Biological Variation in Rotational Thromboelastometry in Patients with Atrial Fibrillation Receiving Rivaroxaban.

Rotational thromboelastometry (ROTEM) is a viscoelastic hemostasis test used primarily in the management of bleeding after trauma or in cardiac surgery. To allow safe and valid clinical interpretation of test results, objective specifications for analytical performance are needed, which are generally based on biological variation within (CVI) and between (CVG) individuals. The aim of this study was to evaluate biological variation in ROTEM in patients receiving rivaroxaban. Sixty patients with atrial fibrillation on stable rivaroxaban therapy were included, from whom blood was collected on six occasions: three times at trough and three at peak rivaroxaban concentrations. ROTEM® Extem and LowTF were measured as well as rivaroxaban concentration, PT, APTT, and anti-Xa. Within- (CVI) and between-subject (CVG) biological estimates were calculated. Knowledge of these biological variation components will help to establish the appropriate objective analytical performance specifications for ROTEM analysis.

Platelets fine-tune effector responses of naïve CD4+ T cells via platelet factor 4-regulated transforming growth factor ß signaling.

BACKGROUND AND AIM: Platelets are an able regulator of CD4+ T cell immunity. Herein, the mechanisms underlying platelet-regulated effector responses of naïve CD4+ T (Tn) cells were investigated. METHODS: Platelet-Tn cell co-cultures of human cells, genetically modified murine models, and high-throughput bioinformatic analyses were combined to elucidate molecular mechanisms of platelet-dependent regulation. RESULTS: Platelets exerted sophisticated regulation on effector responses of type 1, 2, and 17 T helper (Th1/Th2/Th17) and regulatory T (Treg) cells, in time-, concentration-, and organ-dependent manners and with close cooperation of transforming growth factor ß (TGFß) and platelet factor 4 (PF4). PF4 at low concentrations reinforced TGFß signaling by heteromerizing with type III TGFß receptor (TGFBRIII), and subsequently enhanced TGFBRII expression and TGFß signaling. High-concentration PF4 had, however, opposite effects by directly binding to TGFBRII, blocking TGFß-TGFBRII ligation, and thus inhibiting TGFß signaling. Furthermore, platelet depletion markedly hampered Treg and Th17 responses in the spleen but not in the lymph nodes, blockade of platelet-Tn cell contact diminished platelet effects, while spleen injection of PF4-immobilized microparticles in PF4-deficient mice mimicked platelet effects, suggesting the importance of direct platelet-Tn contact and platelet-bound PF4 for the optimal regulatory effects by platelets. CONCLUSION: Platelets exert context-dependent regulations on effector responses of Tn cells via PF4-TGFß duet, suggesting new possibilities of platelet-targeted interventions of T cell immunity.

Using a low-molecular weight heparin-calibrated anti-factor Xa assay to assess the concentration of apixaban and rivaroxaban.

INTRODUCTION: Direct oral anticoagulant (DOAC)-inhibiting factor Xa (FXa-DOAC) are being increasingly used as prophylaxis of venous thromboembolism and for prevention of stroke in patients with atrial fibrillation. In contrast to vitamin K antagonists, DOACs do not require monitoring in general. However, it is sometimes of value in the acute setting, for instance when considering a reversal agent in uncontrolled bleeding in patients on DOAC. METHODS: We evaluated if a low-molecular weight heparin (LMWH)-calibrated anti-factor Xa assay could be used to estimate FXa-DOAC concentration in the concentration range <100 ng/mL by spiking known concentrations of FXa-DOAC and from those result calculate the FXa-DOAC concentration from the response of the LMWH assay. This procedure was then evaluated by comparing the result with a drug-calibrated chromogenic assay and liquid chromatography tandem mass spectrometry (LC-MS/MS) on clinical plasma samples from patients treated with apixaban or rivaroxaban. RESULTS: Although the measuring range was narrower for the LMWH-calibrated assay, concentrations recalculated from the LMWH assay was comparable with those measured by the drug-calibrated method when compared with LC-MS/MS. CONCLUSION: We suggest that an LMWH-calibrated anti-factor Xa assay can be used after characterization of the response of FXa-DOACs to give guidance on the concentration of apixaban and rivaroxaban. Shorter turnaround time than LC-MS/MS and the greater availability than drug-calibrated chromogenic assays could make this a valuable option in the acute setting.

