Heart Failure Risk Assessment Using Biomarkers in Patients With Atrial Fibrillation: Analysis From COMBINE-AF.

BACKGROUND: Heart failure (HF) is common among patients with atrial fibrillation (AF), and accurate risk assessment is clinically important. OBJECTIVES: The goal of this study was to investigate the incremental prognostic performance of N-terminal pro-B-type natriuretic peptide (NT-proBNP), high-sensitivity cardiac troponin T (hs-cTnT), and growth differentiation factor (GDF)-15 for HF risk stratification in patients with AF. METHODS: Individual patient data from 3 large randomized trials comparing direct oral anticoagulants (DOACs) with warfarin (ARISTOTLE [Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation], ENGAGE AF-TIMI 48 [Effective Anticoagulation With Factor Xa Next Generation in Atrial Fibrillation-Thrombolysis in Myocardial Infarction 48], and RE-LY [Randomized Evaluation of Long-Term Anticoagulation Therapy]) from the COMBINE-AF (A Collaboration Between Multiple Institutions to Better Investigate Non-Vitamin K Antagonist Oral Anticoagulant Use in Atrial Fibrillation) cohort were pooled; all patients with available biomarkers at baseline were included. The composite endpoint was hospitalization for HF (HHF) or cardiovascular death (CVD), and secondary endpoints were HHF and HF-related death. Cox regression was used, adjusting for clinical factors, and interbiomarker correlation was addressed using weighted quantile sum regression analysis. RESULTS: In 32,041 patients, higher biomarker values were associated with a graded increase in absolute risk for CVD/HHF, HHF, and HF-related death. Adjusting for clinical variables and all biomarkers, NT-proBNP (HR per 1 SD: 1.68; 95% CI: 1.59-1.77), hs-cTnT (HR: 1.39; 95% CI: 1.33-1.44), and GDF-15 (HR: 1.20; 95% CI: 1.15-1.25) were significantly associated with CVD/HHF. The discrimination of the clinical model improved significantly upon addition of the biomarkers (c-index: 0.70 [95% CI: 0.69-0.71] to 0.77 [95% CI: 0.76-0.78]; likelihood ratio test, P < 0.001). Using weighted quantile sum regression analysis, the contribution to risk assessment was similar for NT-proBNP and hs-cTnT for CVD/HHF (38% and 41%, respectively); GDF-15 provided a statistically significant but lesser contribution to risk assessment. Results were similar for HHF and HF-related death, individually, and across key subgroups of patients based on history of HF, AF pattern, and reduced or preserved left ventricular ejection fraction. CONCLUSIONS: NT-proBNP, hs-cTnT, and GDF-15 contributed significantly and independently to the risk stratification for HF endpoints in patients with AF, with hs-cTnT being as important as NT-proBNP for HF risk stratification. Our findings support a possible future use of these biomarkers to distinguish patients with AF at low or high risk for HF.

Rivaroxaban for Patients with Intermittent Claudication.

BACKGROUND: The combination of rivaroxaban plus aspirin compared with aspirin alone reduces the risk of major adverse cardiovascular and limb events for high-risk patients with peripheral artery disease. It is unknown whether rivaroxaban plus aspirin improves intermittent claudication for adults with lower-risk peripheral arterial disease. METHODS: In this randomized, open-label, multicenter, 24-week clinical trial, we randomly assigned patients with peripheral artery disease and intermittent claudication to receive either 2.5 mg of rivaroxaban twice daily plus 100 mg of aspirin once daily or 100 mg of aspirin once daily. The primary outcome was a 24-week change in total walking distance, measured by the 6-minute walking test. The primary safety outcome was the incidence of major bleeding or clinically relevant nonmajor bleeding. RESULTS: Eighty-eight patients were randomly assigned to either rivaroxaban plus aspirin (n=46) or aspirin alone (n=42). The mean age was 67 years, and 54% were female. The total walking distance measured by 6-minute walk test improved by 89 ± 18 m (mean±standard error) in the rivaroxaban-plus-aspirin group versus 21 ± 16 m in the aspirin-alone group. This corresponded to an absolute difference of 68 ± 24 m (95% confidence interval [CI], 19 to 116 m; P=0.007) and a relative improvement over the aspirin-alone group of 327% (95% CI, 94 to 560%). No major bleeding events were observed in either group. CONCLUSIONS: In patients with peripheral artery disease and intermittent claudication, 2.5 mg of rivaroxaban twice daily plus 100 mg of aspirin daily improved the total walking distance by a 6-minute walking test compared with 100 mg of aspirin daily alone. (Funded by Bayer S.A.; Clinicaltrials.gov number, NCT04853719.).

