Factor XI inhibitors for the prevention of cardiovascular disease: A new therapeutic approach on the horizon?

Anticoagulant drugs that are currently used to prevent and/or treat thrombosis have some limitations that hinder their ability to meet specific clinical requirements. While these drugs effectively reduce the rates of thrombotic events, they simultaneously increase the risk of bleeding. Moreover, their risk-to-benefit balance is problematic in some patients, such as those with severe chronic kidney disease or those at high bleeding risk. A novel anticoagulation method, FXI inhibition has emerged as a promising alternative. It demonstrates a strong rationale for the prevention and treatment of venous thromboembolism and the potential fulfillment of unmet clinical needs in the cardiovascular field. A number of FXI inhibitors are currently undergoing clinical investigation. The objective of this review is to provide an overview of early results of research on FXI inhibitors in the cardiovascular setting, offering valuable insights into their potential role in shaping the future of anticoagulation.

Current and emerging drug strategies for the prevention of venous thromboembolism in acutely ill medical inpatients

INTRODUCTION

Venous thromboembolism (VTE) is a common complication in patients hospitalized for acute medical illnesses. Therefore, medical inpatients require a careful VTE and bleeding risk assessment to drive optimal strategies for VTE prevention. Low molecular weight heparin and fondaparinux have long been used for inhospital prophylaxis for patients at increased risk of VTE. The selection of patients who require post-discharge prophylaxis, and the role of direct oral anticoagulants remain debated. New molecules currently under development may contribute to improve the risk benefit of VTE prevention in this setting.

AREAS COVERED

This text summarizes the evidence on approved treatments and on other drugs for the prevention of VTE in acutely ill medical patients. The main focus is on their pharmacological proprieties, clinical efficacy and safety, and the current license approved by the FDA (Food and Drug Administration) and EMA (European Medicines Agency), giving the readers a way to compare available drugs to date. The trials presented consider both inhospital and extended prophylaxis.

EXPERT OPINION

Thanks to the potentially favorable safety profile, factor XI inhibitors may play a role in the prevention of VTE in this setting. The expert opinion section discusses pharmacological properties, prophylaxis trials, and potential clinical applications of this novel class of drugs.

AB0565 JAK INHIBITORS AND PSORIATIC ARTHRITIS: A SYSTEMATIC REVIEW AND META-ANALYSIS

Background:

Despite the therapeutic armamentarium for the treatment of psoriatic arthritis (PsA) has considerably expanded over the last thirty years, there is a huge necessity of finding effective drugs for this disease. JAK inhibitors (JAKi) are small molecules able to interfere with the JAK/STAT pathway, involved in the pathogenesis of PsA (1). Up to now Tofacitinib is the only JAKi approved by the European Medicines Agency (EMA) for the treatment of PsA but in the next few years the number of approved JAKi is expected to rise significantly.

Objectives:

To assess the efficacy and safety of different JAKi for the treatment of PsA.

Methods:

A systematic review of the literature was performed to identify randomized controlled trials (RCTs), by electronic search of MEDLINE and EMBASE database until October 2020. Studies were considered eligible if they met the following criteria: I) study was a RCT; II) only patients with PsA were included; III) JAKi was compared to placebo in addition to the standard of care. Two reviewers (FC and AZ) performed study selection, with disagreements solved by the opinion of an expert reviewer (AS). The outcomes were expressed as odds ratio (OR) and 95% confidence intervals (95% CI). Statistical heterogeneity was assessed with the I2 statistic.

Results:

We identified 557 potentially relevant studies. A total of 554 studies were excluded based on title and/or abstract screening. Three RCTs for a total of 947 PsA patients treated with JAKi were included (2,3,4). Two were phase III studies on the efficacy and safety of Tofacitinib (OPAL Beyond and OPAL Broaden) and one was a phase II study on Filgotinib (Equator). All three studies were judged at low risk of bias according to Cochrane criteria (5). The primary efficacy outcome in all the studies was the number of patients who achieved the response rate of the American College of Rheumatology 20 score (ACR20). The outcomes evaluation was performed at 12 week for the Filgotinib trial and at 16 week for the Tofacitinib trials. We used for the main analyses the group of patients randomized to Tofacitinib 5 mg because this is the only dosage approved by the EMA for the treatment of PsA. JAKi showed a significantly higher ACR20 response rate compared to placebo (OR 3.54, 95% CI 1.76 - 7.09, I^2 = 74%). JAKi also showed a significantly higher ACR50 response rate (OR 3.36, 95% CI 2.22 - 5.09, I^2 = 0%), ACR70 response rate (OR 2.82, 95% CI 1.67 - 4.76, I^2 = 20%), PsARC response rate (OR 2.67, 95% CI 1.26 - 5.65, I^2 = 79%), PASI75 response rate (OR 3.15, 95% CI 1.61 - 6.15, I^2 = 45%) compared to placebo. JAKi were also associated with significantly better HAQ-DI (mean difference -0.23 95% CI -0.31 - -0.14) and fatigue, measured with FACIT-F (mean difference 3.54 95% CI 2.13 - 4.94). JAKi compared to placebo were associated with a non-statistically significant different risk of serious adverse events (OR 0.56, 95% CI 0.11 - 2.91, I^2 = 38%).

