Integrin Signaling Shaping BTK-Inhibitor Resistance.

Integrins are adhesion molecules that function as anchors in retaining tumor cells in supportive tissues and facilitating metastasis. Beta1 integrins are known to contribute to cell adhesion-mediated drug resistance in cancer. Very late antigen-4 (VLA-4), a CD49d/CD29 heterodimer, is a beta1 integrin implicated in therapy resistance in both solid tumors and haematological malignancies such as chronic lymphocytic leukemia (CLL). A complex inside-out signaling mechanism activates VLA-4, which might include several therapeutic targets for CLL. Treatment regimens for this disease have recently shifted towards novel agents targeting BCR signaling. Bruton's tyrosine kinase (BTK) is a component of B cell receptor signaling and BTK inhibitors such as ibrutinib are highly successful; however, their limitations include indefinite drug administration, the development of therapy resistance, and toxicities. VLA-4 might be activated independently of BTK, resulting in an ongoing interaction of CD49d-expressing leukemic cells with their surrounding tissue, which may reduce the success of therapy with BTK inhibitors and increases the need for alternative therapies. In this context, we discuss the inside-out signaling cascade culminating in VLA-4 activation, consider the advantages and disadvantages of BTK inhibitors in CLL and elucidate the mechanisms behind cell adhesion-mediated drug resistance.

Comparison of Alternative Methods to Assess the Cost-Effectiveness of Tumor-Agnostic Therapies: A Triangulation Approach Using Larotrectinib as a Case Study.

OBJECTIVES: The study objective was to investigate the economic value of tumor-agnostic therapies when only single-arm effectiveness data are available at launch by applying multiple methodologies to establish comparative effectiveness. METHODS: In the absence of direct comparative data, 3 methods were used to estimate the counterfactual: (1) a historical control based on a systematic literature review for each tumor site from the larotrectinib trials, (2) an intracohort comparison using the previous line of therapy time to progression from larotrectinib trials, and (3) a nonresponder control that applied outcomes for larotrectinib nonresponders. Cost-effectiveness was modeled using the partitioned survival approach. Stochastic parameter uncertainty was assessed in a probabilistic sensitivity analysis (PSA). A triangulated estimate of the mean cost-effectiveness result was generated combining all 3 counterfactual estimates. RESULTS: Incremental cost-effectiveness ratios were similar across the 3 methodologies in the deterministic analysis ranging from £83 868 (95% uncertainty interval [UI] £65 698-£107 668) to £104 922 per quality-adjusted life-year (95% UI £80 132-£139 658). PSA results for each method substantially overlapped when plotted on the cost-effectiveness plane. Weighting PSA results for each method equally in the triangulation method produced an incremental cost-effectiveness ratios of £95 587 per quality-adjusted life-year gained (95% UI £70 449-£137 431). CONCLUSIONS: In the absence of direct comparative data, different methods of estimating a counterfactual are possible, each with strengths and limitations. Triangulating results across the methods provides a composite view of the total uncertainty and a more consistent estimation of the cost-effectiveness of the tumor-agnostic intervention compared with choosing a single method.

Direct oral anticoagulants for use in paediatrics.

With the increasing incidence of thromboembolism in children and improvement in management for patients with medically complex diseases, expanded availability of safe and effective anticoagulant medications is needed. Traditionally, the most common anticoagulants used for the treatment or prevention of venous thromboembolism or embolic stroke in children were either unfractionated heparin or the low-molecular-weight heparins. These medications require either intravenous access or daily subcutaneous injections, in addition to multiple venepunctures to monitor drug concentrations. Direct oral anticoagulants provide an alternative, and potentially safer, choice for children, as they are available in oral formulations and do not require drug monitoring. With the approval of the direct factor Xa inhibitor, rivaroxaban (by the European Medicines Agency and Health Canada), and the direct thrombin inhibitor, dabigatran (by the European Medicines Agency and US Food and Drug Administration), the field of paediatric anticoagulation is changing. In this Review, we provide an overview of the four direct oral anticoagulants approved in adults for the treatment and prevention of thrombosis and the completed and ongoing paediatric trials.