Residual Stroke Risk Among Patients With Atrial Fibrillation Prescribed Oral Anticoagulants: A Patient-Level Meta-Analysis From COMBINE AF.

BACKGROUND: Despite oral anticoagulation, patients with atrial fibrillation (AF) remain at risk of ischemic stroke and systemic embolism (SE) events. For patients whose residual risk is sufficiently high, additional therapies might be useful to mitigate stroke risk. METHODS AND RESULTS: Individual patient data from 5 landmark trials testing oral anticoagulation in AF were pooled in A Collaboration Between Multiple Institutions to Better Investigate Non-Vitamin K Antagonist Oral Anticoagulant Use in AF (COMBINE AF). We calculated the rate of ischemic stroke/SE among oral anticoagulation-treated patients with a CHA2DS2-VASc score≥2, across strata of CHA2DS2-VASc score, stroke history, and AF type, as either paroxysmal or nonparoxysmal. We included 71 794 patients with AF (median age 72 years, interquartile range, 13 years, 61.3% male) randomized to a direct oral anticoagulant or vitamin K antagonist, and followed for a mean of 2.1 (±0.8) years. The median CHA2DS2-VASc score was 4 (interquartile range, 3-5), 18.8% had a prior stroke, and 76.4% had nonparoxysmal AF. The overall rate of stroke/SE was 1.33%/y (95% CI, 1.27-1.39); 1.38%/y (95% CI, 1.31-1.45) for nonparoxysmal AF, and 1.15%/y (95% CI, 1.05-1.27) for paroxysmal AF. The rate of ischemic stroke/SE increased by a rate ratio of 1.36 (95% CI, 1.32-1.41) per 1-point increase in CHA2DS2-VASc, reaching 1.67%/y (95% CI, 1.59-1.75) ≥4 CHA2DS2-VASc points. Patients with both nonparoxysmal AF and CHA2DS2-VASc ≥4 had a stroke/SE rate of 1.75%/y (95% CI, 1.66-1.85). In patients with a prior stroke, the risk was 2.51%/y (95% CI, 2.33-2.71). CONCLUSIONS: AF type, CHA2DS2-VASc score, and stroke history can identify patients with AF, who despite oral anticoagulation have a residual stroke/SE risk of 1.5% to 2.5% per year. Evaluation of additional stroke/SE prevention strategies in high-risk patients is warranted.

Incidence and predictors of major gastrointestinal bleeding in patients on aspirin, low-dose rivaroxaban, or the combination: Secondary analysis of the COMPASS randomised controlled trial.

BACKGROUND: The incidence of major gastrointestinal bleeding (GIB) in patients on low-dose direct-acting oral anticoagulants (DOACs) is relatively unknown. Estimates from randomised controlled trials (RCTs) are lacking. AIMS: To assess GIB incidence and predictors from RCT data of patients on aspirin, low-dose rivaroxaban, or both. METHODS: This was a secondary analysis of RCT data wherein patients received aspirin 100 mg daily and rivaroxaban 2.5 mg b.d., aspirin alone, or rivaroxaban 5 mg b.d. Patients were followed from 2013 to 2016 at 602 centres. Outcomes included overall, upper, and lower GIB. We employed multivariable logistic regression to yield odds ratios (ORs) and 95% confidence intervals for potential exposures. RESULTS: Among 27,395 patients, the annual incidence of GIB on rivaroxaban 2.5 mg b.d. with aspirin was 801.7 per 100,000 compared with 372.3 in 100,000 for aspirin. Age (OR 4.16, 2.53-6.82 for ≥75 vs. 55-64), peptic ulcer disease (PUD, OR 1.57, 1.01-2.44), liver disease (OR 2.09, 1.01-4.33), hypertension (OR 1.42, 1.04-1.94), and smoking (OR 1.85, 1.26-2.73) were associated with overall GIB. Kidney disease (OR 1.68, 1.12-2.51) was significantly associated with upper GIB, whereas diverticular disease (OR 3.75, 1.88-7.49) was associated with lower GIB. Addition of rivaroxaban to aspirin was associated more with lower GIB (OR 2.82, 1.64-4.84) than upper GIB (OR 1.86, 1.18-2.92). CONCLUSIONS: We established incidences and identified risk factors for GIB in users of low-dose DOACs. Novel risk factors included current or former smoking and diverticulosis. Future studies should aim to validate these risk factors.