Platelets enhance CD4+ central memory T cell responses via platelet factor 4-dependent mitochondrial biogenesis and cell proliferation.

Platelets regulate multiple aspects of CD4+ T cell immunity, and may exert distinct regulations among different T cell subsets. Our aim was to investigate how platelets regulate CD4+ central memory T cell (Tcm) responses. αCD3/αCD28-stimulated human CD4+ Tcm cells were cultured without or with platelets or platelet-derived mediators. Polyclonal stimulation induced cell proliferation and Th1 and Treg cell activation of Tcm cells. Platelet factor 4/PF4 neutralization abolished platelet-enhanced Tcm effector responses, whilst TGFß neutralization only partially inhibited platelet-enhanced Treg cell activation. PF4 supplementation mimicked the effects of platelet co-cultures, while PF4 receptor CXCR3 blockade and CXCR3 knockdown with siRNAs inhibited or abolished PF4-enhanced Th1 and Treg cell responses. Platelet co-cultures or PF4-treatment increased Tcm cell proliferation, whilst CXCR3 blockade counteracted. PF4-enhanced Tcm proliferation and effector cell responses were associated with mitochondrial biogenesis. Overexpression of mitochondrial transcription factor A (TFAM) mimicked PF4 effects, and PF4 treatment attenuated Akt phosphorylation of activated Tcm cells, leading to mitochondrial biogenesis. Impacts of platelets and PF4 on Tcm proliferation were further confirmed by that CXCR3 knockdown/blockade counteracted PF4-enhanced Tcm cell proliferation. In conclusion, platelets enhance Th1 and Treg cell responses of CD4+ Tcm cells, via PF4-dependent mitochondrial biogenesis and cell proliferation of Tcm cells.

Apixaban concentration variability and relation to clinical outcomes in real-life patients with atrial fibrillation.

In some clinical situations, measurements of anticoagulant effect of apixaban may be needed. We investigated the inter- and intra-individual apixaban variability in patients with atrial fibrillation and correlated these results with clinical outcome. We included 62 patients receiving either 5 mg (A5, n = 32) or 2.5 mg (A2.5, n = 30) apixaban twice-daily. We collected three trough and three peak blood samples 6-8 weeks apart. Apixaban concentration was measured by liquid chromatography-tandem mass-spectrometry (LC-MS/MS) and by anti-Xa. Patients on A2.5 were older, had lower creatinine clearance, higher CHA2DS2VASc (4.7 ± 1.0 vs. 3.4 ± 1.7) and lower trough (85 ± 39 vs. 117 ± 53 ng/mL) and peak (170 ± 56 vs. 256 ± 91 ng/mL) apixaban concentrations than patients on A5 (all p < 0.01). In patients on A5, LC-MS/MS showed a significant difference between through levels and between peak levels (p < 0.01). During apixaban treatment, 21 patients suffered bleeding (2 major). There was no association between bleeding and apixaban concentrations or variability. Four patients who suffered thromboembolic event had lower peak apixaban concentrations than patients without it (159 ± 13 vs. 238 ± 88 ng/mL, p = 0.05). We concluded, that there was a significant intra- and inter-individual variability in apixaban trough and peak concentrations. Neither variability nor apixaban concentrations were associated with clinical outcomes.

The in vitro addition of idarucizumab to plasma samples from patients increases thrombin generation.