Conclusion:

This is the first published systematic review that performed a comprehensive and simultaneous evaluation of the efficacy and safety of JAKi for PsA in RCTs. Our analysis suggests a statistically significant benefit of JAKi, that appears to be effective and safe over placebo. The impact of these data on international clinical guidelines needs further investigation.

References:

[1]George E Fragoulis, et al. JAK-inhibitors. New players in the field of immune-mediated diseases, beyond rheumatoid arthritis, Rheumatology, Volume 58, Issue Supplement_1, February 2019, Pages i43–i54

[2]Mease P, et al. Tofacitinib or adalimumab versus placebo for psoriatic arthritis. N Engl J Med 2017; 377: 1537-50.

[3]Gladman D, et al. Tofacitinib for psoriatic arthritis in patients with an inadequate response to TNF inhibitors. N Engl J Med 2017; 377: 1525-36.

[4]Mease P, et al. Efficacy and safety of filgotinib, a selective Janus kinase 1 inhibitor, in patients with active psoriatic arthritis (EQUATOR): results from a randomised, placebo-controlled, phase 2 trial. Lancet 2018;392:2367–77.

[5]Higgins JP, et Al. Measuring inconsistency in meta-analyses. BMJ 2003;327:557-560

Figure 1.

ACR20 response rate of Jaki over Placebo

Disclosure of Interests:

None declared.

Intracranial bleeding risk after minor traumatic brain injury in patients on antithrombotic drugs

BACKGROUND

Intracranial haemorrhage (ICH) risk after minor traumatic brain injury (mTBI) in patients on antithrombotic treatment is unclear. We compared ICH rates in mTBI patients on single, double and no antithrombotic therapy. Antithrombotic drugs encompassed vitamin K antagonists (VKAs), direct oral anticoagulants (DOACs) and antiplatelets. Secondary aim was to identify potential predictors of ICH.

METHODS

We retrospectively analysed consecutive adults referred to our emergency department for mTBI. All clinical information was retrieved by patients' charts review. Patients were divided in 5 groups: 1) no antithrombotic users, 2) antiplatelet users, 3) vitamin K antagonist users, 4) direct oral anticoagulants users, and 5) double antithrombotic users.

RESULTS

A total of 1846 patients were enrolled, mean age 71 years (IQR 46-83); 1222 (66.2%) were in group 1, 407 (22.0%) in group 2, 120 (6.5%) in group 3, 51 (2.7%) in group 4 and 46 (2.5%) in group 5. At entry, 1387 (75.1%) patients underwent brain CT, 787 (64.4%) in group 1, 387 (95.1%) in group 2, 119 (99.2%) in group 3 and 51 (100%) in group 4 and 43 (93.5%) in group 5. ICH was documented in 36 patients (4.6%; CI 95%: 3.2-6.3) in group 1, 22 (5.9%; CI 95%: 3.6-8.5) in group 2, 5 (4.2%; CI 95%: 1.4-9.5) in group 3, 2 (3.9%; CI 95%: 0.5-13.5) in group 4 and 3 (7.0%; CI 95%: 1.5-19.1) in group 5 (p-value for across groups comparison = 0.86). At multivariable analysis GCS < 15 (OR 7.95 CI 95%: 3.12-20.28), post-traumatic amnesia (OR 6.49; CI 95%:3.57-11.82), vomiting (OR 4.45 CI 95%:1.47-13.50), clinical signs of cranial fractures (OR 8.41 CI 95%: 2.12-33.33), scalp lesions (OR 2.31 CI 95%: 1.09-4.89), but none of antithrombotic drugs were independently associated with ICH.