Corrigendum: Bleeding Risk Prediction in Patients Treated with Antithrombotic Drugs According to the Anatomic Site of Bleeding, Indication for Treatment, and Time Since Treatment Initiation.

[This corrects the article DOI: 10.1055/a-2259-1134.].

Neurofilament Light Chain and Risk of Stroke in Patients With Atrial Fibrillation.

BACKGROUND: Biomarkers reflecting brain injury are not routinely used in risk assessment of stroke in atrial fibrillation (AF). Neurofilament light chain (NFL) is a novel biomarker released into blood after cerebral insults. We investigated the association between plasma concentrations of NFL, other biomarkers, and risk of stroke and death in patients with AF not receiving oral anticoagulation. METHODS: For this observational study, baseline plasma samples were available from 3077 patients with AF randomized to aspirin in ACTIVE A (Atrial Fibrillation Clopidogrel Trial With Irbesartan for Prevention of Vascular Events; 2003 to 2008) and AVERROES (Apixaban Versus Acetylsalicylic Acid [ASA] to Prevent Stroke in Atrial Fibrillation Patients Who Have Failed or Are Unsuitable for Vitamin K Antagonist Treatment; 2007 to 2009). Median follow-up was 1.5 years. NFL was analyzed with a Single Molecule Array (Simoa). Associations with outcomes (total stroke or systemic embolism, ischemic stroke, cardiovascular death, and all-cause death) were explored with Cox regression models. RESULTS: In the combined cohort, the median NFL level was 16.9 ng/L (interquartile range, 11.1-26.5 ng/L), the median age was 71 years, 58% were men, and 13% had a history of previous stroke. NFL was associated with older age, higher creatinine, lower body mass index, previous stroke, female sex, and diabetes but not cardiac rhythm. Higher NFL was associated with a higher risk of stroke or systemic embolism (n=206) independently of clinical characteristics (hazard ratio, 1.27 [95% CI, 1.10-1.46] per doubling of NFL) and other biomarkers (hazard ratio, 1.18 [95% CI, 1.01-1.37]) and including in patients without previous stroke (hazard ratio, 1.23 [95% CI, 1.02-1.48]). NFL was also independently associated with cardiovascular (n=219) and all-cause (n=311) death. The C index for stroke using only NFL was 0.642, on par with the currently used clinical risk scores. Addition of information on NFL improved discrimination in a model also including clinical information, NT-proBNP (N-terminal pro-B-type natriuretic peptide), and high-sensitivity cardiac troponin T, yielding a C index of 0.727. CONCLUSIONS: NFL reflects overt and covert episodes of cerebral ischemia and improves risk assessment of stroke and death in patients with AF without oral anticoagulation, including in patients without previous stroke. The combination of NFL with information on age, history of stroke, and other biomarkers should be explored as a future avenue for stroke risk assessments in patients with AF.

Factor XIa inhibition as a therapeutic strategy for atherothrombosis.

When selecting an anticoagulant, clinicians consider individual patient characteristic, the treatment indication, drug pharmacology, and safety and efficacy as demonstrated in randomized trials. An ideal anticoagulant prevents thrombosis with little or no increase in bleeding. Direct oral anticoagulants represent a major advance over traditional anticoagulants (e.g., unfractionated heparin, warfarin) but still cause bleeding, particularly from the gastrointestinal tract which can limit their use. Epidemiological studies indicate that patients with congenital factor XI (FXI) deficiency have a lower risk of venous thromboembolism (VTE) and ischemic stroke (IS) than non-deficient individuals, and do not have an increased risk of spontaneous bleeding, even with severe deficiency. These observations provide the rationale for targeting FXI as a new class of anticoagulant. Multiple FXI inhibitors have been introduced and several are being evaluated in Phase III trials. In this review, we explain why drugs that target FXI may be associated with a lower risk of bleeding than currently available anticoagulants and summarize the completed and ongoing trials.

Results of the COMPASS Trial Analyzed Using Win Ratio Compared With Conventional Analytic Approaches.