Discovery of Novel Inhibitors of Uridine Diphosphate-N-Acetylenolpyruvylglucosamine Reductase (MurB) from Pseudomonas aeruginosa, an Opportunistic Infectious Agent Causing Death in Cystic Fibrosis Patients.

Pseudomonas aeruginosa is of major concern for cystic fibrosis patients where this infection can be fatal. With the emergence of drug-resistant strains, there is an urgent need to develop novel antibiotics against P. aeruginosa. MurB is a promising target for novel antibiotic development as it is involved in the cell wall biosynthesis. MurB has been shown to be essential in P. aeruginosa, and importantly, no MurB homologue exists in eukaryotic cells. A fragment-based drug discovery approach was used to target Pa MurB. This led to the identification of a number of fragments, which were shown to bind to MurB. One fragment, a phenylpyrazole scaffold, was shown by ITC to bind with an affinity of Kd = 2.88 mM (LE 0.23). Using a structure guided approach, different substitutions were synthesized and the initial fragment was optimized to obtain a small molecule with Kd = 3.57 µM (LE 0.35).

Rivaroxaban and apixaban for the treatment of suspected or confirmed heparin-induced thrombocytopenia.

WHAT IS KNOWN AND OBJECTIVE: Heparin-induced thrombocytopenia (HIT) is an adverse hematologic drug reaction that results in thrombocytopenia. This potentially life-threatening event is due to the administration of heparin products, such as unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH). The incidence of HIT occurs in <0.1%-7% of hospitalized patients treated with heparin products, with a risk of thrombosis as high as 50%. In 2018, the American Society of Hematology (ASH) recommended the utilization of direct oral anticoagulants (DOACs) in clinically stable patients at average bleeding risk with HIT. The objective of this study was to evaluate the prescribing patterns of rivaroxaban and apixaban for the treatment of suspected or confirmed HIT. METHODS: This was a retrospective chart review from January 2013 through October 2019 at the University of Chicago Medicine. Twelve patients were identified to have received a DOAC for suspected or confirmed HIT. RESULTS: Rivaroxaban was utilized in seven (58%) patients, six of whom received argatroban prior to starting rivaroxaban. Five (71%) of these patients were started on the recommended dose of rivaroxaban for VTE. Apixaban was utilized in five (42%) patients; four patients were started on argatroban and transitioned to apixaban. One patient was started on the suggested dose of apixaban for VTE. WHAT IS NEW AND CONCLUSION: After starting DOACs for suspected HIT, no patients had new thrombosis during hospitalization. Eight patients (67%) followed up at our institution within 6 months of their discharge date. No subsequent thrombi formation were identified for any of these patients. The results of this study add to the expanding literature regarding the safety and efficacy of DOAC use in HIT, and indicate DOACs are being increasingly utilized for the treatment of confirmed or suspected HIT.

Risk for Recurrent Venous Thromboembolism and Bleeding With Apixaban Compared With Rivaroxaban: An Analysis of Real-World Data.