Dabigatran interferes with many coagulation tests. To overcome this obstacle the use of idarucizumab as an in vitro antidote to dabigatran has been proposed. The aim of this study was to test the effect of idarucizumab as an in vitro antidote to dabigatran in ex vivo plasma samples from routine clinical patients examined by a thrombin generation assay (TGA). From 44 patients with atrial fibrillation five blood samples were collected. Thrombin generation was measured in all samples before and after the addition of idarucizumab. When idarucizumab was added to baseline plasma (no dabigatran), it caused a significantly shorter Lag Time and Time to Peak Thrombin, and a higher Peak Thrombin and Endogenous Thrombin Potential (ETP) of TGA. Similar results were obtained when idarucizumab was added to dabigatran-containing plasma, with TGA parameters comparable to baseline + idarucizumab plasma, but not to baseline plasma. In summary, our study showed that in vitro addition of idarucizumab to plasma samples from patients increases thrombin generation. The use of idarucizumab to neutralize dabigatran in patient plasma samples as well as the clinical relevance of in vitro increased thrombin generation induced by idarucizumab needs further investigation.

Bleeding and thromboembolism due to drug-drug interactions with non-vitamin K antagonist oral anticoagulants-a Swedish, register-based cohort study in atrial fibrillation outpatients.

PURPOSE: To study the association between interacting drugs and bleeding or thromboembolism in atrial fibrillation outpatients treated with non-vitamin K antagonist oral anticoagulants (NOACs). METHODS: Population-based cohort study of outpatients treated with NOACs in Sweden from 2008 to 2017. Patients with atrial fibrillation and newly initiated NOAC treatment were identified in the Prescribed Drug Register. Comorbidities and outcome data were retrieved from the Patient Register and the Cause of Death Register. Cox-regression analyses were performed to evaluate the primary endpoints any severe bleed and ischemic stroke/transient ischemic attack/stroke unspecified during the first six months of treatment. Secondary endpoints were gastrointestinal bleeding, intracranial bleeding, ischemic stroke, and venous thromboembolism. RESULTS: Increased risk of any severe bleed was found when NOAC treatment, and drugs with pharmacodynamic effect on bleeding were combined, compared to NOAC only. An increased risk with these combinations was evident for apixaban (hazard ratio (HR) 1.47; 95% CI 1.33-1.63), rivaroxaban (HR 1.7; 95% CI 1.49-1.92), and dabigatran (HR 1.26; 95% CI 1.05-1.52). For apixaban, there was an increased risk of any severe bleed when combined with CYP3A4 and/or P-glycoprotein (P-gp) inhibitors (HR 1.23; 95% CI 1.01-1.5). The use of inducers of CYP3A4 and/or P-gp was low in this cohort, and effects on ischemic stroke/TIA/stroke unspecified could not be established. CONCLUSION: Increased risk of bleeding was seen for pharmacodynamic and pharmacokinetic interactions with NOACs. Prescribers need to be vigilant of the effect of interacting drugs on the risk profile of patients treated with NOACs.

Platelet factor 4 enhances CD4+ T effector memory cell responses via Akt-PGC1α-TFAM signaling-mediated mitochondrial biogenesis.

BACKGROUND: Cell metabolism drives T cell functions, while platelets regulate overall CD4+ T cell immune responses. OBJECTIVE: To investigate if platelets influence cell metabolism and thus regulate CD4+ T effector memory cell (Tem) responses. METHODS: Human CD4+ Tem cells were activated with αCD3/αCD28 and cultured without or with platelets or platelet-derived mediators. RESULTS: Polyclonal stimulation induced rapid and marked Th1 and Treg cell activation of CD4+ Tem cells. Platelet co-culture enhanced Th1 response transiently, while it persistently enhanced Treg cell activation of Tem cells, with an enhancement that plateaued by day 3. Platelet factor 4 (PF4) was the key platelet-derived mediator regulating CD4+ Tem cell responses, which involved cellular metabolisms as indicated by mass spectrometric analyses. PF4 exerted its effects via its receptor CXCR3, attenuated Akt activity, and reduced PGC1α phosphorylation, and resulted in elevations of PGC1α function and mitochondrial transcription factor A (TFAM) synthesis. The latter increased mitochondrial biogenesis, and subsequently enhanced Th1 and Treg responses. Consistent with these observations, inhibition of mitochondrial function by rotenone counteracted the enhancements by recombinant PF4, and TFAM overexpression by TFAM-adenovirus infection mimicked PF4 effects. Furthermore, increased mitochondrial mass elevated oxygen consumption, and enhanced adenosine triphosphate and reactive oxygen species production, which, in turn, stimulated Th1 (T-bet) and Treg (FoxP3) transcription factor expression and corresponding CD4+ T effector cell responses. CONCLUSIONS: Platelets enhance CD4+ T cell responses of Tem cells through PF4-dependent and Akt-PGC1α-TFAM signaling-mediated mitochondrial biogenesis. Hence, PF4 may be a promising intervention target of platelet-regulated immune responses.

