do not know.

The development of vaccines to fight COVID-19 has been a remarkable medical achievement. However, this global immunization effort has been complicated by a rare vaccine-related outcome characterized by thrombocytopenia and thrombosis in association with platelet-activating anti-platelet factor 4 antibodies. In this Spotlight, we will discuss the recently described complication of vaccine-induced immune thrombotic thrombocytopenia (VITT) occurring in response to certain COVID-19 vaccines. Although information about this clinical condition is rapidly evolving, we will summarize our current understanding of VITT.

Real-world safety and effectiveness of recombinant porcine sequence factor VIII in acquired haemophilia A: A non-interventional, post-authorization safety study.

INTRODUCTION: Recombinant porcine factor VIII (rpFVIII, susoctocog alfa) is indicated for the treatment of bleeding episodes in adults with acquired haemophilia A (AHA). AIM: To provide long-term real-world safety and effectiveness data for rpFVIII in the management of AHA bleeding episodes. METHODS: US PASS (NCT02610127) was a multicentre, uncontrolled, open-label, post-marketing safety surveillance study conducted in adults with AHA. Data were collected retrospectively or prospectively for 180 days after rpFVIII treatment. The primary outcome was the incidence of treatment-related serious adverse events (SAEs). Secondary outcomes included haemostatic effectiveness of rpFVIII and rpFVIII utilization. RESULTS: Fifty-three patients were enrolled from December 2015 to June 2019 (prospective, n = 30; retrospective, n = 23). Six patients experienced seven treatment-related SAEs (incidence 12.0%). The most common treatment-related SAE was FVIII inhibition (inhibiting antibodies to rpFVIII; incidence 8.0%, 95% CI: 2.2-19.2). Five patients reported seven thromboembolic events; one was an SAE and possibly related to rpFVIII. Of bleeding events treated with rpFVIII, 80.3% (57/71) of bleeds resolved with rpFVIII. The median (range) dose of rpFVIII per infusion was 50 (10-300) units/kg, with a median (range) of 6.0 (1-140) infusions and a median (range) time from bleed onset to bleed resolution of 14.0 (2.0-132.7) days. CONCLUSION: In this real-world study of rpFVIII for AHA, no new safety signals were identified compared with previous clinical trial findings. Eighty percent of bleeds resolved with rpFVIII treatment.

Case Series of Thrombosis With Thrombocytopenia Syndrome After COVID-19 Vaccination-United States, December 2020 to August 2021.

BACKGROUND: Thrombosis with thrombocytopenia syndrome (TTS) is a potentially life-threatening condition associated with adenoviral-vectored COVID-19 vaccination. It presents similarly to spontaneous heparin-induced thrombocytopenia. Twelve cases of cerebral venous sinus thrombosis after vaccination with the Ad26.COV2.S COVID-19 vaccine (Janssen/Johnson & Johnson) have previously been described. OBJECTIVE: To describe surveillance data and reporting rates of all reported TTS cases after COVID-19 vaccination in the United States. DESIGN: Case series. SETTING: United States. PATIENTS: Case patients receiving a COVID-19 vaccine from 14 December 2020 through 31 August 2021 with thrombocytopenia and thrombosis (excluding isolated ischemic stroke or myocardial infarction) reported to the Vaccine Adverse Event Reporting System. If thrombosis was only in an extremity vein or pulmonary embolism, a positive enzyme-linked immunosorbent assay for antiplatelet factor 4 antibodies or functional heparin-induced thrombocytopenia platelet test result was required. MEASUREMENTS: Reporting rates (cases per million vaccine doses) and descriptive epidemiology. RESULTS: A total of 57 TTS cases were confirmed after vaccination with Ad26.COV2.S (n = 54) or a messenger RNA (mRNA)-based COVID-19 vaccine (n = 3). Reporting rates for TTS were 3.83 per million vaccine doses (Ad26.COV2.S) and 0.00855 per million vaccine doses (mRNA-based COVID-19 vaccines). The median age of patients with TTS after Ad26.COV2.S vaccination was 44.5 years (range, 18 to 70 years), and 69% of patients were women. Of the TTS cases after mRNA-based COVID-19 vaccination, 2 occurred in men older than 50 years and 1 in a woman aged 50 to 59 years. All cases after Ad26.COV2.S vaccination involved hospitalization, including 36 (67%) with intensive care unit admission. Outcomes of hospitalizations after Ad26.COV2.S vaccination included death (15%), discharge to postacute care (17%), and discharge home (68%). LIMITATIONS: Underreporting and incomplete case follow-up. CONCLUSION: Thrombosis with thrombocytopenia syndrome is a rare but serious adverse event associated with Ad26.COV2.S vaccination. The different demographic characteristics of the 3 cases reported after mRNA-based COVID-19 vaccines and the much lower reporting rate suggest that these cases represent a background rate. PRIMARY FUNDING SOURCE: Centers for Disease Control and Prevention.

