Ciraparantag, an anticoagulant reversal drug: mechanism of action, pharmacokinetics, and reversal of anticoagulants.

Ciraparantag, an anticoagulant reversal agent, is a small molecule specifically designed to bind noncovalently by charge-charge interaction to unfractionated heparin and low-molecular-weight heparin. It shows binding characteristics that are similar to those of direct oral anticoagulants (DOACs). A dynamic light-scattering methodology was used to demonstrate ciraparantag's binding to the heparins and DOACs and its lack of binding to a variety of proteins including coagulation factors and commonly used drugs. Ciraparantag reaches maximum concentration within minutes after IV administration with a half-life of 12 to 19 minutes. It is primarily hydrolyzed by serum peptidases into 2 metabolites, neither of which has substantial activity. Ciraparantag and its metabolites are recovered almost entirely in the urine. In animal models of bleeding (rat tail transection and liver laceration), a single IV dose of ciraparantag given at peak concentrations of the anticoagulant, but before the bleeding injury, significantly reduced the blood loss. Ciraparantag, given after the bleeding injury, also significantly reduced blood loss. It appears to have substantial ability to reduce blood loss in animal models in which a variety of anticoagulants are used and has potential as a useful DOAC reversal agent.

A Novel Whole Blood Point-of-Care Coagulometer to Measure the Effect of Direct Oral Anticoagulants and Heparins.

The direct oral anticoagulants (DOACs) currently require no monitoring for routine therapy of atrial fibrillation or venous thromboembolism. Measurement of activity, however, may be important in patients with major and life-threatening bleeding, patients needing emergent surgery, in reversal situations, or in patients at high risk of bleeding or thrombosis due to underlying conditions. For these patients, a widely available and rapid turnaround assay would be optimal. To date, there is no such assay available, especially for the direct factor Xa inhibitors. This report describes the performance of a new, rapid turnaround, point-of-care (PoC) assay for measuring the activity of a range of anticoagulants, including DOACs and heparins, in emergency situations and for routine measurement in high-risk patients. Perosphere Technologies' PoC coagulometer is a handheld instrument that performs individual coagulation tests on samples of fresh whole blood (∼10 µL) with clotting activated by glass contact and endpoint determination performed by infrared spectroscopy. In preclinical studies using rats anticoagulated with therapeutic doses of edoxaban or enoxaparin, the PoC coagulometer showed a strong linear correlation between pharmacokinetic parameters and clotting time with edoxaban (r 2 = 0.994) and with enoxaparin (r 2 = 0.967). These preclinical results suggest that this PoC coagulometer would be ideal to assess the pharmacodynamic effects of anticoagulants and their reversal agents. The PoC bedside instrument delivers results within minutes and requires no more than a drop of whole blood. Studies are underway to confirm these results in humans and to further characterize the performance of the instrument.

Single-dose ciraparantag safely and completely reverses anticoagulant effects of edoxaban.

Of the new direct oral anticoagulants, direct factor Xa inhibitors are limited by the absence of a proven reversal agent. We assessed the safety, tolerability and impact on anticoagulation reversal of ciraparantag (PER977) alone and following a 60 mg dose of the FXa inhibitor edoxaban. Escalating, single IV doses of ciraparantag were administered alone and following a 60 mg oral dose of edoxaban in a double-blind, placebo-controlled fashion to healthy subjects. Serial assessments of the pharmacokinetics and pharmacodynamic effects of ciraparantag were performed. Eighty male subjects completed the study. Following edoxaban (60 mg), a single IV dose of ciraparantag (100 to 300 mg) demonstrated full reversal of anticoagulation within 10 minutes and sustained for 24 hours. Fibrin diameter within clots was restored to normal 30 minutes after a single dose of 100 to 300 mg ciraparantag as determined by scanning electron microscopy and change in fibrin diameter quantified by automated image analysis. Potentially related adverse events were periorbital and facial flushing and cool sensation following IV injection of ciraparantag. Renal excretion of ciraparantag metabolite was the main elimination route. There was no evidence of procoagulant activity following ciraparantag as assessed by D-dimer, prothrombin fragments 1.2, and tissue factor pathway inhibitor levels. In conclusion, ciraparantag in healthy subjects is safe and well tolerated with minor, non-dose limiting adverse events. Baseline haemostasis was restored from the anticoagulated state with doses of 100 to 300 mg ciraparantag within 10-30 minutes of administration and sustained for at least 24 hours.