Effects of rivaroxaban and dabigatran on global hemostasis in patients with atrial fibrillation.

: The study was aimed to evaluate the effects of two standard doses of rivaroxaban and dabigatran on global hemostatic assays in patients with atrial fibrillation. The study included 52 patients treated with rivaroxaban (15/20 mg), 50 on dabigatran (110/150 mg) and 20 healthy individuals. Platelet-poor plasma was used for determination of three global hemostatic assays, namely endogenous thrombin potential (ETP), calibrated automated thrombogram (CAT) and overall hemostasis potential (OHP). Rivaroxaban and dabigatran reduced ETP (P < 0.01) although OHP (P < 0.05) was diminished only by dabigatran. Strong correlations were noticed between ETP parameters and the plasma concentrations of rivaroxaban (ETP, r = -0.51; c-max, r = -0.85; t-lag, r = 0.83; t-max, r = 0.66) as well as with plasma concentration of dabigatran (ETP, r = -0.75; c-max, r = -0.74; t-lag, r = 0.73; t-max, r = 0.52). Analysis of dabigatran concentrations under 50 ng/ml showed that ETP parameter has area under the concentration-time curve-receiver operating characteristic value of 0.879 (95% confidence interval 0.776-0.980). Dabigatran treatment paradoxically increased area under the concentration-time curve and peak values although rivaroxaban decreased peak values (P < 0.01). However, significant correlation between CAT parameters and plasma concentration of both direct oral anticoagulants was not observed. We confirmed that the CAT assay is inappropriate for estimation of dabigatran effects and is not fully sensitive as regards rivaroxaban. The ETP assay can potentially be the appropriate method for estimation of global hemostatic capacity as regards both direct oral anticoagulants. The role of OHP needs to be confirmed in additional studies. ETP parameter of chromogenic assay has promising potential in exclusion of high plasma concentrations of dabigatran.

Risk factors for severe bleeding events during warfarin treatment: the influence of sex, age, comorbidity and co-medication.

PURPOSE: To investigate risk factors for severe bleeding during warfarin treatment, including the influence of sex, age, comorbidity and co-medication on bleeding risk. METHODS: Patients initiating warfarin treatment between 2007 and 2011 were identified in the nationwide Swedish Prescribed Drug Register, and diagnoses of severe bleeding were retrieved from the National Patient Register. Hazard ratios (HR) with 95% confidence intervals (CI) for severe bleeding were estimated using multiple Cox regression adjusting for indications and including covariates age, sex, comorbidities and co-medications. Interactions between sex and other covariates were investigated. RESULTS: The study cohort included 232,624 patients ≥ 18 years (101,011 women and 131,613 men). The incidence rate of severe bleeding was 37 per 1000 person-years, lower among women than men with an adjusted HR (95% CI) of 0.84 (0.80-0.88). Incidence of bleeding increased with age, HR 2.88 (2.37-3.50) comparing age ≥ 80 to < 40 years, and comorbidities associated with the highest risk of severe bleeding were prior bleeding, HR 1.85 (1.74-1.97); renal failure, HR 1.82 (1.66-2.00); and alcohol dependency diagnosis, HR 1.79 (1.57-2.05). Other comorbidities significantly associated with bleeding events were hypertension, diabetes, peripheral vascular disease, congestive heart failure, liver failure, stroke/TIA, COPD and cancer. CONCLUSION: Most of the well-established risk factors were found to be significantly associated with bleeding events in our study. We additionally found that women had a lower incidence of bleeding. Potential biases are selection effects, residual confounding and unmeasured frailty.

