Relevant Plasma Concentrations Research Articles

Dabigatran Attenuates the Binding of Thrombin to Platelets-A Novel Mechanism of Action.

Thrombin is a multifunctional regulatory enzyme of the haemostasis and has both pro- and anticoagulant roles. It has, therefore, been a main target for drug discovery over many decades. Thrombin is a serine protease and possesses two positively charged regions called exosites, through which it is known to bind to many substrates. Dabigatran is a thrombin inhibitor and is widely used as an oral anticoagulant for the antithrombotic treatment of atrial fibrillation and venous thromboembolism. The mechanism by which dabigatran inhibits thrombin is the blockage of the active site, however, its effect on thrombin binding to its substrates has not been studied thoroughly and is thus poorly understood. The effect of dabigatran on thrombin binding to platelets was evaluated by flow cytometry using fluorescently labelled thrombin and washed platelets. Further, to confirm the results we utilized modern techniques for biomolecular binding studies, microscale thermophoresis (MST) and surface plasmon resonance (SPR), which validated the results. Dabigatran inhibited thrombin binding to platelets as analysed by flow cytometry. The inhibition was dose dependent with IC50 of 118 nM which was slightly lower than for inhibition of platelet activation and is close to the clinically relevant plasma concentration of dabigatran. MST and SPR also confirmed inhibitory effect of dabigatran on thrombin binding to platelets. Apart from blocking the active site, dabigatran also inhibits thrombin binding to platelets. Since thrombin has numerous functions beyond the cardiovascular system, this finding may have important implications.

Urgent Reversal of Direct Oral Anticoagulants in Critical and Life-Threatening Bleeding: A Multidisciplinary Expert Consensus.

Direct oral anticoagulants (DOACs) are increasingly being used due to their improved efficacy/safety ratio and lower clinical and economic burden when compared to vitamin K antagonists. However, bleeding is still the most frequent complication associated with DOACs, and although rare, bleeding episodes can be life-threatening or critical. The impact of DOAC anticoagulation activity during a bleeding event must be evaluated according to patient clinical assessment, dosage and time from last intake, the presence of comorbidities (especially kidney and liver dysfunction), and, whenever possible, coagulation tests. Unfortunately, DOACs' anticoagulation activity is not easily or usually detectable in routine common coagulation testing. Specific DOAC tests allow for specific drug monitoring, but they are too time consuming, and are usually unavailable in routine emergency practice. If a clinically relevant DOAC plasma concentration is assumed or proven in a severe bleeding scenario, DOAC reversal is needed to restore hemostasis. This experts' consensus provides a narrative review about DOAC reversal and practical life-threatening bleeding management in several scenarios (trauma, intracranial hemorrhage and gastrointestinal bleeding), focusing on the selection of patients to whom specific reversal agents should be given.

Region-independent active CNS net uptake of marketed H+/OC antiporter system substrates.

The pyrilamine-sensitive proton-coupled organic cation (H+/OC) antiporter system facilitates the active net uptake of several marketed organic cationic drugs across the blood-brain barrier (BBB). This rare phenomenon has garnered interest in the H+/OC antiporter system as a potential target for CNS drug delivery. However, analysis of pharmacovigilance data has uncovered a significant association between substrates of the H+/OC antiporter and neurotoxicity, particularly drug-induced seizures (DIS) and mood- and cognitive-related adverse events (MCAEs). This preclinical study aimed to elucidate the CNS regional disposition of H+/OC antiporter substrates at therapeutically relevant plasma concentrations to uncover potential pharmacokinetic mechanisms underlying DIS and MCAEs. Here, we investigated the neuropharmacokinetics of pyrilamine, diphenhydramine, bupropion, tramadol, oxycodone, and memantine. Using the Combinatory Mapping Approach for Regions of Interest (CMA-ROI), we characterized the transport of unbound drugs across the BBB in specific CNS regions, as well as the blood-spinal cord barrier (BSCB) and the blood-cerebrospinal fluid barrier (BCSFB). Our findings demonstrated active net uptake across the BBB and BSCB, with unbound ROI-to-plasma concentration ratio, Kp,uu,ROI, values consistently exceeding unity in all assessed regions. Despite minor regional differences, no significant distinctions were found when comparing the whole brain to investigated regions of interest, indicating region-independent active transport. Furthermore, we observed intracellular accumulation via lysosomal trapping for all studied drugs. These results provide new insights into the CNS regional neuropharmacokinetics of these drugs, suggesting that while the brain uptake is region-independent, the active transport mechanism enables high extracellular and intracellular drug concentrations, potentially contributing to neurotoxicity. This finding emphasizes the necessity of thorough neuropharmacokinetic evaluation and neurotoxicity profiling in the development of drugs that utilize this transport pathway.