BACKGROUND: Apixaban and rivaroxaban are replacing vitamin K antagonists for the treatment of venous thromboembolism (VTE) in adults; however, head-to-head comparisons remain limited. OBJECTIVE: To assess the effectiveness and safety of apixaban compared with rivaroxaban in patients with VTE. DESIGN: Retrospective new-user cohort study. SETTING: U.S.-based commercial health care insurance database from 1 January 2015 to 30 June 2020. PARTICIPANTS: Adults with VTE who were newly prescribed apixaban or rivaroxaban. MEASUREMENTS: The primary effectiveness outcome was recurrent VTE, a composite of deep venous thrombosis and pulmonary embolism. The primary safety outcome was a composite of gastrointestinal and intracranial bleeding. RESULTS: Of 49 900 eligible patients with VTE, 18 618 were new users of apixaban and 18 618 were new users of rivaroxaban. Median follow-up was 102 days (25th, 75th percentiles: 30, 128 days) among apixaban and 105 days (25th, 75th percentiles: 30, 140 days) among rivaroxaban users. After propensity score matching, apixaban (vs. rivaroxaban) was associated with a lower rate for recurrent VTE (hazard ratio, 0.77 [95% CI, 0.69 to 0.87]) and bleeding (hazard ratio, 0.60 [CI, 0.53 to 0.69]). The absolute reduction in the probability of recurrent VTE with apixaban versus rivaroxaban was 0.006 (CI, 0.005 to 0.011) within 2 months and 0.011 (CI, 0.011 to 0.013) within 6 months of initiation. The absolute reduction in the probability of gastrointestinal and intracranial bleeding with apixaban versus rivaroxaban was 0.011 (CI, 0.010 to 0.011) within 2 months and 0.015 (CI, 0.013 to 0.015) within 6 months of initiation. LIMITATION: Short follow-up. CONCLUSION: In this population-based cohort study, patients with VTE who were new users of apixaban had lower rates for recurrent VTE and bleeding than new users of rivaroxaban. PRIMARY FUNDING SOURCE: None.

Cancer-associated thrombosis - treatment and prevention with direct oral factor Xa inhibitors.

BACKGROUND: Venous thromboembolism (VTE) is a frequent cause of morbidity and mortality in patients with cancer. Moreover, management of VTE is frequently connected with complications, namely risk of recurrent VTE and bleeding. Low molecular weight heparins (LMWH) therapy administrated for 3-6 months is currently considered a standard for the treatment of cancer-associated VTE (CA-VTE). Direct oral factor Xa inhibitors (FXaI) apixaban, edoxaban and rivaroxaban have emerged as a new possibility for long-term antithrombotic therapy for VTE. These agents expose several advantages in individuals with cancer, and might overcome several disadvantages connected with LMWH therapy. PURPOSE: First clinical studies with oral FXaI for the treatment of CA-VTE with very promising results were recently published. The article summarizes current data regarding the use of oral FXaI in the treatment of CA-VTE.

Thrombotic events and rebleeding after hemorrhage in patients taking direct oral anticoagulants for non-valvular atrial fibrillation.

Several direct oral anticoagulants have been developed to prevent cardiogenic thrombosis in patients with atrial fibrillation, on the other hand, have the complication of bleeding. Since clinical course after bleeding with direct oral anticoagulant remains unclear, the present retrospective cohort study was to clarify the course after hemorrhage among patients receiving direct oral anticoagulants. Among all 2005 patients prescribed dabigatran, rivaroxaban, apixaban, or edoxaban between April 2011 and June 2017, subjects comprised 96 patients with non-valvular atrial fibrillation who experienced relevant bleeding during direct oral anticoagulant therapy (Bleeding Academic Research Consortium type 2 or above). The clinical course after hemorrhage was reviewed to examine whether rebleeding or thrombotic events occurred up to the end of December 2019. Gastrointestinal bleeding was the most frequent cause of initial bleeding (57 patients, 59%). Rebleeding occurred in 11 patients (4.5%/year), with gastrointestinal bleeding in 10 and subarachnoid hemorrhage in 1. All rebleeding occurred in patients who resumed anticoagulation therapy. Another significant factor related with rebleeding included past history of gastrointestinal bleeding. On the other hand, major adverse cardiac and cerebrovascular events occurred in 6 patients older than 75 years old or more (2.5%/year), with systemic thrombosis in 4 and cardiac death in 2. All 4 patients with systemic thrombosis withheld anticoagulants after index bleeding, although only 10 patients withheld anticoagulation therapy. Rebleeding should be taken care of when anticoagulants are resumed after bleeding, particularly among patients who initially experienced gastrointestinal bleeding. Systemic thrombosis occurred at a high rate when anticoagulant therapy was withheld after bleeding.