Ciraparantag safely and completely reverses the anticoagulant effects of low molecular weight heparin.

Major bleeding with low molecular weight heparin (LMWH) therapy occurs in up to 5% of patients and its anticoagulation is only partially reversed by protamine sulfate. We studied the ability of ciraparantag (PER977), a novel agent that reverses LMWH in preclinical studies, to reverse LMWH in healthy volunteers. METHODS: In this phase 1/2 trial, 4 cohorts of 10 healthy volunteers received escalating doses of ciraparantag (100 to 300mg) or placebo (8:2 ratio) approximately 4h after a single subcutaneous dose of enoxaparin, 1.5mg/kg. Safety, pharmacokinetic and pharmacodynamic effects were assessed. RESULTS: Complete reversal of enoxaparin anticoagulation, measured by a reduction of whole blood clotting time, was observed in all subjects who received a single ciraparantag dose ranging from 100mg to 300mg. The anticoagulation reversal occurred rapidly after bolus injection and persisted for the duration of the study. At 12h and 24h, the differences in whole blood clotting time in the treated group compared to placebo were no longer significant, consistent with the decline in enoxaparin concentrations and anticoagulation effects. No procoagulant signals were detected as measured by D-dimer, F1.2, and tissue factor pathway inhibitor levels. Ciraparantag was well tolerated with only transient, minor side effects. CONCLUSION: Ciraparantag reverses the whole blood clotting time induced by enoxaparin in a dose related manner and produces no procoagulant signal or deleterious adverse events in doses up to 300mg.

Nonclinical Safety Assessment of PER977: A Small Molecule Reversal Agent for New Oral Anticoagulants and Heparins.

A new molecular entity, PER977 (di-arginine piperazine), is in clinical development as an anticoagulant reversal agent for new oral anticoagulants and heparins. The good laboratory practices (GLP)-compliant studies were conducted to evaluate the toxicity of PER977 and its primary metabolite, 1,4-bis(3-aminopropyl)piperazine (BAP). PER977 and BAP were negative for systemic toxicity in dogs and rats. PER977 was rapidly eliminated from the blood with little to no accumulation. PER977 was negative for genotoxicity and did not alter neurological, respiratory, or cardiovascular function. Maximum tolerated doses for PER977 were 40 (rat) and 35 mg/kg (dog), and greater than 80 mg/kg (rat) for BAP. The no observable adverse effect level (NOAEL) for 14-day intravenous exposure to both rats and dogs was 20 mg/kg/d. For BAP, the NOAELs for 14-day intravenous exposure to rats and dogs were 5 and 20 mg/kg, respectively. Based on these results, a safe and conservative dose level of 19.4 mg/d was used for the PER977 first in human study.

Reversal agents in development for the new oral anticoagulants.

The new oral anticoagulants have many advantages over vitamin K antagonists, but they are still associated with a troublesome incidence of major bleeding. Additionally, the absence of a reversal agent for the new oral anticoagulants is a barrier to their more widespread use. Currently, there are 3 potential reversal agents in development: idarucizumab is a humanized murine monoclonal antibody fragment directed specifically at dabigatran; andexanet alfa is a recombinant modified decoy factor Xa that binds to factor Xa inhibitors; and PER977 is a small molecule that binds to factor Xa and IIa inhibitors and to heparin-based anticoagulants through charge interaction. These agents have undergone phase I clinical testing, appear to be well tolerated in healthy volunteers, and are effective in neutralizing their respective targets. All 3 are currently undergoing or entering into a phase II or III clinical study. This article reviews the available data for idarucizumab, andexanet alfa, and PER977.

Ultra-rapid absorption of recombinant human insulin induced by zinc chelation and surface charge masking.

BACKGROUND: In order to enhance the absorption of insulin following subcutaneous injection, excipients were selected to hasten the dissociation rate of insulin hexamers and reduce their tendency to reassociate postinjection. A novel formulation of recombinant human insulin containing citrate and disodium ethylenediaminetetraacetic acid (EDTA) has been tested in clinic and has a very rapid onset of action in patients with diabetes. In order to understand the basis for the rapid insulin absorption, in vitro experiments using analytical ultracentrifugation, protein charge assessment, and light scattering have been performed with this novel human insulin formulation and compared with a commercially available insulin formulation [regular human insulin (RHI)]. METHOD: Analytical ultracentrifugation and dynamic light scattering were used to infer the relative distributions of insulin monomers, dimers, and hexamers in the formulations. Electrical resistance of the insulin solutions characterized the overall net surface charge on the insulin complexes in solution. RESULTS: The results of these experiments demonstrate that the zinc chelating (disodium EDTA) and charge-masking (citrate) excipients used in the formulation changed the properties of RHI in solution, making it dissociate more rapidly into smaller, charge-masked monomer/dimer units, which are twice as rapidly absorbed following subcutaneous injection than RHI (Tmax 60 ± 43 versus 120 ± 70 min). CONCLUSIONS: The combination of rapid dissociation of insulin hexamers upon dilution due to the zinc chelating effects of disodium EDTA followed by the inhibition of insulin monomer/dimer reassociation due to the charge-masking effects of citrate provides the basis for the ultra-rapid absorption of this novel insulin formulation.