Enhanced long-acting simvastatin delivery via effervescent powder-carrying hollow microneedles and nanocrystal-loaded microneedles

Hyperlipidemia and its associated cardiovascular complications are the major causes of mortality and disability worldwide. Simvastatin (SIM) is one of the most commonly prescribed lipid-lowering drugs for the treatment of hyperlipidemia by competitive inhibition of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase. However, the extensive first-pass metabolism leading to low oral bioavailability and frequent daily doses may lead to poor patient compliance and adverse effects caused by plasma fluctuations. To overcome these challenges, this work purposed two microneedle (MN) delivery strategies for the potential enhancement of SIM delivery. Firstly, nanocrystal (NC) formulations of SIM were investigated, followed by incorporation into a trilayer dissolving microneedle (DMN) design. Furthermore, a novel effervescent powder-carrying MN (EMN) design was developed to enhance intradermal delivery by incorporating the effervescent agents into the drug powder. Both MN approaches exhibited significantly improved permeation and in-skin deposition ability in the Franz cell study, with the ex vivo delivery efficiency of 64.33 ± 6.17 % and 40.11 ± 4.53 % for EMNs and DMNs, respectively. Most importantly, in vivo studies using a female Sprague-Dawley rat model confirmed the successful delivery of SIM from NCs-loaded DMNs (Cmax = 287.39 ± 106.82 ng/mL) and EMNs (Cmax = 203.05 ± 17.07 ng/mL) and maintain therapeutically relevant plasma concentrations for 15 days following a single application. The enhanced bioavailabilities of DMNs and EMNs were 24.28 % and 103.82 %, respectively, which were both significantly higher than that of conventional oral administration.

Dysregulation of Human Hepatic Drug Transporters by Proinflammatory Cytokines.

Proinflammatory cytokines, elevated during inflammation caused by infection and/or autoimmune disorders, result in reduced clearance of drugs eliminated primarily by cytochrome P450 enzymes (CYPs). However, the effect of cytokines on hepatic drug transporter expression or activity has not been well-studied. Here, using plated human hepatocytes (PHHs; n = 3 lots), we investigated the effect of interleukin (IL)-6, IL-1β, tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ), on the mRNA expression and activity of hepatic drug transporters. PHHs were incubated for 72 hours at their pathophysiologically relevant plasma concentrations, both individually (0.01, 0.1, 1, 10 ng/ml) or as a cocktail (i.e., when each was combined at 0.1 or 1 ng/ml). Following cytokine cocktail exposure (1 ng/ml), significant downregulation of mRNA expression of organic anion transporting polypeptide 1B1 (OATP1B1), OATP1B3, sodium/taurocholate cotransporting polypeptide (NTCP), breast cancer resistance protein (BCRP), P-glycoprotein (P-gp), multidrug and toxin extrusion protein 1, multidrug resistance proteins (MRP) 2, 3, and 4 was observed. While the mRNA expression of organic anion transporter (OAT) 2 and organic cation transporter (OCT) 1 was downregulated in two lots, it was upregulated in one lot. In agreement (mostly), the 1 ng/ml cytokine cocktail reduced OATP1B1/3, OATP2B1, OAT2, OCT1, and NTCP activity by 75%, 44%, 82%, 47%, and 80%, respectively. Interestingly, upregulation of OAT2 and OCT1 mRNA in one donor did not translate into the same directional change in activity. Although significant interlot variability was observed, in general, the above effects, using individual cytokines, could be attributed to IL-1β, TNF-α, and IFN-γ. SIGNIFICANCE STATEMENT: To date, this is the first comprehensive study to investigate the effect of four major proinflammatory cytokines, both individually and as a cocktail, on the mRNA expression and activity of human hepatic drug transporters. The data obtained can be used in the future to predict transporter-mediated drug clearance changes during inflammation through physiologically based pharmacokinetic modeling and simulation.

Rifampin- and Silymarin-Mediated Pharmacokinetic Interactions of Exogenous and Endogenous Substrates in a Transgenic OATP1B Mouse Model.

Organic anion-transporting polypeptides (OATP) 1B1 and OATP1B3, encoded by the SLCO gene family of the solute carrier superfamily, are involved in the disposition of many exogenous and endogenous compounds. Preclinical rodent models help assess risks of pharmacokinetic interactions, but interspecies differences in transporter orthologs and expression limit direct clinical translation. An OATP1B transgenic mouse model comprising a rodent Slco1a/1b gene cluster knockout and human SLCO1B1 and SLCO1B3 gene insertions provides a potential physiologically relevant preclinical tool to predict pharmacokinetic interactions. Pharmacokinetics of exogenous probe substrates, pitavastatin and pravastatin, and endogenous OATP1B biomarkers, coproporphyrin-I and coproporphyrin-III, were determined in the presence and absence of known OATP/Oatp inhibitors, rifampin or silymarin (an extract of milk thistle [Silybum marianum]), in wild-type FVB mice and humanized OATP1B mice. Rifampin increased exposure of pitavastatin (4.6- and 2.8-fold), pravastatin (3.6- and 2.2-fold), and coproporphyrin-III (1.6- and 2.1-fold) in FVB and OATP1B mice, respectively, but increased coproporphyrin-I AUC0-24h only (1.8-fold) in the OATP1B mice. Silymarin did not significantly affect substrate AUC, likely because the silymarin flavonolignan concentrations were at or below their reported IC50 values for the relevant OATPs/Oatps. Silymarin increased the Cmax of pitavastatin 2.7-fold and pravastatin 1.9-fold in the OATP1B mice. The data of the OATP1B mice were similar to those of the pitavastatin and pravastatin clinical data; however, the FVB mice data more closely recapitulated pitavastatin clinical data than the data of the OATP1B mice, suggesting that the OATP1B mice are a reasonable, though costly, preclinical strain for predicting pharmacokinetic interactions when doses are optimized to achieve clinically relevant plasma concentrations.