Assessment of exposure to direct oral anticoagulants in elderly hospitalised patients.

It is unclear whether elderly patients established on direct oral anticoagulants (DOACs) have greater exposure to these drugs, which could subsequently increase their risk of bleeding. We assessed DOAC exposure and factors affecting it in a real-world elderly cohort of patients. For this, 151 medically stable hospital inpatients (76 established on apixaban, 61 on rivaroxaban, 14 on dabigatran) with a median [interquartile range (IQR)] age of 84 (78-89) years were recruited. Patients provided blood samples for measurement of peak and trough plasma DOAC concentrations. There was up to 48-fold and 13-fold variation in trough and peak plasma drug concentrations respectively. A significantly greater proportion of patients on apixaban had peak plasma drug concentrations within the reported ranges compared to those on either rivaroxaban or dabigatran (82·9% vs. 44·3% vs. 64·3% respectively; P < 0·001). A third of the variability in DOAC plasma concentrations was attributed to the influences of DOAC dosage, renal function and gender. To what extent the observed increases in DOAC exposure in the older patients is the cause of their increased risk of bleeding, which could potentially be ameliorated by dosing titration, requires further investigation.

Factors Influencing the Selection of Non-Vitamin K Antagonist Oral Anticoagulants for Stroke Prevention in Patients With Non-Valvular Atrial Fibrillation.

BACKGROUND: Major atrial fibrillation (AF) guidelines recommend non-vitamin K antagonist oral anticoagulants (NOACs) over warfarin, except in rare clinical circumstances based on 4 randomized controlled trials comparing each NOAC with warfarin. We aimed to investigate the current NOAC prescription behaviors in alignment with the recent clinical evidence available. METHOD: We conducted a cross-sectional analysis of NOAC-using patients with non-valvular atrial fibrillation (NVAF) who were aged ≥65 years on the index date (July 1, 2018) based on nationwide claims data. The types of NOACs being taken were analyzed using chi-squared tests, and factors influencing NOAC selection were identified using multinomial logistic regression analysis. RESULTS: A total of 6,061 patients were included. Among the 4 NOACs, rivaroxaban was the most used NOAC. Patients aged ≥75 years (odds ratio [OR] = 1.270, confidence interval [CI] = 1.089-1.450) and women (OR = 1.148, CI = 1.011-1.284) were more likely to use apixaban relative to rivaroxaban. Patients with prior stroke/transient ischemic attack/thromboembolism had higher odds of using dabigatran (OR = 1.508, CI = 1.312-1.704) and apixaban (OR = 1.186, CI = 1.026-1.346). Patients with renal disease had higher odds of using apixaban (OR = 1.466, 95% CI = 1.238-1.693). These findings are consistent with the efficacy and safety profiles reported in pivotal trials and observational studies comparing individual NOACs. CONCLUSION: Among the 4 NOACs, rivaroxaban was the most commonly used NOAC. Apixaban was preferred for patients aged ≥75 years, females, and patients with renal disease.

Small-molecule polymerase inhibitor protects non-human primates from measles and reduces shedding.

Measles virus (MeV) is a highly contagious pathogen that enters the human host via the respiratory route. Besides acute pathologies including fever, cough and the characteristic measles rash, the infection of lymphocytes leads to substantial immunosuppression that can exacerbate the outcome of infections with additional pathogens. Despite the availability of effective vaccine prophylaxis, measles outbreaks continue to occur worldwide. We demonstrate that prophylactic and post-exposure therapeutic treatment with an orally bioavailable small-molecule polymerase inhibitor, ERDRP-0519, prevents measles disease in squirrel monkeys (Saimiri sciureus). Treatment initiation at the onset of clinical signs reduced virus shedding, which may support outbreak control. Results show that this clinical candidate has the potential to alleviate clinical measles and augment measles virus eradication.