CONCLUSION

mTBI-related ICH rate was similar in patients with and without antithrombotic use. Potential predictors of ICH can be drawn from patients' clinical examination.

Antidotes for the direct oral anticoagulants: What news?

The direct oral anticoagulants (DOACs) are recommended as the first-choice anticoagulants for both stroke prevention in patients with non-valvular atrial fibrillation and the treatment and secondary prevention of venous thromboembolism. DOACs cause bleeding, albeit less than warfarin. Most bleeding complications can be controlled by general reversal strategies and supportive care. However, in case of life-threatening bleeding, or when urgent invasive procedures are needed, a more rapid and thorough reversal may be required. Idarucizumab, andexanet alfa and ciraparantag have been developed as reversal agents for the DOACs. To date idarucizumab is the only approved antidote and is specific for dabigatran. Andexanet alfa, a reversal agent for the factor Xa inhibitors, is still under investigation, but its approval by regulatory agencies is expected soon. Ciraparantag, a universal antidote, is in an earlier stage of development. Based on the results of clinical trials to date, these compounds appear to be breakthrough for urgent and emergency reversal. When administered at fixed doses, they ensured a rapid, efficient and safe restoration of haemostasis. From a practical perspective, all hospitals should develop local protocols to ensure safe and efficient clinical implementation of reversal strategies. Post-marketing studies will be essential to assess the evolution of management strategies and to confirm the safety and effectiveness of these agents.

Optimal treatment duration of venous thrombosis

Randomized controlled trials have shown that patients with venous thromboembolism benefit from a minimum of three months of anticoagulant therapy. After this period, it was suggested that patients with an expected annual recurrence rate of < 5% could safely discontinue treatment. Using a population-based approach for stratification, these patients are those with major transient risk factors, and represent the minority. For all other patients, including those with previous episodes of venous thromboembolism, cancer, or unprovoked events, this treatment duration may not be sufficiently protective. Because extending anticoagulation for additional three to nine months does not result in further, long-term reduction of recurrences, indefinite treatment duration should be considered. However, case-fatality rate for major bleeding in patients taking warfarin for more than three months is higher than case-fatality rate of recurrent venous thromboembolism. Thus, an individual patient approach to improve and increase the identification of those who can safely discontinue treatment at three months becomes necessary. Clinical prediction rules or management strategies based on D-dimer levels or residual vein thrombosis have been proposed and need further refinement and validation. Specific bleeding scores are lacking. Meanwhile, the oral direct inhibitors have been proposed as potential alternatives to the vitamin K antagonists, and aspirin may provide some benefit in selected patients who discontinue anticoagulation. Deep vein thrombosis in unusual sites is associated with less, but potentially more severe recurrences, in particular in patients with splanchnic vein thrombosis who also face an increased risk of bleeding complications while on treatment.

Prognostic clinical prediction rules to identify a low-risk pulmonary embolism: a systematic review and meta-analysis

BACKGROUND

Prognostic assessment is important for the management of patients with a pulmonary embolism (PE). A number of clinical prediction rules (CPRs) have been proposed for stratifying PE mortality risk. The aim of this systematic review was to assess the performance of prognostic CPRs in identifying a low-risk PE.

METHODS

MEDLINE and EMBASE databases were systematically searched until August 2011. Derivation and validation studies that assessed the performance of prognostic CPRs in predicting adverse events-risk in PE patients were included. Weighted mean proportion and 95% confidence intervals (CIs) of adverse events were then calculated and pooled using a fixed and a random-effects model. Statistical heterogeneity was evaluated through the use of I(2) statistics.

RESULTS

Of 1125 references in the original search, 33 relevant articles were included. Nine CPRs were assessed in 37 cohorts, for a total of 35,518 patients. Pulmonary Embolism Severity Index and prognostic Geneva CPR were investigated in 22 and 6 cohorts, respectively. Eleven (29.7%) cohorts were of high quality. The median follow-up was 30 days. In low-risk PE patients, pooled short-term mortality (within 14 days or less) was 0.7% (95% CI 0.3-1.1%, random-effects model; I(2) = 49.6%), 30-day mortality was 1.7% (95% CI 1.1-2.3%, random-effects model; I(2) = 82.4%) and 90-day mortality was 2.2% (95% CI 1.2-3.4%, random-effects model; I(2) = 59.8%).