Indicaxanthin prevents eryptosis induced by cigarette smoke extract by interfering with active Fas-mediated signaling.

A physiological mechanism of programmed cell death called eryptosis occurs in aged or damaged red blood cells (RBCs). Dysregulated eryptosis contributes to abnormal microcirculation and prothrombotic risk. Cigarette smoke extract (CSE) induces a p38 MAPK-initiated, Fas-mediated eryptosis, activating the death-inducing signaling complex (DISC). Indicaxanthin (Ind) from cactus pear fruits, is a bioavailable dietary phytochemical in humans and it is able to incorporate into RBCs enhancing their defense against numerous stimuli. This in vitro work shows that Ind, at concentrations that mimic plasma concentrations after a fruit meal, protects erythrocytes from CSE-induced eryptosis. CSE from commercial cigarettes was prepared in aqueous solution using an impinger air sampler and nicotine content was determined. RBCs were treated with CSE for 3 h in the absence or presence of increasing concentrations of Ind (from 1 to 5 μM). Cytofluorimetric measurements indicated that Ind reduced CSE-induced phosphatidylserine externalization and ceramide formation in a concentration-dependent manner. Confocal microscopy visualization and coimmunoprecipitation experiments revealed that Ind prevented both CSE-triggered Fas aggregation and FasL/FADD/caspase 8 recruitment in the membrane, indicating inhibition of DISC assembly. Ind inhibited the phosphorylation of p38 MAPK, caspase-8/caspase-3 cleavage, and caspase-3 activity induced by CSE. Finally, Ind reduced CSE-induced ATP depletion and restored aminophospholipid translocase activity impaired by CSE treatment. In conclusion, Ind concentrations comparable to nutritionally relevant plasma concentrations, can prevent Fas-mediated RBC death signaling induced by CSE, which suggests that dietary intake of cactus pear fruits may limit the deleterious effects of cigarette smoking.

Therapeutic Implications of Ceritinib in Cholangiocarcinoma beyond ALK Expression and Mutation.

Cholangiocarcinoma (CCA) is a difficult-to-treat cancer, with limited therapeutic options and surgery being the only curative treatment. Standard chemotherapy involves gemcitabine-based therapies combined with cisplatin, oxaliplatin, capecitabine, or 5-FU with a dismal prognosis for most patients. Receptor tyrosine kinases (RTKs) are aberrantly expressed in CCAs encompassing potential therapeutic opportunity. Hence, 112 RTK inhibitors were screened in KKU-M213 cells, and ceritinib, an approved targeted therapy for ALK-fusion gene driven cancers, was the most potent candidate. Ceritinib's cytotoxicity in CCA was assessed using MTT and clonogenic assays, along with immunofluorescence, western blot, and qRT-PCR techniques to analyze gene expression and signaling changes. Furthermore, the drug interaction relationship between ceritinib and cisplatin was determined using a ZIP synergy score. Additionally, spheroid and xenograft models were employed to investigate the efficacy of ceritinib in vivo. Our study revealed that ceritinib effectively killed CCA cells at clinically relevant plasma concentrations, irrespective of ALK expression or mutation status. Ceritinib modulated multiple signaling pathways leading to the inhibition of the PI3K/Akt/mTOR pathway and activated both apoptosis and autophagy. Additionally, ceritinib and cisplatin synergistically reduced CCA cell viability. Our data show ceritinib as an effective treatment of CCA, which could be potentially explored in the other cancer types without ALK mutations.

The use of andexanet alpha in the Polish setting: An interdisciplinary protocol. Expert consensus statement of the Polish Cardiac Society.