Oral Anticoagulants for Nonvalvular Atrial Fibrillation in Patients With High Risk of Gastrointestinal Bleeding.

Importance: Many patients with nonvalvular atrial fibrillation (NVAF) are at a high risk of gastrointestinal (GI) bleeding due to conditions including older age; stage III to V chronic kidney disease (CKD); HAS-BLED (hypertension, kidney or liver disease, stroke history, prior bleeding, unstable international normalized ratio, age >65, drug or alcohol use) score of 3 or greater; corticosteroid, antiplatelet or nonsteroidal anti-inflammatory drug (NSAID) use; or GI conditions. Objective: To compare the risk of stroke and/or systemic embolism (SE) and major bleeding (MB) among patients with NVAF and high risk of GI bleeding who received non-vitamin K antagonist oral anticoagulants (NOACs) vs those who received warfarin. Design, Setting, and Participants: This retrospective cohort study included patients with NVAF who were 75 years and older; had stage III to V CKD; had an HAS-BLED score of 3 or greater; used corticosteroids, antiplatelets, or NSAIDs; or had GI conditions. Data were collected from the Centers for Medicare & Medicaid Services and 4 commercial insurance databases between January 1, 2012, and September 30, 2015. Data analysis was conducted from January 2012 to September 2015. Exposures: New prescription for apixaban, dabigatran, rivaroxaban, or warfarin between January 1, 2013, and September 30, 2015 (identification period). Main Outcomes and Measures: Six propensity score-matched cohorts were created to compare between study drugs. For the primary objective, Cox models were used to estimate stroke and/or SE and MB hazard ratios (HRs). Results: A total of 381 054 patients (187 489 [49.2%] women) with NVAF and at least 1 high-risk GI bleeding factor were identified (HAS-BLED score ≥3: 284 527 [74.7%]; aged ≥75 years: 252 835 [66.4%]; corticosteroid, antiplatelet, or NSAID therapy: 107 675 [28.3%]; prior GI bleeding conditions: 74 818 [19.6%]; and stage III-V CKD: 56 892 [14.9%]). All NOACs were associated with a lower risk of stroke and/or SE vs warfarin (apixaban: HR, 0.60; 95% CI, 0.52-0.68; dabigatran: HR, 0.75; 95% CI, 0.64-0.88; rivaroxaban: HR, 0.79; 95% CI, 0.73-0.86). Compared with warfarin, apixaban and dabigatran were associated with a lower risk of MB (apixaban: HR, 0.59; 95% CI, 0.56-0.63; dabigatran: HR, 0.78; 95% CI, 0.70-0.86), while rivaroxaban was associated with a higher risk (HR, 1.11; 95% CI, 1.05-1.16). Conclusions and Relevance: In this study of patients with NVAF and high risk of GI bleed, NOACs were associated with lower rates of stroke and/or SE, but NOACs had varying risks of MB compared with warfarin. These results may help inform treatment options in this patient population.

Successful treatment of refractory pure red cell aplasia with eltrombopag after ABO-incompatible allogeneic hematopoietic stem cell transplantation.

Pure red cell aplasia (PRCA) is a well-recognized complication of ABO major mismatched allogeneic hematopoietic stem cell transplantation (allo-HSCT), with a reported incidence of 10%-20% (Zhidong et al., 2012; Busca et al., 2018). It is clinically characterized by anemia, reticulocytopenia, and the absence of erythroblasts in a normal-appearing bone marrow biopsy (Shahan and Hildebrandt, 2015). The mechanism for PRCA has been presumed to be persistence of recipient isoagglutinins, produced by residual host B lymphocytes or plasma cells, which can interfere with the engraftment of donor erythroid cells (Zhidong et al., 2012). Several risk factors of PRCA at presentation are known, such as presence of anti-A isoagglutinins before transplantation, reduced intensity conditioning, absence of acute graft-versus-host disease (GVHD), sibling donors, and cyclosporin A (CsA) as GVHD prophylaxis (Hirokawa et al., 2013). PRCA is not considered to be a barrier to HSCT, as some patients can recover spontaneously or benefit from various approaches including high-dose steroids, erythropoietin (EPO), plasma exchange, immunoadsorption, donor lymphocyte infusion (DLI), treatment with rituximab, bortezomib, or daratumumab, and tapering or discontinuation of immunosuppression (Hirokawa et al., 2013; Bathini et al., 2019). However, there are still some patients who fail to respond even to aggressive treatment; they become red cell transfusion-dependent and iron-overloaded, and their life quality is impaired.