BACKGROUND: Win ratio (WR) is a newer analytic approach for trials with composite end points that accounts for the relative importance of individual components. Our objective was to compare the results of the Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) trial analyzed using WR with those obtained using conventional statistical approaches. METHODS: We used an unmatched WR analysis for first and total (first plus recurrent) events to examine effects of rivaroxaban with aspirin and rivaroxaban alone vs aspirin alone on primary efficacy (cardiovascular death, stroke, myocardial infarction), safety (modified International Society on Thrombosis and Haemostasis major bleeding), and net clinical benefit (primary efficacy plus fatal or critical organ bleeding) end points. We compared the WR results with those obtained using the Cox proportional hazards regression model for first events and Anderson-Gill method for total events. We calculated the win difference to estimate absolute treatment effects. RESULTS: The WR approach produced results consistent with those obtained using conventional statistical methods for the primary composite end point (first event: WR, 1.32 [95% confidence interval (CI), 1.14-1.52]; 1/Cox hazard ratio, 1.32 [95% CI, 1.16-1.52]; total [first plus recurrent] events: WR, 1.32 [95% CI, 1.14-1.52]; 1/Anderson-Gill hazard ratio, 1.32 [95% CI, 1.16-1.54]) as well as for main safety and net clinical benefit end points. The absolute benefits of the combination of rivaroxaban and aspirin compared with aspirin alone calculated using the win difference were greatest in those with multiple high-risk features. CONCLUSIONS: Reanalysis of the COMPASS trial results using WR produced results that were consistent with those obtained using conventional statistical approaches. CLINICAL TRIAL REGISTRATION: NCT01776424.

Factor XI inhibition in cardiovascular disease.

Cardiovascular disease remains the leading global cause of mortality, requiring effective antithrombotic strategies to prevent thromboembolic events. Currently available therapies are effective but have inherent bleeding risks which may limit or preclude their use, particularly in patients at the highest risk of bleeding. Factor XI (FXI) inhibitors are a promising new class of anticoagulants which may mitigate the risk of bleeding while maintaining efficacy. Further, they have the potential to provide effective anticoagulation in indications where direct oral anticoagulants (DOACs) are proven less effective than vitamin K antagonists (VKAs) or when DOACs are contraindicated. The development of FXI inhibitors was based on mechanistic considerations suggesting FXI's role in thrombus formation without significantly affecting hemostasis, supported by epidemiological data and animal experiments. FXI inhibitors, including antisense oligonucleotides, monoclonal antibodies, and small­molecule inhibitors, target different stages of FXI production or activation, offering a diversity of therapeutic options with differing onset and offset of action, drug interaction potential, and renal elimination. FXI inhibitors have shown potential benefits in phase II trials, demonstrating similar or reduced bleeding rates to existing agents, including DOACs. The early termination of AZALEA­TIMI 71 (Safety and Tolerability of Abelacimab [MAA868] vs Rivaroxaban in Patients With Atrial Fibrillation) and OCEANIC­AF (A Study to Learn How Well the Study Treatment Asundexian Works and How Safe it is Compared to Apixaban to Prevent Stroke or Systemic Embolism in People With Irregular and Often Rapid Heartbeat [Atrial Fibrillation], and at Risk for Stroke) trials underscores challenges in the selection of appropriate patient populations and anticoagulant class, agent, and dose. Ongoing phase III trials including OCEANIC­STROKE (A Study to Test Asundexian for  Preventing a Stroke Caused by a Clot in Participants After an Acute Ischemic Stroke or After a High­risk Transient Ischemic Attack, a So­called Mini Stroke) and LIBREXIA trials aim to further explore the efficacy of FXI inhibitors in stroke, acute coronary syndrome, and atrial fibrillation. In conclusion, FXI inhibitors hold promise as next­generation anticoagulants, potentially addressing limitations of current therapies. Ongoing research is required to establish their place in clinical practice and address unresolved questions.

Impact of Frailty on the Benefits of Dual Pathway Inhibition for the Secondary Prevention of Cardiovascular Events in the COMPASS Randomised Trial.