Andexanet alfa (AA) is a recombinant inactive analog of human activated factor X (FXa), effectively reversing the effects of its inhibitors - rivaroxaban and apixaban, which are available in Poland. The drug was approved for clinical use registration after the publication of the results of the ANNEXA-4 trial (Andexanet Alfa, a Novel Antidote to the Anticoagulation Effects of FXa Inhibitors 4), in which its efficacy in restoring hemostasis in life-threatening hemorrhages in patients receiving using the aforementioned anticoagulants was demonstrated. Hence, AA is now recommended for patients on apixaban or rivaroxaban therapy with massive and uncontrollable hemorrhages, including hemorrhagic strokes (HS) and gastrointestinal bleeding. Drug-specific chromogenic anti-Xa assays are generally best suited for estimating rivaroxaban and apixaban plasma levels, aside from direct assessment of their concentrations. The absence of anti-Xa activity, determined using these assays, allows us to rule out the presence of clinically relevant plasma concentrations of any FXa inhibitor. On the other hand, the dose of AA should not be modified based on the results of coagulation tests, as it depends solely on the time that elapsed since the last dose of FXa inhibitor and oon the dose and type of FXa inhibitor. AA is administered as an intravenous (i.v.) bolus, followed by an i.v. infusion of the drug. The maximum reversal of anti-Xa activity occurs within two minutes of the end of the bolus treatment, with the continuation of the continuous i.v. infusion allowing the effect to be maintained for up to two hours afterwards. Because anticoagulant activity can reappear after the infusion is completed, it is currently unclear at what point after AA administration FXa inhibitors or heparin should be re-administered. In Poland AA is starting to become available and its urgent need to administer it to patients with severe bleeding on apixaban or rivaroxaban.

Absorption of bioactive peptides following collagen hydrolysate intake: a randomized, double-blind crossover study in healthy individuals.

Collagen hydrolysates (CH) in functional foods and supplements are dietary sources of amino acids (AAs) and di-and tripeptides linked to various health benefits. This study aimed to investigate the single-dose bioavailability of skin- and hide-derived CH from fish, porcine and bovine origin with different molecular weights (bovine 2,000 and 5,000 Da). A randomized, double-blind crossover clinical study was performed with healthy volunteers assessing the plasma concentration of free and peptide-bound hydroxyproline (Hyp) as well as selected peptides reported to be abundantly present in collagen. The pharmacokinetic endpoints demonstrated comparable uptake of free Hyp from all CH. A higher amount of total compared to free Hyp indicated the uptake of substantial amounts of Hyp-containing di- or tripeptides. Independently of source and molecular weight, all CH yielded relevant plasma concentrations of the investigated metabolites. Larger studies are needed to estimate an ideal level of selected circulating metabolites needed to trigger distinct physiological reactions in target tissues.

Resveratrol-Laden Nano-Systems in the Cancer Environment: Views and Reviews.

The genesis of cancer is a precisely organized process in which normal cells undergo genetic alterations that cause the cells to multiply abnormally, colonize, and metastasize to other organs such as the liver, lungs, colon, and brain. Potential drugs that could modify these carcinogenic pathways are the ones that will be used in clinical trials as anti-cancer drugs. Resveratrol (RES) is a polyphenolic natural antitoxin that has been utilized for the treatment of several diseases, owing to its ability to scavenge free radicals, control the expression and activity of antioxidant enzymes, and have effects on inflammation, cancer, aging, diabetes, and cardioprotection. Although RES has a variety of pharmacological uses and shows promising applications in natural medicine, its unpredictable pharmacokinetics compromise its therapeutic efficacy and prevent its use in clinical settings. RES has been encapsulated into various nanocarriers, such as liposomes, polymeric nanoparticles, lipidic nanocarriers, and inorganic nanoparticles, to address these issues. These nanocarriers can modulate drug release, increase bioavailability, and reach therapeutically relevant plasma concentrations. Studies on resveratrol-rich nano-formulations in various cancer types are compiled in the current article. Studies relating to enhanced drug stability, increased therapeutic potential in terms of pharmacokinetics and pharmacodynamics, and reduced toxicity to cells and tissues are the main topics of this research. To keep the readers informed about the current state of resveratrol nano-formulations from an industrial perspective, some recent and significant patent literature has also been provided. Here, the prospects for nano-formulations are briefly discussed, along with machine learning and pharmacometrics methods for resolving resveratrol's pharmacokinetic concerns.

Changes in hypothalamic mu-opioid receptor expression following acute olanzapine treatment in female rats: Implications for feeding behavior

Advances have been made in recent years in using opioid receptor antagonists as an adjunct therapy to psychotropic medication to reduce debilitating weight gain and metabolic adverse effects associated with in particular second generation antipsychotics. However, it is unknown whether second generation antipsychotics produce a change in opioid receptor expression in the brain. The present study investigated early changes in opioid receptor expression in the female rat hypothalamus, a master controller of hunger and metabolic regulation, after acute treatment with olanzapine, a commonly used second generation antipsychotic. Using quantitative spatial in situ hybridization and receptor autoradiography, expression levels of the three opioid receptors; kappa, mu and delta, were determined at mRNA and protein level, respectively, in the five hypothalamic areas: paraventricular nucleus, arcuate nucleus, ventromedial nucleus, dorsomedial nucleus and lateral hypothalamus. After 48 h of olanzapine treatment at clinically relevant plasma concentration weight gain and food intake changes, and increased plasma glucose were observed in female rats. Olanzapine treatment also led to a significant increase in mu opioid receptor availability in the arcuate nucleus, which contains both satiety and hunger controlling neurons. No other areas showed any opioid receptor expressional changes with olanzapine treatment on neither at mRNA nor protein level. Technical difficulties made it impossible to analyze mRNA levels in the lateral hypothalamus and overall binding of delta opioid receptors. Thus, the present study provided insights in to how olanzapine at clinically relevant plasma levels already at an early stage modulated the opioid system in the hypothalamus.