Integrated Human and Murine Clinical Study Establishes Clinical Efficacy of Ruxolitinib in Chronic Myelomonocytic Leukemia.

PURPOSE: Chronic myelomonocytic leukemia (CMML) is a rare leukemia characterized by peripheral monocytosis with no disease-modifying therapies. CMML cells are uniquely hypersensitive to granulocyte-macrophage colony-stimulating factor (GM-CSF) and robustly engraft in immunocompromised mice that secrete human cytokines. To leverage these unique biological features, we conducted an integrated human and murine study evaluating ruxolitinib, a JAK1/2 inhibitor that potently downregulates intracellular GM-CSF signaling. PATIENTS AND METHODS: A total of 50 patients with WHO-defined CMML were enrolled in this open-label, multi-institution phase I/II clinical study, with a ruxolitinib dose of 20 mg twice daily studied in phase II. In parallel, 49 patient-derived xenografts (PDX) derived from 13 study participants were generated and randomized to receive ruxolitinib or vehicle control. RESULTS: The most common grade 3/4 treatment-related toxicities observed were anemia (10%) and thrombocytopenia (6%). The clinical overall response rate was 38% by Myelodysplastic Syndrome/Myeloproliferative Neoplasm (MDS/MPN) International Working Group (IWG) criteria and 43% of patients with baseline splenomegaly achieved a spleen response. Profiling of cytokine levels and somatic mutations at baseline failed to identify predictive biomarkers. PDX models derived from screening samples of study participants recapitulated responses seen in humans, particularly spleen responses, and corroborated ruxolitinib's clinical efficacy in a randomized murine study not feasible in human trials. CONCLUSIONS: Ruxolitinib demonstrated clinical efficacy and an acceptable adverse event profile in patients with CMML, identifying a potential novel therapeutic in this rare malignancy. Furthermore, this study demonstrates proof of concept that PDX modeling can recapitulate responses of patients treated on clinical trial and represents a novel correlative study that corroborates clinical efficacy seen in humans.See related commentary by Shastri and Adrianzen-Herrera, p. 6069.

Characteristics of patients receiving extended treatment after incident venous thromboembolism.

Given high recurrence risk after venous thromboembolism (VTE), guidelines recommend extended dose rivaroxaban (10 mg OD) or apixaban (2.5 mg BID) to be considered after 6 months of initial treatment. This study aimed to provide insight into clinical practice regarding the use of extended preventive treatment and to describe duration of the initial treatment. Linkage of nationwide health registers identified all in- and outpatients with VTE from April 2017 through 2018. Hazard ratios (HR) with 95% confidence intervals (CIs) were calculated adjusting for other VTE-related factors. The study included 6030 patients with VTE. Among rivaroxaban users, 2.2% (n = 113) received the extended 10-mg dose after mean 9.4 (SD 3.1) months of standard treatment. For apixaban, 4.7% (n = 40) received extended 2.5-mg dose after mean 8.0 months (SD 3.9). After adjustments, incident pulmonary embolism (HR 1.81 95% CI 1.12;2.91) and trauma/fracture (HR 1.42 95% CI 0.46;4.43) were associated with switching to extended dose, whereas patients with unprovoked VTE were less likely to receive the extended dose (HR 0.68 95% CI 0.30;1.55). Less than 3% of patients with incident VTE received extended treatment after initial standard treatment. Even though international guidelines suggest that the risk-benefit balance is in favour of extended VTE treatment, this was yet to be translated into clinical practice as of 2018. Studies using contemporary data are warranted to investigate routine clinical practice of extended treatment for VTE recurrence.