BACKGROUND: Individuals with frailty are at higher risk of adverse cardiovascular outcomes and bleeding. The objective of this study was to determine whether the effects of 2.5 mg rivaroxaban twice daily in addition to low-dose aspirin are similar among frail compared with nonfrail patients with chronic atherosclerotic vascular disease. METHODS: In the COMPASS trial (NCT01776424), patients with chronic atherosclerotic vascular disease were randomised to receive 100 mg aspirin daily, 100 mg aspirin daily plus 2.5 mg rivaroxaban twice daily, or 5 mg rivaroxaban twice daily. In this post hoc analysis, frailty was evaluated by constructing a cumulative deficit index from 37 diseases, signs, and symptoms. The frailty index for each participant was calculated as the proportion of the 37 deficits exhibited, with values > 0.2 considered to be frail. The primary outcome was the composite of cardiovascular death, myocardial infarction, or stroke. Hazard ratios (HRs) and 95% confidence intervals (CIs) are reported. RESULTS: Frailty was present in 13% of the trial population. In nonfrail individuals, adding 2.5 mg rivaroxaban twice daily to aspirin reduced the primary outcome (HR 0.69, 95% CI 0.59-0.80) and mortality (HR 0.75, 95% CI 0.63-0.90), but increased major bleeding (HR 1.87, 95% CI 1.51-2.31); Among participants with frailty, its effects on the primary outcome (HR 1.06, 95% CI 0.79-1.42), mortality (HR 1.08, 0.80-1.46), and major bleeding (HR 1.10, 95% CI 0.71-1.70) were not evident (respective interaction P values 0.011, 0.049, and 0.032). CONCLUSIONS: In adults with chronic atherosclerotic vascular disease, the benefit of adding 2.5 mg rivaroxaban twice daily to aspirin was not evident in patients with frailty. CLINICAL TRIAL REGISTRATION: NCT01776424.

Design and rationale of the CLEAR SYNERGY (OASIS 9) trial: A 2x2 factorial randomized controlled trial of colchicine versus placebo and spironolactone vs placebo in patients with myocardial infarction.

BACKGROUND: Patients experiencing myocardial infarction (MI) remain at high risk of future major adverse cardiovascular events (MACE). While low-dose colchicine and spironolactone have been shown to decrease post-MI MACE, more data are required to confirm their safety and efficacy in an unselected post-MI population. Therefore, we initiated the CLEAR SYNERGY (OASIS 9) trial to address these uncertainties. METHODS: The CLEAR SYNERGY trial is a 2 × 2 factorial randomized controlled trial of low-dose colchicine 0.5 mg daily versus placebo and spironolactone 25 mg daily versus placebo in 7,062 post-MI participants who were within 72 hours of the index percutaneous coronary intervention (PCI). We blinded participants, healthcare providers, research personnel, and outcome adjudicators to treatment allocation. The primary outcome for colchicine is the first occurrence of the composite of cardiovascular death, recurrent MI, stroke, or unplanned ischemia-driven revascularization. The coprimary outcomes for spironolactone are (1) the composite of the total numbers of cardiovascular death or new or worsening heart failure and (2) the first occurrence of the composite of cardiovascular death, new or worsening heart failure, recurrent MI or stroke. We finished recruitment with 7,062 participants from 104 centers in 14 countries on November 8, 2022, and plan to present the results in the fall of 2024. CONCLUSIONS: CLEAR SYNERGY is a large international randomized controlled trial that will inform the effects of low-dose colchicine and spironolactone in largely unselected post-MI patients who undergo PCI. (ClinicalTrials.gov Identifier: NCT03048825).

Perioperative management and outcomes in patients receiving low-dose rivaroxaban and/or aspirin: a subanalysis of the Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) trial.

BACKGROUND: No study has investigated the perioperative management and clinical outcomes in patients who are receiving rivaroxaban 2.5 mg twice a day and acetylsalicylic acid (ASA) 81 to 100 mg daily. OBJECTIVE: To assess perioperative management and outcomes in patients who are receiving low-dose rivaroxaban, 2.5 mg twice-daily, and low-dose ASA, 81 to 100 mg daily. To assess perioperative management and outcomes in patients who are receiving low-dose rivaroxaban, 2.5 mg twice-daily, and low-dose ASA, 81 to 100 mg daily. METHODS: Subanalysis of the Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) trial was performed to assess perioperative management and clinical outcomes in patients with stable coronary or peripheral artery disease who were randomized to receive rivaroxaban 2.5 mg twice a day plus ASA 100 mg daily, rivaroxaban 5 mg twice a day, or ASA 100 mg daily. Patients studied required a surgery/procedure during the trial. The study outcomes, which included myocardial infarction, angina, stroke, acute limb ischemia, bleeding, and death, were assessed according to treatment allocation. RESULTS: There were 2632 patients studied (mean age, 68 years; 80% male) who had a surgery/procedure, comprising percutaneous coronary interventions (∼43%), carotid or other arterial angioplasty (∼15%), pacemaker or internal cardiac defibrillator implantation (∼9%), and coronary artery bypass graft surgery (∼7%). Perioperative study drug management varied, with about one-third of patients not interrupting study drug and the remainder interrupting it between 1 and ≥10 days preprocedure. The incidences of adverse outcomes across treatment groups were 12.7% to 15.3% for myocardial ischemia, 0.8% to 1.2% for stroke, 0.1% to 0.2% for venous thromboembolism, and 3.1% to 4.2% for any bleeding. There was no statistically significant difference in outcome rates across treatment groups. CONCLUSION: In patients in the COMPASS trial who required a surgery/procedure, there was no significant difference in perioperative adverse outcomes whether patients were receiving rivaroxaban 2.5 mg twice a day and ASA 100 mg daily, rivaroxaban 5 mg twice a day, or ASA alone.