Aspirin effects on platelet gene expression are associated with a paradoxical, increase in platelet function.

Aspirin has known effects beyond inhibiting platelet cyclooxygenase-1 (COX-1) that have been incompletely characterized. Transcriptomics can comprehensively characterize the on- and off-target effects of medications. We used a systems pharmacogenomics approach of aspirin exposure in volunteers coupled with serial platelet function and purified platelet mRNA sequencing to test the hypothesis that aspirin's effects on the platelet transcriptome are associated with platelet function. We prospectively recruited 74 adult volunteers for a randomized crossover study of 81- vs. 325 mg/day, each for 4 weeks. Using mRNA sequencing of purified platelets collected before and after each 4-week exposure, we identified 208 aspirin-responsive genes with no evidence for dosage effects. In independent cohorts of healthy volunteers and patients with diabetes, we validated aspirin's effects on five genes: EIF2S3, CHRNB1, EPAS1, SLC9A3R2 and HLA-DRA. Functional characterization of the effects of aspirin on mRNA as well as platelet ribosomal RNA demonstrated that aspirin may act as an inhibitor of protein synthesis. Database searches for small molecules that mimicked the effects of aspirin on platelet gene expression in vitro identified aspirin but no other molecules that share aspirin's known mechanisms of action. The effects of aspirin on platelet mRNA were correlated with higher levels of platelet function both at baseline and after aspirin exposure-an effect that counteracts aspirin's known antiplatelet effect. In summary, this work collectively demonstrates a dose-independent effect of aspirin on the platelet transcriptome that counteracts the well-known antiplatelet effects of aspirin.

Andexanet alfa and four-factor prothrombin complex concentrate for reversal of apixaban and rivaroxaban in patients diagnosed with intracranial hemorrhage.

Limited data exists regarding the clinical outcomes of andexanet alfa and four factor prothrombin complex concentrate (4F-PCC) for reversal of apixaban or rivaroxaban in the setting of intracranial hemorrhage (ICH). The objective of this study was to evaluate clinical outcomes of 4F-PCC and andexanet alfa for reversal of ICH associated with oral factor Xa inhibitors. This was a retrospective, single-center, case series evaluating hemostatic efficacy of patients receiving andexanet alfa) or 4F-PCC for reversal of apixaban or rivaroxaban after ICH. Secondary endpoints included in-hospital mortality, thrombotic complications, timing of reversal agents, intensive care unit and hospital length of stay, patient disposition, and 30-day readmission rate. During the study period, 21 patients received andexanet alfa and 35 received 4F-PCC. Hemostatic efficacy occurred in 64.7% of patients receiving andexanet alfa and 54.8% of receiving 4F-PCC. Thirty-day all-cause mortality was 45.2% for 4F-PCC and 30% for andexanet alfa. Thrombotic events were higher with 4F-PCC (31.4%) compared to andexanet alfa (14.3%). Median time from presentation to administration of reversal agent was 2.67 [1.75-4.13] hours with andexanet alfa and 1.73 [1.21-3.55] hours with 4F-PCC. Discharge to skilled nursing facilities and 30-day readmission were similar between groups. In this cohort, reversal with andexanet alfa and 4F-PCC differed in terms ofhemostatic efficacy and thrombotic events after ICH in patients anticoagulated with apixaban or rivaroxaban.