Comparison of Low-Dose Direct Acting Anticoagulant and Warfarin in patients Aged ≥80 years With Atrial Fibrillation.

Low dose direct acting oral anticoagulants (LDDOACS) were approved for elderly atrial Fibrillation (AF) patients with limited information. A retrospective analysis collecting baseline characteristics and outcomes in AF patients ≥ 80 prescribed LDDOAC or warfarin (W), from a multidisciplinary practice between 1/1/11 (First LDDOAC available) and 5/31/17 was conducted. From 9660 AF patients, 514 ≥ 80 received a LDDOAC and 422 W. A multivariable comparison found LDDOAC patients were older (p <0.001), had lower creatinine clearance (CrCl) (p = 0.006), used more anti-platelet drugs (p <0.001), and more often had new onset AF verses those prescribed W (p <0.001). There were no clinically significant differences among those patients receiving Dabigatran 75 mgs BID (D), Rivaroxaban 15mgs (R) or Apixaban 2.5mgs BID (A). Forty-eight and 50% of the patients remained on their LDDOAC or W for the observation period (p = 0.55). Stroke/systemic embolism (SSE) and CNS bleeds were 1.16 vs 2.22%/yr., (p = 0.143) and 1.46 vs 0.93%/yr., (p = 0.24). Mortality and major bleeds were 6.26 vs 1.67%/yr., and 12.3vs 3.77%/yr. (p <0.001). SSE were 1.1%/yr for D, R, and A (p = 0.94). CNS bleeds were 2.2 for D, 1.7 for R and 0.8%/yr. for A: p = 0.53. Major bleeding was: 14.3 for D, 14.1 for R and 9.1%/yr. for A, p = 0.048 (with A < R, p = 0.01). Mortality was 5.5 for D, 4.2 for R and 9.5% for A, p = 0.031. In conclusion, half the patients remained on their assigned anti-coagulant. SSE and intracranial bleed rates were similar and low. Major bleeds and deaths were different between groups emphasizing the need for prospective randomized trials in this growing population with AF.

Does atorvastatin therapy change the anti-Xa activity in xabans-treated patients with atrial fibrillation?

Atorvastatin and direct oral factor Xa inhibitors (xabans) are frequently co-administrated in patients with atrial fibrillation (AF). However, no studies investigating the possibility of the pharmacologic interaction between these agents have been conducted. The aim of this prospective observational study was to determine the impact of atorvastatin therapy on anti-Xa activity in xabans-treated patients with AF. We enrolled 115 AF patients on long-term rivaroxaban (52 patients) and long-term apixaban (63 patients) therapy. Long-term atorvastatin (40 mg once daily) was administrated to 28 rivaroxaban-treated patients and to 28 apixaban-treated patients. Trough and peak samples were tested for anti-Xa activity with drug-specific anti-Xa chromogenic analysis. For rivaroxaban, there were no significant differences in trough activity (45.5 ± 39.5 ng/ml vs. 46.2 ± 30.1 ng/ml; p = .34) and peak anti-Xa activity (179.2 ± 108.8 ng/ml vs. 208.1 ± 104.1 ng/ml; p = .94) between atorvastatin-treated patients and those without atorvastatin. Similarly, atorvastatin did not impact the trough activity (127.7 ± 71.1 ng/ml vs. 100.8 ± 61.1 ng/ml; p = .12) or peak anti-Xa activity (213.8 ± 103.6 ng/ml vs. 179.3 ± 72.9 ng/ml; p = .14) among apixaban-treated patients with AF. This observational study did not show a significant impact of atorvastatin on trough and peak anti-Xa activity in xabans-treated patients with AF.