Cost-effectiveness of low-dose colchicine in patients with chronic coronary disease in the netherlands.

AIMS: Recent trials have shown that low-dose colchicine (0.5 mg once daily) reduces major cardiovascular events in patients with acute and chronic coronary syndromes. We aimed to estimate the cost-effectiveness of low-dose colchicine therapy in patients with chronic coronary disease when added to standard background therapy. METHODS AND RESULTS: This Markov cohort cost-effectiveness model used estimates of therapy effectiveness, transition probabilities, costs and quality of life obtained from the Low-dose Colchicine 2 (LoDoCo2) trial, as well as meta-analyses and public sources. In this trial, Low-dose colchicine was added to standard of care and compared to placebo. The main outcomes were cardiovascular events including myocardial infarction, stroke and coronary revascularisation, quality-adjusted life-year (QALY), the cost per QALY gained (incremental cost-effectiveness ratio), and net monetary benefit. In the model, low-dose colchicine therapy yielded 0.04 additional QALYs compared with standard of care at an incremental cost of €455 from a societal perspective and €729 from a healthcare perspective, resulting in a cost per QALY gained of €12,176/QALY from a societal perspective and €19,499/QALY from a healthcare perspective. Net monetary benefit was €1,414 from a societal perspective and €1,140 from a healthcare perspective. Low-dose colchicine has a 96% and 94% chance of being cost effective, from respectively a societal and healthcare perspective when using a willingness to pay of €50,000/QALY. Net monetary benefit would decrease below zero when annual low-dose colchicine costs would exceed an annual cost of €221 per patient. CONCLUSION: Adding low-dose colchicine to standard of care in patients with chronic coronary disease is cost-effective according to commonly accepted thresholds in Europe and Australia and compares favourably in cost-effectiveness to other drugs used in chronic coronary disease.

A Phase II randomized controlled trial evaluated antithrombotic treatment with fesomersen in patients with kidney failure on hemodialysis.

Patients with kidney failure on hemodialysis (KF-HD) are at high risk for both atherothrombotic events and bleeding. This Phase IIb study evaluated the dose-response of fesomersen, an inhibitor of hepatic Factor XI expression, versus placebo, for bleeding and atherothrombosis in patients with KF-HD. Patients were randomized to receive fesomersen 40, 80, or 120 mg once-monthly, or matching placebo, for up to 12 months. The primary safety endpoint was a composite of major bleeding and clinically relevant non-major bleeding (MB/CRNMB). Exploratory endpoints included post-dialysis arterio-venous (AV)-access bleeding, major atherothrombotic events (composite of fatal or non-fatal myocardial infarction, ischemic stroke, acute limb ischemia/major amputation, systemic embolism, symptomatic venous thromboembolism), AV-access thrombosis, and clotting of the hemodialysis circuit. Of 308 participants randomized, 307 received study treatment and were analyzed. Fesomersen led to a dose-dependent and sustained reduction of steady-state median FXI levels by 53.6% (40 mg group), 71.3% (80 mg group), 86.0% (120 mg group), versus 1.9% in the placebo group. MB/CRNMB events occurred in 6.5% (40 mg group), 5.1% (80 mg group), 3.9% (120 mg group), and in 4.0% of those receiving placebo (pooled fesomersen versus placebo P = 0.78). Major atherothrombotic events occurred in 1 patient (1.3%) in each treatment arm. MB/CRNMB bleeding and post-dialysis AV-access bleeding were not related to predicted FXI levels. Lower predicted FXI levels were associated with reductions in hemodialysis circuit clotting (P = 0.002) and AV-access thrombosis (P = 0.014). In patients with KF-HD, fesomersen produced a dose-dependent reduction in FXI levels associated with similar rates of major bleeding compared with placebo. REGISTRATION: URL: https://www.clinicaltrials.gov; unique identifier: NCT04534114.