CONCLUSIONS

Prognostic CPRs efficiently identify PE patients at a low risk of mortality. Before implementing prognostic CPRs in the routine care of PE patients, well-designed management studies are warranted.

Bleeding risk in randomized controlled trials comparing warfarin and aspirin: a systematic review and meta-analysis

BACKGROUND

Warfarin and aspirin (acetylsalicylic acid [ASA]) are the most commonly used anticoagulant and antiplatelet drugs in the treatment of cardiovascular disease.

OBJECTIVES

To provide a pooled estimate of the bleeding risk from randomized controlled trials (RCTs) comparing warfarin and ASA at the dose ranges recommended in evidence-based guidelines.

PATIENTS/METHODS

Ovid MEDLINE, Embase and the Cochrane Library, up to September 2011, were searched for RCTs comparing bleeding rates in adult patients randomized to warfarin, target International Normalized Ratio (INR) 2.0-3.5, and ASA, 50-650 mg daily, with at least 3 months of follow-up. Pooled odds ratios (ORs) and associated 95% confidence intervals (CIs) were calculated with the inverse variance method and the random effects model.

RESULTS

Four thousand four hundred and forty-two abstracts were screened, resulting in eight included studies for final analysis. A pooled estimate derived from the 2904 patients enrolled indicated a trend towards an increase in major bleeding risk in those randomized to warfarin (OR 1.27; 95% CI 0.83-1.94). The pooled OR for intracranial hemorrhage in patients treated with warfarin vs. ASA was 1.64 (95% CI 0.71-3.78), and that for extracranial major bleeding was 1.03 (95% CI 0.61-1.75). Minor bleeding, from a 1748-patient sample, was more common in warfarin patients (OR 1.50; 95% CI 1.13-2.00).

CONCLUSIONS

This meta-analysis failed to find a statistically significant difference in major bleeding between warfarin, target INR 2.0-3.5, and ASA, 50-650 mg daily. The trend towards increased bleeding with warfarin appears to be explained by an excess of intracranial bleeding in warfarin patients.

Splanchnic vein thrombosis

Die Venenthrombose im Splanchnikusgebiet – einschließlich Thrombosen der Pfortader, der Mesenterial-, Milz- und suprahepatischen Venen – ist eine unterdiagnostizierte Erkrankung mit einem heterogenen klinischen Bild und einer nicht unbeträchtlichen Quote an Zufallsbefunden.

Die Hauptrisikofaktoren umfassen abdominelle Erkrankungen oder Eingriffe (z.B. Infektionen, Zirrhose, abdominelle Krebserkrankungen oder chirurgische Maßnahmen), hämatologische

Störungen (insbesondere myeloproliferative Neoplasien), hereditäre Thrombophilien und hormonelle Störungen. Kürzlich wurden neue Biomarker für subklinische Erkrankungen identifiziert: die JAK2-Mutation und die Durchflusszytometrie für CD55 und CD59. Die klinische Manifestation ist gewöhnlich unspezifisch. In der akuten Phase können als wichtigste Symptome Bauchschmerzen, gas-trointestinale Blutungen und Aszites auftre-ten; zu den langfristigen Folgen hingegen gehören die Leberzirrhose und die portale Hypertonie.

Fortschritte bei der nicht invasiven Gefäßdarstellung (Doppler-Ultraschall, Gefäß-Computertomografie und Magnetresonanztomogra-fie) haben die Diagnostik der splanchnischen Venenthrombose verbessert. Auffällige Blutbefunde können auf eine zugrunde liegende hämatologische oder hepatische Störung hinweisen.

Die optimale Behandlung der splanchnischen Venenthrombose ist noch eine offene Frage, da große klinische Studien fehlen. Experten empfehlen übereinstimmend, die akute, symptomatische, nicht zirrhotische Pfortaderthrombose im akuten Stadium mittels parenteraler Antikoagulation zu behandeln und an-schließend über mindestens 3 Monate orale Antikoagulanzien zu geben; bei persistieren-den prothrombotischen Faktoren wird jedoch eine lebenslange Behandlung empfohlen. Bei einem Budd-Chiari-Syndrom wird für alle Pa-tienten ohne größere Kontraindikationen eine Antikoagulation empfohlen. Allerdings muss das Nutzen-/Risikoverhältnis einer gerinnungshemmenden Therapie sowohl für die Akutbehandlung als auch für die langfristige Sekundärprävention noch besser untersucht werden.