Bad weed: synthetic cannabinoid-associated coagulopathy.

Recent multistate outbreaks of coagulopathy caused by brodifacoum-tainted synthetic cannabinoids or "fake weed" highlight the public health impact of long-acting anticoagulant rodenticides (LAARs). Patients presenting with this syndrome have had recent exposure to synthetic cannabinoids, evidence of isolated vitamin K antagonism with or without bleeding, and detectable levels of brodifacoum and other LAARs in circulation. This article will provide information on synthetic cannabinoids, LAARs, and coagulopathic manifestations arising from use of adulterated synthetic cannabinoids and their management.

Cancer-Associated Venous Thromboembolic Disease, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology.

NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Cancer-Associated Venous Thromboembolic Disease focus on the prevention, diagnosis, and treatment of patients with cancer who have developed or who are at risk for developing venous thromboembolism (VTE). VTE is a significant concern among cancer patients, who are at heightened risks for developing as well as dying from the disease. The management of patients with cancer with VTE often requires multidisciplinary efforts at treating institutions. The NCCN panel comprises specialists from various fields: cardiology, hematology/hematologic oncology, internal medicine, interventional radiology, medical oncology, pharmacology/pharmacy, and surgery/surgical oncology. This article focuses on VTE prophylaxis for medical and surgical oncology inpatients and outpatients, and discusses risk factors for VTE development, risk assessment tools, as well as management methods, including pharmacological and mechanical prophylactics. Contraindications to therapeutic interventions and special dosing, when required, are also discussed.

Successful Management of Catastrophic Thrombotic Storm in a Young Boy: A Case Report From Northern India.

Thrombotic storm is a rare clinical entity characterized by acute to subacute thrombosis developing at multiple sites over a few days to a few weeks. An 11-year-old boy presented with headache and facial nerve palsy. He was found to have cortical sinus venous thrombosis and was initiated on low molecular weight heparin, but rapidly progressed with thromboses involving the pulmonary arteries and deep veins of the legs. Thereafter managed on high-dose unfractionated heparin, he eventually stabilized after a hospital stay of 34 days. Genetic analysis showed potentially pathogenic variants in the factor V and stabilin-2 genes.

Platelet reactivity in response to aspirin and ticagrelor in African-Americans and European-Americans.

Platelet gene polymorphisms are associated with variable on-treatment platelet reactivity and vary by race. Whether differences in platelet reactivity and aspirin or ticagrelor exist between African-American and European-Americans remains poorly understood. Biological samples from three prior prospective antiplatelet challenge studies at the Duke Clinical Research Unit were used to compare platelet reactivity between African-American and European-American subjects. Platelet reactivity at baseline, on-aspirin, on-ticagrelor, and the treatment effect of aspirin or ticagrelor were compared between groups using an adjusted mixed effects model. Compared with European-Americans (n = 282; 50% female; mean ± standard deviation age, 50 ± 16), African-Americans (n = 209; 67% female; age 48 ± 12) had lower baseline platelet reactivity with platelet function analyzer-100 (PFA-100) (p < 0.01) and with light transmission aggregometry (LTA) in response to arachidonic acid (AA), adenosine diphosphate (ADP), and epinephrine agonists (p < 0.05). African-Americans had lower platelet reactivity on aspirin in response to ADP, epinephrine, and collagen (p < 0.05) and on ticagrelor in response to AA, ADP, and collagen (p < 0.05). The treatment effect of aspirin was greater in European-Americans with an AA agonist (p = 0.002). Between-race differences with in vitro aspirin mirrored those seen in vivo. The treatment effect of ticagrelor was greater in European-Americans in response to ADP (p < 0.05) but with collagen, the treatment effect was greater for African-Americans (p < 0.05). Platelet reactivity was overall lower in African-Americans off-treatment, on aspirin, and on ticagrelor. European-Americans experienced greater platelet suppression on aspirin and on ticagrelor. The aspirin response difference in vivo and in vitro suggests a mechanism intrinsic to the platelet. Whether the absolute level of platelet reactivity or the degree of platelet suppression after treatment is more important for clinical outcomes is uncertain.