Time to Review Authorisation and Funding for New Cancer Medicines in Europe? Inferences from the Case of Olaratumab.

The potential benefits of early patient access to new medicines in areas of high unmet medical need are recognised, but uncertainties concerning effectiveness, safety and added value when new medicines are authorised, and subsequently funded based on initial preliminary data only, have important implications. In 2016 olaratumab received accelerated conditional approval from both the European Medicines Agency and the US Food and Drug Administration for the treatment of soft-tissue sarcoma, based on the claims of a substantial reduction in the risk of death with an 11.8-month improvement in median overall survival in a phase II trial in combination with doxorubicin vs. doxorubicin alone. The failure to confirm these benefits in the post-authorisation pivotal trial has highlighted key concerns regarding early access and conditional approvals for new medicines. Concerns include potentially considerable clinical and economic costs, so that patients may have received suboptimal treatment and any money spent has foregone the opportunity to improve access to effective treatments. As a result, it seems reasonable to reconsider current marketing authorisation models and approaches. Potential pathways forward include closer collaboration between regulators, pharmaceutical companies and payers to enhance the generation of rapid and comparative confirmatory trials in a safe and fair manner, with minimal patient exposure as required to achieve robust evidence. Additionally, it may be time to review early access systems, and to explore new avenues regarding who should pay or part pay for new treatments whilst information is being collected as part of any obligations for conditional marketing authorisation. Greater co-operation between countries regarding the collection of data in routine clinical care, and further research on post-marketing data analysis and interpretation, may also contribute to improved appraisal and continued access to new innovative cancer treatments.

Intra- and inter- individual rivaroxaban concentrations and potential bleeding risk in patients with atrial fibrillation.

BACKGROUND: Routine laboratory monitoring of rivaroxaban and dose adjustment relating to exposure is currently not recommended. However, in certain clinical situations, assessment of rivaroxaban levels is desirable. OBJECTIVES: To examine inter- and intra-subject plasma rivaroxaban variability in patients with atrial fibrillation (AF) and to correlate these results to clinical outcomes. PATIENTS/METHODS: We included 60 patients with AF treated with rivaroxaban: half on 20 mg daily (R20) and half on 15 mg daily (R15). Three trough and peak blood samples were collected with an interval of 6-8 weeks apart. Plasma rivaroxaban concentration was measured directly by liquid chromatography-tandem mass-spectrometry (LC-MS/MS) and indirectly by anti-Xa for rivaroxaban, prothrombin time (PT), and activated partial thromboplastin time (APTT). RESULTS: Patients on R15 were older (76 ± 6 vs 71 ± 6 years), had lower creatinine clearance (60 ± 26 vs 99 ± 32 mL/min), higher CHADS2 (2.5 ± 1.2 vs 1.8 ± 1.3), all p < 0.01, but had similar rivaroxaban concentrations in trough samples to patients on R20. There was no significant intra-individual variability for trough or peak rivaroxaban concentration assessed by LC-MS/MS, anti-Xa, or PT. Trough rivaroxaban levels determined by LC-MS/MS (48 ± 30 vs 34 ± 26, p = 0.02) and anti-Xa, but not with PT and APTT, were higher in patients with bleeding than in patients without it. CONCLUSIONS: There is a pronounced inter-, but not intra-individual variability in the rivaroxaban trough levels in patients with AF. Assessment of trough rivaroxaban concentration with LC-MS/MS or anti-Xa, but not with APTT or PT, may help to identify patients at increased risk of bleeding.