Reduction of postprandial glycemic excursions in patients with type 1 diabetes: a novel human insulin formulation versus a rapid-acting insulin analog and regular human insulin.

BACKGROUND: Evaluation of postprandial glycemic excursions in patients with type 1 diabetes with three prandial insulins: VIAject™ (Linjeta™), an ultra-fast insulin (UFI); insulin lispro (LIS); and regular human insulin (RHI). METHODS: After stabilization of preprandial glycemia, 18 patients received a subcutaneous injection with an individualized insulin dose prior to a meal. RESULTS: Injection of UFI resulted in a more rapid insulin absorption than with either LIS or RHI (time to half-maximal insulin levels: 13.1 ± 5.2 vs 25.4 ± 7.6 and 38.4 ± 19.5 min; p = .001 vs LIS and p < .001 vs RHI, LIS vs. RHI p < .001). Maximal postprandial glycemia was lower with UFI (0-180 min; 157 ± 30 mg/dl; p = .002 vs RHI) and LIS (170 ± 42 mg/dl; p = .668 vs RHI) than after RHI (191 ± 46 mg/dl; RHI vs LIS p = .008). The difference between maximum and minimum glycemia was smaller with UFI (70 ± 17 mg/dl) than with either RHI (91 ± 33 mg/dl; p = .007 vs UFI) or LIS (89 ± 18 mg/dl; p = .011 vs UFI). Also, the area under the blood glucose profile was lower with UFI than with RHI (0-180 min; 21.8 ± 5.8 vs 28.4 ± 7.6 g·min/dl; p < .001). CONCLUSIONS: The rapid absorption of UFI results in a reduction of postprandial glycemic excursions.

Stabilized glucagon formulation for bihormonal pump use.

BACKGROUND: A promising approach to treat diabetes is the development of an automated bihormonal pump administering glucagon and insulin. A physically and chemically stable glucagon formulation does not currently exist. Our goal is to develop a glucagon formulation that is stable as a clear ungelled solution, free of fibrils at a pH of 7 for at least 7 days at 37 °C. METHODS: Experimental glucagon formulations were studied for stability at 25 and 37 °C. Chemical degradation was quantified by reverse phase ultra-performance liquid chromatography. Physical changes were studied using light obscuration and visual observations. RESULTS: Glucagon content of Biodel glucagon and Lilly glucagon at pH 2 and pH 4, as measured by high-performance liquid chromatography at 25 °C, was 100% at 7 days compared to 87% and <7%, respectively. Light obscuration measurements indicated Lilly glucagon at pH 4 formed an opaque gel, while Biodel glucagon formulation remained a clear solution beyond 50 days at 37 °C. Visual observations confirmed these results. CONCLUSIONS: Biodel glucagon is a stabilized formulation at physiological pH and remains chemically and physically stable beyond 7 days at 37 °C, suggesting its utility for use in a bihormonal pump.

Postprandial vascular effects of VIAject compared with insulin lispro and regular human insulin in patients with type 2 diabetes.