Anti-Cancer Effects of Artesunate in Human 3D Tumor Models of Different Complexity.

The anti-malaria drug Artesunate (ART) shows strong anti-cancer effects in vitro; however, it shows only marginal treatment results in clinical cancer studies. In this study, ART was tested in preclinical 3D cancer models of increasing complexity using clinically relevant peak plasma concentrations to obtain further information for translation into clinical use. ART reduced cell viability in HCT-116 and HT-29 derived cancer spheroids (p < 0.001). HCT-116 spheroids responded dose-dependently, while HT-29 spheroids were affected more strongly by ART than by cytostatics (p < 0.001). HCT-116 spheroids were chemo-sensitized by ART (p < 0.001). In patient-derived cancer spheroids (PDCS), ART led to inhibition of cell viability in 84.62% of the 39 samples tested, with a mean inhibitory effect of 13.87%. Viability reduction of ART was 2-fold weaker than cytostatic monotherapies (p = 0.028). Meanwhile, tumor-stimulation of up to 16.30% was observed in six (15.38%) PDCS-models. In 15 PDCS samples, ART modulated chemotherapies in combined testing, eight of which showed chemo-stimulation (maximum of 36.90%) and seven chemo-inhibition (up to 16.95%). These results demonstrate that ART's anti-cancer efficacy depends on the complexity of the tumor model used. This emphasizes that cancer treatment with ART should be evaluated before treatment of the individual patient to ensure its benefits and prevent unwanted effects.

Viloxazine Increases Cortical Serotonin Without Inhibiting Serotonin Reuptake at Doses Used to Treat ADHD

AbstractBackgroundMost FDA-approved ADHD treatments increase norepinephrine (NE) and dopamine (DA); however, our prior preclinical studies of the non-stimulant ADHD treatment viloxazine ER (Qelbree®) demonstrated that viloxazine also increases serotonin (5-HT). A prior microdialysis study showed increases in NE, DA, and 5-HT in the rat prefrontal cortex (PFC); however, the 50 mg/kg dose resulted in supratherapeutic plasma concentrations. Viloxazine is a moderate affinity selective NE reuptake inhibitor, structurally different than traditional SSRI antidepressants. Viloxazine has negligible activity at the serotonin reuptake transporter (SERT), suggesting viloxazine has a different mechanism of 5-HT PFC elevation than SSRIs. The current microdialysis study was undertaken to further characterize if viloxazine affects 5-HT and its 5-HIAA metabolite at therapeutically relevant plasma concentrations. Results are compared to similar microdialysis studies of SSRIs.MethodsRats were implanted with I-shaped microdialysis probes connected to a microperfusion pump, delivering artificial cerebrospinal fluid, in the PFC. After a 2-hour baseline period, viloxazine (1, 3, 10, or 30 mg/kg) was administered (ip). Dialysate samples were collected from the interstitial fluid (ISF) of the PFC before and after dosing. LC-MS/MS was used to determine the dialysate concentrations of viloxazine and viloxazine-induced changes in NE, 5-HT, and their respective metabolites, DHPG and 5-HIAA. Viloxazine plasma concentrations were also measured.Animal research was approved by the Institutional Animal Care and Use Committee and conducted in accordance with the National Research Council’s Guide for the Care and Use of Laboratory Animals.ResultsViloxazine administration resulted in significant dose-dependent increases in ISF NE levels and corresponding decreases in DHPG (NE metabolite) at all doses tested, reflecting viloxazine’s activity as a NET inhibitor. Viloxazine treatment also resulted in a dose-dependent elevation of ISF 5-HT levels in the PFC. Of the doses tested, 30 mg/kg was found to be clinically relevant as it induced ISF concentrations approximating unbound plasma concentrations in pediatric ADHD patients. At this dose, 5-HT levels were significantly increased over baseline and higher than vehicle levels. Coincident changes in 5-HIAA concentrations were not observed, reaffirming viloxazine’s lack of activity as a SERT inhibitor.ConclusionViloxazine induced dose-dependent increases in NE and 5-HT in the PFC, a critical target region for ADHD therapies. At clinically relevant viloxazine plasma concentrations, 5-HT was increased in the PFC. Unlike SSRIs, which correspondingly decrease the 5-HT metabolite in the PFC (indicating serotonin reuptake inhibition), viloxazine did not affect 5-HIAA levels. Thus, viloxazine increases cortical 5-HT levels by a different mechanism than SSRIs. Whether 5-HT effects aid in viloxazine therapeutic efficacy in ADHD is yet unknown.FundingSupernus Pharmaceuticals, Inc.

Bleeding management in patients with direct oral anticoagulants.