16th International Congress on Antiphospholipid Antibodies Task Force Report on Antiphospholipid Syndrome Treatment Trends.

Antiphospholipid syndrome (APS), an acquired autoimmune thrombophilia, is characterised by thrombosis and/or pregnancy morbidity in association with persistent antiphospholipid antibodies. The 16th International Congress on Antiphospholipid Antibodies Task Force on APS Treatment Trends reviewed the current status with regard to existing and novel treatment trends for APS, which is the focus of this Task Force report. The report addresses current treatments and developments since the last report, on the use of direct oral anticoagulants in patients with APS, antiplatelet agents, adjunctive therapies (hydroxychloroquine, statins and vitamin D), targeted treatment including rituximab, belimumab, and anti-TNF agents, complement inhibition and drugs based on peptides of beta-2-glycoprotein I. In addition, the report summarises potential new players, including coenzyme Q10, adenosine receptor agonists and adenosine potentiation. In each case, the report provides recommendations for clinicians, based on the current state of the art, and suggests a clinical research agenda. The initiation and development of appropriate clinical studies requires a focus on devising suitable outcome measures, including a disease activity index, an optimal damage index, and a specific quality of life index.

Physical Activity in the Hospital: Documentation and Influence on Venous Thromboembolism Prophylaxis.

This study describes the availability of physical activity information in the electronic health record, explores how electronic health record documentation correlates with accelerometer-derived physical activity data, and examines whether measured physical activity relates to venous thromboembolism (VTE) prophylaxis use. Prospective observational data comes from community-dwelling older adults admitted to general medicine (n = 65). Spearman correlations were used to examine association of accelerometer-based daily step count with documented walking distance and with duration of VTE prophylaxis. Only 52% of patients had documented walking in nursing and/or physical therapy/occupational therapy notes during the first three hospital days. Median daily steps recorded via accelerometer was 1,370 (interquartile range = 854, 2,387) and correlated poorly with walking distance recorded in physical therapy/occupational therapy notes (median 33 feet/day [interquartile range = 12, 100]; r = .24; p = .27). Activity measures were not associated with use or duration of VTE prophylaxis. VTE prophylaxis use does not appear to be directed by patient activity, for which there is limited documentation.

Initiation of Emicizumab Therapy in an Adult Patient With Hemophilia A With Inhibitors and Associated Drug Cost Savings.

Objective: To report the utilization of emicizumab in a patient with severe hemophilia A with inducible inhibitors and the reduction of drug costs related to decreased on-demand recombinant factor VIIa use. Case Summary: A 65-year-old African American man with established hemophilia A with an inducible factor VIII inhibitor presented with a bleeding hematoma from the right posterior thigh. The patient was historically managed on frequent administration of recombinant factor VIIa to achieve hemostasis and was started on every 2-hour dosing during this admission. Emicizumab, a new therapy for hemophilia A, became available during this admission, and the patient discontinued recombinant factor VIIa and transitioned to weekly emicizumab injections. The patient did not require any recombinant factor VIIa during the following 12 months resulting in substantial drug cost savings. Discussion: After initiation of emicizumab therapy, the patient no longer required on-demand treatment with recombinant factor VIIa for bleeds. Through this reduction in recombinant factor VIIa, there was a large decrease in inpatient drug costs and inpatient admissions for bleeding events. Conclusion: The potential reduction in drug costs and inpatient admissions should be considered when determining if emicizumab therapy is appropriate for hemophilia A patients with inhibitors. Further research is needed to confirm that continued long-term use of emicizumab remains associated with a reduction in on-demand treatment.