Did we see it Coming? An Evaluation of the Swedish Early Awareness and Alert System.

BACKGROUND: Early awareness and alert systems have been established in many countries but evidence on their ability to accurately prioritize new medicines (for early assessment) is limited. OBJECTIVE: The purpose of this study was to assess whether the Swedish Early Awareness and Alert System identified and prioritized (i.e., produced early assessment reports for) new medicines that would go on to have substantial economic impact. METHODS: We adapted a study design commonly used in the assessment of diagnostic test accuracy. The prioritization made by the Swedish Early Awareness and Alert System prior to marketing authorization comprised the index test and the national drug sales data in the second year post-authorization served as the reference standard. All initial marketing authorization applications for medicinal products processed by the European Medicines Agency between 2010 and 2015 (study population) were classified using the index test and the reference standard. RESULTS: Two hundred and fifty-three new medicinal products processed by the European Medicines Agency comprised the study population. Of these, 71 were prioritized by the Swedish Early Awareness and Alert System and 21 were classified as having substantial economic impact. The sensitivity and positive predictive value were 76.2% and 22.5%, respectively. Subgroup analyses showed that the accuracy of prioritization, in terms of sensitivity, was 100% for antineoplastic/immunomodulating agents. CONCLUSIONS: The Swedish Early Awareness and Alert System identified all new medicines that would go on to have substantial economic impact and prioritized most of these medicines. Our findings provide reassurance to decision makers who rely on the outputs of the Swedish Early Awareness and Alert System to keep informed about new medicines. Moreover, this study also provides valuable insights to stakeholders willing to establish or evaluate their own early awareness and alert activities and systems.

Sex differences in spontaneous reports on adverse drug events for common antihypertensive drugs.

PURPOSE: To explore sex differences in spontaneously reported adverse drug events (ADEs) for antihypertensives in routine care. METHODS: A cross sectional analysis combining number of reports from the national pharmacovigilance database with data from the Swedish Prescribed Drug Register, from 2005 to 2012 for ACE inhibitors (ACE-I) and angiotensin receptor blockers (ARB), with or without thiazide, diuretics (thiazides, potassium-sparing agents, sulfonamides, aldosterone antagonists), selective betablockers, and dihydropyridine calcium-channel-blockers (DHPs). The total number of reports was adjusted to exposed patients and dispensed DDDs among women and men. Dose exposures, co-medications, and co-prescriptions were also analyzed. RESULTS: In women, a higher prevalence of ADE-reports was seen in ACE-I (odds ratio, OR 1.21; 95% CI 1.09-1.35), ACE-I-combinations (OR 1.61; 1.44-1.79), ARB-combinations (OR 2.12; 1.47-3.06), thiazides (OR 1.78; 1.33-2.39), diuretics and potassium-sparing agents (OR 1.62; 1.22-2.17), and DHPs (OR 1.40; 1.17-1.67), with a potential linkage to dose exposure. For aldosterone antagonists, we observed a higher prevalence of ADE reports in men (OR 0.75; 0.59-0.97) but without any sex difference in dose exposure. CONCLUSIONS: This ecological study of reported ADEs showed a higher prevalence of reports in women in six out of ten groups of antihypertensive drugs, and this may potentially be linked to dose exposure. Aldosterone antagonists was the only group with a higher prevalence of ADE-reports in men with a similar dose exposure between women and men.

Patients' knowledge and attitudes to the Wise List - a drug formulary from the Stockholm Drug and Therapeutic committee.