Bleeding events in patients under direct oral anticoagulation (DOAC) can be life-threating but are commonly not related to drug overdose. However, a relevant DOAC plasma concentration impairs the hemostasis and should therefore be ruled out immediately after hospital admission. The effect of DOAC is typically not visible in standard coagulation tests such as activated partial thrombin time or thromboplastin time. Specific anti-Xa or anti-IIa assays allow a specific drug monitoring, but they are too time-consuming in critical bleeding events and typically not available 24 h/7 d in routine care. Recent advantages in point-of-care (POC) testing might improve patient care by early exclusion of relevant DOAC levels, but sufficient validation is still lacking. POC urine analysis help to exclude DOAC in emergency patients, but does not provide a quantitative information about plasma concentration. POC viscoelastic testing (VET) can determine the DOAC effect on clotting time and helps further to reveal other concomitant bleeding disorders in emergency, e.g., factor deficiency or hyperfibrinolysis. If a relevant plasma concentration of the DOAC is assumed or was proven by either laboratory assays or POC testing, restoration of factor IIa or factor IIa activity is key for effective hemostasis. Limited evidence suggests that specific reversals for DOAC, e.g., idarucizumab for dabigatran and andexanet alfa for apixaban or rivaroxaban, might be superior to increasing thrombin generation by administration of prothrombin complex concentrates. To determinate, if DOAC reversal is indicated or not, time from last intake, anti-Xa/dTT values or results from POC tests can be considered. This experts' opinion provides a feasible decision algorithm for clinical practice.

Development and Evaluation of Dissolving Microarray Patches for Co-administered and Repeated Intradermal Delivery of Long-acting Rilpivirine and Cabotegravir Nanosuspensions for Paediatric HIV Antiretroviral Therapy

PurposeWhilst significant progress has been made to defeat HIV infection, the efficacy of antiretroviral (ARV) therapy in the paediatric population is often hindered by poor adherence. Currently, two long-acting (LA) intramuscular injectable nanosuspensions of rilpivirine (RPV) and cabotegravir (CAB) are in clinical development for paediatric populations. However, administration requires access to healthcare resources, is painful, and can result in needle-stick injuries to the end user. To overcome these barriers, this proof-of-concept study was developed to evaluate the intradermal delivery of RPV LA and CAB LA via self-disabling dissolving microarray patches (MAPs).MethodsDissolving MAPs of two conformations, a conventional pyramidal and a bilayer design, were formulated, with various nanosuspensions of RPV and CAB incorporated within the respective MAP matrix. MAPs were mechanically robust and were capable of penetrating ex vivo skin with intradermal ARV deposition.ResultsIn a single-dose in vivo study in rats, all ARV MAPs demonstrated sustained release profiles, with therapeutically relevant plasma concentrations of RPV and CAB detected to at least 63 and 28 d, respectively. In a multi-dose in vivo study, repeated MAP applications at 14-d intervals maintained therapeutically relevant plasma concentrations throughout the duration of the study.ConclusionsThese results illustrate the potential of the platform to repeatedly maintain plasma concentrations for RPV and CAB. As such, these MAPs could represent a viable option to improve adherence in the paediatric population, one that is capable of being painlessly administered in the comfort of the patient’s own home on a biweekly or less frequent basis.Graphical abstract

Abstract CT185: A phase I dose escalation study of a tegavivint (BC2059) a first-in-class TBL1 inhibitor for patients with progressive, unresectable desmoid tumors

Abstract Introduction: The hallmark of sporadic desmoid tumors is increased nuclear β-catenin levels. Tegavivint (BC2059) selectively disrupts the interaction of β-catenin and TBL1/TBLR1 resulting in the specific degradation of nuclear β-catenin. The primary objective of this dose escalation study was to determine the maximum tolerated dose (MTD) and safety of tegavivint. Methods: This phase I study (NCT03459469) utilized an accelerated dose escalation phase for the initial two dose levels followed by a 3+3 design to determine the MTD/recommended phase 2 dose (RP2D). The study included adult patients with desmoid tumors that were progressive (20% increase in tumor volume, recurrent in one year from surgery or desmoid symptoms), unresectable, and measurable via WHO criteria. Patients were excluded if they had familial adenomatous polyposis, metabolic bone disease, or history of significant pulmonary disease. Tegavivint was administered IV and dosed weekly (three weeks on, one week off) for up to two years. Results: A total of 17 patients with a median age of 41 years (range 18-66 years) were enrolled in six dose levels from 0.5 mg/kg to 5 mg/kg. The median time from initial desmoid diagnosis to study treatment was 2.1 years with a median of one prior systemic treatment (range 0-6). Prior radiation and/or surgical resection occurred in 42% (n=7). No dose-limiting toxicities were observed and the MTD was not determined. The RP2D was declared at 5 mg/kg based on achieving pharmacologically relevant plasma concentrations and preliminary efficacy. Trough plasma concentrations (Cmin) exceeded in vitro IC50 efficacy estimates at 4 mg/kg and 5 mg/kg. Median half-life was 38 hours supporting once weekly administration. Tegavivint exposure (AUC and Cmax) correlated with total dose administered. Treatment-related adverse events (TRAEs) occurring in ≥20% of patients included fatigue (71%), nausea (35%), headache (35%), decreased appetite (24%) and dysgeusia (24%), mostly Grade 1-2. Grade 3 TRAEs of hypophosphatemia, stomatitis, ALT increased, and headache occurred in 4 separate patients. No grade 4-5 adverse events were observed. One serious adverse event of Grade 2 infusion site extravasation occurred. Median time on study was 11.8 months, with a median relative dose intensity of 97%; one patient remains on study. Three (18%) partial responses (WHO criteria) were observed at 1, 4 and 5 mg/kg with a median duration of response of 329 days and all responses were ongoing. The clinical benefit rate was 82% (n = 14). Conclusions: Tegavivint is well tolerated with mostly Grade 1/2 adverse events and no Grade 3 TRAEs occurring in more than one patient. The preliminary objective response rate of 18% in progressive desmoid tumors warrants continued research in the ongoing dose expansion portion of the study at the 5 mg/kg RP2D. Citation Format: Lee Cranmer, Albiruni A. RAZAK, Ravin Ratan, Edwin Choy, Suzanne George, David Liebner, David Stenehjem, Mrinal Gounder. A phase I dose escalation study of a tegavivint (BC2059) a first-in-class TBL1 inhibitor for patients with progressive, unresectable desmoid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT185.