OBJECTIVE: Recent studies suggested an impact of prandial insulin delivery on postprandial regulation of tissue blood flow. This study compared the effect of VIAject with human regular insulin and insulin lispro on postprandial oxidative stress and endothelial function in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: Fourteen patients (seven men; aged 61.5 +/- 1.8 years; duration of diabetes 6.6 +/- 4.6 years; A1C 7.2 +/- 0.5% [mean +/- SEM]) received a prandial injection of VIAject, human regular insulin, and insulin lispro. At baseline and after a standardized liquid meal test (Ensure Plus), the postprandial increases in asymmetric dimethylarginine (ADMA) and nitrotyrosine levels were investigated. In addition, the postprandial effects on microvascular blood flow, skin oxygenation, and vascular elasticity were measured. RESULTS: Treatment with VIAject resulted in a significant reduction in the peak postprandial generation of ADMA compared with human insulin and insulin lispro (VIAject -27.3 +/- 22.6, human insulin 97.7 +/- 24.4, and insulin lispro 66.9 +/- 33.9 nmol/l; P < 0.05, respectively). The postprandial increases in nitrotyrosine levels were significantly less after VIAject than after human regular insulin (VIAject -0.22 +/- 0.17 vs. human insulin 0.25 +/- 0.15 microg/ml; P < 0.05), whereas nitrotyrosine after insulin lispro was in between (insulin lispro 0.09 +/- 0.07 microg/ml; NS). In parallel, earlier and more pronounced increases in microvascular blood flow and skin oxygenation were obtained after VIAject compared with those after human insulin or insulin lispro (P < 0.05, respectively). All insulin formulations resulted in comparable improvements in central arterial elasticity. CONCLUSIONS; Treatment with VIAject reduced postprandial oxidative stress and improved endothelial function compared with human regular insulin or insulin lispro.

Intra-individual variability of the metabolic effect of a novel rapid-acting insulin (VIAject) in comparison to regular human insulin.

BACKGROUND: The variability of the metabolic action of insulin after subcutaneous (sc) injection hampers optimal insulin therapy. Insulin formulations with a reduced tendency to form hexamers might exhibit a reduced variability of absorption from the sc insulin depot into the blood stream. METHODS: We investigated the within-subject variability of pharmacodynamic and pharmacokinetic properties of an ultra-fast insulin (UFI) formulation and regular human insulin (RHI) in patients with type 1 diabetes. Fourteen patients participated in six 10-hour euglycemic glucose clamp experiments. In this double-blind, crossover study, subjects were randomly assigned to a sequence of two experimental blocks: each block consisted of three doses of 0.1 IU/kg UFI or RHI, respectively, administered on separate days by abdominal sc injection. RESULTS: Ultra-fast insulin has an earlier onset of action and shorter time to maximal plasma insulin concentration when compared to RHI (tGIR(max) 99 +/- 36 min vs. 154 +/- 74 min, p = 0.002; tC(max) 33 +/- 16 min vs. 97 +/- 39 min, p = 0.00001). The within-subject variability of plasma insulin tC(max) (p = 0.027) and of tGIR(max) (p = 0.022) was less for UFI than for RHI. CONCLUSIONS: In patients with type 1 diabetes, this UFI showed reduced within-subject variability when compared with RHI.

Technosphere/Insulin--a new approach for effective delivery of human insulin via the pulmonary route.

The development of pulmonary insulin formulation offers an attractive alternative to the current requirement of repeated subcutaneous (s.c.) injections for insulin administration. Technosphere/Insulin is a formulation of regular human insulin that was designed to produce an efficient transport of insulin across the respiratory epithelium into the systemic circulation. Several studies using the euglycemic clamp technique were performed in healthy volunteers and patients with Type 2 diabetes to assess the pharmacokinetic and pharmacodynamic properties of Technosphere/Insulin. The investigations revealed a very rapid systemic insulin uptake (insulin T(max) approximately 12-14 min), a fast onset of action (maximum activity approximately 20-30 min), and a short duration of action (approximately 2-3 h) in healthy volunteers and in patients with Type 2 diabetes. In the first study, employing a commercially available inhaler, the relative bioavailability (compared with s.c. injections) was initially reported to be 26% for the first 3 h and 16% for the entire observation period of 6 h. With the development of a specific inhaler adapted to the physical properties of Technosphere/Insulin, the MedTone Inhaler, relative bioavailability was 50% for the first 3 h and 30% over the entire 6-h period. A clear linearity of systemic insulin uptake was observed in a study employing 12 healthy volunteers inhaling doses of 25, 50, and 100 IU. Repeated inhalation of 100 IU of Technosphere/Insulin by 12 patients with Type 2 diabetes revealed a lower variability in comparison with published s.c. injection data from healthy volunteers. This new Technosphere/Insulin formulation was well tolerated, and no serious adverse events were reported in any of the investigations. Given its attractive time-action profile, Technosphere/Insulin may become a suitable alternative to s.c. injection for prandial insulin delivery, especially in patients with Type 2 diabetes, if the long-term safety, tolerability, and efficacy of this pulmonary insulin are established and confirmed in future studies.