BACKGROUND: Involving patients in decisions about their pharmacotherapy is crucial for a satisfactory treatment outcome. Information and opinions about medicines are available from a variety of sources. The Wise List is the drug formulary of recommended essential medicines for the Stockholm healthcare region and is issued by the Drug and Therapeutics Committee (DTC). To inform the public about treatment for common diseases and the concept of recommended medicines, a patient edition of the Wise List was developed. The aim of this study was to explore patients' knowledge, needs and attitudes to the Wise List, DTC and information about medicines in general. METHODS: To examine patient knowledge about recommended medicines a survey (n = 312) was carried out at four large primary healthcare centres in Stockholm, Sweden. To further elucidate the patients' needs of the information on recommended medicines and medicines in general, three focus group discussions (FGDs) were performed. RESULTS: Of the respondents 57% did not recognise the Wise List, 26% recognised but did not use it and 17% used it. A total of 63% reported that they search for information about medicines. The most common information source was "asking their doctor" (36%) followed by searching the internet (31%). The FGDs revealed that the patients were not interested in medicines in general, only in the medicines they use themselves. They did not understand the aim of the Wise List or how they could benefit from information about recommended medicines. The patients expressed a wish to access all information they need about their own care as well as public healthcare information at one location. CONCLUSION: The intended aim of the DTC with providing information to the public was not achieved as the patients have difficulties to understand the information and how they should use it. The patients were not interested in medicines in general, they wanted information tailored to their specific needs. The findings highlight the importance of creating tools for patients in collaboration with them and evaluate the concept continuously.

The changing multiple sclerosis treatment landscape: impact of new drugs and treatment recommendations.

PURPOSE: The purpose of this study is to describe the utilization of disease-modifying treatments (DMTs) in relapsing-remitting multiple sclerosis (MS) and assess the impact of both the introduction of new drugs and treatment recommendations (local recommendation on rituximab use issued at the largest MS clinic in Stockholm and regional Drug and Therapeutics Committee (DTC) recommendation on how dimethyl fumarate should be used). METHODS: Interrupted time series analyses using monthly data on all MS patients treated with DMTs in the Stockholm County, Sweden, from January 2011 to December 2017. RESULTS: There were 4765 individuals diagnosed with MS residing in the Stockholm County from 2011 to 2017. Of these, 2934 (62%) were treated with an MS DMT. Since 2011, fingolimod, alemtuzumab, teriflunomide, dimethyl fumarate, peginterferon beta-1a, and daclizumab were introduced. Only fingolimod and dimethyl fumarate significantly impacted MS DMT utilization. In parallel, the use of rituximab off-label increased steadily, reaching 58% of all DMT-treated MS patients by the end of the study period. The local recommendation on rituximab was associated with an increase in rituximab use. The regional DTC recommendation on dimethyl fumarate was associated with a decrease in dimethyl fumarate use. CONCLUSIONS: Three MS DMTs-fingolimod, dimethyl fumarate, and rituximab off-label-impacted MS DMT utilization in the Stockholm County. The associations between the treatment recommendations and the subsequent changes in MS DMT utilization indicate that such interventions can influence the uptake and utilization of new drugs used in the specialized care setting.

Persistence with dimethyl fumarate in relapsing-remitting multiple sclerosis: a population-based cohort study.

PURPOSE: To describe patients initiating dimethyl fumarate (DMF) and measure persistence with DMF, discontinuation, and switching in treatment-naïve DMF patients and patients switching to DMF from other multiple sclerosis disease-modifying treatments (DMTs). METHODS: A population-based cohort study of all Stockholm County residents initiating DMF from 9 May 2014 until 31 May 2017. All data were derived from a regional database that collects individual-level data on healthcare and drug utilization of all residents. The study outcomes were persistence with DMF and DMF discontinuation and switching to other DMTs. Persistence was measured as the number of days until either DMF discontinuation (treatment gap ≥ 60 days) or switching to another DMT. RESULTS: The study included 400 patients (median follow-up = 2.5 years). The majority had previously been treated with other DMTs (61%). Throughout the follow-up period, 124 patients (31%) discontinued DMF and 114 patients (29%) switched treatment. Overall, 34% of patients initiating DMF stopped treatment within 1 year and only 43% of patients remained on DMF at 2 years from treatment initiation. CONCLUSIONS: DMF had a rapid market uptake likely due to high expectations held by both patients and clinicians. However, persistence with DMF in routine clinical practice was found to be low.