Results of a phase I dose escalation and expansion study of tegavivint (BC2059), a first-in-class TBL1 inhibitor for patients with progressive, unresectable desmoid tumor.

11523 Background: Desmoid tumors are known to have increased nuclear β-catenin levels. Tegavivint selectively disrupts the interaction of β-catenin and TBL1/ TBLR1, resulting in specific degradation of nuclear β-catenin. The primary objectives of this study were to determine the maximum tolerated dose (MTD), safety, and preliminary efficacy of tegavivint in patients (pts) with desmoid tumors. Methods: This study ( NCT03459469) utilized an accelerated dose escalation schema for the first two dose levels followed by a 3+3 design to determine the MTD/recommended phase 2 dose (RP2D) of tegavivint, followed by a dose expansion phase. The study included adult pts with sporadic desmoid tumors that were progressive (20% increase in tumor volume, recurrent in one year from surgery, or symptomatic), unresectable, and measurable via WHO criteria. Tegavivint was administered IV weekly (three weeks on, one week off) up to two years. Results: 24 pts were enrolled. Dose escalation enrolled 17 pts in six dose levels from 0.5 - 5 mg/kg. In dose expansion, 7 additional pts were enrolled. Dose expansion cohort also included 6 pts in dose escalation that were escalated to RP2D and 3 pts treated at RP2D in dose escalation (n = 16 total). Median age was 43 years (18-66). Median time from diagnosis was 3.1 years with median of one prior systemic treatment (range 0-6). Median time on study was 9.4 months; 3 pts remain on study at data cut-off. No dose-limiting toxicities were observed; MTD was not determined. RP2D was declared at 5 mg/kg based on pharmacologically relevant plasma concentrations and preliminary efficacy. Trough plasma concentrations (Cmin) exceeded in vitro IC50 efficacy estimates at 4 mg/kg and 5 mg/kg. Median half-life was 38 hours supporting once weekly administration. Treatment-related adverse events (TRAEs) occurring in ≥20% of pts included fatigue (71%), headache (38%), nausea (33%), constipation (21%), decreased appetite (21%), and dysgeusia (21%), mostly Grade 1-2. Grade 3 TRAEs of hypophosphatemia, stomatitis, increased ALT, diarrhea, and headache occurred in 5 separate pts. There were no grade 4-5 adverse events (AEs). One serious AE of Grade 2 extravasation occurred. Objective response rate (ORR) of 17% across all dose levels and 25% at RP2D (WHO and RECIST criteria) were observed. Median duration of response was 8.1 months (range 6 to 11.8 months) with all responses ongoing. The 9-month progression free survival rate was 76% (95% CI: 54 - 90%) among all pts and 79% (95% CI: 51 – 93%) among those treated at RP2D. Patient reported outcomes and correlative science will be included in the presentation. Conclusions: Tegavivint is well tolerated with mostly Grade 1/2 AEs and no serious toxicity associated with WNT inhibition. The ORR of 25% at the RP2D warrants continued development of tegavivint in desmoid tumors. Clinical trial information: NCT03459469.

Needle-Free Jet Injectors and Nanosuspensions: Exploring the Potential of an Unexpected Pair.