The Early Awareness and Alert System in Sweden: History and Current Status.

Introduction: Over the past decades, early awareness and alert (EAA) activities and systems have gained importance and become a key early health technology assessment (HTA) tool. While a pioneer in HTA, Sweden had no national level EAA activities until 2010. We describe the evolution and current status of the Swedish EAA System. Methods: This was a historical analysis based on the knowledge and experience of the authors supplemented by a targeted review of published and gray literature as well as documents relating to EAA activities in Sweden. Key milestones and a description of the current state of the Swedish EAA System is presented. Results: Initiatives to establish a system for the identification and assessment of emerging health technologies in Sweden date back to the 1980s. In the 1990s, the Swedish Agency for HTA and Assessment of Social Services (SBU) supported the development of EuroScan as one of its founder members. In the mid-2000s, an independent regional initiative, driven by the Stockholm County Drug and Therapeutics Committee, resulted in the establishment of a regional horizon scanning function. By 2009, this work had expanded to a collaboration between the four biggest counties in Sweden. The following year it was further expanded to the national level and since then the Swedish EAA System has been carrying out identification, filtration and prioritization of new medicines, early assessment of the prioritized medicines, and dissemination of information. In 2015, the EAA System was incorporated into the Swedish national process for managed introduction and follow-up of new medicines. Outputs from the EAA System are now used to select new medicines for inclusion in this process. Conclusions: The Swedish EAA System started as a regional initiative and rapidly grew to become a national level activity. An important feature of the system today is its complete integration into the national process for managed introduction and follow-up of new medicines. The system will continue to evolve as a response both to the changing landscape of health innovations and to new policy initiatives at the regional, national and international level.

Effects of direct oral anticoagulants on lupus anticoagulant assays in a real-life setting.

Laboratory diagnosis of lupus anticoagulant (LA) is based on prolongation in at least one coagulation assay (diluted Russell's viper venom time - dRVVT or activated partial thromboplastin time - aPTT), which normalises after addition of phospholipids. Both assays may be influenced by anticoagulants and therefore LA should not be tested during warfarin or heparin treatment. It has been shown (primarily in vitro) that direct oral anticoagulants (DOACs - dabigatran [DAB], rivaroxaban [RIV] and apixaban [API]) may also influence LA testing. We tested the effects of DOACs on assays routinely used for the diagnosis of LA in patients treated with these drugs in a real-life setting. Plasma from patients with atrial fibrillation treated with DAB (n=30), RIV (n=20) and API (n=17) and not known to have LA were tested using dRVVT (LA-screen and LA-confirm, Life Diagnostics) and aPTT (PTT-LA, Diagnostica Stago and aPTT Actin FS, Siemens Healthcare Diagnostics) assays. According to the diagnostics algorithm, dRVVT and aPTT ratios of <1.2 were considered negative, ratios of >1.4 positive, while if the ratios were 1.2-1.4 LA could not be ruled out. Plasma concentrations varied between 8-172 µg/l for DAB, 8-437 µg/l for RIV and 36-178 µg/l for API. LA diagnosis was negative in only eight (27 %) plasma samples from patients treated with DAB, and in five (25 %) and four samples (24 %) from patients treated with RIV and API, respectively. LA Positivity (dRVVT and aPTT ratios >1.4) was found in 5 cases (17 %) among patients treated with DAB, in 10 cases (50 %) treated with RIV and in 7 cases (41 %) treated with API. A concentration-dependent effect of DOACs on dRVVT-based parameters was observed, particularly as regards DAB. At lower concentrations, RIV and API had only minor effects on the confirmatory tests (below 100 µg/l and 70 µg/l, respectively). Our results suggest that a risk of overestimation of LA detection is present in samples from patients treated with DOACs. Therefore, LA testing should not be performed during treatment with DOACs. Prolongation in confirmatory assays may be helpful for the recognition of false positivity, especially as regards DAB.