Needle-free liquid jet injectors are medical devices used to administer pharmaceutical solutions through the skin. Jet injectors generate a high-speed stream of liquid medication that can puncture the skin and deliver the drug to the underlying tissues. In this work, we investigated the feasibility of using liquid jet injectors to administer nanosuspensions, assessing the impact of the jet injection on their pharmaceutical and physicochemical properties. For this purpose, the model drug diclofenac was used to prepare a set of nanosuspensions, stabilized by poloxamer 188, and equilibrated at different pHs. The hydrodynamic diameter and morphology of the nanocrystals were analyzed before and after the jet injection across porcine skin in vitro, together with the solubility and release kinetics of diclofenac in a simulated subcutaneous environment. The efficacy of the jet injection (i.e., the amount of drug delivered across the skin) was evaluated for the nanosuspension and for a solution, which was used as a control. Finally, the nanosuspension was administered to rats by jet injector, and the plasma profile of diclofenac was evaluated and compared to the one obtained by jet injecting a solution with an equal concentration. The nanosuspension features were maintained after the jet injection in vitro, suggesting that no structural changes occur upon high-speed impact with the skin. Accordingly, in vivo studies demonstrated the feasibility of jet injecting a nanosuspension, reaching relevant plasma concentration of the drug. Overall, needle-free jet injectors proved to be a suitable alternative to conventional syringes for the administration of nanosuspensions.

Improving lithium dose prediction using population pharmacokinetics and pharmacogenomics: a cohort genome-wide association study in Sweden

Lithium is the most effective treatment for bipolar disorder, resulting in strong suicide prevention effects. The therapeutic range of lithium, however, is narrow and treatment initiation requires individual titration to address inter-individual variability. We aimed to improve lithium dose prediction using clinical and genomic data. We performed a population pharmacokinetic study followed by a genome-wide association study (GWAS), including two clinical Swedish cohorts. Participants in cohort 1 were from specialised outpatient clinics at Huddinge Hospital, in Stockholm, Sweden, and participants in cohort 2 were identified using the Swedish National Quality Registry for Bipolar disorder (BipoläR). Patients who received a lithium dose corresponding to at least one tablet of lithium sulphate (6 mmol) per day and had clinically relevant plasma concentrations of lithium were included in the study. Data on age, sex, bodyweight, height, creatinine concentration, estimated glomerular filtration rate (eGFR), lithium preparation, number of tablets of lithium per day, serum lithium concentration, and medications affecting kidney function (C09 antihypertensives, C03 [except C03D] sodium-retaining diuretics, and non-steroidal anti-inflammatory drugs) were obtained retrospectively for several timepoints when possible from electronic health records, BipoläR, and the Swedish prescription registry. The median time between timepoints was 1·07 years for cohort 1 and 1·09 years for cohort 2. The primary outcome of interest was the natural logarithm of total body clearance for lithium (CLLi) associated with the clinical variables. The residual effects after accounting for age and sex, representing the individual-level effects (CLLi,age/sex), were used as the dependent variable in a GWAS. 2357 patients who were administered lithium (1423 women [60·4%] and 934 men [39·6%]; mean age 53·6 years [range 17-89], mainly of European descent) were included and 5627 data points were obtained. Age (variance explained [R2]: R2cohort1=0·41 and R2cohort2=0·31; both p<0·0001), sex (R2cohort1=0·0063 [p=0·045] and R2cohort2=0·026 [p<0·0001]), eGFR (R2cohort1=0·38 and R2cohort2=0·20; both p<0·0001), comedication with diuretics (R2cohort1=0·0058 [p=0·014] and R2cohort2=0·0026 [p<0·0001]), and agents acting on the renin-aldosterone-angiotensin system (R2cohort1=0·028 and R2cohort2=0·015; both p<0·0001) were clinical predictors of CLLi. Notably, an association between CLLi and serum lithium was observed, with a lower CLLi being associated with higher serum lithium (R2cohort1=0·13 and R2cohort2=0·15; both p<0·0001). In a GWAS of CLLi,age/sex, one locus was associated with a change in CLLi (rs583503; β=-0·053 [95% CI -0·071 to -0·034]; p<0·00000005). We also found enrichment of the associations with genes expressed in the medulla (p=0·0014, corrected FDR=0·04) and cortex of the kidney (p=0·0015, corrected FDR=0·04), as well as associations with polygenic risk scores for eGFR (p value threshold: 0·05, p=0·01), body-mass index (p value threshold: 0·05, p=0·00025), and blood urea nitrogen (p value threshold: 0·001, p=0·00043). The model based on six clinical predictors explained 61·4% of the variance in CLLi in cohort 1 and 49·8% in cohort 2. Adding genetic markers did not lead to major improvement of the models: within the subsample of genotyped individuals, the variance explained only increased from 59·32% to 59·36% in cohort 1 and from 49·21% to 50·03% in cohort 2 when including rs583503 and the four first principal components. Our model predictors could be used clinically to better guide lithium dosage, shortening the time to reach therapeutic concentrations, thus improving care. Identification of the first genomic locus and PRS to be associated with CLLi introduces the opportunity of individualised medicine in lithium treatment. Stanley Medical Research Institute, Swedish Research Council, Swedish Foundation for Strategic Research, Swedish Brain Foundation, Swedish Research Council, Söderström-Königska Foundation, Bror Gadelius Minnesfond, Swedish Mental Health Fund, Karolinska Institutet and Hospital.